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查尔斯·达尔文
人的后裔
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第二版序言 •600字
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在本书于 1871 年出版的第一版的连续重印过程中,我做出了一些重要的修正;现在时间已经过去了,我努力从这本书所经历的激烈考验中获益,并利用了所有我认为合理的批评。我还非常感谢众多记者,他们传播了数量惊人的新事实和言论。这些内容太多了,我只能使用较重要的内容;其中,以及更重要的更正,我将附上一个列表。引入了一些新插图,其中四张旧图已被 TW Wood 先生根据生活绘制的更好的图所取代。我必须特别提请注意一些关于人类和高等猿类大脑之间差异本质的观察结果,这些观察结果应归功于赫胥黎教授的善意(在第一部分末尾作为补充)。我特别高兴地提出这些意见,因为在过去的几年里,欧洲大陆出现了几本关于这个主题的回忆录,而它们的重要性在某些情况下被流行作家大大夸大了。

我可以借此机会指出,我的批评者经常认为我将所有肉体结构和精神力量的变化完全归因于通常被称为自发变化的自然选择。然而,即使在《物种起源》第一版中,我也明确指出,必须高度重视使用和不使用对身体和心灵的遗传影响。我还将一定程度的改变归因于生活条件改变的直接和长期作用。偶尔的结构调整也必须给予一定的考虑。我们也不能忘记我所说的“相关”增长,即组织的各个部分以某种未知的方式相互联系,当一个部分发生变化时,其他部分也会发生变化;如果通过选择积累了其中一项的变化,则其他部分将被修改。一些批评家再次指出,当我发现人类结构的许多细节无法通过自然选择来解释时,我发明了性选择;然而,我在《物种起源》第一版中对这一原理进行了相当清晰的概述,并且我在那里指出它适用于人类。在目前的工作中,性选择这个主题得到了充分的讨论,仅仅是因为这里首先给了我一个机会。我对许多对性选择半赞成的批评的相似之处感到震惊,这些批评最初出现在自然选择上。例如,它会解释一些细节,但肯定不适用于我使用它的程度。我对性选择力量的信念始终没有动摇。但很可能,或者几乎可以肯定,我的一些结论今后将被发现是错误的。在对象的第一次治疗中几乎不可能不出现这种情况。我相信,当博物学家熟悉了性选择的概念后,它就会被更多人接受。它已经得到了几位有能力的法官的充分好评。

唐,贝肯汉姆,肯特,
九月1874。

第一版,24 年 1871 月 XNUMX 日。
第二版,1874 年 XNUMX 月。

介绍 •1,300字

通过简要说明本书的写作方式,可以更好地理解本书的性质。多年来,我收集了有关人类起源或血统的笔记,无意发表有关该主题的文章,而是决定不发表,因为我认为这样只会增加对我的观点的偏见。在我的《物种起源》第一版中,我认为这足以表明这部著作“将阐明人类的起源及其历史”;这意味着,在任何关于人在地球上的出现方式的一般性结论中,人都必须与其他有机生物一起被包括在内。现在,案件呈现出完全不同的一面。当像卡尔·沃格特这样的博物学家在他作为日内瓦国家学会主席的演讲(1869年)中冒险说“personne, en Europe au moins, n'ose plus soutenir la Creation indépendante et de toutes pièces, des espèces”时,显然,至少有大量博物学家必须承认物种是其他物种的改良后代;这对于年轻的、正在崛起的博物学家尤其适用。更多的人接受自然选择的作用;尽管有些人强烈要求,无论未来是否必须由正义来决定,我都大大高估了它的重要性。不幸的是,在自然科学领域的老一辈和受人尊敬的领袖中,许多人仍然反对一切形式的进化论。

由于现在大多数博物学家所采用的观点,并且最终将像在所有其他情况下一样,被其他不科学的人所遵循,我被迫将我的笔记放在一起,以便看看一般性结论在多大程度上是可行的。我以前的作品中得出的结论也适用于人类。这似乎更可取,因为我从未故意将这些观点应用于单独的物种。当我们将注意力局限于任何一种形式时,我们就被剥夺了源自将整个有机体群体联系在一起的亲缘关系的本质的重要论据——它们在过去和现在的地理分布,以及它们的地质演替。一个物种的同源结构、胚胎发育和基本器官仍有待考虑,无论是人类还是任何其他动物,我们的注意力可能会集中在这些方面;但在我看来,这些伟大的事实提供了支持渐进进化原则的充足而确凿的证据。然而,应始终牢记从其他论点中获得的强有力的支持。

这项工作的唯一目的是首先考虑人类是否像其他物种一样是某种预先存在的形式的后代;其次,他的发展方式;第三,所谓人类种族之间差异的价值。由于我将仅限于这些要点,因此没有必要详细描述几个种族之间的差异——这是一个巨大的主题,在许多有价值的著作中已经得到了充分的描述。最近,从布歇·德佩尔特斯先生开始,许多杰出人士的努力证明了人类的悠久历史。而这是了解他的出身不可或缺的基础。因此,我将认为这个结论是理所当然的,并且可以向我的读者推荐查尔斯·莱尔爵士、约翰·拉伯克爵士和其他人的令人钦佩的论文。我也没有机会做更多的事情,只是提及人类和拟人猿之间的巨大差异。因为赫胥黎教授在大多数有能力的法官看来,已经明确地表明,在每一个可见的性格中,人类与高等猿类的差异都小于这些与同一灵长类动物目中低等成员的差异。

这部作品几乎不包含任何关于人类的原创事实;但是,在草拟了草稿之后,我得出的结论对我来说似乎很有趣,我认为它们可能会引起其他人的兴趣。人们经常自信地断言,人的起源永远无法得知:但无知比知识更容易产生自信:是那些知之甚少的人,而不是那些知之甚少的人,如此积极地断言这个或那个问题将被解决。永远无法用科学来解决。人类是其他某些古老、低等和灭绝形式的物种的共同后裔,这一结论在任何程度上都不是什么新鲜事。拉马克很久以前就得出了这个结论,最近几位著名的自然学家和哲学家也坚持这一结论。例如,华莱士(Wallace)、赫胥黎(Huxley)、莱尔(Lyell)、沃格特(Vogt)、拉伯克(Lubbock)、布赫纳(Buchner)、罗尔(Rolle)等人的作品。在英国不太出名,我会给他们:-“Sechs Vorlesungen über die Darwin'sche Theorie:”zweite Auflage,1年,von L. Buchner博士;翻译成法语,标题为“Conférences sur la Théorie Darwinienne”,1868年. 'Der Mensch im Lichte der Darwin'sche Lehre,' 1869, von Dr. F. Rolle. 我不会尝试引用所有持相同观点的作者。因此 G. Canestrini 发表了 ( “Annuario della Soc. d. Nat.”,摩德纳,1865 年,第 1867 页)这是一篇关于基本特征的非常好奇的论文,与人类的起源有关。弗朗西斯科·巴拉戈 (Francesco Barrago) 博士出版了另一部作品 (81),其中包含意大利语的标题是“人是按照上帝的形象创造的,也是按照猿的形象创造的。”),尤其是海克尔。这位最后的博物学家,除了他的伟大著作《一般形态学》(1869 年)外,最近(1866 年,1868 年第二版)出版了他的《自然形态史》,其中他充分讨论了人类的谱系。如果这部作品在我写论文之前就出现了,我可能永远不会完成它。我发现几乎我得出的所有结论都得到了这位博物学家的证实,他在许多方面的知识比我丰富得多。无论我在海克尔教授的著作中添加任何事实或观点,我都会在文本中给予他的权威;我在手稿中保留了其他陈述,偶尔在脚注中引用他的作品,作为对更可疑或有趣的观点的确认。

多年来,在我看来,性选择很可能在人类种族的分化中发挥了重要作用。但在我的《物种起源》(第一版,第 199 页)中,我仅仅提及这一信念就满足了。当我把这个观点应用到人类身上时,我发现有必要详细地讨论整个主题。 (2. 海克尔教授是唯一一位在本书首次发表时讨论过性选择这一主题的作者,自《起源》出版以来,他充分认识到了它的重要性;他在因此,本著作的第二部分(讨论性选择)与第一部分相比,篇幅过长。但这是无法避免的。

我本来打算在现在的书中添加一篇关于人类和低等动物表达各种情感的文章。许多年前,查尔斯·贝尔爵士令人钦佩的工作引起了我对这个主题的关注。这位杰出的解剖学家认为,人类被赋予某些肌肉只是为了表达他的情感。由于这种观点显然与人是其他较低形式的后裔的信念相反,因此我有必要考虑它。我同样想确定不同种族的人类在多大程度上以相同的方式表达情感。但由于目前的工作篇幅较长,我认为最好保留我的文章单独出版。

第一部分•人类的起源或起源

第一章 •9,000字
人类起源于某种低等形态的证据

关于人类起源的证据的性质——人类和低等动物的同源结构——各种对应点——发展——基本结构、肌肉、感觉器官、毛发、骨骼、生殖器官等——这些的轴承关于人类起源的三大事实

想要确定人是否是某种先前存在形式的改良后裔的人,可能会首先询问人在身体结构和智力方面是否有变化,无论变化多么微小;如果是这样,这些变异是否按照低等动物普遍存在的法则遗传给他的后代。再一次,就我们的无知允许我们判断,这些变异是否是相同一般原因的结果,并且它们是否受到相同一般规律的支配,就像其他生物体的情况一样?例如,通过相关性,使用和不使用的遗传效应等?人类是否会遭受类似的畸形,这是发育停滞、部件重复等的结果,并且他是否在任何异常中表现出对某种以前和古老的结构类型的回归?人们也自然会问,人类是否像许多其他动物一样,产生了彼此间略有差异的变种和亚种,或者差异如此之大以至于必须被归类为可疑物种的种族?这些种族在世界各地的分布情况如何?当杂交时,它们在第一代和后续世代中如何相互反应?许多其他观点也是如此。

探究者接下来会谈到重要的一点,即人类是否倾向于以如此快的速度增长,以至于偶尔会导致严重的生存斗争?因此,有益的变异,无论是身体上的还是心灵上的变异,都被保留下来,有害的变异被消除。人类的种族或物种,无论使用哪个术语,是否会互相蚕食和取代,以致某些人最终灭绝?我们将看到,所有这些问题对于大多数问题来说确实是显而易见的,必须以与低等动物相同的方式得到肯定的回答。但刚才提到的几个考虑因素可以方便地推迟一段时间:我们将首先看到人类的身体结构在多大程度上显示出他从某种较低形式的血统的痕迹,或多或少是明显的。在接下来的章节中,我们将讨论人类的智力与低等动物的智力的比较。

人的身体结构

众所周知,人类是按照与其他哺乳动物相同的一般类型或模型构建的。他骨骼中的所有骨头都可以与猴子、蝙蝠或海豹的相应骨头进行比较。他的肌肉、神经、血管和内脏也是如此。正如赫胥黎和其他解剖学家所表明的那样,大脑是所有器官中最重要的,也遵循同样的规律。 Bischoff (1. ‘Grosshirnwindungen des Menschen’,1868,第 96 节。赫胥黎教授将在序言中提到的附录中讨论该作者以及 Gratiolet 和 Aeby 关于大脑的结论),他是一个敌对证人,他承认人类大脑中的每一个主要裂缝和褶皱都与红毛人的相似。但他补充说,在任何发育阶段,他们的大脑都不会完全一致。也不能指望完全一致,否则他们的精神力量就会相同。 Vulpian(2. 'Lec. sur la Phys.' 1866,第 890 页,M. Dally 引用,'L'Ordre des Primates et le Transformisme,' 1868,第 29 页。),评论:“Les différences réelles qui Existent人类的脑部和超级大脑的中心,sont bien minimes。 Il ne faut pas se faire d'illusions a cet égard. L'homme est bien plus près desinges anthropomorphes par les caractères anatomiques de son cerveau que ceux-ci ne le sont non seulement des autres mammifères, mais même de certainsquarumanes, des guenons et des macaques.”但在这里进一步详细说明人类和高等哺乳动物在大脑和身体所有其他部分的结构上的对应关系是多余的。

然而,可能值得指定一些与结构没有直接或明显联系的点,通过这些点可以很好地显示这种对应或关系。

人类很容易从低等动物那里接收某些疾病,并向它们传播某些疾病,如恐水症、天花、马鼻疽、梅毒、霍乱、疱疹等。(3. W. Lauder Lindsay 博士在某些方面治疗过这个问题。长度见《心理科学杂志》,1871 年 1858 月;以及《爱丁堡兽医评论》,4 年 1 月);这一事实证明了我在这里所说的非常严厉和蔑视的密切相似性(1871.一位评论家批评了(“英国季刊评论”,472年5月1830日,第50页)我在这里所说的非常严厉和轻蔑;但因为我不使用“身份”一词,我看不出我犯了很大的错误。在我看来,在两种不同的动物中产生相同结果或非常相似的相同感染或传染病与用相同化学物质测试两种不同液体之间存在很强的类比它们的组织和血液的微小结构和成分,比在最好的显微镜下或借助最好的化学分析进行的比较要清楚得多。猴子和我们一样容易患上许多非传染性疾病。因此,Rengger (6. 'Naturgeschichte der Säugethiere von Paraguay,' 7, s. 1864.),他在其故乡仔细观察了 Cebus Azarae 很长一段时间,发现它容易患粘膜炎,并具有常见的症状,并且,时常反复发作,导致消耗。这些猴子还患有中风、肠道炎症和眼睛白内障。年幼的孩子在掉乳牙时往往会因发烧而死亡。药物对他们产生的效果与对我们相同。许多种类的猴子都对茶、咖啡和烈性酒有着浓厚的兴趣:正如我亲眼所见,它们也会愉快地吸烟。 (75.同样的味道对于一些等级低得多的动物来说是常见的。A.尼科尔斯先生告诉我,他在澳大利亚昆士兰饲养了三只灰豆角豆;并且,没有以任何方式进行教导,他们对朗姆酒和吸烟产生了浓厚的兴趣。)布雷姆断言,非洲东北部的当地人通过暴露盛有浓啤酒的容器来捕获野生狒狒,然后将其灌醉。他曾见过一些被他圈养的动物处于这种状态。他对他们的行为和奇怪的鬼脸进行了可笑的描述。第二天早上,他们都很生气,心情郁闷。他们双手捂着疼痛的头,表情极其可怜:给他们啤酒或葡萄酒时,他们厌恶地转过身去,却津津有味地喝着柠檬汁。 (86. Brehm, 'Thierleben,' B. i. 105, s. 25, 107. On the Ateles, s. XNUMX. 对于其他类似的陈述,参见 s. XNUMX, XNUMX。) 一只美洲猴子,一只 Ateles,之后喝醉了白兰地,就再也不会碰它,因此比许多人聪明。这些琐碎的事实证明,猴子和人类的味觉神经是多么相似,而且它们的整个神经系统受到的影响是多么相似。

人类体内感染了寄生虫,有时会造成致命的影响;并受到外部寄生虫的困扰,所有这些寄生虫都与感染其他哺乳动物的寄生虫属于同一属或科,就疥疮而言,属于同一物种。 (8. W. Lauder Lindsay 博士,《爱丁堡兽医评论》,1858 年 13 月,第 9 页。)人类是主体,就像其他哺乳动物、鸟类,甚至昆虫一样(1842. 关于昆虫,请参见 Laycock 博士,“ 《关于生命周期的一般法则》,《英国协会》,305 年。Macculloch 博士,《西利曼的北美科学杂志》,第 XVII 卷,第 10 页,看到一只狗患有疟疾。此后我将回到这个主题。),到那个神秘的法则,它导致某些正常过程,例如妊娠,以及各种疾病的成熟和持续时间,遵循农历周期。他的伤口也通过同样的愈合过程得到修复。截肢后留下的残肢,特别是在胚胎早期,偶尔具有一定的再生能力,就像最低等的动物一样。 (15. 我已经在我的《驯化下的动物和植物的变异》第 ii 卷第 XNUMX 页中提供了关于这一点的证据,还可以添加更多内容。)

最重要功能的整个过程,即物种的繁殖,在所有哺乳动物中都惊人地相同,从雄性的第一次求爱行为开始(11. Mares e diversisgeneribus Quadrumanorum sine dubio dignoscunt feminas humanas a maribus。 Primum, Youatt 先生,在 Hortis Zoologicis (Bestiariis) medicus Animalium Erat, vir in rebus observandis cautus et sagax, hoc mihi certissime probavit, et curatores ejusdem loci et alii e ministris informaverunt. 安德鲁·史密斯爵士等人Brehm notabant idem in Cynoc​​ephalo. Illustrissimus Cuvier etiam narrat multa de hac re, qua ut opinor, nihil turpius potest indicari interomnia hominibus et Quadrumanis commia. Narrat enim Cynoc​​ephalum quendam infurorem inciderespectu feminarum aliquarem, sed nequam accendi tanto Furore abomnibus.森帕eligebat Juniores、et dignoscebat in turba、et advocabat voce gestuque.),以出生和养育年轻人。猴子出生时几乎和我们的婴儿一样无助。在某些属中,年轻人在外表上与成年人完全不同,就像我们的孩子与成年父母的差异一样。 (12. 这一评论是由 Geoffroy Saint-Hilaire 和 F. Cuvier 在《Histoire Nat. des Mammifères》,tom. i. 1824 中针对犬头猿和拟人猿做出的。)一个重要的区别是,人类的幼崽比任何其他动物都晚得多:但如果我们观察居住在热带国家的人类种族,差异并不大,因为人们相信红毛猩猩还没有成年直到十岁到十五岁。 (13. 赫胥黎,《男人在自然中的地位》,1863 年,第 34 页。)男人与女人的不同之处在于体型、体力、多毛等,以及思想上的不同,就像男女之间的区别一样。许多哺乳动物。因此,人与高等动物,特别是拟人猿,在总体结构、组织的微小结构、化学成分和体质上的对应关系是极其接近的。

胚胎发育

[如图。 1. 显示了来自 Ecker 的人类胚胎和来自 Ecker 的狗胚胎
比肖夫。每个标签中都有:

A。前脑、大脑半球等b.中脑,四叠体。 C。后脑、小脑、延髓。 d.眼睛。 e.耳朵。 F。第一内脏弓。 G。第二内脏弓。 H. 发育过程中的脊柱和肌肉。我。四肢前侧。 K. 后肢。 L. 尾部或尾骨。]

人类是由直径约125英寸的胚珠发育而来的,这与其他动物的胚珠没有任何区别。胚胎本身在非常早期的阶段很难与脊椎动物界其他成员的胚胎区分开来。在这个时期,动脉以拱形分支走行,仿佛将血液输送到高等脊椎动物中不存在的鳃,尽管颈部两侧的缝隙仍然存在(参见f,g,图1) ,标记他们以前的位置。在稍后的时期,当四肢发育时,“蜥蜴和哺乳动物的脚”,正如著名的冯·贝尔所说,“鸟类的翅膀和脚,不亚于人的手和脚,都是从相同的基本形式。”赫胥黎教授说(14.《人类在自然中的地位》,1863年,第67页),“在发育的后期阶段,年轻的人类与年轻的猿呈现出显着的差异,而后者则远离了年轻的猿。”狗的发展与人的发展一样多。尽管最后的断言可能看起来令人震惊,但它显然是正确的。”

由于我的一些读者可能从未见过胚胎图,所以我给出了一张人类胚胎图和另一张狗胚胎图,它们处于大致相同的早期发育阶段,是从两幅毫无疑问的准确性的作品中仔细复制的。 (15. 人类胚胎(上图)来自 Ecker, 'Icones Phys.,' 1851-1859, tab. xxx。图 2。这个胚胎有十行长,所以图被放大了很多。狗的胚胎来自 Bischoff, 'Entwicklungsgeschichte des Hunde-Eies,' 1845, tab. xi. 图 42B。这张图放大了五倍,胚胎已经二十五天了。内脏已被省略,并且两幅图中的子宫附属物都被移除了。赫胥黎教授引导我去看这些人物,他的作品《人类在自然中的地位》中提出了赋予它们的想法。海克尔也在他的《Schopfungsgeschichte》中给出了类似的图画。 )

在如此高的权威发表上述声明之后,我就没有必要提供一些借来的细节来表明人类的胚胎与其他哺乳动物的胚胎非常相似。然而,可以补充的是,人类胚胎在成年时在不同的结构点上同样类似于某些低等形式。例如,心脏最初是作为一个简单的脉动血管而存在的。排泄物通过泄殖腔通道排出;尾骨像真正的尾巴一样突出,“远远超出了基本的腿”。 (16. Wyman 教授,《美国科学院院刊》,1860 年第 iv 卷,第 17 页。)在所有呼吸空气的脊椎动物的胚胎中,某些腺体(称为沃尔夫氏体)与其作用类似于成熟鱼类的肾脏。 (17. Owen,《脊椎动物解剖学》,第 533 卷。)即使在胚胎后期,也可以观察到人类和低等动物之间的一些惊人的相似之处。比肖夫说,“人类胎儿的大脑在第七个月末时达到了与成年狒狒相同的发育阶段。” (18. 'Die Grosshirnwindungen des Menschen,' 1868, s. 95.) 大脚趾,正如欧文教授所说 (19. '脊椎动物解剖学', vol. ii. p. 553.),“当站立或行走,也许是人体结构中最具特色的特征;”但在大约一英寸长的胚胎中,怀曼教授(20. 'Proc. Soc. Nat. Hist.' Boston, 1863, vol. ix. p. 185.)发现“大脚趾比大脚趾短”。其他的;并且,不是与它们平行,而是从脚的侧面以一定角度突出,从而与四足中这部分的永久状态相对应。”我将引用赫胥黎的一句话作为结束语(21.“人类在自然中的地位”,第 65 页。)赫胥黎在询问后,人类的起源是否与狗、鸟、青蛙或鱼不同?说:“这个答复暂时没有疑问;毫无疑问,人类的起源方式和发展的早期阶段,与等级上紧随其后的动物是相同的:毫无疑问,在这些方面,人类与猿类的距离比猿类与猿类的距离要近得多。狗。”

初级

尽管这个主题本质上并不比后两个主题更重要,但出于多种原因,这里将更全面地讨论这个主题。 (22. 在阅读一篇有价值的论文“Caratteri rudimentali in ordine all' origine dell' uomo”(“Annuario della Soc. d. Naturalisti”,摩德纳,1867 年,第 81 页)之前,我已经写了本章的粗略副本,作者:G. Canestrini,我对这篇论文深表感激。海克尔在他的“一般形态学”和“Schöpfungsgeschichte”中以“发育不良学”为题对整个主题进行了令人钦佩的讨论。)没有一种高等动物可以命名不具备基本状态的某些部分;人类也不例外。必须将未发育的器官与新生的器官区分开来;尽管在某些情况下区分并不容易。前者要么完全无用,例如雄性四足动物的乳房,要么反刍动物的门齿,它们永远不会切穿牙龈;或者它们对现在的拥有者的作用如此之小,以至于我们很难假设它们是在现在存在的条件下发展起来的。严格来说,处于后一种状态的器官并不处于初级状态,但它们正在朝这个方向发展。另一方面,新生器官虽然尚未完全发育,但对其拥有者有很高的服务,并且能够进一步发育。发育不全的器官差异很大。这在一定程度上是可以理解的,因为它们是无用的,或者几乎是无用的,因此不再受到自然选择的影响。他们常常被完全压制。然而,当这种情况发生时,它们偶尔会通过回归而重新出现——这种情况非常值得关注。

导致器官发育不全的主要因素似乎在器官主要使用的生命时期(通常是在成熟期间)被废弃,并且在相应的生命时期也被遗传。 “废用”一词不仅仅涉及肌肉活动的减弱,还包括由于受到较少的压力交替或以任何方式变得不习惯活动而导致流向某个部位或器官的血液减少。然而,一种性别中可能会出现通常存在于另一种性别中的那些部分的雏形;正如我们将在下文中看到的,这些雏形的起源往往与这里提到的不同。在某些情况下,器官通过自然选择而减少,因为在生活习惯改变的情况下,器官对物种变得有害。减少的过程可能经常通过补偿和经济增长这两个原则来帮助;但在减少的后期阶段,在废止完成了所有可以公平地归因于它之后,并且当经济增长所影响的储蓄将非常小的时候(23.先生们对这个问题提出了一些很好的批评) Murie 和 Mivart,《Transact. Zoological Society》,1869 年,第 vii 卷,第 92 页),很难理解。对已经无用且尺寸大大缩小的部分进行最终和彻底的抑制,在这种情况下,补偿和经济都无法发挥作用,也许可以借助泛生假说来理解。但是,由于基本器官的整个主题已在我以前的作品中进行了讨论和说明(24。“驯化下动物和植物的变异”,第二卷,第 317 和 397 页。另请参阅“物种起源”,第 5 版,第 535 页) XNUMX.),这个问题我就不用多说了。

在人体的许多部位都观察到了各种肌肉的雏形(25. 例如,M. Richard(“Annales des Sciences Nat.”,第 3 系列,Zoolog. 1852,tom. xviii. p. 13)描述并绘制了图他称之为“主足肌”(muscle pedieux de la main)的雏形,他说有时是“无穷小”。另一块肌肉,称为“胫骨后部”,通常在手上完全不存在,但时不时会出现在手上。或多或少的基本条件。);一些低等动物中常见的肌肉偶尔也能在人类身上发现,但其状况却大大恶化。每个人一定都注意到许多动物,尤其是马,拥有移动或抽动皮肤的力量;这是由肉膜实现的。这种肌肉在有效状态下的残余物存在于我们身体的各个部位。例如,额头上的肌肉,通过它可以抬起眉毛。颈部发育良好的颈阔肌就属于这个系统。爱丁堡的特纳教授告诉我,他偶尔会在五种不同的情况下检测到肌束,即在腋窝、肩胛骨附近等,所有这些都必须涉及脂膜系统。他还表明(26. W. Turner 教授,“爱丁堡皇家学会学报”,1866-67,第 65 页)胸骨肌或粗胸肌不是腹直肌的延伸,但与脂膜密切相关,发生比例约为百分之三。在超过 600 个身体中:他补充说,这块肌肉“很好地说明了偶然和基本结构特别容易发生排列变化的说法。”

有些人有能力收缩头皮上的浅层肌肉;有些人有能力收缩头皮上的浅层肌肉。这些肌肉处于可变且部分初级的状态。 MA de Candolle 向我传达了一个奇怪的例子,说明这种力量的长期持续存在或继承,以及它不寻常的发展。他认识一个家庭,其中一位成员,即现在的一家之主,在年轻时,仅靠头皮的运动就能从头上甩出几本厚重的书;他通过表演这一壮举赢得了赌注。他的父亲、叔叔、祖父和他的三个孩子都拥有同样不寻常的力量。这个家族在八代之前就分成了两个分支。因此,上述分支的首领与另一个分支的首领是七等亲。这位远房表亲住在法国的另一个地方。当被问及他是否拥有同样的能力时,他立即展示了他的力量。这个案例很好地说明了一种绝对无用的能力的传承是多么持久,这种能力可能源自我们遥远的半人类祖先。因为许多猴子拥有并且经常使用大幅上下移动头皮的力量。 (27. 参见我的《人和动物的情感表达》,1872 年,第 144 页。)

用于移动外耳的外在肌肉和用于移动不同部位的内在肌肉在人类中处于初级状态,它们都属于脂膜系统;它们在发展过程中,或者至少在功能上,也是可变的。 我见过一个人可以把整个耳朵向前拉;其他人可以把它向上拉;另一个可以把它向后拉的人(28. 卡内斯特里尼引用了希尔特尔的话。 (《社会年鉴》。 dei Naturalisti,摩德纳,1867 年,第 XNUMX 页。 97) 达到同样的效果。);从其中一位人士告诉我的情况来看,我们大多数人很可能通过经常触摸我们的耳朵,从而将我们的注意力集中到耳朵上,可以通过反复尝试来恢复一些运动能力。 竖起耳壳并将其指向罗盘各个点的能力无疑对许多动物来说是最重要的,因为它们因此能够感知危险的方向;但我从未听说过有足够的证据表明有哪个人拥有这种可能对他有用的力量。 整个外壳可以被认为是一个雏形,连同各种褶皱和突出物(耳轮和对耳轮,耳屏和对耳屏等),在低等动物中,它们在直立时加强和支撑耳朵,而不增加太多它的重量。 然而,一些作者认为贝壳的软骨用于将振动传递到听神经。但先生。 汤因比 (29. 《耳朵的疾病》,J. 汤因比,FRS,1860,p。 12. 一位杰出的生理学家,Prof. 普莱尔(Preyer)告诉我,他最近一直在试验耳壳的功能,得出的结论与这里给出的几乎相同。),在收集了有关这个头的所有已知证据后,得出的结论是,外壳没有明显的用途。 黑猩猩和红毛猩猩的耳朵与人类的耳朵非常相似,其适当的肌肉也同样发达,但非常轻微。 (30。 教授 A. 麦卡利斯特,《自然历史年鉴和杂志》,卷。 vii. 1871。 342.) 动物园的饲养员也向我保证,这些动物永远不会移动或竖起耳朵;因此,就功能而言,它们与人类处于同样初级的状态。 为什么这些动物以及人类的祖先都失去了竖起耳朵的能力,我们无法说清楚。 尽管我对这种观点不满意,但可能是由于它们的树栖习性和强大的力量,它们很少遇到危险,所以在很长一段时间内它们的耳朵很少动,从而逐渐失去了移动的能力。他们。 这与那些又大又重的鸟类的情况类似,它们来自海岛,没有受到猛兽的攻击,因此失去了用翅膀飞行的能力。 然而,人类和一些猿类无法移动耳朵,但它们可以在水平面上自由移动头部,从而捕捉来自各个方向的声音,这在一定程度上弥补了这一点。 有人断言,只有人的耳朵才有小叶。但“在大猩猩身上发现了它的雏形”(31. 先生。 圣 乔治·米瓦特,《初级解剖学》,1873 年,第 XNUMX 页。 396。);而且,正如我从教授那里听到的那样

[如图。 2. 人耳,由 Woolner 先生建模和绘制。投影点标记为 a。]

著名雕塑家,先生。 伍尔纳告诉我外耳的一个小特点,他经常在男性和女性身上观察到这一点,并且他意识到了这一点的全部意义。 他第一次注意到这个主题是在创作帕克的雕像时,他给帕克画了尖耳朵。 因此,他被引导检查各种猴子的耳朵,随后更仔细地检查人的耳朵。 其独特之处在于有一个小钝点,从向内折叠的边缘或螺旋突出。 如果存在的话,它是在出生时就发育出来的,并且根据教授的说法。 路德维希·迈耶(Ludwig Meyer),男性比女性更常见。 先生。 伍尔纳制作了一个此类案例的精确模型,并将附图发送给我。 (图。 2)。 这些点不仅向耳朵的中心向内突出,而且通常从耳朵的平面稍微向外突出,以便当从正面或后面直接观察头部时可以看到这些点。 它们的大小各不相同,位置也各不相同,有的高一点,有的低一点。有时它们会出现在一只耳朵上,而不会出现在另一只耳朵上。 它们并不局限于人类,因为我在我们动物园的一只蜘蛛猴(Ateles beelzebuth)身上观察到了一个案例;和先生。 E. 雷·兰克斯特告诉我汉堡花园里的另一起黑猩猩病例。 耳轮显然是由向内折叠的耳朵的最边缘组成的;这种折叠似乎以某种方式与整个外耳被永久向后压有关。 在许多猴子中,它们的地位并不高,如狒狒和某些猕猴物种(32. 另请参阅 Messrs 中的一些评论和 Lemuroidea 耳朵的图画。 Murie 和 Mivart 在《动物学会汇刊》第一卷上发表的优秀论文。 vii. 1869页。 6和90.),耳朵的上部略尖,边缘完全没有向内折叠;但是,如果边缘如此折叠,那么一个小点必然会向中心向内突出,并且可能会从耳朵的平面稍微向外突出;我相信这在很多情况下都是它们的起源。 另一方面,教授。 L. Meyer 在最近发表的一篇出色的论文中 (33. “Über das Darwin'sche Spitzohr”,路径档案。 阿纳特。 与物理学,1871 年,第 XNUMX 页。 485.),坚持认为整个案件只是一种变异;并且这些突起不是真实的,而是由于点两侧的内部软骨尚未完全发育所致。 我很愿意承认,这在许多情况下都是正确的解释,正如教授所提出的那样。 Meyer,其中有几个微小的点,或者整个边缘是蜿蜒的。 我亲眼目睹了,通过博士的仁慈。 L. 向下,是小头白痴的耳朵,其耳轮外侧有一个突起,而不是向内折叠的边缘,因此该点与以前的耳尖没有关系。 尽管如此,在某些情况下,我最初的观点,即这些点是以前直立和尖尖的耳朵尖端的遗迹,在我看来仍然是可能的。 从它们出现的频率以及与尖耳尖的位置的一般对应关系来看,我认为是这样。 在一个案例中,我收到了一张照片,投影是如此之大,假设,根据教授的说法。 迈耶认为,要使耳朵变得完美,就要使软骨在整个边缘范围内均匀发展,它会完全覆盖整个耳朵的三分之一。 我收到了两个案例,一个在北美,另一个在英国,其上缘根本没有向内折叠,而是尖的,因此它的轮廓与普通四足动物的尖耳朵非常相似。 在其中一个案例中,这是一个年幼的孩子,父亲将耳朵与我给出的图画进行了比较(34. “情感的表达”,p。 136.)的猴子(Cynopithecus niger)的耳朵,并说它们的轮廓非常相似。 如果在这两种情况下,边缘以正常方式向内折叠,则必定形成向内的突出部。 我可以补充一点,在另外两种情况下,轮廓仍然有些尖,尽管耳朵上部的边缘通常向内折叠——然而,在其中一种情况下,折叠得非常窄。 [图3. 红毛猩猩的胎儿(?)。 照片的精确复制品,显示了早期耳朵的形状。] 以下木刻(No.1) 3)是一张猩猩胎儿照片的准确副本(由 Dr. 发给我) Nitsche),其中可以看出这一时期耳朵的尖锐轮廓与其成年状态有多么不同,当时它与人类的耳朵非常相似。 显然,这种耳朵尖端的折叠,除非在进一步发展过程中发生很大变化,否则会产生向内突出的点。

瞬膜或第三眼睑及其附属肌肉和其他结构在鸟类中尤其发达,对它们具有重要的功能,因为它可以快速拉过整个眼球。它存在于一些爬行动物和两栖动物以及某些鱼类(如鲨鱼)中。它在哺乳动物系列的两个低等类,即单孔目动物和有袋动物,以及一些高等哺乳动物(如海象)中相当发达。但正如所有解剖学家所承认的那样,在人类、四肢动物和大多数其他哺乳动物中,它仅作为一个雏形存在,称为半月褶皱。 (35. Muller 的《生理学原理》,英译,1842 年,第 ii 卷,第 1117 页。Owen,《脊椎动物解剖学》,第 iii 卷,第 260 页;同上,关于海象,《Proceedings of the Vertebrates》动物学会,8 年 1854 月 106 日。另请参阅 R. Knox,“伟大的艺术家和解剖学家”,第 129 页。黑人和澳大利亚人的这种雏形显然比欧洲人要大一些,请参阅卡尔·沃格特的“关于人类的讲座”,英译,第 XNUMX 页。)

嗅觉对于大多数哺乳动物来说是最重要的——对于一些哺乳动物来说,比如反刍动物,嗅觉可以警告它们危险;对于其他动物,如食肉动物,在寻找猎物时;对于其他人来说,再次,作为野猪,将这两个目的结合起来。但是,即使对于深色人种来说,嗅觉的作用(如果有的话)也是极其微弱的,因为他们的嗅觉比白人和文明人种发达得多。 (36. 洪堡对南美洲原住民拥有嗅觉力量的描述是众所周知的,并已被其他人证实。M. Houzeau ('Études sur les Facultés Mentales,' et al., tom. i. 1872年,第91页)声称他反复进行了实验,并证明黑人和印第安人可以通过气味在黑暗中识别人。W.奥格尔博士对气味的力量和颜色之间的联系做出了一些奇怪的观察嗅觉区域的粘膜以及身体的皮肤的问题。因此,我在文本中谈到深色人种比白人人种具有更好的嗅觉。请参阅他的论文,“ Medico-Chirurgical Transactions,' London,vol. liii. 1870,p. 276。)然而,它并没有警告他们有危险,也没有引导他们去吃食物;它也不妨碍爱斯基摩人在最恶臭的气氛中睡觉,也不妨碍许多野蛮人吃半腐烂的肉。在欧洲人中,不同个体的力量有很大差异,正如一位杰出的博物学家向我保证的那样,他拥有高度发展的这种感觉,并且关注了这个主题。那些相信渐进进化原理的人不会轻易承认目前状态下的嗅觉最初是由人类获得的,就像现在的人类一样。他从一些早期的祖先那里继承了一种虚弱且初级的权力,这种权力对他们来说非常有用,并且不断地被他们使用。在那些具有高度发达的这种感觉的动物中,例如狗和马,对人和地点的回忆与它们的气味密切相关。因此,我们也许可以理解,正如莫兹利博士所言(​​37.《心灵的生理学和病理学》,第 2 版。1868 年,第 134 页),人类的嗅觉“是独一无二的”。能够有效地生动地回忆起被遗忘的场景和地点的想法和图像。”

人类与其他灵长类动物的显着不同之处在于,人类几乎赤身裸体。但在男性身体的大部分部位都发现了一些短而散乱的毛发,而女性则在身体的大部分部位发现了细小的毛发。不同种族的毛羽差异很大;在同一种族的个体中,毛发变化很大,不仅在数量上,而且在位置上也有很大差异:因此,一些欧洲人的肩膀完全裸露,而另一些欧洲人则长着浓密的毛发。 (38. Eschricht, Über die Richtung der Haare am menschlichen Körper, Muller's 'Archiv Fur Anat. und Phys.' 1837, s. 47。我经常不得不参考这篇非常好奇的论文。)毫无疑问,散布在全身的毛发是低等动物均匀的毛皮的雏形。这种观点更有可能,因为众所周知,四肢和身体其他部位的细、短、浅色毛发有时会发展成“浓密、长且相当粗糙的深色毛发”,当老发炎表面附近异常滋养。 (39. Paget,《外科病理学讲座》,1853 年,第 71 卷。)

詹姆斯·佩吉特爵士告诉我,一个家庭中的几位成员的眉毛中往往有几根比其他人长得多的头发;因此,即使是这种轻微的特殊性似乎也是遗传的。这些毛发似乎也有其代表。因为在黑猩猩和某些猕猴物种中,眼睛上方裸露的皮肤上散布着相当长的毛发,与我们的眉毛相对应。一些狒狒的眉毛脊部的毛状覆盖物也有类似的长毛。

人类胎儿在第六个月时全身覆盖着一层厚厚的细羊毛状毛发,或所谓的胎毛,提供了一个更奇怪的例子。它首先在第五个月时出现在眉毛和面部,尤其是嘴周围,那里比头上的长得多。 Eschricht (40. Eschricht, 同上 s. 40, 47.) 在一个女性胎儿身上观察到了这种胡须;但这并不像乍看起来那样令人惊讶,因为在成长的早期阶段,两性在所有外部特征上通常都相似。胎儿身体各部位毛发的方向和排列与成人相同,但变化很大。整个表面,甚至包括额头和耳朵,都覆盖着厚厚的衣服;但一个重要的事实是,手掌和脚底是完全裸露的,就像大多数低等动物的所有四个肢体的下表面一样。由于这不可能是偶然的巧合,因此胎儿的羊毛覆盖物可能代表了那些生来就有毛的哺乳动物的第一层永久毛发。据记载,有三四例人出生时全身和脸上都长满了细长的毛发。这种奇怪的情况具有很强的遗传性,并且与牙齿的异常状况相关。 (41. 请参阅我的《驯化下的动物和植物的变化》,第 ii 卷,第 327 页。亚历克斯·勃兰特教授最近向我发送了另外一个案例,其中有一对出生在俄罗斯的父子,具有这些特点。我已从巴黎收到了两者的图纸。)亚历克斯教授。勃兰特告诉我,他将一个三十五岁的男人脸上的头发与胎儿的胎毛进行了比较,发现它们的质地非常相似;因此,正如他所说,该病例可能归因于头发发育停滞及其持续生长。正如儿童医院的一位外科医生向我保证的那样,许多娇弱的孩子的背部都覆盖着相当长的丝状毛发;此类案件可能属于同一类别。

在更文明的人类种族中,后磨牙或智齿似乎趋于发育不全。这些牙齿比其他臼齿小得多,黑猩猩和猩猩的相应牙齿也是如此。它们只有两颗独立的尖牙。它们直到十七岁左右才会切开牙龈,而且我确信它们比其他牙齿更容易腐烂,而且脱落得更早。但这一说法被一些著名牙医否认。与其他牙齿相比,它们在结构和发育时期上更容易发生变化。 (42. Webb 博士,“人类和类人猿的牙齿”,C. Carter Blake 博士在《人类学评论》中引用,1867 年 299 月,第 43 页。) 另一方面,在梅拉尼娅种族中,智慧-牙齿通常具有三个独立的尖牙,并且通常是健全的;它们的臼齿大小也与其他臼齿不同,小于白种人种的臼齿。 (320. Owen,《脊椎动物解剖学》,第三卷,第 321、325 和 44 页。)Schaaffhausen 教授通过“下颌的后牙部分总是缩短”来解释种族之间的差异。 (1868.《论头骨的原始形式》,英译,《人类学评论》,426 年 45 月,第 XNUMX 页),我认为,这种缩短可能习惯性地归因于文明人以软的、煮熟的食物为食,因此较少使用下巴。布雷斯先生告诉我,在美国,去除儿童的一些臼齿已成为一种常见的做法,因为下颌长得不够大,无法完美发育正常数量。 (XNUMX. 蒙特加扎教授从佛罗伦萨给我写信说,他最近一直在研究人类不同种族的最后一颗臼齿,并得出了与我的文本中给出的结论相同的结论,即,在较高等的臼齿中,或文明种族,他们正走在萎缩或消灭的道路上。)

关于消化道,我所看到的只是一个雏形,即盲肠的蠕虫状附属物。盲肠是肠道的一个分支或憩室,终止于死胡同,在许多以植物为食的低等哺乳动物中盲肠非常长。对于有袋考拉来说,它的长度实际上是整个身体的三倍多。 (46. Owen, 'Anatomy of Vertebrates,' vol. iii. pp. 416, 434, 441.) 它有时会形成一个长的逐渐变细的点,有时会部分收缩。看来,由于饮食或习惯的改变,各种动物的盲肠变得大大缩短,蠕虫状附属物被留下作为缩短部分的雏形。我们可以从它的小尺寸以及 Canestrini 教授 (47. 'Annuario della Soc. d. Nat.' Modena, 1867, p. 94.) 收集的关于其变异性的证据中推断出这个附属物是一个雏形。在人身上。有时它完全不存在,或者又在很大程度上得到发展。有时,通道的一半或三分之二长度是完全封闭的,终端部分由扁平的固体扩展部分组成。在红毛猩猩身上,这个附属物又长又复杂:在人类身上,它从短盲肠的末端伸出,通常长四到五英寸,直径只有三分之一英寸左右。它不仅没有用,有时还会导致死亡,最近我听到过两个例子:这是由于小硬体,例如种子,进入通道,引起炎症。 (48. MC Martins(“De l'Unité Organique”,《Revue des Deux Mondes》,15 年 1862 月 16 日,第 278 页)和 Haeckel(“Generelle Morphologie”,B. ii. s. XNUMX)都拥有评论了这种雏形有时会导致死亡的独特事实。)

在一些下肢动物、狐猴科和食肉目动物以及许多有袋动物中,在肱骨下端附近有一个通道,称为髁上孔,前肢的大神经和经常通过该通道大动脉经过。现在,在人类的肱骨中,通常存在该通道的痕迹,该通道有时相当发达,由悬垂的钩状骨突形成,并由韧带完成。斯特拉瑟斯博士 (49. 关于继承,参见斯特拉瑟斯博士在《柳叶刀》,15 年 1873 月 24 日,以及另一篇重要论文,同上。1863 年 83 月 63 日,第 1867 页。诺克斯博士,正如我据了解,他是第一位提请人们注意人类这种特殊结构的解剖学家;请参阅他的“伟大的艺术家和解剖学家”,第 448 页。另请参阅格鲁伯博士在“Bulletin de l”中关于这一过程的重要回忆录Acad. Imp. de St. Petersbourg,' tom. xii. XNUMX, p. XNUMX.)密切关注这个主题,现在已经表明,这种特性有时是遗传的,就像发生在父亲身上的那样,而在他的七个孩子中不少于四个。当存在时,大神经总是穿过它;当存在时,大神经总是穿过它。这清楚地表明它是低等动物髁上孔的同源物和雏形。特纳教授告诉我,他估计这种情况的发生率约为百分之一。最近的骷髅。但是,如果人类这种结构的偶尔发展(看起来很可能)是由于回归,那么它就是回归到事物的非常古老的状态,因为在更高的Quadrumana中它是不存在的。

肱骨上还有另一个孔或穿孔,偶尔存在于男性中,可称为髁间孔。这种情况在各种类人猿和其他猿类中发生,但并非经常发生(50. St. George Mivart 先生,“Transactions Phil. Soc.” 1867,第 310 页),并且在许多低等动物中也同样发生。值得注意的是,这种穿孔似乎在古代比现代更频繁地出现在人类身上。巴斯克先生(51.《论直布罗陀洞穴》,《国际史前考古学大会汇刊》,第三届会议,1869 年,第 159 页。怀曼教授最近展示了(第四次年度报告,皮博迪博物馆,1871 年,第 20 页),这种穿孔存在于美国西部和佛罗里达州古代土丘中的一些人类遗骸中。这种穿孔经常发生在黑人身上。)已收集了以下关于这一点的证据:布罗卡教授“注意到百分之四半的穿孔。巴黎“Cimetière du Sud”收集的臂骨;在奥罗尼石窟中,其中的内容被称为青铜时期,三十二个肱骨中多达八个被穿孔。但他认为,这种非凡的比例可能是由于该洞穴是一种“家庭金库”。杜邦先生再次发现百分之三十。莱斯山谷洞穴中的穿孔骨头,属于驯鹿时期;而勒圭先生在阿让特伊的一个支石墓里观察到了百分之二十五。被穿孔; M. Pruner-Bey 发现了百分之二十六。 Vaureal 的骨头也处于同样的状态。也不应该忽视的是,M. Pruner-Bey 指出这种情况在关彻骨骼中很常见。一个有趣的事实是,在这个例子和其他几个例子中,古代种族比现代人更频繁地呈现出类似于低等动物的结构。一个主要原因似乎是,在漫长的血统谱系中,古代种族与它们遥远的类似动物的祖先有些距离。

在人类中,尾骨以及下文将要描述的某些其他椎骨,虽然没有尾巴的功能,但清楚地代表了其他脊椎动物的这部分。在胚胎早期,它是自由的,并且突出到下肢之外;正如人类胚胎图(图 1)所示。即使在出生后,在某些罕见和异常的情况下,它也是已知的(52。Quatrefages 最近收集了关于这个主题的证据。“Revue des Cours Scientifiques”,1867-1868,第 625 页。1840 年,Fleischmann 展示了一个人类胎儿一条游离的尾巴,但情况并不总是如此,其中包括椎体;这条尾巴受到了埃尔兰根博物学家会议上出席的许多解剖学家的严格检查(见马歇尔在 Niederlandischen Archiv für Zoologie,1871 年 53 月)。形成尾巴的外部雏形。尾骨很短,通常只包括四块椎骨,全部固定在一起:这些都处于初级状态,因为除了基底椎骨之外,它们仅由椎体组成。 (1849. 欧文,《论肢体的本质》,114 年,第 XNUMX 页。)它们具有一些小肌肉;据特纳教授告诉我,其中一项被泰尔明确描述为尾部伸肌的基本重复,尾部伸肌是许多哺乳动物中广泛发育的一种肌肉。

人类的脊髓仅向下延伸至最后一块背椎或第一块腰椎;但线状结构(终丝)沿着椎管骶骨部分的轴线延伸,甚至沿着尾骨的背面延伸。正如特纳教授告诉我的那样,这条细丝的上部无疑与脊髓同源;但下部显然仅由软脑膜或血管覆盖膜组成。即使在这种情况下,尾骨也可以说拥有像脊髓这样重要的结构的遗迹,尽管不再被封闭在骨管内。以下事实,我也感谢特纳教授,它表明了低等动物的尾骨与真正的尾巴是多么接近:卢什卡最近在尾骨的末端发现了一个非常奇特的卷曲体,它是与骶中动脉连续;这一发现促使克劳斯和迈耶检查了猴子(Macacus)和猫的尾巴,他们在这两者中都发现了类似的复杂的身体,尽管不是在末端。

生殖系统提供各种基本结构;但这些案件在一个重要方面与前述案件有所不同。在这里,我们关心的不是不属于有效状态下的物种的部分的遗迹,而是在一种性别中有效的部分,而在另一种性别中则仅以雏形表示。然而,基于每个物种单独创造的信念,这些雏形的出现与前述情况一样难以解释。此后,我将不得不再次讨论这些基础知识,并表明它们的存在通常仅取决于遗传,即一种性别所获得的部分已部分遗传给另一种性别。我在此仅给出此类基础知识的一些实例。众所周知,包括人类在内的所有雄性哺乳动物都存在未发育成熟的乳房。在某些情况下,它们已经发育良好,并且产生了充足的牛奶供应。他们在两性中的基本身份同样可以通过在麻疹发作期间他们的交感神经偶尔增强来表明。在许多雄性哺乳动物中观察到的前列腺囊泡以及相关通道现在被普遍认为是雌性子宫的同源体。如果不承认洛卡特结论的公正性,就不可能阅读洛伊卡特对这个器官的精辟描述和他的推理。对于那些真正的雌性子宫分叉的哺乳动物来说,这一点尤其明显,因为在这些哺乳动物中,囊泡同样分叉。 (54. Leuckart,托德的《解剖学百科全书》1849-52,第 iv 卷,第 1415 页。在人体中,这个器官的长度只有三到六行,但是,像许多其他基本部分一样,它是可变的发育以及其他特征。)这里可能已经列举了属于生殖系统的一些其他基本结构。 (55. 关于这个主题,请参见 Owen,《脊椎动物解剖学》,第三卷,第 675、676、706 页。)

现在给出的三大类事实的意义是明确无误的。 但重述我在《物种起源》中详细给出的论点是完全多余的。如果我们承认同一类成员的整个框架的同源性构造是可以理解的,如果我们承认他们来自一个共同的祖先,以及他们随后对不同条件的适应。 从任何其他观点来看,人或猴子的手、马的脚、海豹的鳍、蝙蝠的翅膀等之间的图案相似性是完全无法解释的。 (56。 教授 比安科尼(Bianconi)在最近出版的一部作品中,用令人钦佩的版画进行了插图(“La Théorie Darwinienne et la création dite indépendante”,1874),努力表明,在上述和其他情况下,同调结构可以用机械原理来充分解释,根据其用途。 没有人能如此出色地展示出这些结构是如何完美地适应其最终目的的。我相信,这种适应可以通过自然选择来解释。 在考虑蝙蝠的翅膀时,他提出了(第 17 页)。 218)在我看来(用奥古斯特·孔德的话来说)纯粹是形而上学的原则,即“保持动物哺乳动物性质的完整性”。他只在少数情况下讨论初级,而且只讨论那些部分初级的部分,例如猪和牛的小蹄子,它们不接触地面;他清楚地表明这些对动物有帮助。 不幸的是,他没有考虑到诸如从未切穿牛下颌的微小牙齿,或雄性四足动物的乳房,或存在于焊接翼盖下的某些甲虫的翅膀,或遗迹等情况。各种花中的雌蕊和雄蕊,以及许多其他这样的情况。 虽然我非常佩服Prof. 比安科尼的作品,但在我看来,现在大多数博物学家所持有的信念似乎没有动摇,即同源结构仅凭适应原理是无法解释的。)断言它们都是按照同一个理想计划形成的,这并不是科学的解释。 关于发育,我们可以清楚地理解,根据胚胎晚期发生变异并在相应时期遗传的原理,形态截然不同的胚胎如何仍然或多或少完美地保留着,它们共同祖先的结构。 对于人类、狗、海豹、蝙蝠、爬行动物等的胚胎最初几乎无法区分的这一奇妙事实,没有其他解释。

因此,我们可以理解人类和所有其他脊椎动物是如何建立在相同的一般模型上的,为什么他们经历相同的早期发展阶段,以及为什么他们保留某些共同的基础。因此,我们应该坦率地承认它们的血统共同体:采取任何其他观点,就等于承认我们自己的结构以及我们周围所有动物的结构只是一个陷阱,旨在诱骗我们的判断。如果我们关注整个动物系列的成员,并考虑从它们的亲缘关系或分类、地理分布和地质演替中得出的证据,这个结论就会得到极大的加强。只是我们天生的偏见,以及让我们的祖先宣称他们是半神的后裔的傲慢,才导致我们对这个结论表示异议。但不久之后,人们会认为,熟悉人类和其他哺乳动物的比较结构和发育的博物学家应该相信每一种动物都是单独的创造行为的产物,这将被认为是美妙的。

第二章 •17,800字
论人从某种低级形态的发展方式

人类身心的变异性——遗传——变异的原因——人类与低等动物相同的变异规律——生活条件的直接作用——部件使用和废弃增加的影响——发展受阻——回归——相关变异——增长速度——增加的检查——自然选择——人类是世界上最主要的动物——其身体结构的重要性——导致其直立的原因——随之而来的结构变化——犬科动物的尺寸减小牙齿——头骨尺寸增大和形状改变——赤身露体——没有尾巴——人类毫无防御能力的状况。

显然,人类现在面临着很大的可变性。同一种族中没有两个人是完全相同的。我们可以比较数以百万计的面孔,每张面孔都是不同的。身体各部分的比例和尺寸也同样存在巨大差异。腿的长度是变化最大的点之一。 (1.《美国士兵的军事和人类学统计调查》,BA Gould,1869 年,第 256 页。)尽管世界上某些地区普遍存在长头骨,而另一些地区则普遍存在短头骨,但即使在同一种族的范围内,形状也存在多样性,例如美国和南澳大利亚的原住民——后者是一个“在血统、习俗和语言上可能与现存的任何种族一样纯正和同质的种族”——甚至与居民像桑威奇群岛这样狭小的区域。 (2. 关于“美国原住民的颅骨形态”,参见 Aitken Meigs 博士,《Proc. Acad. Nat. Sci.》,费城,1868 年 1863 月。关于澳大利亚人,参见 Huxley,载于 Lyell 的《Antiquity of Man》 ”,87 年,第 1868 页。关于三明治岛民,J. Wyman 教授,“对颅骨的观察”,波士顿,18 年,第 1040 页。)一位杰出的牙医向我保证,牙齿的多样性几乎与在特征中。主动脉经常出现异常走行,因此人们发现,从 3 具尸体中计算出每个走行发生的频率对于外科手术来说非常有用。 (1844.《动脉解剖学》,R. Quain 着,前言,第 4 卷,175 年。)肌肉变化很大:因此特纳教授发现了足部的肌肉(189.《英国皇家学会汇刊》爱丁堡,' vol. xxiv. pp. 5, 1867.) 五十个机构中的任何两个都不是严格相似的;在某些情况下,偏差相当大。他补充说,执行适当动作的力量必须根据几个偏差进行修改。 J. Wood 先生记录了(544.《皇家学会学报》,1868 年,第 483 页;还有 524 年,第 1866、229 页。之前有一篇论文,295 年,第 558 页。)6 种肌肉变异的发生在三十六个科目中,以及在另一组相同数量的不少于五百五十八个变化中,发生在身体两侧的变化仅算作一个。在最后一组中,三十六具尸体中没有一具被发现“完全不符合解剖教科书上对肌肉系统的标准描述”。一具尸体呈现出数量惊人的二十五种不同的异常现象。同一块肌肉有时会在很多方面发生变化:因此,麦卡利斯特教授描述了(1868.“Proc.R.爱尔兰学院”,第 x.141 卷,第 XNUMX 页)掌侧附件肌的不少于 XNUMX 种不同的变化。

著名的老解剖学家沃尔夫 (7. 'Act. Acad. St. Petersburg,' 1778, Part ii. p. 217.) 坚持认为内部脏器比外部部分更具变化性:Nulla particula est quae non aliter et aliter in aliis se habeat hominibus。他甚至还写了一篇关于选择内脏典型例子来表示的论文。讨论肝、肺、肾等的完美状态,以及人脸的神圣性,听起来很奇怪。

同一种族的人的智力的变异性或多样性,更不用说不同种族的人之间的巨大差异,是众所周知的,以至于无需在此多说。低等动物也是如此。所有负责动物园的人都承认这一事实,我们在我们的狗和其他家畜身上清楚地看到了这一点。布雷姆特别坚持认为,他在非洲驯养的每只猴子都有自己独特的性情和脾气:他提到了一只狒狒以其高智商而闻名;动物园的管理员给我指了一只猴子,属于新世界区,同样聪明。伦格尔还坚持认为,他在巴拉圭饲养的同一物种的猴子在各种心理特征上存在多样性。他补充说,这种多样性部分是与生俱来的,部分是他们所受到的对待或教育方式的结果。 (8. Brehm,“Thierleben”,B. i. ss. 58, 87。Rengger,“Säugethiere von Paraguay”,第 57 节。)

我在其他地方(9.“驯化下的动物和植物的变异”,第二卷第十二章)如此充分地讨论了继承的主题,因此我在这里几乎不需要添加任何内容。关于人类最微不足道以及最重要的特征的遗传,我们收集到的事实比任何低等动物都要多。尽管关于后者的事实已经足够充分了。因此,就心理品质而言,它们的传播体现在我们的狗、马和其他家畜身上。除了特殊的品味和习惯外,一般的智力、勇气、坏脾气和好脾气等也肯定会遗传。对于人类来说,我们几乎在每个家庭中都能看到类似的事实。我们现在知道,通过高尔顿先生令人钦佩的努力(10.《遗传天才:对其法则和后果的探究》,1869),天才往往是遗传的,它意味着一种奇妙而复杂的高级才能的组合。另一方面,可以肯定的是,精神错乱和智力衰退同样会在家庭中遗传。

对于变异的原因,我们在所有情况下都非常无知;但我们可以看到,人类和低等动物一样,它们与每个物种几代人所经历的条件存在某种关系。 驯养的动物比自然状态下的动物差异更大。这显然是由于他们所经历的条件的多样性和不断变化的性质造成的。 在这方面,不同种族的人类就像驯养的动物,同一种族的个体在居住在像美国这样广阔的地区时也是如此。 我们在更文明的国家中看到了多样化条件的影响;因为属于不同等级、从事不同职业的成员比野蛮民族的成员表现出更广泛的性格。 但野蛮人的统一性常常被夸大,在某些情况下甚至很难说存在。 (11。 先生。 贝茨评论(《亚马逊的博物​​学家》,1863 年,第 XNUMX 卷) 二页 159),对于同一个南美部落的印第安人来说,“他们中没有两个人的头部形状完全相似;一个人有一张椭圆形的脸,五官精致,另一个人的脸颊宽阔、突出、鼻孔张开、眼睛倾斜,这完全是蒙古人的特征。”)然而,谈论人是一个错误,即使我们只看他所面临的条件,“更加驯化”(12. 布卢门巴赫,《人类学论文》。工程师。 译,1865 年,第 XNUMX 页。 205.) 比任何其他动物都要多。 一些野蛮种族,例如澳大利亚人,所面临的环境并不比许多具有广泛范围的物种更加多样化。 在另一个更重要的方面,人类与任何严格驯养的动物都有很大不同。因为它的繁殖从未长期受到有条不紊或无意识选择的控制。 没有任何一个种族或群体被其他人如此彻底地征服,以至于某些个体应该被保留下来,从而在不知不觉中被选择,以某种方式为他们的主人提供卓越的效用。 除了众所周知的普鲁士掷弹兵的例子外,也没有故意挑选和匹配某些男性和女性个体。在这种情况下,正如人们所预料的那样,人类遵守了有条不紊的选择法则。因为据说,掷弹兵及其高个子妻子居住的村庄里养育了许多高个子男人。 在斯巴达,也遵循了一种选择形式,因为规定所有儿童在出生后不久都应接受检查;那些结构良好、充满活力的被保存下来,其他的则被消灭。 (13。 米特福德的《希腊史》,卷。 i. p. 282. 它也出现在色诺芬的《大事记》中的一段话中,B. II。 4(牧师引起了我的注意。 JN 霍尔),这是希腊人公认的原则,即男人应该根据孩子的健康和活力来选择妻子。 生活在公元前 550 年的希腊诗人泰奥格尼斯 (Theognis) 清楚地看到,如果仔细应用选择,对于人类的进步将有多么重要。 同样,他发现财富常常会制约性选择的正确行为。

“有牛和马,库努斯!我们继续
通过合理的规则,选择一个品种
为了利润和增长,不惜任何代价:
原料完好,无缺陷或缺陷。
但是,在我们日常的比赛中,
价格就是一切:为了钱,
男人结婚:女人在婚姻中被赋予
粗鲁或恶棍,在财富中蓬勃发展,
可能会将他的后代与最骄傲的种族相匹配:
因此,一切都是混合的,高贵的和卑鄙的!
如果在外在的态度、形式和心灵上,
你发现我们是一种堕落的、杂七杂八的人,
不要再好奇了,我的朋友!原因很简单,
哀叹其后果是徒劳的。”

(J. Hookham Frere 的著作,第二卷,1872 年,第 334 页。))

如果我们把人类的所有种族视为一个单一的物种,那么他的范围是巨大的;但一些不同的种族,如美洲人和波利尼西亚人,其分布范围非常广泛。众所周知,分布广泛的物种比分布范围有限的物种变化更大。人类的变异性与分布广泛的物种相比,比与家养动物的变异性进行比较更为真实。

人类和低等动物的变异似乎不仅是由相同的一般原因引起的,而且身体的相同部位也以非常相似的方式受到影响。 Godron 和 Quatrefages 已经非常详细地证明了这一点,因此我在这里只需参考他们的著作即可。 (14. Godron,“De l'Espèce”,1859 年,tom.ii.livre 3. Quatrefages,“Unité de l'Espèce Humaine”,1861 年。还有人类学讲座,发表于“Revue des Cours Scientifiques”,1866 年-1868.) 怪物在人类和低等动物中同样如此相似,它们会逐渐产生细微的变化,以至于相同的分类和相同的术语可以用于两者,正如伊西多尔·杰弗里·圣伊莱尔所表明的那样。 (15.《Hist. Gen. et Part. des Anomalies de l'Organise》,三卷,Tom. i. 1832。)在我关于家畜变异的著作中,我试图以粗鲁的方式安排变异法则在以下几个方面:——变化条件的直接而明确的作用,如同一物种的所有或几乎所有个体所表现出的,在相同的情况下以相同的方式变化。长期持续使用或不使用零件的影响。同源部分的内聚力。多个部分的可变性。成长补偿;但我在人类身上没有找到关于这条法则的好例子。一个零件的机械压力对另一零件的影响;就像子宫里婴儿的骨盆和头盖骨一样。发展受阻,导致零部件减少或受到抑制。通过回归,消失已久的人物重新出现。最后,相关变异。所有这些所谓的法则同样适用于人类和低等动物。其中大多数甚至对植物。在这里讨论所有这些都是多余的(16。我在我的“驯化下的动物和植物的变异”中充分讨论了这些定律,第 ii 卷,第 xxii 章和第 xxiii 章。MJP Durand 最近(1868 年)发表了一篇有价值的文章,“De l'Influence des Milieux”等。就植物而言,他非常强调土壤的性质。);但其中有几个是如此重要,以至于必须用相当长的篇幅来讨论。

条件变化的直接而确定的作用

这是一个最令人困惑的话题。不可否认,条件的改变会对各种生物体产生一些影响,有时甚至是相当大的影响。乍一看,如果有足够的时间,这很可能是必然的结果。但我未能获得支持这一结论的明确证据;另一方面,至少就无数为特殊目的而调整的结构而言,可以提出合理的理由。然而,毫无疑问,变化的条件会引起几乎无限量的波动变化,从而使整个组织在某种程度上具有可塑性。

在美国,对在战争后期服役的超过 1,000,000 名士兵进行了测量,并记录了他们出生和长大的国家。 (17.“军事和人类统计调查”等,1869 年,BA Gould 着,第 93、107、126、131、134 页。)从这些数量惊人的观察结果可以证明,某种地方影响直接作用于身材;我们进一步了解到,“身体在很大程度上发生发育的状态,以及表明血统的出生状态,似乎对身材产生了显着的影响。”例如,可以确定的是,“居住在西方国家,在成长的岁月里,往往会导致身材的增长”。另一方面,可以肯定的是,对于水手来说,他们的生命会延迟成长,正如“十七岁和十八岁时士兵和水手的身材差异巨大”所表明的那样。 BA 古尔德先生致力于查明影响身材的性质。但他只得到了负面结果,即它们与气候、土地海拔、土壤无关,甚至与生活的丰富性或舒适性需求也“没有任何控制程度”。后一个结论与维莱尔姆根据法国不同地区应征入伍者身高的统计得出的结论直接相反。当我们比较同一岛屿内的波利尼西亚酋长和低等人之间的身材差异时,或者同一海洋中肥沃的火山岛和低贫瘠的珊瑚岛的居民之间的身材差异时(18。对于波利尼西亚人,请参阅普里查德的《自然历史》 Mankind,” vol. v. 1847,第 145, 283 页。还有 Godron,“De l'Espèce”,tom. ii. p. 289。居住在上层的密切盟友的印度人之间在外表上也存在显着差异。恒河和孟加拉;见埃尔芬斯通的《印度历史》,第 324 卷。)或者在他们国家东海岸和西海岸的火地岛人之间,那里的生存手段非常不同,几乎不可能避免这样的结论更好的食物和更大的舒适度确实会影响身高。但前面的陈述表明,要得出任何精确的结果是多么困难。贝多博士最近证明,对于英国居民来说,居住在城镇和某些职业对身高的影响越来越大。他推断,这种结果在一定程度上是遗传的,美国也是如此。贝多博士进一步认为,只要“一个种族的身体发展达到最大程度,它的能量和道德活力就会达到最高水平”。 (19.《人类学协会回忆录》,第三卷,1867-69,第 561、565、567 页。)

外部条件是否会对人类产生任何其他直接影响尚不清楚。人们可能认为气候的差异会产生显着的影响,因为肺和肾在低温下活动,而肝脏和皮肤在高温下活动。 (20. Brakenridge 博士,《素质理论》,《医学时报》,19 年 17 月 1869 日和 XNUMX 月 XNUMX 日。)以前人们认为皮肤的颜色和头发的特性是由光或热决定的;然而,现在人们认为皮肤的颜色和头发的特性是由光或热决定的。虽然很难否认这样会产生一些影响,但几乎所有观察者现在都同意,即使在暴露了许多年之后,这种影响仍然非常小。但当我们讨论人类的不同种族时,这个问题的讨论会更恰当。对于我们家畜来说,有理由相信寒冷和潮湿会直接影响毛发的生长。但就人类而言,我还没有找到任何关于这一点的证据。

零件使用和废弃增加的影响

众所周知,使用可以增强个人的肌肉,而完全不使用或破坏适当的神经会削弱肌肉。当眼睛被破坏时,视神经通常会萎缩。当动脉被结扎时,侧通道不仅直径增加,而且其涂层的厚度和强度也增加。当一个肾脏因疾病而停止活动时,另一个肾脏就会变大,并承担双重工作。由于承受更大的重量,骨骼不仅厚度增加,而且长度也增加。 (21. 我在《驯化下的动物和植物的变异》,第 ii 卷,第 297-300 页中为这几项陈述提供了权威。Jaeger 博士,“Über das Langenwachsthum der Knochen”,“Jenäischen Zeitschrift”, B. v. 体重 i.) 习惯上从事的不同职业会导致身体各部分的比例发生变化。因此,美国委员会确定(22.“调查”等,BA Gould,1869 年,第 288 页),战争后期雇用的水手的腿比其他人长了 0.217 英寸。士兵中,虽然水手平均身材矮小;而他们的手臂则短了 1.09 英寸,因此,与身高相比,手臂更短,不成比例。手臂的这种短短显然是由于它们的使用量更大,并且是一个意想不到的结果:但水手们主要使用手臂来拉动,而不是支撑重量。与士兵相比,水手的颈围和脚背的深度更大,而胸围、腰围和臀围则更小。

如果许多代人都遵循相同的生活习惯,上述几种改变是否会遗传,目前尚不清楚,但这是有可能的。 Rengger (23. 'Säugethiere von Paraguay,' 1830, s. 4.) 将帕亚瓜斯印第安人的细腿和粗臂归因于连续几代人,他们几乎一生都在独木舟中度过,他们的下肢一动不动。其他作者在类似案例中也得出了类似的结论。根据与爱斯基摩人一起生活了很长时间的克兰兹(24.《格陵兰岛历史》,英译,1767 年,第 230 卷)的说法,“当地人相信捕捉海豹的聪明才智和灵巧(他们的捕猎能力)最高的艺术和美德)是世袭的;这其中确实有一些东西,因为一位著名的海豹捕手的儿子将脱颖而出,尽管他在童年时失去了父亲。”但在这种情况下,精神能力和身体结构似乎都是遗传的。有人断言,英国劳工的双手天生就比贵族的双手大。 (25.“通婚”,Alex. Walker,1838 年,第 377 页。)从至少在某些情况下存在的相关性来看(26.“驯化下动物的变异”,第 173 卷),由于四肢和下颌的发育,在那些手脚不怎么劳作的阶级中,下颌的尺寸可能会因此而减小。可以肯定的是,文雅而文明的人的体型通常比勤劳的人或野蛮人的体型要小。但对于野蛮人来说,正如赫伯特·斯宾塞先生(27.《生物学原理》,第 455 卷)所说,更多地使用下巴来咀嚼粗糙的、未煮熟的食物,会直接作用于咀嚼肌,以及它们所附着的骨骼上。对于婴儿来说,早在出生之前,脚底的皮肤就比身体其他部位的皮肤厚。 (28. Paget,《外科病理学讲座》,第二卷,1853 年,第 209 页。)毫无疑问,这是由于几代人中压力的遗传效应所致。

众所周知,钟表匠和雕刻师容易近视,而经常生活在户外的人,尤其是野蛮人,通常都是远视的。 (29. 这是一个奇怪且出乎意料的事实,水手在清晰视力的平均距离方面不如陆地人。BA Gould 博士(《叛乱战争卫生回忆录》,1869 年,第 530 页)证明了这一点事实确实如此;他通过水手的普通视力范围“受限于船只的长度和桅杆的高度”来解释这一点。)近视和远视当然倾向于遗传。 (30.《驯养动物的变异》,第 8 卷。)与野蛮人相比,欧洲人在视力和其他感官上的劣势无疑是许多代人减少使用的累积和传播的结果; Rengger 的著作(31.“Säugethiere von Paraguay”,第 8、10 节。我有很好的机会观察火地岛人非凡的视力。另请参见 Lawrence(“生理学讲座”等,1822 年,第 404 页)。 1870)关于同一主题。M. Giraud-Teulon 最近收集了(“Revue des Cours Scientifiques”,625 年,第 32 页)大量有价值的证据,证明近视的原因“C'est le travail assidu, de près”)指出,他多次观察欧洲人,他们是与野生印第安人一起长大并度过一生的,但他们的感官敏锐程度却无法与他们相比。这位博物学家还观察到,美洲原住民的头骨中用于接收多种感觉器官的空腔比欧洲人的要大。这可能表明器官本身的尺寸存在相应的差异。布卢门巴赫还评论了美国原住民头骨中鼻腔的巨大尺寸,并将这一事实与他们异常敏锐的嗅觉联系起来。根据帕拉斯的说法,北亚平原的蒙古人拥有极其完美的感官。普里查德认为,他们的头骨横跨颧骨的宽度源于他们高度发达的感觉器官。 (1851. Prichard,《人类物理史》,根据 Blumenbach 的权威,第 311 卷,1844 年,第 407 页;Pallas 的陈述,第 XNUMX 卷,XNUMX 年,第 XNUMX 页。)

克丘亚印第安人居住在秘鲁的高原上。阿尔西德·多比尼 (Alcide d'Orbigny) 指出(33. 普里查德引述,“人类物理史研究”,第 463 卷),通过不断呼吸高度稀薄的大气,他们获得了非凡尺寸的胸部和肺部。而且,肺细胞比欧洲人更大、数量更多。这些观察结果受到质疑,但 D.福布斯先生仔细测量了许多生活在 10,000 至 15,000 英尺高度的艾马拉人,这是一个同盟种族;他告诉我(34.福布斯先生的宝贵论文现在发表在《伦敦民族学学会杂志》,新系列,第 ii 卷,1870 年,第 193 页。)他们与他所看到的所有其他种族的身体周长和长度。在他的测量表中,每个人的身高都是1000,其他测量值都减少到这个标准。从这里可以看出,艾马拉人伸出的手臂比欧洲人的手臂短,比黑人的手臂短得多。腿也同样较短;他们呈现出一个显着的特点,即在每一个艾马拉测量中,股骨实际上都比胫骨短。平均而言,股骨与胫骨的长度为211比252;而在两个欧洲人中,同时测量,股骨与胫骨的比值为 244 比 230;三个黑人的比例为 258 至 241。同样,肱骨相对于前臂较短。正如福布斯先生向我建议的那样,肢体最接近身体的部分的缩短似乎是与躯干长度大大增加有关的补偿情况。艾马拉人还存在其他一些结构奇点,例如脚跟的非常小的突出部分。

这些人已经完全适应了寒冷而高大的住所,以前被西班牙人带到东部低平原,现在又受到高工资的诱惑而去洗金,他们的死亡率高得惊人。尽管如此,福布斯先生还是发现了一些延续了两代的纯正家族:他观察到他们仍然继承了自己的特色。但很明显,即使没有测量,这些特性都已减弱。经过测量,发现他们的身体没有高原上的男人那么长。同时他们的股骨和胫骨也有所延长,尽管程度较小。实际的测量可以通过查阅福布斯先生的回忆录来了解。从这些观察来看,我认为,毫无疑问,在高海拔地区居住了许多代,往往会直接或间接地引起身体比例的遗传性改变。 (35. Wilckens 博士(《Landwirthschaft. Wochenblatt》,第 10 期,1869 年)最近发表了一篇有趣的文章,展示了生活在山区的家畜如何改变其框架。)

尽管人在其存在的后期阶段可能并没有通过增加或减少零件的使用而发生太大的改变,但现在给出的事实表明,他在这方面的责任并没有消失;我们确实知道同样的法则也适用于低等动物。因此,我们可以推断,当人类的祖先在遥远的时代处于过渡状态,从四足动物转变为两足动物时,不同部位的使用增加或减少所产生的遗传效应可能会极大地帮助自然选择身体的。

发展受阻

发育停滞和生长停滞之间存在差异,因为前一种状态的部分会继续生长,同时仍保留其早期状态。各种各样的怪物都属于这个范畴。有些,如腭裂,已知偶尔会遗传。正如沃格特的回忆录中所描述的那样,提及小头白痴的大脑发育停滞就足以满足我们的目的。 (36.《Mémoire sur les Microcephales》,1867 年,第 50, 125, 169, 171, 184-198 页。) 他们的头骨更小,大脑的回旋也不像正常人那么复杂。额窦(即眉毛上的突出部分)非常发达,下颌前突到“令人恼火”的程度;所以这些白痴有点像低等人类。他们的智力,以及他们的大部分心智能力,都极其微弱。他们无法获得言语的力量,完全无法长时间集中注意力,而是非常容易模仿。它们很强壮,而且非常活跃,不断地嬉戏、跳跃、做鬼脸。他们经常用四肢爬楼梯;并且非常喜欢爬家具或树。这让我们想起了几乎所有男孩在爬树时所表现出的快乐;这再次提醒我们,最初是高山动物的羔羊和小山羊多么喜欢在任何小山丘上嬉戏,无论山丘多么小。白痴在其他方面也与低等动物相似。因此,有几起案例记录了他们在吃每一口食物之前都会仔细闻一闻。据描述,有一个白痴在寻找虱子时经常用嘴来帮助双手。他们的习惯常常肮脏,没有正派观念;已经发表了几起他们身上长满毛的案例。 (37. 雷科克教授通过称他们为“theroid”来总结像野兽一样的白痴的特征;《心理科学杂志》,1863 年 2 月。斯科特博士(《聋哑人》,第 1870 版,10 年,第 1870 页) 46)经常观察到低能者闻食物的味道。参见,关于同一主题,以及白痴的毛茸茸的问题,Maudsley 博士,“身体与思想”,51 年,第 XNUMX-XNUMX 页。皮内尔还给出了一个引人注目的案例白痴身上的毛茸茸的。)

反转

这里给出的许多案例可能是在最后一个标题下介绍的。当一个结构在其发展过程中受到抑制,但仍然继续生长,直到它与同一群体中某些较低级和成年成员的相应结构非常相似时,它在某种意义上可以被视为一种回归情况。群体中的较低成员让我们了解共同祖先可能是如何构建的。令人难以置信的是,一个复杂的部分在胚胎发育的早期阶段被阻止,应该继续生长以最终发挥其应有的功能,除非它在某些较早的存在状态中获得了这种能力,当当前的特殊或阻滞结构正常。一个小头白痴的简单大脑,就其与猿猴的相似之处而言,可以说在这个意义上提供了一个回归的例子。 (38. 在我的《驯养动物的变异》(第 ii 卷,第 57 页)中,我将女性中并非非常罕见的多生乳房的情况归因于回归。我得出了这一可能的结论,因为附加的乳房通常对称地放置在乳房上;更特别的是,在一个案例中,一个有效的乳房出现在一名妇女的腹股沟区域,该妇女是另一位拥有多余乳房的妇女的女儿。但我现在发现(例如,参见, Preyer 教授,“Der Kampf um das Dasein”,1869 年,第 45 节)指出,mammae erraticae 也发生在其他情况下,如背部、腋窝和大腿;在后一种情况下,mammae 给出了这样的结果孩子因此得到了很多乳汁。因此,额外的乳房是由于回复而产生的可能性大大减弱了;尽管如此,在我看来,这仍然是可能的,因为经常在乳房上发现两对对称的乳房;对此,我自己也有在一些案例中收到的信息。众所周知,一些狐猴的乳房上通常有两对乳房。已记录的五个案例表明,人类男性中存在超过一对乳房(当然是初级的);参见《阿纳特杂志》。和生理学,1872 年,p。 56,汉迪赛德博士给出的一个案例,其中两个兄弟表现出了这种特殊性;另请参见 Bartels 博士的一篇论文,载于“Reichert's and du Bois-Reymond's Archive.”,1872 年,第 304 页。 XNUMX. 在 Bartels 博士提到的一个案例中,一名男子生有五个乳房,一个位于内侧,位于肚脐上方;另一个位于内侧,位于肚脐上方;另一个位于内侧,位于肚脐上方。梅克尔·冯·赫姆斯巴赫 (Meckel von Hemsbach) 认为后一种情况可以通过某些翅目动物中出现的内侧乳房来说明。总的来说,我们很可能怀疑,如果人类的早期祖先没有多于一对的话,人类的两性是否会发育出更多的乳房。

在上述工作(第 ii 卷第 12 页)中,我也将人类和各种动物中常见的多指症归咎于回归,尽管我很犹豫。欧文教授的说法部分引导我得出这一结论,即一些鱼翅目拥有超过五趾的手指,因此,正如我所认为的,保留了原始状态;但 Gegenbaur 教授(“Jenaischen Zeitschrift”,B. v. Heft 3,第 341 节)对欧文的结论提出异议。另一方面,根据冈瑟博士最近提出的观点,在角鼻属的桨上,中央骨链的两侧都设有铰接的骨射线,似乎不难承认有六个或更多一侧或两侧的数字可能会通过恢复而重新出现。 Zouteveen 博士告诉我,有一个记录在案的男子有二十四个手指和二十四个脚趾!我主要得出这样的结论:多余数字的存在可能是由于这样的事实的回归:这些数字不仅具有很强的遗传性,而且正如我当时所相信的那样,与正常的数字一样,在截肢后具有再生的能力属于低等脊椎动物。但我在《驯化下的变异》第二版中解释了为什么我现在很少依赖这种再生的记录案例。尽管如此,它仍然值得关注,因为发展停滞和回归是密切相关的过程。胚胎或停滞状态下的各种结构,如腭裂、双歧子宫等,经常伴有多指畸形。 Meckel 和 Isidore Geoffroy St.-Hilaire 强烈主张这一点。但目前最安全的做法是完全放弃这样的想法,即多余数字的发展与人类某些低级组织祖先的回归之间存在任何关系。)还有其他情况更严格地属于我们目前的回归范畴。 。某些结构经常出现在人类所属群体的低等成员中,但偶尔也会出现在人类身上,尽管在正常人类胚胎中没有发现。或者,如果正常存在于人类胚胎中,它们就会发育异常,尽管其发育方式在该群体的低等成员中是正常的。下面的插图将使这些评论变得更加清楚。

在各种哺乳动物中,子宫从有两个不同孔口和两个通道的双器官(如有袋动物)发展为单一器官,除了具有轻微的内部褶皱(如高等猿和人)之外,该器官绝不是双重的。啮齿动物在这两种极端状态之间表现出一系列完美的渐变。所有哺乳动物的子宫都是由两个简单的原始管发育而来,其下部形成角;用法雷博士的话来说,“人体的子宫体是通过两个角在其下端的结合而形成的;通过两个角在其下端的结合,子宫的主体形成了。”而在那些不存在中间部分或身体的动物中,角仍然不连在一起。随着子宫发育的进行,两个角逐渐变短,直到最终消失,或者可以说,被吸收到子宫体中。”即使在像低等猿类和狐猴这样等级较高的动物中,子宫的角度仍然会形成角。

现在,在女性中,异常情况并不少见,其中成熟的子宫具有角,或部分分为两个器官;欧文认为,这种情况重复了某些啮齿动物所达到的“集中发展的程度”。在这里,也许我们有一个简单的胚胎发育停滞的例子,随后生长和完美的功能发育;因为部分双子宫的任一侧都能够进行正常的妊娠。在其他更罕见的情况下,会形成两个不同的子宫腔,每个子宫腔都有其适当的孔口和通道。 (39. 参见 A. Farre 博士在《解剖学和生理学百科全书》中的著名文章,第 1859 卷,第 642 页。欧文,《脊椎动物解剖学》,第 1868 卷,687 年,第 1865 页.特纳教授,发表于《爱丁堡医学杂志》,XNUMX 年 XNUMX 月。)在胚胎的正常发育过程中不会经历这样的阶段。尽管也许并非不可能,但很难相信这两个简单、微小、原始的管子应该知道如何(如果可以使用这样的表达)长成两个不同的子宫,每个子宫都有一个结构良好的孔口和通道,如果它们以前没有像现有的有袋动物那样经历过类似的发育过程,那么它们都具有大量的肌肉、神经、腺体和血管。没有人会认为,像女性异常双子宫这样完美的结构可能只是偶然的结果。但是,即使在经过了很长一段时间之后,回归原理(即一种长期消失的结构被恢复存在)也可以作为其全面发展的指南。

卡内斯特里尼教授在讨论了上述情况和各种类似案例后,得出了与刚才给出的结论相同的结论。他还举了另一个例子,即颧骨的情况(40.“Annuario della Soc. dei Naturalisti”,摩德纳,1867 年,第 83 页。Canestrini 教授给出了来自不同权威人士关于该主题的摘录。Laurillard 评论说,正如他所指出的那样,他发现几个人类受试者和某些猿类的两块颧骨的形状、比例和连接完全相似,他不能认为这些部件的这种布置只是偶然的。关于同一异常现象的另一篇论文已由博士发表萨维奥蒂在 1871 年都灵的《Gazzetta delle Cliniche》中说,在大约百分之二的成人头骨中可以检测到分裂的痕迹;他还指出,这种情况更常见于前颌头骨,而不是下颌骨。雅利安人种,而不是其他人种。另见 G. Delorenzi 关于同一主题的内容;“Tre nuovi casi d'anomalia dell' osso malare”,都灵,1872 年。此外,E. Morselli,“Sopra una rara anomalia dell”osso malare,摩德纳,1872 年。最近,格鲁伯写了一本关于这块骨头的划分的小册子。我提供这些参考文献是因为审稿人毫无根据或毫无顾忌地对我的陈述提出了质疑。),在某些四足兽和其他哺乳动物中,通常由两部分组成。这是人类胎儿两个月大时的情况;由于发育受阻,它有时会在成年后保留在人类身上,尤其是在下颌前突的种族中。因此卡内斯特里尼得出结论,某些古代人类祖先一定将这块骨头通常分为两部分,然后融合在一起。人类的额骨由单块组成,但在胚胎、儿童以及几乎所有低等哺乳动物中,额骨由两块组成,并由明显的缝合线隔开。这种缝合有时或多或少地在成年后的人身上明显地持续存在。古代的颅骨比近代的颅骨更常见,特别是,正如卡内斯特里尼所观察到的,在从漂流中挖掘出来的颅骨中,属于短头颅类型。在这里,他再次得出了与颧骨类似情况相同的结论。在这个例子以及即将给出的其他例子中,古代种族在某些特征上比现代种族更频繁地接近低等动物的原因似乎是,后者在长的血统中处于稍远的距离。来自他们早期的半人类祖先。

不同的作者已经提出了人类的各种其他异常现象,或多或少与前述相似,作为回归的例子。但这些似乎并没有什么值得怀疑的,因为在我们发现通常存在的这种结构之前,我们必须在哺乳动物系列中下降到极低的水平。 (41. Isidore Geoffroy St.-Hilaire 给出了一系列案例,“Hist. des Anomalies”,tom, iii, p. 437。审稿人(“Journal of Anatomy and Physiology”,1871 年,第 366 页)他责怪我没有讨论大量已记录的发育过程中各个部位受阻的案例。他说,根据我的理论,“一个器官在其发育过程中的每一个短暂状态不仅仅是一种手段”在我看来,这并不一定成立。为什么在发展的早期阶段不应该发生变化,与回归无关;然而,这种变化可能会被保留和积累,如果以任何方式有用,例如,在缩短和简化发育过程方面?再说一遍,为什么不应该在早期发生有害的异常,例如与以前的存在状态无关的萎缩或肥大的部分?期间,以及成熟期间?)

对于人类来说,犬齿是非常有效的咀嚼工具。但正如欧文(Owen)(42.《脊椎动物解剖学》,第 1868 卷,323 年,第 43 页)所说,它们真正的犬科特征是“由圆锥形的冠所表明,其终止于钝点,呈凸形”向外且内部平坦或近凹,在其表面的底部有微弱的突出部。圆锥形在梅拉尼亚人种中得到了最好的体现,尤其是澳大利亚人种。犬齿植入得更深,而且比门牙更坚固。”然而,这颗牙齿不再是人类撕碎敌人或猎物的特殊武器;而是人类的牙齿。因此,就其适当功能而言,它可以被认为是初级的。正如海克尔(Haeckel)(1866.“Generelle Morphologie”,44,B. ii. s. clv.)所观察到的那样,在每一个大型人类头骨收藏中都可能发现一些犬齿,其犬齿以与其他犬齿相同的方式突出得多。拟人猿,但程度较轻。在这些情况下,一侧下颌的牙齿之间留有开放空间,用于容纳另一侧下颌的犬齿。瓦格纳描绘的卡菲尔头骨中的这种间隙出奇地宽。 (1864. Carl Vogt 的《人类讲座》,英译,151 年,第 45 页。)考虑到与现代头骨相比,已检查过的古代头骨有多么少,一个有趣的事实是,至少在三个犬齿突出的情况下;在诺莱特下巴中,它们被认为是巨大的。 (1867. C. Carter Blake,论 La Naulette 的下巴,《人类学评论》,295 年,第 1868 页。Schaaffhausen,同上,426 年,第 XNUMX 页。)

在拟人猿中,只有雄性的犬齿发育完全。但在雌性大猩猩中,以及在较小程度上在雌性红毛猩猩中,这些牙齿明显超出其他牙齿。因此,我确信,女性有时有相当突出的犬齿,这一事实并不严重反对这样一种信念,即她们在男性中偶尔的巨大发展是回归到类人猿祖先的情况。如果有人轻蔑地拒绝相信自己的犬齿的形状以及其他人偶尔出现的犬齿的巨大发育是由于我们的早期祖先拥有这些强大的武器,那么他很可能会通过嘲笑来揭示他的血统。 。因为虽然他不再打算也没有能力使用这些牙齿作为武器,但他会无意识地缩回他的“咆哮肌肉”(C.贝尔爵士如此命名)(46.表达解剖学,1844年,第110页) ,131.),以便暴露他们准备采取行动,就像狗准备战斗一样。

人类偶尔会发育出许多肌肉,这是四足动物或其他哺乳动物所特有的。 Vlacovich 教授(47 岁。引自 Canestrini 教授在《Annuario della Soc. dei Naturalisti》,1867 年,第 90 页。)检查了 XNUMX 名男性受试者,并在其中 XNUMX 名受试者身上发现了一块他称之为坐骨耻骨的肌肉。 ;另外三个有一条韧带代表这块肌肉;而在剩下的十八个中却没有任何踪迹。在三十名女性受试者中,只有两人两侧都有这种肌肉,但在其他三名女性受试者中,存在原始韧带。因此,这种肌肉在男性中比在女性中更为常见。相信人是从某种低等形式起源的,这一事实是可以理解的。因为它已在几种低等动物中被发现,并且在所有这些动物中,它专门用于帮助雄性进行繁殖行为。

先生。 J. 伍德在他的一系列有价值的论文中(48. 这些论文值得任何想要了解我们的肌肉变化频率以及变化与四足人肌肉相似程度的人仔细研究。 以下参考文献与我的文本中提到的几点有关:“Proc。 皇家社会。卷。 十四。 1865页。 379-384;卷。 十五 1866页。 241、242;卷。 十五 1867。 544;卷。 xvi。 1868。 524. 我可以在这里补充一点,博士。 穆里和先生。 圣 乔治·米瓦特 (George Mivart) 在其关于 Lemuroidea 的回忆录中展示了这一点(“交易,动物学会”,卷 1)。 vii. 1869。 96),这些动物(灵长类动物中最低等的成员)的某些肌肉变化有多大。 此外,在等级较低的动物中发现的肌肉结构的等级在狐猴总科中也有很多。)详细描述了人类的大量肌肉变化,这些变化类似于低等动物的正常结构。 这些肌肉与我们最近的盟友——四方人——中经常出现的肌肉非常相似,但数量太多,甚至无法在这里详细说明。 在一名具有强壮的身体框架和形状良好的头骨的男性受试者中,观察到至少七种肌肉变异,所有这些都清楚地代表了各种猿类特有的肌肉。 例如,这个人的脖子两侧有一个真正而强大的“锁骨提肌”,就像在所有种类的猿类中都发现的那样,据说大约每六十个人类受试者中就有一个出现这种情况。 (49。 另请参见Prof. 麦卡利斯特在《爱尔兰皇家学院议事录》,卷。 x. 1868。 124.) 同样,这个人有“第五指跖骨的特殊外展肌,例如赫胥黎教授和先生。 花已被证明在高等和低等猿类中均存在。”我只给出另外两个案例;肩峰基底肌存在于人类以下的所有哺乳动物中,并且似乎与四足步态相关(50. 先生。 钱普尼斯在《解剖学和生理学杂志》上,十一月。 1871。 178.),大约六十个人类受试者中就有一个发生这种情况。 在下肢先生。 布拉德利 (51. 同上。 1872 年 XNUMX 月,第 XNUMX 页。 421.)在人的双脚中发现了跖骨外展肌;迄今为止,人类还没有记录到这种肌肉,但拟人猿中一直存在这种肌肉。 手和手臂的肌肉——人类最显着的特征部分——极易发生变化,以类似于低等动物的相应肌肉。 (52。 教授 麦卡利斯特(同上。 p. 121)将他的观察结果制成表格,发现肌肉异常最常见于前臂,其次是面部,第三是足部等。)这种相似性要么是完美的,要么是不完美的;但在后一种情况下,它们显然具有过渡性。 某些变异在男性中更为常见,而另一些变异在女性中更为常见,但我们无法找出任何原因。 先生。 伍德在描述了无数的变化之后,发表了以下意味深长的言论。 “与普通类型的肌肉结构明显不同的是,它们在凹槽或方向上运行,这必须表明某些未知因素,对于一般和科学解剖学的综合知识非常重要。” (53. 牧师 Dr. 霍顿,给予后('Proc. R. 爱尔兰学院,27 年 1864 月 XNUMX 日,第 XNUMX 页。 715)人类拇长屈肌变异的一个显着案例,补充道,“这个显着的例子表明,人类有时可能拥有猕猴特有的拇指和手指肌腱的排列;但这种情况到底是猕猴向上变成了人,还是人向下变成了猕猴,或者是一种先天的畸形,我不敢说。”听到如此有能力的解剖学家和如此愤怒的进化论反对者甚至承认他的第一个命题中的任何一个的可能性,这是令人满意的。 教授 麦卡利斯特还描述了(“爱尔兰皇家学院学报”,卷。 x. 1864。

可以承认,这一未知因素是向以前的存在状态的回归,这是最有可能的。 (54. 自本书第一版出版以来,伍德先生在《哲学汇刊》,1870 年,第 83 页上出版了另一本回忆录,内容涉及人类颈部、肩部和胸部的肌肉种类。他在这里展示了如何这些肌肉的变化非常大,以及这些变化与低等动物正常肌肉的相似程度和相似程度。他总结道:“如果我成功地展示了更重要的形式,那么对于我的目的来说就足够了。在人类主体中以变体的形式出现,往往以足够明显的方式展示出可以被视为达尔文回归原理或遗传定律的证明和例子,在解剖学的这个部门。”)令人难以置信的是,如果一个人的肌肉之间没有遗传联系,那么他的至少七块肌肉应该只是偶然地与某些猿类异常相似。另一方面,如果人类是某种类猿生物的后裔,那么就没有合理的理由可以解释为什么某些肌肉不会在几千代之后突然重新出现,就像马、驴和骡子一样。经过数百代或更可能是数千代之后,深色条纹突然重新出现在腿部和肩膀上。

这些不同的回归案例与第一章中给出的初级器官的案例密切相关,以至于其中许多案例可能是在那里或在这里被漠不关心地介绍的。因此,具有鸡角的人类子宫可以说在初级状态下代表了某些哺乳动物正常状态下的相同器官。人类的一些不成熟的部分始终存在,例如两性的尾骨和男性的乳房。而其他孔,例如髁上孔,只是偶尔出现,因此可能被引入到复位头下方。这几个回归结构,以及严格的初级结构,以明确无误的方式揭示了人类从某种较低形式的下降。

相关变异

在人类身上,就像在低等动物身上一样,许多结构是如此密切相关,以至于当一个部分发生变化时,另一个部分也会发生变化,而在大多数情况下,我们无法给出任何原因。我们不能说一个部分是否支配另一个部分,或者两者是否都受到某个较早发展的部分的支配。正如 I. Geoffroy 反复强调的那样,各种怪物之间是紧密相连的。同源结构特别容易一起改变,正如我们在身体的两侧以及上肢和下肢看到的那样。梅克尔很久以前就说过,当手臂的肌肉偏离其正确的类型时,它们几乎总是模仿腿部的肌肉;腿部肌肉也是如此。视觉和听觉器官、牙齿和头发、皮肤和头发的颜色、颜色和体质,都或多或少地相关。 (55. 这几项陈述的权威在我的《驯养动物的变异》,第 ii 卷,第 320-335 页中给出。)沙夫豪森教授首先提请注意肌肉框架和强烈的肌肉之间明显存在的关系。明显的轨道上脊,这是低等人类的特征。

除了可以或多或少概率地归入上述类别的变异之外,还有一大类变异可以暂时称为自发变异,因为在我们的无知中,它们似乎是在没有任何令人兴奋的原因的情况下出现的。然而,可以证明的是,这种变异,无论是由轻微的个体差异组成,还是由结构上明显和突然的偏差组成,更多地取决于有机体的构成,而不是它所经历的条件的性质。受到。 (56. 这整个主题已在我的《驯化下的动物和植物的变异》第二十三章第二卷中讨论过。)

增长率

众所周知,在有利的条件下,例如在美国,文明人口的数量在二十五年内翻了一番。根据欧拉的计算,这可能会在十二年多一点的时间内发生。 (57. 参见Rev. T. Malthus 所著的令人难忘的“人口原理论文”,第 1826 卷,6 年,第 517 页,第 657 页。)按照之前的比率,美国目前的人口( XNUMX 万),在 XNUMX 年内将覆盖整个陆地地球,其厚度如此之大,以至于每平方码的表面上必须站立四个人。人类持续增长的主要或根本的制约因素是难以获得生存和舒适的生活。我们可以从我们看到的情况来推断,比如在美国,生活很容易,空间也很大。如果英国的这种手段突然增加一倍,我们的人数也会很快增加一倍。对于文明国家来说,这种主要的制衡主要是通过限制婚姻来发挥作用。最贫困阶层的婴儿死亡率较高也很重要;拥挤而简陋的房屋中各个年龄段的居民因各种疾病而死亡率更高。在处于有利条件下的国家,严重流行病和战争的影响很快就会被抵消,而且超过被抵消。移民也可以作为一种临时手段来提供援助,但对于极端贫困的阶层来说,援助的程度并不大。

正如马尔萨斯所说,我们有理由怀疑,野蛮种族的生殖能力实际上比文明种族的生殖能力要低。我们对此一无所知,因为没有对野蛮人进行过人口普查。但从传教士以及其他长期与这些人住在一起的人的共同证词来看,他们的家庭通常很小,而大家庭则很少见。据认为,这可能部分归因于妇女长时间哺乳婴儿。但很可能的是,野蛮人经常遭受许多苦难,并且无法像文明人那样获得那么多有营养的食物,因此他们的生育能力实际上要低一些。我在以前的著作(58.《驯化下的动物和植物的变异》,第二卷,第 111-113, 163 页)中表明,我们所有驯化的四足动物和鸟类,以及所有我们栽培的植物,都更加肥沃。比自然状态下的相应物种。动物突然被供给过量的食物,或者变得非常肥胖,这并不能有效地反驳这一结论。大多数植物在突然从非常贫瘠的土壤转移到非常肥沃的土壤时,都会或多或少地变得不育。因此,我们可以预期,在某种意义上高度驯化的文明人会比野蛮人更加多产。文明国家生育率的提高也很可能会像我们的家畜一样成为一种遗传特征:至少我们知道,人类有在家庭中生育双胞胎的倾向。 (59. Sedgwick 先生,《英国和外国医学外科评论》,1863 年 170 月,第 XNUMX 页。)

尽管野蛮人似乎不如文明人多产,但如果不通过某种方式严格限制他们的数量,他们的数量无疑会迅速增加。印度的桑塔利(Santali)或山地部落最近为这一事实提供了一个很好的例证。因为,正如亨特先生所指出的(60.“孟加拉农村年鉴”,WW Hunter,1868 年,第 259 页),自从引入疫苗接种、其他瘟疫减轻以及战争以来,它们以惊人的速度增加严厉镇压。然而,如果这些粗鲁的人没有扩散到邻近地区并受雇工作,这种增长是不可能的。野蛮人几乎总是结婚;然而,也有一些审慎的限制,因为他们通常不会尽早结婚。年轻男子经常被要求表现出他们可以赡养妻子;他们通常必须首先从她的父母那里赚到购买她的价格。对于野蛮人来说,获得生存的困难有时会比文明人更直接地限制他们的数量,因为所有部落都会定期遭受严重的饥荒。在这种时候,野蛮人被迫吃下许多劣质食物,他们的健康难免受到损害。许多报道都描述了他们在饥荒之后和期间的突出的胃和消瘦的四肢。然后,他们也被迫经常流浪,而且,正如我在澳大利亚确信的那样,他们的婴儿大量死亡。由于饥荒是周期性的,主要取决于极端季节,因此所有部落的数量必然会波动。它们不可能稳定、有规律地增加,因为食物供应没有人为增加。野蛮人遇到困难,就会互相侵占领土,结果就会发生战争;但他们确实几乎总是与邻国交战。它们在陆地和水上寻找食物时容易发生许多事故;在一些国家,它们饱受大型猛兽的侵害。即使在印度,一些地区的人口也因老虎的肆虐而减少。

马尔萨斯讨论了这几项检查,但他没有足够重视可能是最重要的一项,即杀婴,尤其是女婴,以及堕胎的习惯。这些做法现已在世界许多地区盛行。正如 M'Lennan 先生(61.《原始婚姻》,1865 年)所表明的那样,杀婴行为以前似乎盛行,而且规模更为广泛。这些做法似乎起源于野蛮人认识到抚养所有出生的婴儿的困难,或者更确切地说是不可能的。前述检查中还可以添加不正当行为;但这并不是由于生存手段不足造成的;尽管有理由相信,在某些情况下(例如在日本),它被有意鼓励作为抑制人口的一种手段。

如果我们回顾一个极其遥远的时代,在人类获得男子气概之前,他会比当今最低等的野蛮人更多地受到本能的引导,而不是受到理性的引导。我们早期的半人类祖先不会杀婴或多夫。因为低等动物的本能从来没有如此变态(62. 《旁观者》(12 年 1871 月 320 日,第 XNUMX 页)的一位作家对这段话的评论如下:——“达尔文先生发现自己不得不重新引入一种新的他表明,高等动物的本能远高于人类野蛮种族的习惯,因此,他发现自己不得不重新引入——以一种实质正统的形式他似乎完全无意识地提出了这一学说,即人类知识的获得是暂时但持久的道德堕落的原因,正如野蛮人的许多肮脏习俗,尤其是婚姻习俗所表明的那样。犹太传统认为,人通过夺取最高本能所禁止的知识而导致人的道德堕落,除此之外,它还断言了什么?)以至于导致他们定期毁灭自己的后代,或者完全没有嫉妒。婚姻不会受到审慎的限制,两性在很小的时候就可以自由地结合。因此,人类的祖先往往会迅速增加。但是某种形式的检查,无论是定期的还是持续的,一定会限制他们的数量,甚至比现有的野蛮人更严重。与大多数其他动物一样,我们无法说出这些检查的确切性质。我们知道,马和牛并不是多产的动物,当它们第一次在南美洲放归时,它们的数量就以惊人的速度增长。大象是所有已知动物中繁殖速度最慢的动物,几千年后它的数量就会遍布整个世界。每种猴类的增长都必须通过某种手段加以抑制;但正如布雷姆所说,并不是猛兽的攻击。没有人会认为美洲野马和野牛的实际繁殖能力一开始就得到了任何明显的程度的提高。或者说,当每个地区的库存都充足时,这种力量就会减弱。毫无疑问,在这种情况下,以及在所有其他情况下,许多检查是一致的,并且在不同情况下有不同的检查;周期性的短缺(取决于不利的季节)可能是最重要的。人类的早期祖先也是如此。

自然选择

我们现在已经看到,人的身体和心灵是可变的。与低等动物一样,这些变异是由相同的一般原因直接或间接引起的,并遵循相同的一般规律。人类已经在地球表面广泛传播,并且在不断的迁徙过程中一定已经暴露在外(63。参见 W. Stanley Jevons 对此的一些精彩评论,“达尔文理论的演绎”,《自然》,1869 ,第 231 页。),以适应最多样化的条件。一个半球的火地岛、好望角和塔斯马尼亚岛的居民,以及另一个半球的北极地区的居民,在到达现在的家园之前,一定经历了许多气候,多次改变了他们的习惯。 (64. Latham,《人类及其迁徙》,1851 年,第 135 页。)人类的早期祖先也一定像所有其他动物一样,不断增长,超出了他们的生存手段。因此,它们必定偶尔会面临生存斗争,从而受到严格的自然选择法则的影响。因此,各种有益的变异将偶尔或习惯性地被保留下来,而有害的变异将被消除。我指的不是明显的结构偏差,这种偏差只在很长的时间间隔内发生,而是指纯粹的个体差异。例如,我们知道,我们的手和脚的肌肉决定了我们的运动能力,就像低等动物的肌肉一样,(65. Murie 和 Mivart 先生在他们的“Lemuroidea 的解剖学”中(“ Transact. Zoolog. Soc.' vol. vii. 1869,第 96-98 页)说,“有些肌肉的分布非常不规则,以至于无法很好地分为上述任何一组。”这些肌肉甚至在同一个人的相反两面。)不断变化。如果居住在任何地区的人类祖先,特别是那些环境条件正在发生变化的地区,都被分成两个平等的群体,其中一半包括所有最适合通过其运动能力获得生存或保卫自己的个体,平均而言,他们的生存数量会比另一半和条件较差的一半更多,并且会生育更多的后代。

人类现在所处的最粗鲁的状态是地球上曾经出现过的最具统治力的动物。他比任何其他高度组织的形式传播得更广泛:所有其他形式都在他之前屈服了。他显然将这种巨大的优势归功于他的智力、他的社会习惯(这些习惯使他能够帮助和保护他的同胞)以及他的肉体结构。这些人物的至高无上的重要性已被生命之战的最终裁决所证明。通过他的智力,清晰的语言得以发展。他的出色进步主要取决于此。正如昌西·赖特 (Chauncey Wright) 先生所说(66.《自然选择的限制》,《北美评论》,1870 年 295 月,第 67 页):“对语言能力的心理学分析表明,即使是最熟练的语言也可能需要比任何其他领域最熟练的人都拥有更多的脑力。”他发明并能够使用各种武器、工具、陷阱等来保护自己、杀死或捕捉猎物,以及以其他方式获取食物。他制作木筏或独木舟用于捕鱼或穿越邻近肥沃的岛屿。他发现了生火的艺术,通过这种方法可以使坚硬而粘稠的根茎变得可消化,并使有毒的根茎或草药变得无害。火的发现可能是人类有史以来最伟大的发现(除了语言之外),其历史可以追溯到历史黎明之前。人类在最原始的状态下变得如此卓越,正是通过这几项发明,人类的观察力、记忆力、好奇心、想象力和推理能力发展的直接结果。因此,我无法理解华莱士先生(1869.《季刊评论》,392 年 1870 月,第 1870 页。这个主题在华莱士先生的《自然选择理论的贡献》,1864 年中有更全面的讨论,欧洲最杰出的动物学家之一克拉帕雷德教授在《宇宙图书馆》上发表了一篇文章,对《论人》进行了巧妙的批评。 ” 1865 年 479 月。我的文字中引用的这句话会让每一个读过华莱士先生的著名论文“从自然选择理论推导出的人类起源”的人感到惊讶,该论文最初发表在 XNUMX 年 XNUMX 月的“人类学评论”上, p. clviii. 在这里,我忍不住引用 J. Lubbock 爵士(《史前时代》,XNUMX 年,第 XNUMX 页)关于本文的最公正的评论,即华莱士先生“以特有的无私态度,将其归因于(即自然选择的思想)毫无保留地属于达尔文先生,尽管众所周知,他独立地提出了这个思想,并在同一时间发表了它,尽管没有进行同样的阐述。”)坚持认为,“自然选择只能赋予野蛮人比猿类稍微优越一点的大脑。”

尽管人的智力和社会习惯对他来说至关重要,但我们绝不能低估他的身体结构的重要性,本章剩余部分将专门讨论这个主题;智力和社会或道德能力的发展将在后面的章节中讨论。

即使是精确地锤击也不是一件容易的事,每一个尝试学习木工的人都会承认。要想像火地岛人一样有目的地投掷石头来自卫或杀死鸟类,需要手、手臂和肩膀肌肉的相关动作达到最完美的完美状态,此外,还需要有良好的感觉。触碰。在投掷石头或长矛以及许多其他动作时,一个人必须站稳脚跟。这又需要众多肌肉的完美配合。要将燧石打入最粗糙的工具,或者用骨头制成带刺的矛或钩子,都需要使用完美的手;作为最有能力的法官,斯库克拉夫特先生(68。被劳森·泰特先生在他的《自然选择法则》中引用,《都柏林医学科学季刊》,1869 年 XNUMX 月。同样,凯勒博士也被引用到相同的效果。),评论说,将石头碎片塑造成刀、矛或箭头,显示出“非凡的能力和长期的练习”。原始人实行分工的事实在很大程度上证明了这一点。每个人都没有自己制造燧石工具或粗糙的陶器,但某些人似乎致力于此类工作,毫无疑问,他们以狩猎的产物作为交换。考古学家确信,在我们的祖先想到将碎燧石磨成光滑的工具之前,已经过去了很长一段时间。毫无疑问,一种类人动物拥有足够完美的手和手臂,可以精确地投掷石头,或者将燧石打造成粗糙的工具,只要进行足够的练习,就机械技能而言,它是可以的,几乎可以制造文明人可以制造的任何东西。在这方面,手的结构可以与发声器官的结构进行比较,在猿类中,发声器官用于发出各种信号叫声,或者,如在一个属中,发出音乐节奏;但在人类中,由于使用清晰语言的遗传效应,非常相似的发声器官已经变得适应。

现在转向人类最亲密的盟友,因此转向我们早期祖先的最佳代表,我们发现Quadrumana的手是按照与我们自己相同的一般模式构建的,但远不那么完美地适应多样化的用途。他们的手不像狗的脚那样能很好地移动。正如黑猩猩和猩猩等猴子所见,它们用手掌的外缘或指关节行走。 (69. 欧文,《脊椎动物解剖学》,第三卷,第 71 页。)然而,他们的手非常适合爬树。猴子抓住细树枝或绳子,一侧是拇指,另一侧是手指和手掌,方式与我们相同。因此,他们还可以将相当大的物体(例如瓶颈)举到嘴里。狒狒翻石头,用手刮根。它们用拇指相对的手指抓住坚果、昆虫或其他小物体,毫无疑问,它们因此从鸟巢中取出蛋和幼崽。美洲猴把野橙子敲在树枝上,直到果皮裂开,然后用两只手的手指把它撕下来。在野生状态下,它们用石头敲开坚硬的水果。其他猴子用两个拇指打开贻贝壳。他们用手指拔出荆棘和刺,并寻找彼此的寄生虫。他们滚下石头,或者把石头扔向敌人:然而,他们在这些不同的动作中都很笨拙,而且,正如我亲眼所见,他们完全无法精确地扔石头。

在我看来,这似乎远非事实,因为猴子“笨拙地抓住物体”,“一个不太专业的抓握器官”本来可以为它们服务(70。《季刊评论》,1869 年 392 月,第 71 页。)他们现在的手。相反,我认为没有理由怀疑构造更完美的手对它们来说是一个优势,只要它们不因此变得不太适合爬树。我们可能会怀疑,像人类一样完美的手对于攀爬来说是不利的;对于世界上大多数树栖猴子来说,即美洲的阿特勒斯猴、非洲的疣猴和亚洲的长臂猴,它们要么没有拇指,要么脚趾部分连在一起,因此它们的四肢只能变成抓钩。 (50. 正如其名称所表达的,在 Syndactylus 中,两个脚趾经常连在一起;正如 Blyth 先生告诉我的那样,H. agilis、lar 和 leuciscus 的脚趾偶尔也会出现这种情况。Colobus 是严格树栖的而且非常活跃(Brehm,“Thierleben”B. 是 XNUMX),但我不知道是否比同类属的物种更好的攀爬能力。值得注意的是,树懒的脚是树懒中最树栖的动物世界,都是奇妙的钩状。

一旦灵长类动物的伟大系列中的某些古老成员由于其获取食物的方式发生变化,或由于周围条件的某些变化,变得不再像树栖一样,其惯常的进化方式就会被改变:因此,它会被渲染为更严格的四足动物或双足动物。狒狒经常出没于丘陵和岩石地区,只有在必要时才会爬上高树(72. Brehm,“Thierleben”,B. 是 80。);他们几乎已经学会了狗的步态。唯独人类已成为两足动物;我认为,我们可以部分地看到他是如何采取直立态度的,这构成了他最引人注目的性格之一。如果不使用双手,人类不可能获得目前在世界上的主导地位,因为双手非常适合服从他的意志。 C. Bell 爵士(73.《手》等,《布里奇沃特论文》,1833 年,第 38 页)坚持认为“手提供所有工具,并且通过与智力的对应,手赋予他普遍的统治权。”但是,只要手和手臂习惯性地用于移动和支撑身体的整个重量,或者,之前说过,只要它们特别适合爬树。这种粗暴的处理也会削弱触觉,而触觉的灵敏使用很大程度上取决于触觉。仅出于这些原因,人类成为两足动物就会有好处。但对于许多动作来说,手臂和整个上半身必须保持自由,这是必不可少的。为此,他必须站稳脚跟。为了获得这个巨大的优势,脚被打平了。大脚趾也发生了特殊的变化,尽管这导致其抓握能力几乎完全丧失。它符合整个动物界盛行的生理劳动分工原则,即当手变得完美用于抓握时,脚也应该变得完美用于支撑和运动。然而,对于一些野蛮人来说,脚并没有完全失去其抓握能力,正如他们爬树和以其他方式使用树木的方式所表明的那样。 (74. 海克尔对人类成为两足动物的步骤进行了精彩的讨论:“Natürliche Schöpfungsgeschichte”,1868 年,第 507 节。布赫纳博士(“Conférences sur la Théorie Darwinienne”,1869 年,第 135 页)给出了很好的解释。人类使用脚作为抓握器官的案例;并且还写了关于高等猿类进化方式的文章,我在下一段中提到了这一点:另见欧文(《脊椎动物解剖学》,第三卷) . 第 71 页)关于后一个主题。)

如果人能站稳脚跟并解放双手和双臂是一种优势,从他在生命之战中取得的卓越成功来看,这一点是毫无疑问的,那么我看不出有什么理由这样做。变得越来越直立或两足行走对人类的祖先来说本不应该是有利的。因此,他们能够更好地用石头或棍棒保护自己,攻击猎物,或者以其他方式获取食物。从长远来看,体格最好的个体会取得最大的成功,并且能够大量生存。如果大猩猩和一些类似的物种已经灭绝,那么人们可能会以极大的力量和明显的事实争辩说,动物不可能逐渐从四足动物转变为两足动物,因为所有处于中间状态的个体都会非常不适合进步。但我们知道(这很值得反思)拟人猿现在实际上处于中间状态;毫无疑问,他们总体上已经很好地适应了自己的生活条件。因此,大猩猩以一种侧向蹒跚的步态奔跑,但更常见的是通过弯曲的手休息来前进。长臂猿偶尔会像拐杖一样使用手臂,在它们之间向前摆动身体,某些种类的长臂猿无需经过训练,就能以相当快的速度直立行走或奔跑;然而,它们的行动却很笨拙,而且比人类更不安全。简而言之,我们在现有的猴子中看到了一种介于四足动物和两足动物之间的进化方式。但是,作为一位公正的法官(75.布罗卡教授,LaConstitution des Vertèbres caudales;“La Revue d'Anthropologie”,1872年,第26页(单独副本)。)坚持认为,拟人猿在结构上更接近于双足类型比四足类型。

随着人类的祖先变得越来越直立,他们的手和手臂越来越多地被改造以用于抓握和其他目的,他们的脚和腿同时转变为牢固的支撑和进步,无穷无尽的其他结构变化将变得必要的。骨盆必须加宽,脊柱必须特别弯曲,头部必须固定在改变的位置,所有这些改变都是人类实现的。 Schaaffhausen 教授(76.《论头骨的原始形式》,译自《人类学评论》,1868 年 428 月,第 1866 页。欧文(《脊椎动物解剖学》,第 ii 卷,551 年,第 XNUMX 页)高等猿类的乳突。)坚持认为“人类头骨强大的乳突是直立姿势的结果;”而这些突起在红毛猩猩、黑猩猩等动物中是不存在的,并且在大猩猩中比在人类中更小。各种其他看起来与人的直立位置有关的结构可能已被添加在这里。很难确定这些相关的修饰在多大程度上是自然选择的结果,以及在多大程度上是某些部分的使用增加或一个部分对另一部分的作用的遗传效应。毫无疑问,这些改变的手段经常相互配合:因此,当某些肌肉以及它们所附着的骨嵴因习惯使用而变大时,这表明某些动作是习惯性执行的并且必须是有用的。因此,表现最好的个体往往会大量生存。

手臂和手的自由使用,部分是人类直立姿势的原因,部分是其结果,似乎以间接的方式导致了结构的其他改变。如前所述,人类早期的男性祖先可能长有巨大的犬齿。但当他们逐渐养成使用石头、棍棒或其他武器与敌人或对手战斗的习惯时,他们会越来越少地使用下巴和牙齿。在这种情况下,下巴和牙齿都会变小,我们从无数类似的案例中几乎可以肯定这一点。在下一章中,我们将遇到一个密切相似的案例,即雄性反刍动物的犬齿减少或完全消失,这显然与它们的角的发育有关。对于马来说,则与它们用门牙和蹄子战斗的习惯有关。

正如 Rutimeyer (77. 'Die Grenzen der Thierwelt, eine Betrachtung zu Darwin's Lehre,' 1868, s. 51.) 和其他人所坚持的那样,在成年雄性拟人猿中,这是大发育对头骨的影响下颌肌肉的缺陷导致它们在许多方面与人类有很大不同,并赋予这些动物“真正可怕的面貌”。因此,随着人类祖先的下巴和牙齿逐渐缩小,成年的头骨会越来越像现有人类的头骨。正如我们将在下文中看到的,雄性犬齿的大幅减少几乎肯定会通过遗传影响雌性的牙齿。

随着各种心智能力逐渐发展,大脑几乎肯定会变得更大。我想,没有人会怀疑,与大猩猩或红毛猩猩相比,人脑的大小在其身体中所占的比例之大,与他较高的智力密切相关。我们在昆虫中遇到了非常相似的事实,因为蚂蚁的大脑神经节具有非凡的尺寸,并且在所有膜翅目中,这些神经节比智力较低的目(例如甲虫)大许多倍。 (78. Dujardin,“Annales des Sciences Nat.”第 3 系列,Zoolog.,tom. xiv. 1850,第 203 页。另请参阅 Lowne 先生,“Musca vomitoria 的解剖学和物理学”,1870 年,第 14 页(我的儿子 F. 达尔文先生为我解剖了红蚁的大脑神经节。)另一方面,没有人认为任何两种动物或任何两个人的智力可以通过立方含量来准确衡量他们的头骨。可以肯定的是,神经物质的绝对质量极小,就可能存在非凡的精神活动:因此,蚂蚁的本能、精神力量和情感极其多样化,这是众所周知的,但它们的大脑神经节却没有四分之一个小神经节那么大。针的头。从这个角度来看,蚂蚁的大脑是世界上最奇妙的物质原子之一,也许比人的大脑更重要。

野蛮人与文明人、古代人与现代人头骨的比较以及整个人类的类比都支持了人类大脑的大小与智力发展之间存在某种密切关系的信念。脊椎动物系列。 J. Barnard Davis 博士通过多次仔细的测量证明(79.《哲学汇刊》,1869,第 513 页),欧洲人头骨的平均内部容量为 92.3 立方英寸;美国人为 87.5;亚洲人 87.1;而澳大利亚人只有 81.9 立方英寸。 Broca 教授(80.“Les Selections”,MP Broca,“Revue d'Anthropologies”,1873 年;另见 C. Vogt 的“Lectures on Man”中引用的内容,英译本,1864 年,第 88、90 页。普里查德(Prichard),《人类物理史》,第一卷,1838 年,第 305 页。)发现巴黎坟墓中出土的 1484 世纪头骨比 1426 世纪墓穴中出土的头骨要大,比例为 81 年至 82 年;通过测量确定,增大的尺寸仅出现在头骨的前部——智力的所在地。普里查德相信,现在的英国居民比古代居民“脑容量大得多”。然而,必须承认的是,一些非常古老的头骨,例如著名的尼安德特人的头骨,是发育良好且宽敞的。 (1. 在刚才提到的那篇有趣的文章中,布罗卡教授很好地指出,在文明国家,必须通过保存相当数量的身心衰弱的个体来降低头骨的平均容量,他们会在野蛮状态下,这些人很快就被淘汰了。另一方面,对于野蛮人来说,平均水平只包括那些更有能力的人,他们能够在极其艰苦的生活条件下生存。布罗卡因此解释了一个令人费解的事实,即平均水平古代洛泽尔穴居人的头骨容量大于现代法国人的头骨容量。)关于低等动物,ME Lartet(1868.“Comptes-rendus des Sciences”等,83 年 124 月 129 日),作者:通过比较属于同一类群的第三纪和现代哺乳动物的头盖骨,得出了一个显着的结论:在较现代的形式中,大脑通常更大,回旋也更复杂。另一方面,我已经表明(XNUMX.《驯化下动植物的变异》,第 XNUMX 卷,第 XNUMX-XNUMX 页),与家兔的大脑相比,家兔的大脑体积显着减小。野兔或野兔;这可能是由于他们在许多代以来一直受到严格的限制,因此他们很少发挥自己的智力、本能、感官和随意运动。

人类大脑和头骨重量的逐渐增加一定影响了支撑脊柱的发育,尤其是在他直立时。 当位置发生变化时,大脑的内部压力也会影响头骨的形状。许多事实表明头骨是多么容易受到影响。 人类学家认为,它是由婴儿睡觉的摇篮类型改变的。 肌肉的习惯性痉挛和严重烧伤留下的疤痕已经永久性地改变了面部骨骼。 由于疾病,头部向一侧或向后固定的年轻人中,两只眼睛中的一只改变了位置,并且头骨的形状由于大脑向新方向的压力而明显改变。 (84。 沙夫豪森在 10 月 10 日的《人类学评论》中给出了布卢门巴赫和布施的痉挛和疤痕病例。 1868。 420. Dr. 贾罗德(《人类学》,1808 年,第 XNUMX 页) 115, 116)从坎珀和他自己的观察中引述了将头部固定在不自然位置的头骨改造案例。 他认为,在某些行业中,例如鞋匠的行业,头习惯性地向前倾,前额会变得更加圆润和突出。)我已经证明,对于长耳兔子来说,即使是像向前迈步这样微不足道的原因,一只耳朵向前拖着那一侧头骨的几乎每一块骨头;使得对面的骨头不再严格对应。 最后,如果任何动物的总体尺寸增加或减少很多,但其精神力量没有任何变化,或者如果精神力量增加或减少很多,而身体的大小没有任何重大变化,那么动物的形状头骨几乎肯定会被改变。 我从对家兔的观察中推断出这一点,其中一些种类已经变得比野生动物大得多,而另一些则几乎保持相同的大小,但在这两种情况下,大脑相对于身体的大小都大大缩小。 起初,我非常惊讶地发现,所有这些兔子的头骨都变长了,或者变成了长头状。例如,两个宽度几乎相等的头骨,一个来自野兔,另一个来自大型家兔,前者的长度为 3.15 英寸,后者的长度为 4.3 英寸。 (85。 “驯化下动植物的变异”,卷。 i. p. 117、关于头骨的伸长; p。 119,关于剪掉一只耳朵的影响。)不同种族的男性最显着的区别之一是,有些人的头骨是拉长的,而另一些人的头骨是圆形的;在这里,兔子的例子所暗示的解释可能是正确的;韦尔克发现矮个子“男性更倾向于短头畸形,而高个子男性更倾向于长头畸形”(86. 引用自沙夫豪森,《人类学评论》,10 月 10 日。 1868。

从这几个事实中,我们可以在一定程度上了解人类是如何获得巨大尺寸和或多或少圆形的头骨的。与低等动物相比,这些都是他的显着特征。

人类与低等动物之间另一个最显着的区别是皮肤的裸露。 鲸鱼和鼠海豚 (Cetacea)、儒艮 (Sirenia) 和河马都是赤裸的;这可能有利于它们在水中滑行;失去温暖也不会伤害它们,因为栖息在寒冷地区的物种受到一层厚厚的鲸脂的保护,其作用与海豹和水獭的毛皮相同。 大象和犀牛几乎没有毛;由于某些以前生活在北极气候下的灭绝物种被长毛或毛发覆盖,因此这两个属的现有物种几乎看起来都因为暴露在高温下而失去了毛茸茸的覆盖物。 这似乎更有可能,因为生活在高地和凉爽地区的印度大象毛发较多(87. 欧文,《脊椎动物解剖学》,卷。 III。 p. 619.)比低地地区的人要多。 那么我们是否可以推断,人类因原住民居住在热带地区而失去了头发呢? 雄性的毛发主要保留在胸部和面部,两性的毛发主要保留在所有四个肢体与躯干的交界处,这支持了这一推论——假设毛发在男人勃起之前就已经脱落了;因为现在保留大部分头发的部分将得到最大程度的保护,免受阳光的照射。 然而,头顶却是一个奇怪的例外,因为它在任何时候都一定是最暴露的部分之一,但它却长满了厚厚的头发。 然而,事实上,人类所属的灵长目动物的其他成员,虽然居住在不同的炎热地区,但都长有毛发,通常上表面最厚(88. 伊西多尔·杰弗里·圣伊莱尔 (Isidore Geoffroy St.-Hilaire) 评论 ('Histoire Nat. 将军,汤姆。 II。 1859页。 215-217)在长着长发的男人的头上;猴子和其他哺乳动物的上表面也比下表面衣服更厚。 不同的作者也观察到了这一点。 教授 P. 热尔韦 ('Histoire Nat. des Mammifères,汤姆。 i. 1854。 28)然而,指出大猩猩背部的毛发比下表面的毛发更薄,部分毛发被擦掉。),这与人类因太阳的作用而变得赤裸的假设相反。 先生。 贝尔特相信(89. 《尼加拉瓜的博物学家》,1874 年,第 XNUMX 页。 209. 作为先生的一些确认。 对于贝尔特的观点,我可以引用W. 丹尼森(《副王室生活的多样性》,卷。 i. 1870。 440):“据说澳大利亚人有一种做法,当害虫变得麻烦时,他们会烧自己。”)在热带地区,没有头发对人类来说是一个优势,因为这样他就能够释放头发他自己身上有大量蜱虫(螨)和其他寄生虫,他经常被这些寄生虫感染,有时会引起溃疡。 但这种邪恶是否严重到足以通过自然选择导致他的身体被剥削,可能值得怀疑,因为据我所知,居住在热带地区的许多四足动物都没有获得任何专门的缓解手段。

人们普遍认为,没有尾巴是人类的显着特征。但由于那些离他最近的猿类缺乏这个器官,因此它的消失并不完全与人类有关。在同一属内,尾巴的长度常常有显着差异:因此,在某些猕猴物种中,尾巴比整个身体还要长,并且由二十四块椎骨组成;在另一些情况下,它由几乎不可见的残肢组成,仅包含三到四块椎骨。某些狒狒有 90 块,而山魈有 1865 块发育不良的非常小的尾椎,或者根据居维叶的说法(562. St. George Mivart 先生,“Proc. Zoolog. Soc.” 583 年,第. 517, 244. JE Gray 博士,“Cat. Brit. Mus.:‘骨骼’。”Owen,“脊椎动物解剖学”,第 ii 卷,第 91 页。 Isidore Geoffroy,“Hist. Nat. Gen.” 汤姆.ii.第1872页。),有时只有五个。尾巴,无论是长还是短,几乎总是向末端逐渐变细。我认为,这是由于末端肌肉及其动脉和神经因废弃而萎缩,导致末端骨骼萎缩的结果。但目前还无法解释其长度经常出现的巨大差异。然而,在这里,我们更特别关心尾巴的完全外部消失。布罗卡教授最近表明(XNUMX。《人类学评论》,XNUMX 年;《尾部脊椎动物宪法》。)所有四足动物的尾巴都由两部分组成,通常彼此突然分开;基底部分由椎骨组成,或多或少具有完美的通道,并像普通椎骨一样具有隆起;而末端部分的那些没有通道,几乎是光滑的,并且几乎不像真正的椎骨。尾巴虽然外表不可见,但确实存在于人类和拟人猿身上,并且两者的构造完全相同。在末端部分,构成尾骨的椎骨相当初级,尺寸和数量都大大减少。在基底部分,椎骨同样较少,牢固地结合在一起,并且发育受到抑制;但它们比其他动物尾巴中相应的椎骨更宽、更平坦:它们构成了布罗卡所说的副骶椎。这些通过支持某些内部部件和以其他方式具有功能重要性;它们的变形与人类和拟人猿的直立或半直立姿态直接相关。这个结论更可信,因为布罗卡以前曾持有不同的观点,但现在他已经放弃了。因此,人类和高等猿类的基底尾椎的改变可能是通过自然选择直接或间接实现的。

但是,对于形成尾骨的尾部末端部分的基本椎骨和可变椎骨,我们该如何说呢? 摩擦力与尾部外部消失有关这一观点经常被嘲笑,而且毫无疑问将再次被嘲笑,但这一观点并不像乍看起来那么可笑。 Dr. 安德森 (92. 《动物学会学报》,1872 年,第 XNUMX 页。 210.)指出,Macacus brunneus 极短的尾巴由十一块椎骨组成,包括嵌入的基底椎骨。 四肢是肌腱,没有椎骨;接下来是五个基本的,如此之小,它们加起来只有一条半长,并且它们永久地向一侧弯曲成钩子的形状。 尾巴的自由部分长度仅略高于一英寸,仅包括四个小椎骨。 这条短尾巴是直立的;但其总长度的大约四分之一在左侧加倍;该终端部分包括钩状部分,用于“填充胼胝上部发散部分之间的间隙”;以至于动物坐在上面,从而使其变得粗糙和冷酷。 Dr. 安德森这样总结他的观察:“在我看来,这些事实只有一种解释;这条尾巴由于尺寸较短,当猴子坐下时,它会挡住它的路,当它处于这种姿势时,它经常会被放在猴子的下面;从它没有延伸到坐骨结节末端的情况来看,尾巴似乎最初是根据动物的意志而弯曲的,进入老茧之间的间隙,以避免被压在老茧和老茧之间。地面上,随着时间的推移,曲率变得永久,当器官碰巧坐在上面时,曲率会自动适应。”在这种情况下,尾巴的表面变得粗糙并变得冷酷也就不足为奇了,博士。 穆里 (93. 《动物学会学报》,1872 年,第 XNUMX 页。 786.),他在动物园里仔细观察了这个物种,以及其他三种密切相关的尾巴稍长的物种,他说,当动物坐下时,尾巴“必然被推到臀部的一侧;无论长短,它的根都容易被摩擦或擦伤。”正如我们现在有证据表明,残肢偶尔会产生遗传效应(94. 我提到博士。 布朗-塞卡德对引起豚鼠癫痫的手术的传播效应的观察,以及最近对切断颈部交感神经的类似效应的观察。 以后有机会我会提到先生。 萨尔文(Salvin)提出了一个有趣的例子,该案例讲述了猫鼬咬掉自己尾羽倒刺的明显遗传效应。 另请参见一般主题“驯化下动物和植物的变异”,卷。 II。 第 22-24.),在短尾猴中,尾巴的突出部分在功能上无用,在经过许多代之后,由于不断的摩擦和擦伤,变得简陋和扭曲,这并不是不可能的。 我们在棕猕猴中看到了这种情况下的突出部分,而在猕猴中则完全中止了。 ecudatus 和一些高等猿类。

我现在努力表明,人类的一些最独特的特征很可能是通过自然选择直接获得的,或更常见的是间接获得的。我们应该记住,如果结构或构成的改变不能使有机体适应其生活习惯、其所消耗的食物或被动地适应周围条件,则不可能通过这种方式获得。然而,我们不能太自信地决定哪些修改对每个生物有用:我们应该记住,我们对许多部件的用途知之甚少,或者血液或组织的哪些变化可能有助于使有机体适应某种环境。新的气候或新的食物种类。我们也不能忘记关联原理,正如伊西多尔·杰弗鲁瓦在人类的例子中所表明的那样,通过该原理,许多奇怪的结构偏差被联系在一起。与相关性无关,一个部分的变化常常会通过增加或减少其他部分的使用而导致其他非常意外的变化。反思这些事实也是有好处的,例如昆虫的毒引起植物上虫瘿的奇妙生长,以及鹦鹉在吃某些鱼或接种了某种鱼的毒后羽毛颜色的显着变化。蟾蜍(95.“驯化下的动物和植物的变异”,第 ii 卷,第 280、282 页);因为我们因此可以看到,如果为了某种特殊目的而改变系统的流体,可能会引起其他变化。我们应该特别记住,在过去的时代中为了某种有用的目的而获得和持续使用的修改可能会被牢固地固定下来,并且可能会被长期继承。

因此,可以安全地对自然选择的直接和间接结果进行大而未定义的扩展;但我现在承认,在阅读了纳吉利关于植物的文章以及不同作者关于动物的评论之后,尤其是布罗卡教授最近发表的评论后,我在《物种起源》的早期版本中可能也归因于很大程度上取决于自然选择或适者生存的行为。我对《起源》第五版进行了修改,以便将我的言论限制在结构的适应性变化上;但我相信,从最近几年所获得的启示来看,许多现在看来无用的结构,今后将被证明是有用的,因此将进入自然选择的范围。尽管如此,我以前并没有充分考虑结构的存在,就我们目前所能判断的而言,结构的存在既无益也无害。我相信这是我的工作中迄今为止发现的最大的疏忽之一。作为某种借口,我可能会被允许说,我有两个不同的目标:首先,表明物种并不是单独创造的;其次,自然选择是变化的主要推动者,尽管很大程度上得益于习惯的遗传效应,也有少量周围条件的直接作用。然而,我无法消除我以前的信念的影响,当时几乎是普遍的,即每个物种都是有目的地被创造的。这导致我心照不宣地认为,除了基本结构之外,结构的每一个细节都有某种特殊的、尽管未被认识到的服务。任何心里有这种假设的人都会自然地把自然选择的作用延伸得太远,无论是在过去还是现在。一些承认进化原理但拒绝自然选择的人在批评我的书时似乎忘记了我所考虑的上述两个目标;因此,如果我错误地赋予了自然选择巨大的力量(这一点我远未承认),或者夸大了自然选择的力量(这本身就是可能的),那么我至少如我所希望的那样,在帮助推翻自然选择方面做出了良好的贡献。单独创作的教条。

正如我现在所看到的,很可能所有有机生物,包括人类,都具有结构的特殊性,这些特殊性无论现在还是以前都对它们没有任何帮助,因此,在生理上不重要。我们不知道是什么造成了每个物种的个体之间无数的细微差异,因为回归只会使问题倒退几步,但每一个特性必定有其有效的原因。如果这些原因,无论它们是什么,在一段较长的时间内更加一致和有力地发挥作用(对此没有任何理由可以解释),那么结果可能不仅仅是轻微的个体差异,而是一种明显而恒定的差异。修饰,尽管这种修饰在生理上并不重要。改变的结构毫无益处,无法通过自然选择保持一致,尽管有害的将被消除。然而,性格的一致性自然会源于假设的令人兴奋的原因的一致性,同样也源于许多个体的自由交叉。在连续的时期内,同一个有机体可能以这种方式获得连续的修饰,只要令人兴奋的原因保持不变并且存在自由交叉,这些修饰就会以几乎一致的状态传播。至于令人兴奋的原因,我们只能说,就像在谈到所谓的自发变异时一样,它们与变化的有机体的构成更为密切相关,而不是与它所遭受的条件的性质密切相关。

结论

在本章中,我们已经看到,当今的人类与其他所有动物一样,容易受到多种个体差异或轻微变异的影响,人类的早期祖先无疑也是如此。以前的变化是由相同的一般原因引起的,并受与现在相同的一般和复杂的规律支配。正如所有动物都倾向于繁殖超出其生存能力一样,人类的祖先也一定如此。这将不可避免地导致生存斗争和自然选择。零件使用增加的继承效应将极大地帮助后一个过程,并且这两个过程将不断地相互反应。而且,正如我们将在下文中看到的那样,人类似乎通过性选择获得了各种不重要的特征。必须将无法解释的残余变化留给那些未知机构假定的统一行动,这些机构有时会在我们的国内生产中引起强烈显着和突然的结构偏差。

从野蛮人和大多数夸德鲁马纳人的习惯来看,原始人,甚至他们的类人猿祖先,可能生活在社会中。对于严格社会性的动物,自然选择有时会通过保留对群体有益的变异来作用于个体。一个包含大量有天赋的个体的社区,其数量会增加,并且会战胜其他较不受欢迎的个体;即使每个单独的成员与同一社区的其他成员相比没有任何优势。因此,相关昆虫获得了许多显着的结构,这些结构对个体几乎没有或没有任何帮助,例如花粉收集装置,或工蜂的刺,或兵蚁的大颚。对于高等社会性动物,我不知道任何结构的修改只是为了社区的利益,尽管有些结构对社区的服务是次要的。例如,反刍动物的角和狒狒的大犬齿似乎是雄性获得的,作为性冲突的武器,但它们被用来保卫牛群或部队。正如我们将在第五章中看到的,对于某些精神力量而言,情况完全不同。因为这些能力主要甚至完全是为了社会的利益而获得的,而社会的个人同时也间接地获得了优势。

上述观点常常遭到反对,即人是世界上最无助和最无助的生物之一;而且,在他早期且发育欠佳的情况下,他会更加无助。例如,阿盖尔公爵坚持认为(96.《原始人》,1869,第 66 页)“人类的体格已经与野兽的结构不同,在身体上更加无助和虚弱。也就是说,在所有其他分歧中,这种分歧最不可能归因于纯粹的自然选择。”他列举了身体赤裸且不受保护的状态,没有用于防御的大牙齿或爪子,人的力量和速度微弱,以及通过嗅觉发现食物或避免危险的微弱能力。除了这些缺陷之外,可能还有一个更严重的缺陷,即他无法快速攀爬,从而逃离敌人。对于温暖国家的居民来说,脱发不会造成重大伤害。因为我们知道,不穿衣服的火地岛人可以在恶劣的气候下生存。当我们将人类与猿类的手无寸铁的状态进行比较时,我们必须记住,后者所拥有的巨大犬齿是雄性在完全发育时才拥有的,并且主要被它们用来与对手战斗;然而,没有这样提供的雌性却设法生存下来。

就身体大小或力量而言,我们不知道人类是黑猩猩等小型物种的后裔,还是大猩猩等强大物种的后裔。因此,我们不能说人类与他的祖先相比是变得更大、更强,还是更小、更弱。然而,我们应该记住,一种拥有巨大体型、力量和凶猛性的动物,并且像大猩猩一样,可以保护自己免受所有敌人的侵害,它也许不会变得社会化:这将最有效地抑制社会性的获得。更高的精神品质,例如同情心和对同胞的爱。因此,对于人类来说,由某种相对较弱的生物产生可能是一个巨大的优势。

人的力量和速度较小,缺乏天然武器等,首先可以通过他的智力来平衡,通过智力,他为自己创造了武器、工具等,尽管仍然处于野蛮状态其次,他的社会品质使他能够向同胞提供援助并接受同胞的帮助。世界上没有哪个国家比南部非洲更盛产危险的野兽。没有哪个国家比北极地区的物质条件更令人恐惧;然而,布须曼人是最弱小的种族之一,却在南部非洲生存,就像北极地区矮小的爱斯基摩人一样。毫无疑问,人类的祖先在智力上,甚至在社会性格上,都低于现有的最低等野蛮人。但完全可以想象,如果他们的智力有所进步,同时逐渐失去像爬树等那样的野蛮能力,那么他们可能会存在,甚至繁荣。但是这些祖先不会接触到任何东西。如果他们居住在一些温暖的大陆或大岛屿上,例如澳大利亚、新几内亚或婆罗洲(现在是红毛猩猩的家园),即使他们比任何现有的野蛮人更加无助和无助,也会面临特殊的危险。在某些如此大的地区,部落与部落之间的竞争所产生的自然选择,再加上习惯的遗传效应,在有利的条件下,足以使人类在有机尺度上达到目前的崇高地位。 。

第三章 •14,600字
人与低等动物智力的比较

最高等的猿类和最低等的野蛮人之间的精神力量差异巨大——某些共同的本能——情感——好奇心——模仿——注意力——记忆——想象力——理性——进步进步——动物使用的工具和武器——抽象、自我——意识——语言——美感——对上帝的信仰、精神力量、迷信。

我们在前两章中已经看到,人的身体结构中带有明显的来自某种低等形态的痕迹。但有人可能会指出,由于人的智力与所有其他动物有很大不同,因此这个结论肯定有一些错误。毫无疑问,在这方面的差异是巨大的,即使我们比较一个最低级的野蛮人的思想,他没有语言来表达任何高于四的数字,并且几乎不使用任何抽象术语来表达常见的物体或情感( 1. 请参阅拉伯克在《史前时代》第 354 页等中给出的有关这些观点的证据,以及组织最严密的猿类的证据。毫无疑问,这种差异仍然是巨大的,即使其中一种高等猿类已经得到改进或文明化,就像狗与其母体狼或豺相比一样。火地岛人属于最低等的野蛮人。但令我不断感到惊讶的是,英国皇家海军“小猎犬”号上的三个当地人在英国生活了几年,会说一点英语,他们的性情和大部分智力与我们非常相似。如果除了人类之外,没有任何有机体拥有任何精神力量,或者如果他的力量与低等动物的力量完全不同,那么我们永远无法说服自己,我们的高级能力是逐渐发展起来的。但可以看出,这种本质上的区别并不存在。我们还必须承认,最低等的鱼类(如七鳃鳗或文昌鱼)与高等猿类之间的智力差距,比猿与人之间的智力差距要大得多。然而这个间隔却被无数的层次所填满。

野蛮人与霍华德或克拉克森之间在道德性格上也存在着不小的差异,例如老航海家拜伦所描述的那个人,他的孩子因为一篮子海胆掉在了岩石上而被猛烈地摔在岩石上;而野蛮人与霍华德或克拉克森之间的道德品质也有不小的差异。在智力上,介于几乎不使用任何抽象术语的野蛮人与牛顿或莎士比亚之间。最高等种族的最高等人和最低等野蛮人之间的这种差异,是通过最细微的等级联系起来的。因此,它们有可能通过并相互发展。

本章的目的是要表明,人类和高等哺乳动物在心智能力方面没有根本区别。该主题的每个部分都可以扩展为一篇单独的文章,但这里必须进行简要处理。由于心智能力的分类还没有被普遍接受,我将按照最方便我的目的的顺序来安排我的评论;并会挑选那些给我印象最深的事实,希望对读者产生一些影响。

对于等级非常低的动物,我将在性选择中给出一些额外的事实,表明它们的智力比预期的要高得多。同一物种个体的能力差异对我们来说很重要,这里将给出一些说明。但是,在这个问题上讨论许多细节是多余的,因为我在经常询问中发现,所有长期关注包括鸟类在内的多种动物的人都一致认为,个体之间的差异很大。每一个心理特征。最低等生物体的精神力量最初是以何种方式发展起来的,就像生命本身最初是如何起源的一样,是一个毫无希望的探究。如果人类要解决这些问题,那么这些都是遥远的未来的问题。

由于人与低等动物具有相同的感官,因此他的基本直觉必然是相同的。人类也有一些共同的本能,如自我保护、性爱、母亲对新生儿的爱、后者所具有的吮吸欲望等等。但人类的本能也许比系列中紧随其后的动物所拥有的本能要少一些。东部岛屿的红毛猩猩和非洲的黑猩猩会搭建睡觉的平台;而且,由于这两个物种都遵循相同的习惯,因此可以说这是出于本能,但我们不能确定这不是两种动物具有相似需求并拥有相似推理能力的结果。正如我们所假设的,这些猿类避开了热带地区的许多有毒水果,而人类却没有这样的知识:但作为我们的家畜,当被带到异国他乡时,当春天第一次出现时,经常会吃有毒的草药,我们不能确定猿类不会从自己的经验或父母的经验中学习选择什么水果。然而,可以肯定的是,正如我们很快就会看到的,猿类对蛇,可能还有其他危险的动物,有一种本能的恐惧。

与低等动物相比,高等动物的本能数量极少且相对简单,这是显着的。居维叶认为,本能和智力是成反比的。有些人认为高等动物的智力是从他们的本能中逐渐发展起来的。但 Pouchet 在一篇有趣的文章中(2.“L'Instinct chez les Insectes”,“Revue des Deux Mondes”,1870 年 690 月,第 3 页)表明,这种反比并不真正存在。那些拥有最奇妙本能的昆虫当然是最聪明的。在脊椎动物系列中,最不聪明的成员,即鱼类和两栖动物,不具备复杂的本能;在哺乳动物中,海狸的本能最为显着,它非常聪明,每一个读过摩根先生出色著作的人都会承认这一点。 (1868.《美国海狸和他的作品》,XNUMX 年。)

尽管根据 Herbert Spencer 先生的说法(4.《心理学原理》,第 2 版,1870 年,第 418-443 页),智力的最初曙光是通过反射动作的倍增和协调而发展起来的。 ,虽然许多更简单的本能逐渐发展为反射行为,并且很难与它们区分开来,就像幼小动物吸吮的情况一样,但更复杂的本能似乎是独立于智力而起源的。然而,我绝不希望否认本能行为可能会失去其固定的和未经教导的特征,而被自由意志帮助下的其他行为所取代。另一方面,一些智能行为经过几代人的执行后,会转化为本能并被遗传,就像大洋岛屿上的鸟类学会避开人类一样。这些行为可以说是品质上的退化,因为它们不再是通过理性或经验来执行的。但更多更复杂的本能似乎是以完全不同的方式获得的,即通过对更简单的本能行为的变化进行自然选择。这种差异似乎是由作用于大脑组织的相同未知原因引起的,这会引起身体其他部位的轻微差异或个体差异;由于我们的无知,这些差异通常被认为是自发产生的。我认为,当我们反思不育的工蚁和蜜蜂的奇妙本能时,我们无法就更复杂的本能的起源得出其他结论,因为它们不会让后代继承经验和改良的影响。习惯。

尽管,正如我们从上述昆虫和海狸身上学到的那样,高度的智力肯定与复杂的本能兼容,而且尽管最初自愿学习的动作可以很快通过习惯以反射动作的快速和确定性来执行,然而,自由智力和本能的发展之间存在一定程度的干扰也并非不可能——后者意味着大脑的某些遗传性改变。我们对大脑的功能知之甚少,但我们可以看出,随着智力的高度发展,大脑的各个部分必须通过非常复杂的、最自由的相互交流的渠道连接起来;因此,每个单独的部分可能不太适合以明确的、遗传的(即本能的)方式回应特定的感觉或联想。智力低下与形成固定习惯(尽管不是遗传习惯)的强烈倾向之间似乎甚至存在某种联系。因为正如一位睿智的医生对我所说的那样,稍微低能的人往往会按照常规或习惯行事。如果这一点得到鼓励,他们就会更加快乐。

我认为这个题外话值得一提,因为当我们将基于对过去事件的记忆、远见、理性和想象力的高等动物的行为与完全相似的行为进行比较时,我们可能很容易低估高等动物的智力,尤其是人类的智力。低等动物本能地进行的动作;在后一种情况下,执行此类行为的能力是通过精神器官的可变性和自然选择逐步获得的,而动物在每一代中都没有任何有意识的智力。毫无疑问,正如华莱士先生所言(5.“对自然选择理论的贡献”,1870年,第212页),人类所做的许多智能工作都是由于模仿而不是推理;但是,人类的行为与许多低等动物的行为之间有一个巨大的区别,即人类无法在第一次尝试时,通过模仿的能力来制造一把石斧或独木舟。他必须通过实践来学习他的工作;另一方面,海狸可以建造水坝或运河,鸟也可以或几乎可以建造巢,蜘蛛也可以建造奇妙的网(6.有关这一点的证据,请参阅J. Traherne Moggridge 先生最有趣的作品,《收获蚂蚁和活板蜘蛛》,1873 年,第 126、128 页),这是在年老且经验丰富时第一次尝试。

回到我们当前的主题:低等动物,就像人一样,明显地感受到快乐和痛苦、幸福和痛苦。小狗、小猫、小羊等小动物在一起玩耍时,就像我们自己的孩子一样,最能体现幸福。甚至昆虫也会一起玩耍,正如杰出观察家 P. Huber 所描述的那样(7. 'Recherches sur les Moeurs des Fourmis,' 1810, p. 173.),他看到蚂蚁追逐并假装互相咬,就像这样很多小狗。

低等动物与我们人类有同样的情绪,这一事实已得到充分证实,因此不必因许多细节而使读者感到厌倦。恐惧对他们的作用与对我们的作用是一样的,导致肌肉颤抖、心脏跳动、括约肌松弛、毛骨悚然。怀疑是恐惧的产物,是大多数野生动物的显着特征。我认为,阅读 E. Tennent 爵士对用作诱饵的雌象的行为的描述时,不可能不承认它们故意进行欺骗,并且非常了解它们的含义。勇气和胆怯是同一物种个体之间差异极大的品质,这一点在我们的狗身上显而易见。有的狗、马脾气暴躁,容易生闷气;别人脾气好;这些品质当然是遗传的。每个人都知道动物是多么容易发怒,而且它们表现得多么明显。关于各种动物迟来已久的巧妙复仇的许多轶事已经发表,而且可能是真实的。准确的 Rengger 和 Brehm (8. 以下所有陈述均以这两位博物学家的权威给出,均取自 Rengger 的《Naturgesch. der Säugethiere von Paraguay》,1830 年,第 41-57 节,以及 Brehm 的《Thierleben, B. 是 10-87。) 指出他们驯服的美洲和非洲猴子肯定会报复自己。安德鲁·史密斯爵士是一位动物学家,他的严谨准确性众所周知,他给我讲了下面这个故事,他本人也是这个故事的目击者;在好望角,一名军官经常困扰一只狒狒,周日,狒狒看到他即将参加游行,便将水倒入洞中,并匆忙制作了一些厚泥,当军官经过时,他熟练地将其泼在了军官身上,让很多围观的人都觉得好笑。此后很长一段时间,每当狒狒看到受害者时,他都会感到高兴和胜利。

狗对主人的爱是众所周知的;正如一位老作家古怪地说的那样(9.引自劳德·林赛博士,在他的《低等动物心智生理学》,《心理科学杂志》,1871 年 38 月,第 XNUMX 页。)这个地球上有一个东西,爱你胜过爱自己。”

人们都知道,在死亡的痛苦中,狗会爱抚主人,每个人都听说过狗在活体解剖中遭受痛苦,它舔了操作者的手;这个人,除非由于我们知识的增长而完全证明了手术的合理性,或者除非他有一颗铁石心肠,否则他一定会在生命的最后一刻感到悔恨。

正如惠厄尔(10.《布里奇沃特论文》,第 263 页)所提出的很好的问题,“谁读到了母爱的感人事例,这些事例经常涉及到所有国家的妇女和所有动物的雌性,谁会怀疑这两种情况的作用原理是一样的吗?”我们在最琐碎的细节中看到母爱的体现;因此,伦格尔观察到一只美洲猴(Cebus)小心翼翼地驱赶困扰她婴儿的苍蝇。杜沃塞尔看到长臂猿在小溪里给孩子们洗脸。雌性猴子对于失去幼崽的悲痛如此强烈,以至于不可避免地会导致布雷姆在北非圈养的某些种类的死亡。孤儿猴总是被其他猴子(无论雄性还是雌性)收养并精心看护。一只雌性狒狒心胸宽广,不仅收养了其他物种的小猴子,还偷走了小狗和小猫,并不断随身携带。然而,她的好意并没有达到与收养的后代分享食物的程度,这让布雷姆感到惊讶,因为他的猴子总是与自己的孩子公平地分配一切。一只被收养的小猫抓伤了这只深情的狒狒,狒狒当然有很好的智力,因为她对被抓伤感到非常惊讶,并立即检查小猫的脚,毫不费力地咬掉了爪子。 (11. 一位批评家毫无根据(《季刊评论》,1871 年 72 月,第 XNUMX 页),对布雷姆所描述的这种行为的可能性提出质疑,目的是为了抹黑我的工作。因此,我尝试了一下,发现我我可以用自己的牙齿轻易地抓住一只近五周大的小猫锋利的小爪子。)在动物园里,我从饲养员那里听说一只老狒狒(C. chacma)收养了一只恒河猴;但当一只小钻和山魈被放进笼子里时,她似乎意识到这些猴子虽然是不同的物种,但却是她的近亲,因为她立即拒绝了恒河猴并收养了它们。正如我所看到的,幼恒河猴对被如此拒绝感到非常不满,它会像一个顽皮的孩子一样,在安全的情况下骚扰和攻击幼钻和山魈。这种行为激起了老狒狒的极大愤慨。根据布雷姆的说法,当猴子受到任何一只狗的攻击时,猴子也会保护它们的主人,也会保护它们所依附的狗免受其他狗的攻击。但我们在这里讨论的是同情和忠诚的主题,我将再次讨论这一点。一些布雷姆猴非常喜欢以各种巧妙的方式戏弄它们不喜欢的某只老狗以及其他动物。

大多数更复杂的情绪是高等动物和我们人类所共有的。每个人都见过,如果主人对其他动物倾注大量感情,狗会多么嫉妒。我在猴子身上也观察到了同样的事实。这表明动物不仅有爱,而且渴望被爱。动物显然有模仿的感觉。他们喜欢认可或赞美;一只狗为主人提着篮子,表现出高度的自满或自豪。我认为,毫无疑问,狗会感到羞耻,这与恐惧不同,当过于频繁地乞讨食物时,它会感到羞耻,就像谦虚一样。大狗蔑视小狗的咆哮,这可以称为宽宏大量。一些观察家表示,猴子当然不喜欢被嘲笑。他们有时会虚构一些罪行。在动物园里,我看到一只狒狒,当它的饲养员拿出一封信或一本书大声朗读给它听时,它总是会勃然大怒。他的愤怒如此强烈,正如我有一次亲眼所见,他咬住了自己的腿,直到鲜血直流。狗表现出一种可以称之为幽默感的东西,这与单纯的玩耍不同。如果向一个人扔一根棍子或其他类似的物体,他通常会把它带走一小段距离;然后蹲下来,把它放在他面前的地上,等到他的主人走近了,才把它拿走。然后狗会抓住它并胜利地冲走,重复同样的动作,显然很喜欢这个恶作剧。

现在我们将转向更多的智力情感和能力,它们非常重要,因为它们构成了更高智力发展的基础。动物显然喜欢兴奋,但也会感到无聊,正如狗身上所见,根据伦格的说法,猴子也是如此。所有动物都会感到惊奇,许多动物表现出好奇心。它们有时会遭受后一种品质的困扰,例如当猎人做出滑稽动作来吸引它们时;我在鹿、警惕的羚羊和某些野鸭身上都亲眼目睹了这一点。布雷姆奇怪地描述了他的猴子对蛇表现出的本能恐惧。但他们的好奇心是如此之大,以至于他们忍不住偶尔会以一种最人类的方式来满足他们的恐惧,即打开装着蛇的盒子的盖子。我对他的叙述感到非常惊讶,以至于我把一条毛绒玩具卷起来的蛇带进了动物园的猴舍,由此引起的兴奋是我见过的最奇怪的奇观之一。最受惊吓的是三种猴类:它们在笼子里跑来跑去,发出尖锐的危险信号叫声,其他猴子都能听懂。几只小猴子和一只老阿努比斯狒狒没有注意到这条蛇。然后我将填充标本放在地上一个较大的隔间中。过了一会儿,所有的猴子都围成一个大圈,目不转睛地盯着它,一副可笑的样子。他们变得极度紧张。因此,当一个他们熟悉的玩具木球不小心被移动到部分隐藏在稻草下面的木球时,他们立刻就逃走了。当一条死鱼、一只老鼠(12。我在我的《人与动物的情感表达》第 43 页中简要描述了它们这次的行为)、一只活乌龟、以及其他新物品被放入它们的笼子里;尽管一开始他们很害怕,但他们很快就走近、处理并检查了它们。然后,我将一条活蛇放入一个纸袋中,并将其嘴松散地封闭在一个较大的隔间中。其中一只猴子立刻走近,小心翼翼地把袋子打开一点,往里看了一眼,然后立刻就跑开了。然后我亲眼目睹了布雷姆所描述的,一只又一只的猴子,高高地抬起头,转向一侧,忍不住向直立的袋子里看了一眼,看到静静地躺在底部的可怕物体。看起来,猴子似乎具有某种动物学亲缘关系的概念,因为布雷姆饲养的猴子对无辜的蜥蜴和青蛙表现出一种奇怪的、尽管是错误的本能恐惧。众所周知,红毛猩猩在第一眼看到海龟时也会非常惊慌。 (13. WCL Martin,《哺乳动物自然史》,1841 年,第 405 页。)

模仿的原则对于人类来说是很强烈的,正如我自己所观察到的,对于野蛮人来说尤其如此。在大脑的某些病态状态下,这种趋势被夸大到了非同寻常的程度:一些偏瘫患者和其他人,在大脑炎症软化开始时,无意识地模仿所说的每一个单词,无论是用自己的语言还是外语,以及在他们附近进行的每个手势或动作。 (14. Bateman 博士,“论失语症”,1870 年,第 110 页。)Desor(15. 引自 Vogt,“Mémoire sur les Microcephales”,1867 年,第 168 页。)指出没有动物会自愿模仿某个动作由人类执行,直到在上升的范围内,我们来到猴子,众所周知,猴子是可笑的嘲笑者。然而,动物有时会模仿彼此的行为:因此,由狗饲养的两种狼学会了吠叫,有时豺狼也学会了吠叫(16.“驯化下动植物的变异”,第 27 卷) .),但这是否可以称为自愿模仿是另一个问题。鸟儿会模仿父母的歌声,有时还会模仿其他鸟儿的歌声。众所周知,鹦鹉善于模仿它们经常听到的任何声音。 Dureau de la Malle 描述了一只由猫养大的狗的故事(17.《Annales des Sciences Nat.》(第 1 系列),tom.xxii.p.397.),猫学会了模仿猫的众所周知的动作。猫舔她的爪子,从而清洗她的耳朵和脸;著名博物学家奥杜安也见证了这一点。我收到了几个确认账户;其中一个例子中,一只狗不是由猫哺乳的,而是与一只猫和小猫一起长大的,因此养成了上述习惯,他在十三年的一生中一直如此。 Dureau de la Malle 的狗也向小猫们学习了玩球的方法,用前爪滚动球,然后在球上跳跃。一位记者向我保证,他家里的一只猫过去常常把爪子放进牛奶罐里,因为它的嘴对于它的头来说太窄了。这只猫的小猫很快就学会了同样的技巧,并且以后一有机会就练习它。

许多动物的父母相信幼崽的模仿原则,尤其是相信它们的本能或遗传倾向,可以说是在教育它们。当一只猫把一只活老鼠带给她的小猫时,我们就看到了这一点;杜洛·德拉马勒(Dureau de la Malle)对他对鹰的观察进行了有趣的描述(在上面引用的论文中),这些观察通过首先将死去的老鼠和麻雀从空中扔下来(年轻人通常将死老鼠和麻雀扔到空中)来教会它们年轻人的灵活性和距离判断。未能捕获,然后将活鸟带回并释放。

对于人类的智力进步来说,几乎没有什么能力比注意力更重要了。动物清楚地体现了这种力量,就像猫在洞边观察并准备扑向猎物时一样。野生动物有时会变得如此专注,以至于很容易接近它们。巴特利特先生给了我一个奇怪的证据,证明猴子的这种能力有多么多变。一个训练猴子表演戏剧的人,过去常常从动物学会以每只五英镑的价格购买常见的猴子;但他提出愿意出双倍的价格,如果他能保留三四件几天,以便选择一件。当被问到他怎么可能这么快就知道一只特定的猴子是否会成为一名好演员时,他回答说这完全取决于它们的注意力。如果当他向一只猴子说话和解释任何事情时,它的注意力很容易被墙上的苍蝇或其他琐碎的物体分散,那么情况就毫无希望了。如果他试图通过惩罚来让一只不专心的猴子做出行为,它就会变得闷闷不乐。另一方面,细心照顾他的猴子总是可以被训练的。

说动物对人和地方有极好的记忆力几乎是多余的。据安德鲁·史密斯爵士告知,好望角的一只狒狒在阔别九个月后高兴地认出了他。我有一只狗,它性格凶猛,对所有陌生人都厌恶,我在离开五年零两天后特意测试了它的记忆力。我走到他住的马厩附近,用我以前的方式对他喊道。他没有表现出任何喜悦,而是立即跟着我出去散步,并且服从我,就像我半小时前才与他分开一样。一连串沉睡了五年的旧联想,瞬间在他脑海中被唤醒。正如 P. Huber (18. 'Les Moeurs des Fourmis,' 1810, p. 150.) 所清楚表明的那样,即使是蚂蚁,在分离四个月后也能认出它们的同伴属于同一群落。动物当然可以通过某种方式判断重复事件之间的时间间隔。

想象力是人类最高的特权之一。通过这种能力,他将以前的图像和想法结合起来,独立于意志,从而创造出辉煌而新颖的成果。正如让·保罗·里希特 (Jean Paul Richter) 所评论的那样(19. 引自莫兹利博士的《心灵生理学和病理学》,1868 年,第 19, 220 页),一位诗人“必须反思他是否应该让一个角色说是或否——魔鬼与他同在;他只是一具愚蠢的尸体。”梦让我们对这种力量有了最好的认识。正如让·保罗再次所说:“梦是一种不由自主的诗歌艺术。”我们想象的产物的价值当然取决于我们印象的数量、准确性和清晰度,取决于我们选择或拒绝非自愿组合的判断和品味,并且在一定程度上取决于我们自愿组合它们的能力。狗、猫、马,可能还有所有高等动物,甚至鸟类(20. Jerdon 博士,“印度鸟类”,第 1862 卷,136 年,第 xxi 页。Houzeau 说,他的长尾小鹦鹉和金丝雀鸟会做梦: 'Etudes sur les Facultes Mentales des Animaux,' tom. ii. p. 21.) 有生动的梦,这从他们的动作和发出的声音中可以看出,我们必须承认他们拥有一定的想象力。一定有什么特别的东西,导致狗在夜间,尤其是在月光下嚎叫,以一种称为吠叫的非凡而忧郁的方式。并不是所有的狗都会这样做;而且,根据 Houzeau 的说法(1872.同上,181,tom.ii.p.XNUMX.),他们并不看月亮,而是看地平线附近的某个固定点。乌佐认为,他们的想象力受到周围物体模糊轮廓的干扰,在他们面前浮现出奇异的图像:如果是这样,他们的感觉几乎可以被称为迷信。

我认为,在人类心灵的所有能力中,理性处于巅峰。现在只有少数人质疑动物拥有一定的推理能力。人们可能会不断地看到动物停顿、深思熟虑和下定决心。一个重要的事实是,博物学家对任何特定动物的习性研究得越多,他就越会归因于理性,而不是归因于未习得的本能。 (22. LH 摩根先生 1868 年所著的《美国海狸》很好地说明了这一点。然而,我不禁想到,他过分低估了本能的力量。)在以后的章节中,我们将看到一些等级极低的动物显然表现出一定的理性。毫无疑问,通常很难区分理性的力量和本能的力量。例如,海耶斯博士在他的《开放的极地海洋》一书中反复指出,他的狗并没有继续以紧凑的身体拉雪橇,而是在遇到薄冰时分叉和分开,因此它们的重量可能分布得更均匀。这通常是旅行者收到的第一个警告:冰层正在变薄且危险。现在,狗的行为是根据每个人的经验,还是根据年长和更聪明的狗的例子,还是根据遗传的习惯,即本能?这种本能可能从很久以前,当当地人第一次用狗来拉雪橇时就已经出现了。或者,北极狼(爱斯基摩狗的亲本)可能已经获得了一种本能,促使它们在薄冰上不会以紧密的群体攻击猎物。

我们只能根据行为发生的环境来判断,是出于本能,还是出于理性,或者仅仅是观念的联想:然而,后者的原则与理性密切相关。莫比乌斯教授给出了一个奇怪的案例(23.“Die Bewegungen der Thiere”等,1873年,第11页),一条梭子鱼被一块玻璃板与毗邻的养有鱼的水族馆隔开,并且为了捕捉其他鱼,他经常猛烈地撞向玻璃,有时甚至完全惊呆了。梭子鱼就这样持续了三个月,但最后学会了谨慎,不再这样做了。然后玻璃板被移开,但是梭子鱼不会攻击这些特定的鱼,尽管它会吞食后来引入的其他鱼;他脆弱的头脑中强烈地想到了对他的前邻居的袭击,这让他感到强烈的震惊。如果一个从未见过大平板玻璃窗的野蛮人向它猛冲一撞,那么他会在很长一段时间内将震动与窗框联系起来;但与梭子鱼截然不同的是,他可能会反思障碍的性质,并在类似情况下保持谨慎。现在,对于猴子来说,正如我们即将看到的,一旦执行过某个动作,就会产生痛苦或仅仅令人不快的印象,有时就足以阻止动物重复该行为。如果我们将猴子和梭子鱼之间的这种差异仅仅归因于其中一种比另一种更强烈和更持久的思想联想,尽管梭子鱼经常受到更严重的伤害,那么我们是否可以在人类的情况下坚持这一点?类似的差异意味着拥有根本不同的思想?

Houzeau 提到(24. 'Études sur les Facultés Mentales des Animaux,' 1872, tom. ii. p. 265.),当他穿过德克萨斯州广阔而干旱的平原时,他的两只狗严重口渴,并且在 XNUMX 岁之间他们四十次冲下洼地去寻找水源。这些洼地不是山谷,里面没有树木,也没有任何其他植被的差异,而且由于它们绝对干燥,不可能有潮湿泥土的气味。这些狗的表现就好像它们知道浸入地下是它们找到水的最佳机会,而乌佐也经常在其他动物身上看到同样的行为。

我见过,正如我敢说其他人也看到的那样,当一个小物体被扔到动物园里的一头大象够不到的地面上时,它会吹过物体上方地面上的鼻子,从而使电流反射各方都可以将物体驱动到他的范围内。一位著名的民族学家韦斯特罗普先生再次告诉我,他在维也纳观察到一只熊故意用爪子在靠近笼子栅栏的水中制造水流,以便抓起一块漂浮的面包在他力所能及的范围内。大象和熊的这些行为很难归因于本能或遗传习惯,因为它们对自然状态下的动物没有什么用处。那么,这样的行为,由一个未受过教育的人所执行的,与由一种高等动物所执行的,有什么区别呢?

野人与狗经常在低处找到水源,这种情况下的巧合在他们的脑海中产生了联系。一个有教养的人也许会就这个问题提出一些一般性的主张;但从我们对野蛮人的了解来看,他们是否会这样做是非常值得怀疑的,而狗肯定不会这样做。但野蛮人和狗都会以同样的方式寻找,尽管常常会失望。在这两者中,这似乎同样是一种理性行为,无论是否有意识地将有关该主题的任何一般命题摆在脑海中。 (25. 赫胥黎教授以令人钦佩的清晰分析了一个人和一只狗在与我的文本中给出的类似案例中得出结论的心理步骤。请参阅他的文章“达尔文先生的批评者, ”,《当代评论》,1871 年 462 月,第 1873 页,以及他的《评论与散文》,279 年,第 XNUMX 页。)这同样适用于大象和熊在空气或水中产生电流。野蛮人当然既不知道也不关心所期望的运动是根据什么规律来实现的。然而,他的行为将受到粗鲁的推理过程的指导,就像哲学家在他最长的演绎链中一样。毫无疑问,他和高等动物之间存在着这样的区别,他会注意到更细微的环境和条件,并在经历更少的经验后观察到它们之间的任何联系,这是至关重要的。我每天记录我的一个婴儿的行为,当他大约十一个月大时,在他能说出一个词之前,我不断地被他更快的速度所震惊,各种物体和声音都以这种速度出现。与我所认识的最聪明的狗相比,它在他的脑海中联系在一起。但高等动物与低等动物(如梭子鱼)的联想能力以及推理和观察能力也有完全相同的不同。

在经历了非常短暂的经验之后,美国猴子的以下行为很好地表明了理性的提示,这些猴子在它们的等级中排名较低。伦格是一位最细心的观察者,他说,当他第一次给巴拉圭的猴子喂鸡蛋时,它们把鸡蛋打碎了,因此损失了很多内容物;然后,他们用一端轻轻敲击某个坚硬的物体,然后用手指将贝壳碎片剔下来。在用任何锋利的工具只割伤自己一次之后,他们就不会再碰它,或者会非常小心地处理它。他们通常会收到用纸包着的糖块。伦格尔有时会在纸上放一只活黄蜂,这样在匆忙展开纸时就会被蜇伤。一旦发生这种情况,他们总是先将包裹放在耳边,以检测里面是否有任何动静。 (26. 贝尔特先生在他最有趣的著作《尼加拉瓜的博物学家》,1874 年(第 119 页)中,同样描述了驯服的塞布斯的各种行为,我认为,这清楚地表明这种动物拥有某种推理能力。力量。)

以下案例与狗有关。 Colquhoun 先生(27.《摩尔与湖》,第 45 页。Hutchinson 上校在《Dog Breaking》,1850 年,第 46 页。)飞过两只野鸭,它们落在溪流的另一边;他的猎犬试图同时把两者带过来,但没有成功。然后,尽管她以前从未知道过会弄乱羽毛,但她故意杀死了一只,带了另一只,然后回来寻找那只死鸟。哈钦森上校称,两只鹧鸪同时被射杀,一只被打死,另一只受伤。后者逃跑了,被猎犬抓住,猎犬回来时发现了那只死鸟。 “她停了下来,显然非常困惑,经过一两次尝试,发现她无法在不让带翅膀的鸟逃脱的情况下把它拿起来,她考虑了一会儿,然后故意用力咬碎它来杀死它,然后把它带来一起离开。这是她在任何比赛中故意伤害的唯一已知例子。”这里我们有理由,虽然不完全完美,因为猎犬可能先带了受伤的鸟,然后再回来寻找死鸟,就像两只野鸭的情况一样。我给出上述案例是基于两个独立证人的证据,因为在这两种情况下,猎犬经过深思熟虑,都打破了他们继承的习惯(不杀死猎物),并且因为他们表明他们的推理能力必须多么强大才能克服固定的习惯。

最后,我将引用著名的洪堡的一句话。 (28.《个人叙事》,英译,第 106 卷,第 29 页。)“南美的赶骡人说,‘我不会给你走得最轻松的骡子,但从理性上来说,——最能推理的人”;和;他补充道,“这种流行的表达方式是由长期经验决定的,它与动画机器系统作斗争,也许比所有思辨哲学的论点都更好。”然而,有些作家甚至否认高等动物具有一丝理性。他们试图通过看似纯粹的废话来解释,(1873.我很高兴发现像莱斯利·斯蒂芬先生这样敏锐的推理家(“达尔文主义和神性,自由思想论文”,80年,第XNUMX页) ),在谈到人类与低等动物心灵之间所谓的不可逾越的障碍时,他说:“事实上,在我们看来,所得出的区别并不比许多其他形而上学的区别更好;是这样的假设:因为你可以给两种事物赋予不同的名称,因此它们必定具有不同的性质。很难理解任何养过狗或见过大象的人怎么会对动物的能力产生怀疑。执行基本的推理过程。”)上述所有事实。

我认为,现在已经表明,人类和高等动物,尤其是灵长类动物,有一些共同的本能。所有人都有相同的感官、直觉和感觉——相似的激情、感情和情感,甚至更复杂的情感,如嫉妒、怀疑、竞争、感激和宽宏大量;他们行诡诈、报复心强;他们有时容易受到嘲笑,甚至有幽默感;他们感到惊奇和好奇;他们拥有相同的模仿、注意力、深思熟虑、选择、记忆、想象力、思想联想和推理能力,尽管程度截然不同。同一物种的个体在智力上从绝对的低能到卓越。他们也容易精神错乱,尽管比人类的情况要少得多。 (30. 参见 W. Lauder Lindsay 博士所著的《动物的疯狂》,发表于《心理科学杂志》,1871 年 XNUMX 月。)然而,许多作者坚持认为,人类与所有低等动物之间存在着不可逾越的障碍。他的智力。我以前收集了二十多条这样的格言,但它们几乎毫无价值,因为它们的巨大差异和数量证明了这种尝试的难度,如果不是不可能的话。有人断言,只有人类才有能力不断进步。他独自使用工具或火、驯养其他动物或拥有财产;没有动物具有抽象能力或形成一般概念的能力,没有自我意识并理解自己;没有动物会使用语言;只有人类才有美感,容易反复无常,有感恩感、神秘感等;相信上帝,或者被赋予良心。我将冒昧地对这些要点中更重要和更有趣的部分发表一些评论。

萨姆纳大主教以前主张(31。引自 C. Lyell 爵士,《人类的古代》,第 497 页。)只有人类才有能力不断进步。毫无疑问,他比任何其他动物都能取得更大、更快的进步。这主要得益于他的演讲能力和传授知识的能力。对于动物来说,首先要看个体,凡是有过设置陷阱经验的人都知道,年轻的动物比年老的动物更容易被抓住;而且敌人更容易接近它们。即使是古老的动物,也不可能在同一个地方、用同一种陷阱捕获许多动物,也不可能用同一种毒药消灭它们;但不可能所有人都中了毒,也不可能所有人都落入陷阱。他们必须通过看到自己的弟兄被捕或中毒而学会谨慎。在北美,毛皮动物长期以来一直受到追捕,根据所有观察者的一致证词,它们表现出几乎令人难以置信的睿智、谨慎和狡猾;但诱捕已经存在了很长时间,遗传可能已经发挥了作用。我收到过一些报道,当任何地区首次安装电报机时,许多鸟儿都会因逆着电线飞翔而自杀,但在短短几年的时间里,它们学会了通过观察来避免这种危险,就像看起来的那样。 ,他们的战友被杀了。 (32. 有关更多证据和详细信息,请参见 M. Houzeau,“Études sur les Facultés Mentales des Animaux”,tom. ii. 1872,第 147 页。)

如果我们着眼于连续几代或种族,毫无疑问,鸟类和其他动物逐渐获得和失去对人类或其他敌人的谨慎(33。参见,关于海洋岛屿上的鸟类,我的“日记” “小猎犬号航行期间的研究”,1845 年,第 398 页。“物种起源”,第 5 版,第 260 页。);这种谨慎当然主要是一种遗传的习惯或本能,但部分是个人经验的结果。勒罗伊(Leroy)是一位优秀的观察家(34. 'Lettres Phil. sur l'Intelligence des Animaux,' nouvelle edit., 1802, p. 86.),他指出,在狐狸遭到大量猎杀的地区,幼年狐狸第一次离开它们的栖息地时,毫无疑问,洞穴中的洞穴比那些不受太多干扰的地区的老洞穴要警惕得多。

我们的家养狗是狼和豺狼的后代(35.请参阅第一章第一卷“论驯养下动植物的变异”中关于这一点的证据。),尽管它们可能没有在他们狡猾,可能在警惕和怀疑方面失败了,但他们在某些道德品质方面却取得了进步,例如情感、可信度、脾气,可能还有一般智力。普通老鼠已经征服并击败了整个欧洲、北美部分地区、新西兰以及最近在台湾和中国大陆的其他几个物种。 Swinhoe 先生(36,《动物学学会论文集》,1864 年,第 186 页)描述了后两个案例,他将普通老鼠对大老鼠的胜利归因于它的狡猾。后一种品质可能归因于人类习惯性地运用其所有能力来避免灭绝,以及几乎所有不那么狡猾或意志薄弱的老鼠都被人类不断地消灭。然而,普通老鼠的成功可能是因为它在与人类联系之前比其他物种更狡猾。独立于任何直接证据,坚持认为随着时间的推移,没有任何动物在智力或其他心智方面取得进步,这就是回避物种进化的问题。根据拉尔特的说法,我们已经看到,现有的几个目哺乳动物的大脑比它们古老的第三纪原型的大脑更大。

人们常说,没有动物会使用任何工具;动物只是使用工具而已。但在自然状态下,黑猩猩会用石头敲碎一种本地水果,有点像核桃。 (37. Savage 和 Wyman,《Boston Journal of Natural History》,第 iv. 1843-44,第 383 页。)Rengger(38.“Säugethiere von Paraguay”,1830 年,第 51-56 节。)美洲猴因此能撬开坚硬的棕榈坚果;后来,它又自发地用石头打开其他种类的坚果和盒子。因此,它还去除了具有令人讨厌的味道的软果皮。另一只猴子被教导用一根棍子打开一个大盒子的盖子,然后它用棍子作为杠杆来移动重物;我亲眼目睹了一个年轻的红毛猩猩将一根棍子插入缝隙中,然后将手滑到另一端,并以正确的方式将其用作杠杆。众所周知,印度驯服的大象会折断树枝并用它们来驱赶苍蝇。在自然状态下的大象身上也观察到了同样的行为。 (39.《印第安原野》,4 年 1871 月 40 日。)我见过一只年轻的红毛猩猩,当她以为自己要被鞭打时,她用毯子或稻草盖住并保护自己。在这几个例子中,石头和棍棒被用作工具。但它们同样也被用作武器。 Brehm (79. 'Thierleben,' B. 82, 41.) 根据著名旅行家 Schimper 的权威指出,在阿比西尼亚,当属于一种狒狒 (C. gelada) 的狒狒成群结队地从山上下来时为了掠夺田地,他们有时会遇到另一种物种(C. hamadryas)的军队,然后就会发生战斗。狒狒从大石头上滚下来,狒狒试图避开,然后两个物种发出巨大的骚动,猛烈地互相冲撞。布雷姆在陪同科堡-哥达公爵时,协助在阿比西尼亚门萨山口用火器攻击一群狒狒。作为回报,狒狒从山上滚下了如此多的石头,有些有一个人的头那么大,攻击者不得不仓促撤退。事实上,山口曾一度对商队关闭。值得注意的是,这些狒狒的行动是一致的。华莱士先生(1869.《马来群岛》,第 87 卷,XNUMX 年,第 XNUMX 页)曾三次看到雌性红毛猩猩带着幼崽,“折断榴莲树的树枝和大刺的果实,每一次愤怒的表现;造成如此多的导弹,有效地阻止了我们离树太近。”正如我多次看到的,黑猩猩会向冒犯他的人扔手边的任何物体;前面提到的好望角的狒狒为此目的准备了泥土。

在动物园里,一只牙齿脆弱的猴子常常用石头敲开坚果;饲养员向我保证,他用完石头后,就把它藏在稻草里,不会让其他猴子碰它。那么,这里就有了财产的概念。但这种想法对于每只有骨头的狗以及大多数或所有有巢的鸟来说都是共同的。

阿盖尔公爵 (42. 'Primeval Man,' 1869, pp. 145, 147.) 评论说,为了特殊目的而制造工具绝对是人类所特有的。他认为这在他和畜生之间形成了不可估量的鸿沟。这无疑是一个非常重要的区别;但在我看来,J. 拉伯克爵士的建议(43.《史前时代》,1865,第 473 页等)很有道理,即当原始人第一次将燧石用于任何目的时,他可能会不小心将它们打碎,然后就会使用锋利的碎片。从这一步开始,故意打碎燧石就只是一小步,而粗鲁地塑造它们则不是一个很大的步骤。然而,如果我们可以根据新石器时代的人们开始研磨和抛光石器之前所经过的漫长时间来判断,后一种进步可能需要很长时间。正如 J. Lubbock 爵士同样指出的那样,在打碎燧石时,会发出火花,在研磨燧石时会产生热量:因此,“可能起源于”两种通常的“获得火”的方法。在熔岩偶尔流经森林的许多火山地区,人们会了解火的本质。拟人化的猿类可能是在本能的引导下,为自己建造了临时的平台。但由于许多本能在很大程度上受理性控制,因此更简单的本能,例如构建平台,可能很容易转变为自愿和有意识的行为。众所周知,红毛猩猩会在夜间用露兜树的叶子遮盖自己。布雷姆说,他的一只狒狒曾经通过在头上扔一张草席来保护自己免受阳光的照射。在这几种习惯中,我们可能看到了一些更简单的艺术的第一步,例如粗鲁的建筑和服装,因为它们出现在人类的早期祖先中。

抽象、一般概念、自我意识、心理个性

对于任何比我拥有更多知识的人来说,要确定动物在多大程度上表现出这些高级精神力量的痕迹都是非常困难的。这种困难源于无法判断动物大脑中的想法。而且,作者对上述术语的含义有很大不同,这一事实又造成了进一步的困难。如果从最近发表的各种文章来看,最大的重点似乎是认为动物完全不具备抽象能力或形成一般概念的能力。但是,当一只狗远远地看到另一只狗时,它通常会清楚地感觉到那是一只抽象的狗;因为当他走近时,如果另一只狗是朋友,他的整个态度就会突然改变。最近的一位作家评论说,在所有这些情况下,断言动物的心理行为与人类的心理行为在本质上并不相同,这纯粹是一种假设。如果其中任何一个将他用感官感知到的东西归结为心理概念,那么两者都会如此。 (44. 胡克姆先生,1873 年 XNUMX 月《伯明翰新闻》给马克斯·穆勒教授的一封信中。)当我用热切的声音对我的小猎犬说时(我已经尝试过很多次了),“嗨嗨,这是哪里?”她立即​​将其视为要狩猎某物的信号,通常首先快速环顾四周,然后冲进最近的灌木丛,寻找任何猎物,但什么也没发现,她抬头望向邻近的任何一棵树,寻找猎物。松鼠。现在,这些行为难道不清楚地表明,她心中有一个总体的想法或概念,即某种动物应该被发现并被猎杀吗?

可以坦率地承认,没有动物是有自我意识的,如果这个术语暗示动物会思考这些问题,比如他从哪里来,他将去往何处,或者什么是生与死,等等。但是,我们怎么能确信,一只具有出色记忆力和一定想象力的老狗,正如他的梦所表明的那样,不会反思他过去在追逐中的快乐或痛苦呢?这将是一种自我意识。另一方面,正如布赫纳 (Buchner) (45. 'Conférences sur la Théorie Darwinienne,' French translat. 1869, p. 132.) 所言,一个堕落的澳大利亚野蛮人的辛勤工作的妻子能做多少事,她很少使用抽象的东西。无法数到四以上,无法发挥她的自我意识,或反思她自己存在的本质。人们普遍承认,高等动物具有记忆力、注意力、联想力,甚至还有一定的想象力和理性。如果这些在不同动物身上差异很大的能力能够得到改进,那么通过发展和组合而进化出更复杂的能力,例如更高形式的抽象和自我意识等,似乎也没有什么大的不可能。比较简单的。有人强烈反对这里坚持的观点,即不可能说动物在上升尺度的什么时候变得能够抽象等等;但谁能说清楚我们的孩子在什么年龄会出现这种情况呢?我们至少看到,这种能力在儿童身上以难以察觉的程度发展起来。

动物保留其心理个性是毫无疑问的。当我的声音唤醒了前面提到的狗头脑中的一连串旧联想时,他一定保留了他的精神个性,尽管他大脑的每个原子在五年的时间里可能已经经历了不止一次的变化。这只狗可能会提出最近提出的论点来粉碎所有进化论者,并说:“我住在所有精神情绪和所有物质变化中......原子留下它们的印象作为其他原子落入它们腾出的地方的遗产的教义是与意识的表述相矛盾,因此是错误的;但这是进化论所必需的教导,因此这个假设是错误的。” (46. J. M'Cann 博士牧师,“反达尔文主义”,1869 年,第 13 页。)

语言

这种能力被公正地认为是人类与低等动物之间的主要区别之一。但是,作为一位非常有能力的法官,沃特利大主教评论道,“人类并不是唯一能够利用语言来表达自己脑海中所想内容的动物,并且或多或少能够理解他人所表达的内容。” (47. 引自《人类学评论》,1864 年,第 158 页。) 在巴拉圭,Cebus azarae 在兴奋时会发出至少六种不同的声音,这会激发其他猴子类似的情绪。 (48. Rengger,同上,第 45 节。) 正如 Rengger 和其他人所宣称的那样,我们可以理解猴子的特征和手势的运动,并且它们也部分地理解我们的动作。更值得注意的事实是,狗自从被驯化以来,就学会了用至少四种或五种不同的声调吠叫(49。参见我的“驯化下的动物和植物的变化”,第 27 卷)。虽然吠叫是一门新艺术,但毫无疑问,狗的野生亲本通过各种叫声来表达自己的感情。对于家养的狗,我们有渴望的吠叫,就像在追逐时一样;愤怒,以及咆哮;绝望的叫喊或嚎叫,就像被关起来时一样;夜间的吠叫;喜悦的叫声,就像和主人一起散步时一样;以及非常明显的要求或恳求,例如希望打开一扇门或一扇窗户时。乌佐特别关注这个问题,他表示,家禽至少会发出十几种有意义的声音。 (50.《动物的心理》,tom.ii.1872,第 346-349 页。)

然而,清晰语言的习惯使用是人类所特有的。但与低等动物一样,他使用无法言喻的叫声来表达他的意思,并借助手势和面部肌肉的运动。 (51. 请参阅 EB Tylor 先生非常有趣的著作“人类早期历史研究”,1865 年,第二章至第四章中对此主题的讨论。)这尤其适用于更简单和生动的感受,这些与我们的更高智力关系不大。我们痛苦、恐惧、惊讶、愤怒的呼喊,连同他们适当的行动,以及母亲对她心爱的孩子的呢喃,比任何言语都更能表达。人类与低等动物的区别并不是对清晰声音的理解,因为众所周知,狗能理解许多单词和句子。在这方面,他们与十到十二个月大的婴儿处于同一发展阶段,他们能理解许多单词和短句,但还不能说出一个单词。我们的独特特征不仅仅是发音,因为鹦鹉和其他鸟类都拥有这种能力。它也不仅仅是将确定的声音与确定的想法联系起来的能力;而是将确定的声音与确定的想法联系起来的能力。因为可以肯定的是,一些被教导说话的鹦鹉能够准确无误地将词语与事物、人与事件联系起来。 (52. 我收到了几份关于这方面的详细说明。据我所知,海军上将 BJ Sulivan 爵士是一位细心的观察者,他向我保证,长期饲养在他父亲家里的非洲鹦鹉总是称家里的某些人为“他在早餐时对每个人说“早上好”,在晚上离开房间时对每个人说“晚安”,并且从来没有颠倒过这些问候语。对 BJ Sulivan 爵士的父亲,他过去常这样说:在“早上好”的基础上加上一句简短的句子,这句话在他父亲去世后就再也没有重复过。他猛烈地斥责了一只从开着的窗户进入房间的陌生狗;他还斥责了另一只鹦鹉(说“你这个淘气的波利”)它已经从笼子里出来了,正在吃厨房桌子上的苹果。同样,请参见 Houzeau 关于鹦鹉的文章,“Facultés Mentales”,汤姆. ii. p. 309。A. Moschkau 博士告诉我,他认识一只椋鸟,它从来不会错误地用德语对到来的人说“早上好”,对离开的人说“再见,老伙计”。我还可以添加其他几个这样的例子。)低等动物与人类的不同之处仅在于其将最多样化的声音和想法联系在一起的几乎无限大的能力;而这显然取决于他精神力的高度发达。

正如高贵的语言学创始人之一霍恩·图克(Horne Tooke)所言,语言是一门艺术,就像酿造或烘焙一样;它是一门艺术。但写作可能是一个更好的比喻。这当然不是真正的本能,因为每种语言都需要学习。然而,它与所有普通艺术有很大不同,因为人类有一种本能的说话倾向,正如我们在幼儿的牙牙学语中看到的那样;然而,没有一个孩子有酿造、烘焙或写作的本能倾向。此外,现在没有语言学家认为任何语言都是故意发明的。它是通过许多步骤慢慢地、无意识地发展起来的。 (53. 参见惠特尼教授在他的《东方与语言学研究》,1873 年,第 354 页中对这个问题的一些精彩评论。他观察到,人与人之间交流的愿望是生机勃勃的力量,在语言,“有意识和无意识地起作用;有意识地考虑到要达到的直接目的;无意识地考虑到行为的进一步后果。”)对于所有成员来说,鸟类发出的声音在几个方面提供了与语言最接近的类比同一物种发出相同的本能呼喊来表达他们的情感;一切歌唱的种类,都本能地发挥着它们的力量;但真正的歌曲,甚至是呼唤音符,都是从他们的父母或养父母那里学来的。这些声音,正如戴恩斯·巴林顿 (Daines Barrington) (54. Hon. Daines Barrington in ‘Philosoph. Transactions’, 1773, p. 262. 另见 Dureau de la Malle, in ‘Ann. des. Sc. Nat.’ 第三系列,Zoolog.,汤姆.xp 3.)已经证明,“它们并不比人类的语言更天生。”第一次尝试唱歌“可以比作孩子牙牙学语的不完美努力”。年轻的雄鸟会继续练习,或者用捕鸟者的话来说,“记录”十到十一个月。他们的第一篇文章几乎没有展示出未来歌曲的雏形;但随着他们年龄的增长,我们就能明白他们的目标是什么;最后据说他们“唱起他们的歌来”。雏鸟学会了特定物种的歌声,就像在蒂罗尔受教育的金丝雀鸟一样,将它们的新歌传授给它们的后代。正如巴林顿所说,居住在不同地区的同一物种的歌曲的细微自然差异可以恰当地与“省方言”进行比较。尽管可以将不同物种的语言与不同人类种族的语言进行比较,但联盟的歌曲。我给出上述细节是为了表明,获得一门艺术的本能倾向并不是人类所特有的。

关于清晰语言的起源,一方面阅读了 Hensleigh Wedgwood 先生、F. Farrar 牧师和 Schleicher 教授的非常有趣的著作(55.《论语言的起源》,作者 H . Wedgwood, 1866. 'Chapters on Language,' by the Rev. FW Farrar, 1865. 这些作品非常有趣。另请参阅 'De la Phys. et de Parole,' par Albert Lemoine, 1865, p. 190. 该作品已故的 Aug. Schleicher 教授关于这个主题的著作,已被 Bikkers 博士翻译成英文,标题为“语言科学对达尔文主义的检验”,1869 年),以及 Max Muller 教授的著名讲座另一方面,我毫不怀疑语言的起源是对各种自然声音、其他动物的声音、人类本能的呼喊以及手势的模仿和修改。当我们讨论性选择时,我们将看到原始人,或者更确切地说,人类的某些早期祖先,可能首先使用他的声音来产生真正的音乐节奏,即歌唱,就像当今的一些长臂猿一样;我们可以从一个广泛流传的类比中得出结论,这种力量在两性求爱期间尤其会发挥出来,表达各种情感,例如爱、嫉妒、胜利,并且会成为对性的挑战。竞争对手。因此,通过清晰的声音模仿音乐哭声很可能产生了表达各种复杂情感的词语。我们最近的盟友,猴子,小头白痴中的强烈倾向(56. Vogt,“Mémoire sur les Microcephales”,1867,第169页。关于野蛮人,我在我的“研究杂志”中给出了一些事实,等,1845,第206页。),在人类的野蛮种族中,模仿他们听到的任何东西都值得关注,因为与模仿的主题有关。因为猴子当然能理解人类对它们说的很多话,并且在狂野时,会对它们的同伴发出危险的信号(57。在布雷姆和伦格尔经常引用的两本著作中,可以看到关于这一点的明确证据。);而且由于家禽对地面上的危险或天空中鹰发出的危险发出明确的警告(两者以及第三种叫声,狗都能听懂)(58。Houzeau 在他的《 Facultés Mentales des Animaux,' tom. ii. p. 348.),难道不是某种异常聪明的猿类动物模仿了猛兽的咆哮,从而告诉他的猴子同伴预期危险的本质吗?这将是形成语言的第一步。

随着声音的使用越来越多,发声器官会通过使用的遗传效应原理得到加强和完善;这会对言语的力量产生反应。但语言的持续使用与大脑发育之间的关系无疑更为重要。在甚至最不完善的语言形式得以使用之前,某些早期人类祖先的心智能力一定比任何现存的猿类都更加发达。但我们可以自信地相信,这种力量的持续使用和进步会对心灵本身产生反应,使其能够进行长期的思考。没有语言(无论是口头的还是无声的)的帮助,复杂的思路就无法进行,就像不使用数字或代数就无法进行长时间的计算一样。而且,似乎即使是普通的思维方式也几乎需要某种形式的语言,或者说极大地促进了某种形式的语言,因为哑、聋、盲女孩劳拉·布里奇曼(Laura Bridgman)被发现在做梦时使用手指。 (59. 参见莫兹利博士关于这一点的评论,“心灵的生理学和病理学”,第 2 版,1868 年,第 199 页。)然而,一长串生动且相互关联的想法可能会在头脑中掠过,而无需经过大脑的思考。任何形式的语言的帮助,正如我们可以从狗在梦中的动作中推断出来的那样。我们还发现,动物在某种程度上能够进行推理,显然无需语言的帮助。我们现在所发展的大脑与言语能力之间的密切联系,在那些奇怪的脑部疾病案例中得到了很好的体现,在这些疾病中,言语受到特别影响,例如当我们丧失了记忆实质内容的能力时,其他词可以正确使用,或者某一类实词,或者除了实词首字母和专有名称之外的所有词都被遗忘。 (60. 记录了许多奇怪的案例。例如,参见贝特曼博士的“论失语症”,1870 年,第 27、31、53、100 页等。此外,参见贝特曼博士的“关于智力的调查”。 Abercrombie, 1838, p. 150.) 持续使用精神和发声器官导致其结构和功能发生遗传性变化的可能性并不比手写的情况更不可能,手写部分取决于书写的形式。手,部分取决于头脑的性格;笔迹当然是遗传的。 (61.“驯化下动植物的变异”,第 ii 卷,第 6 页。)

一些作家,尤其是马克斯·穆勒教授(62.《达尔文先生的语言哲学》讲座,1873)最近坚持认为,语言的使用意味着形成一般概念的力量;语言的使用意味着形成一般概念的力量。由于任何动物都不应该拥有这种力量,因此它们和人类之间形成了不可逾越的障碍。 (63. 一位杰出的语言学家,例如惠特尼教授,在这一点上的判断比我能说的任何话都重要得多。他评论道(“东方和语言学研究”,1873年,第297页),在讲话中布莱克的观点是:“因为从宏观上来说,语言是思想的必要辅助,对于思维能力的发展,对于认知的清晰性、多样性和复杂性,对于意识的充分掌握都是不可缺少的;因此,他很乐意让思想成为思想的基础。”没有言语,将能力与其工具等同起来,这绝对是不可能的。他可能会合理地断言,没有工具,人手就无法行动。以这样的学说为出发点,他无法避免马克斯·穆勒最严重的悖论,即婴儿(马克斯·穆勒 (Max Muller) 用斜体字表示(《达尔文先生哲学讲座》) 《语言学》,1873 年,第三讲)这句格言:“没有语言就没有思想,就像没有思想的语言一样。”这里必须给“思想”这个词一个多么奇怪的定义!)关于动物,我他们已经努力表明他们拥有这种权力,至少是在粗鲁和初级的程度上。对于十到十一个月大的婴儿和聋哑人来说,在我看来难以置信的是,他们能够像他们一样快地将某些声音与某些一般概念联系起来,除非这些想法已经在儿童中形成了。他们的想法。同样的说法也适用于更聪明的动物。正如莱斯利·斯蒂芬先生所观察到的(64.《自由思想随笔》等,1873年,第82页),“狗构建了猫或羊的一般概念,并且像哲学家一样知道相应的词语。理解能力与说话能力一样,都是声音智力的良好证明,尽管程度较低。”

不难看出,为什么现在用于说话的器官最初应该是为此目的而完善的,而不是任何其他器官。正如胡贝尔所表明的那样,蚂蚁通过触角具有相当大的相互交流能力,他用了整整一章来讨论它们的语言。我们可以用手指作为有效的工具,因为一个有练习的人可以向一个聋子快速地向一个聋子报告在公开会议上发言的每一个字;但是,如果我们这样工作的话,失去双手将会带来严重的不便。由于所有高等哺乳动物都拥有发声器官,其结构与我们的发声器官相同,并用作交流手段,因此,如果必须提高交流能力,这些相同的器官显然很可能会进一步发展。这是通过相邻且相适应的部分(即舌头和嘴唇)的帮助来实现的。 (65. 请参阅 Maudsley 博士对此的一些精彩评论,“心灵的生理学和病理学”,1868 年,第 199 页。)高等猿类不使用发声器官来说话的事实,无疑取决于它们的发声器官。智力还不够先进。它们所拥有的器官,经过长期的持续练习,可能会被用来说话,尽管它们并没有这样使用,这与许多鸟类拥有适合歌唱的器官的情况相似,尽管它们从不歌唱。因此,夜莺和乌鸦的发声器官结构相似,前者用于发出多样化的歌曲,后者仅用于发出呱呱叫声。 (66. Macgillivray,《英国鸟类史》,第 ii 卷,1839 年,第 29 页。一位出色的观察者布莱克沃尔先生指出,喜鹊比几乎所有喜鹊更容易学会发音单个单词,甚至是短句。任何其他英国鸟类;然而,正如他补充的,在长期仔细研究其习性后,他从未发现它在自然状态下表现出任何不寻常的模仿能力。《动物学研究》,1834 年,第 158 页。 )如果有人问为什么猿类的智力没有发展到与人类相同的程度,那么只能用一般原因来回答,考虑到我们对连续性的无知,期待任何更明确的事情是不合理的。每个生物所经历的发展阶段。

不同语言和不同物种的形成,以及两者都是通过渐进过程发展起来的证据,惊人地相似。 (67. 请参阅 C. Lyell 爵士在《人类古代的地质证据》,1863 年,第 xxiii 章中提出的物种和语言发展之间非常有趣的平行关系。)但是我们可以追踪许多单词的形成比物种更早,因为我们可以感知它们实际上是如何通过模仿各种声音而产生的。我们发现,在不同的语言中,由于血统共同体而具有惊人的同源性,并且由于相似的形成过程而具有类比性。当其他字母或声音发生变化时,某些字母或声音也会发生变化,这与相关增长非常相似。在这两种情况下,我们都会遇到零件的重复、长期持续使用的影响等等。更值得注意的是,语言和物种中频繁出现的雏形。 am 中的字母 m 表示“我”;因此,在“我是”这个表达中,保留了一种多余的、无用的雏形。在单词的拼写中,字母通常仍然是古代发音形式的雏形。语言就像有机体一样,可以分为不同的组别。他们可以根据血统自然地分类,也可以根据其他角色人为地分类。主流语言和方言广泛传播,并导致其他语言逐渐灭绝。正如 C. Lyell 爵士所说,一种语言就像一个物种,一旦灭绝,就永远不会再出现。同一种语言从来没有两个诞生地。不同的语言可以交叉或混合在一起。 (68. 参见牧师 FW Farrar 在一篇有趣的文章中对此的评论,题为“语言学和达尔文主义”,发表于《自然》,24 年 1870 月 528 日,第 69 页。)我们看到每种语言都有差异,并且新词不断出现;但由于记忆的能力是有限的,单个单词就像整个语言一样,逐渐消失。正如马克斯·穆勒 (Max Muller)(6.《自然》,1870 年 257 月 XNUMX 日,第 XNUMX 页)所言:“每种语言的单词和语法形式之间不断进行着生存斗争。更好、更短、更容易的形式不断占据上风,它们的成功归功于其内在的美德。”除了这些某些词语得以幸存的更重要原因之外,还可以加上新颖性和时尚性。因为人的内心深处对一切事物的细微变化有着强烈的喜爱。在生存斗争中某些受青睐的词的生存或保存是自然选择。

许多野蛮国家的语言的完全规则和极其复杂的结构常常被认为是这些语言的神圣起源的证明,或者是它们的创始人的高雅艺术和前文明的证明。因此,F. von Schlegel 写道:“在那些看似处于最低智力文化水平的语言中,我们经常在其语法结构中观察到非常高且复杂的艺术程度。巴斯克语、拉普兰语以及许多美洲语言尤其如此。” (70. 引自 CS Wake,“Chapters on Man”,1868 年,第 101 页。)但是,将任何语言视为一门艺术无疑是错误的,因为它是经过精心且有条理地形成的。语言学家现在承认,词形变化、词形变化等最初是作为不同的词存在的,后来又结合在一起了;由于这些词表达了物体和人之间最明显的关系,因此它们在最早的时代被大多数种族的人使用也就不足为奇了。就完美而言,下图最能说明我们是多么容易犯错:海百合有时由不少于 150,000 块贝壳组成(71. Buckland,“Bridgewater Treatise”,第 411 页),所有贝壳都以完美对称的方式排列在辐射线中;但博物学家并不认为这种动物比身体部位相对较少的双侧动物更完美,而且除了身体的两侧外,这些部位没有一个是相似的。他公正地认为器官的分化和特化是完美的标准。语言也是如此:最对称、最复杂的语言不应该排在不规则、缩写和混杂的语言之上,这些语言借用了各种征服、被征服或移民种族的表达性词语和有用的结构形式。

从这些少数且不完美的评论中,我得出的结论是,许多野蛮语言的极其复杂和规则的结构并不能证明它们的起源归功于特殊的创造行为。 (72. 请参阅 J. Lubbock 爵士关于语言简化的一些精彩评论,《文明的起源》,1870 年,第 278 页。)正如我们所见,清晰的言语能力本身并没有提供任何不可克服的能力。反对人是从某种低等形式发展而来的信念。

美感

这种感觉被认为是人类所特有的。我在这里仅指某些颜色、形状和声音所带来的愉悦感,这完全可以称为美感;然而,对于有教养的人来说,这种感觉与复杂的想法和思路密切相关。当我们看到一只雄鸟在雌鸟面前精心展示其优雅的羽毛或绚丽的色彩,而其他没有如此装饰的鸟却没有这样的表现,那么毫无疑问,雌鸟欣赏她的雄性伴侣的美丽。由于世界各地的妇女都用这些羽毛装饰自己,因此此类装饰品的美丽无可争议。正如我们稍后将看到的,蜂鸟的巢穴和园丁鸟的玩耍通道都装饰着色彩鲜艳的物品,十分雅致。这表明他们一定会从看到这些东西中得到某种快乐。然而,据我们判断,对于绝大多数动物来说,对美的品味仅限于异性的吸引力。许多雄鸟在爱情季节所倾注的甜蜜气息,无疑受到雌鸟的赞赏,下文将给出事实证据。如果雌鸟无法欣赏雄鸟美丽的色彩、装饰和声音,那么雄鸟在雌鸟面前展示自己魅力时所付出的所有努力和焦虑都会被浪费掉;这是不可能承认的。我认为,为什么某些鲜艳的颜色会令人愉悦,就像为什么某些味道和气味令人愉悦一样无法解释。但习惯与结果有关,因为最初令我们感觉不愉快的事情,最终会变得愉快,而习惯是遗传的。关于声音,亥姆霍兹在一定程度上从生理原理上解释了为什么和声和某些节奏是令人愉快的。但除此之外,经常以不规则的间隔重复出现的声音是非常令人讨厌的,因为每个人都会承认,谁在晚上听过船上绳索不规则的拍打声。同样的原理似乎也适用于视觉,因为眼睛更喜欢对称或有规律重现的图形。即使是最低级的野蛮人也会使用这种图案作为装饰品。它们是通过性选择而发展起来的,用于装饰一些雄性动物。无论我们能否给出任何理由来解释从视觉和听觉中获得的快乐,人类和许多低等动物都同样对相同的颜色、优雅的阴影和形状以及相同的声音感到高兴。

对美的品味,至少就女性美而言,在人类头脑中并不是一种特殊的性质;因为它在人类的不同种族中差异很大,甚至在同一种族的不同国家中也不完全相同。从大多数野蛮人所欣赏的丑陋的装饰品和同样丑陋的音乐来看,我们可能会认为,他们的审美能力并不像某些动物(例如鸟类)那么发达。显然,没有任何动物能够欣赏夜晚的天空、美丽的风景或优美的音乐等场景;但如此高的品味是通过文化获得的,并且依赖于复杂的联想;野蛮人或未受过教育的人不喜欢它们。

许多能力对人类的进步有着不可估量的贡献,例如想象力、惊奇力、好奇心、不确定的美感、模仿倾向以及对刺激或新奇事物的热爱,都可以几乎不会导致习俗和时尚的反复无常的变化。我提到这一点,是因为最近的一位作家(73。《旁观者》,4 年 1869 月 1430 日,第 XNUMX 页)奇怪地将随想曲视为“野蛮人和野蛮人之间最显着和最典型的区别之一”。 ”但我们不仅可以部分地理解人类是如何因各种相互冲突的影响而变得反复无常的,而且正如我们稍后将看到的,低等动物的喜爱、厌恶和美感也同样反复无常。我们也有理由怀疑他们喜欢新奇,只是为了新奇本身。

信仰上帝——宗教

没有证据表明人类最初就被赋予了对全能上帝存在的崇高信念。相反,有充分的证据,不是来自匆忙的旅行者,而是来自长期与野蛮人一起生活的人们,证明许多种族曾经存在,并且仍然存在,他们不知道一个或多个神,也没有语言。他们的语言来表达这样的想法。 (74. 请参阅 Rev. FW Farrar 在《人类学评论》,1864 年 2 月,第 ccxvii 页上发表的一篇有关此主题的优秀文章。有关更多事实,请参阅 J. Lubbock 爵士,《史前时代》,第 1869 版。 564 年,第 1870 页;特别是他的《文明的起源》中关于宗教的章节,XNUMX 年。)这个问题当然与那个更高层次的问题完全不同:是否存在宇宙的创造者和统治者?一些有史以来最伟大的智者对此给出了肯定的回答。

然而,如果我们把对看不见的或精神力量的信仰纳入“宗教”一词,情况就完全不同了。因为这种信念似乎在不太文明的种族中是普遍存在的。也不难理解它是如何产生的。一旦想象力、好奇心和某种推理能力等重要能力得到部分发展,人类就会自然而然地渴望了解周围发生的事情,并模糊地推测自己的存在。正如 M'Lennan 先生(第 75 页,《对动物和植物的崇拜》,《双周评论》,1 年 1869 月 422 日,第 76 页)所言,“对生命现象的一些解释,一个人必须为自己假装,并从其普遍性来判断,最简单的假设,也是人类首先想到的,似乎是自然现象归因于动物、植物和事物以及力量的存在大自然的力量,人们意识到自己拥有的那种促使人们采取行动的精神。”正如泰勒先生所表明的那样,梦也可能首先产生了精神的概念。因为野蛮人不容易区分主观印象和客观印象。当一个野蛮人做梦时,出现在他面前的人物被认为是从远处而来,站在他的上方。或者“做梦者的灵魂外出旅行,带着所见所闻的回忆回家”。 (1865. 泰勒,《人类早期历史》,6 年,第 1870 页。另见拉伯克《文明的起源》,1 年关于“宗教发展”的三个引人注目的章节。赫伯特·斯宾塞先生也以同样的方式在《双周评论》(1870 年 535 月 XNUMX 日,第 XNUMX 页)上发表的巧妙文章中,阐述了世界各地最早的宗教信仰形式,人类在梦境、阴影和其他原因的引导下,他自己是双重本质,肉体和精神。由于精神存在应该在死后存在并且具有强大的力量,因此通过各种礼物和仪式来安抚它,并调用它的帮助。然后他进一步表明,某些人给出的名字或绰号对于一个部落的早期祖先或创始人来说,动物或其他物体在很长一段时间后被认为代表了该部落的真正祖先;并且这样的动物或物体自然地被认为仍然作为精神存在,被认为是神圣的,并被当作神来崇拜。然而,我不能不怀疑还有一个更早、更原始的阶段,那时任何表现出力量或运动的东西都被认为被赋予了某种形式的生命,以及与我们相似的心智能力。)在人类头脑中的想象力、好奇心、理性等能力得到相当充分的发展之前,他的梦不会让他相信有灵魂,就像狗一样。

野蛮人倾向于想象自然物体和机构是由精神或生命本质赋予生命的,这也许可以用我曾经注意到的一个小事实来说明:我的狗,一只成年且非常明智的动物,在一次活动中躺在草坪上。天又热又静;但在不远的地方,一阵微风偶尔会吹动一把打开的阳伞,如果有人站在它附近,狗会完全忽视它。结果,每当阳伞稍微一动,狗就会猛烈地咆哮起来。我认为,他一定以一种快速而无意识的方式对自己进行推理,没有任何明显原因的运动表明存在某种奇怪的活体,并且没有陌生人有权进入他的领土。

对精神力量的信仰很容易转变为对一个或多个神的存在的信仰。因为野蛮人自然会赋予神灵同样的激情、同样的复仇之爱或最简单的正义形式,以及他们自己所感受到的同样的情感。火地岛人在这方面似乎处于中间状态,因为当“小猎犬”号上的外科医生射杀了一些小鸭子作为标本时,约克大教堂以最庄严的方式宣布:“哦,拜诺先生,雨很大,雨很大,雪,吹得多”;这显然是对浪费人类食物的报应。于是,他又讲述了,当他的兄弟杀死一个“野人”时,暴风雨肆虐,大雨大雪。然而,我们永远无法发现火地岛人相信我们所谓的上帝,或举行任何宗教仪式;杰米·巴顿带着无可非议的骄傲,坚决坚称他的土地上没有恶魔。后一种说法更为引人注目,因为对于野蛮人来说,相信恶灵比相信善灵要普遍得多。

宗教虔诚的感觉是一种高度复杂的感觉,包括爱、对崇高而神秘的上级的完全服从、强烈的依赖感(77。参见L.欧文·派克(Owen Pike),《人类学评论》,1870 年 78 月,第 lxiii 页),恐惧、崇敬、感激、对未来的希望,也许还有其他元素。没有人能够体验如此复杂的情感,除非他的智力和道德能力至少达到中等的高水平。然而,我们在狗对主人的深爱中看到了这种心理状态的某种遥远的接近,与完全服从、一些恐惧,也许还有其他感觉相关。狗在离开主人后回到主人身边时的行为,以及,正如我可能补充的那样,猴子对他心爱的饲养员的行为,与它们对待同伴的行为有很大不同。在后一种情况下,喜悦的情绪似乎少了一些,而平等感却表现在每一个动作中。布劳巴赫教授甚至坚持认为狗看着他的主人就像看着神一样。 (1869.“宗教、道德等,达尔文艺术教育”,53 年,第 1871 节。据说(W. Lauder Lindsay 博士,“心理科学杂志”,43 年,第 XNUMX 页) ,很久以前培根和诗人伯恩斯也持有同样的观点。)

同样的高级智力首先使人相信看不见的精神力量,然后相信拜物教、多神教,最终相信一神论,只要他的推理能力仍然不发达,就会毫无疑问地引导他走向各种奇怪的迷信和习俗。其中许多事情想想都令人毛骨悚然——比如将人类献祭给嗜血的神;用毒药或火刑审判无辜者;巫术等等——然而,偶尔反思一下这些迷信是有好处的,因为它们向我们展示了我们对理性的进步、对科学和我们所积累的知识的无限感激。正如 J. Lubbock 爵士(79.《史前时代》,第 2 版,第 571 页。在这部著作(第 571 页)中,我们可以找到对野蛮人许多奇怪而反复无常的习俗的精彩描述。) ”,“毫不夸张地说,对未知邪恶的可怕恐惧就像一朵厚厚的云笼罩在野蛮的生活上,让每一种快乐都变得痛苦。”我们最高的能力所造成的这些悲惨和间接的后果可以与低等动物本能的偶然和偶然的错误相比较。

第四章 •14,100字
人类与低等动物智力的比较——续

道德感——基本命题——社会性动物的品质——社交性的起源——对立本能之间的斗争——人是社会性动物——更持久的社会本能征服其他不那么持久的本能——野蛮人所推崇的社会美德——利己主义发展后期获得的美德——同一群体成员对行为判断的重要性——道德倾向的传递——总结。

我完全同意那些坚持认为人与人之间存在所有差异的作家的判断(1. 例如,参见 Quatrefages,“Unité de l'Espèce Humaine”,1861 年,第 21 页,关于这个主题)对于低等动物来说,道德感或良知是最重要的。正如麦金托什(Mackintosh)(2.《伦理哲学论文》,1837 年,第 231 页等)所说,这种意义“对人类行为的所有其他原则具有合法的至高无上的地位”;它被概括为“应该”这个简短而专横的词,充满了崇高的意义。它是人类所有属性中最崇高的,它使人毫不犹豫地为了同类而冒着生命危险;或者经过深思熟虑后,仅仅出于强烈的权利或义务感的驱使,为了某种伟大的事业而牺牲它。伊曼努尔·康德感叹道:“责任!奇妙的思想,它的作用既不是通过善意的暗示、奉承,也不是通过任何威胁,而只是通过在灵魂中高举你赤裸裸的律法,从而为自己不断地恭敬,如果不是总是服从的话;在他面前,所有的欲望都是愚蠢的,无论它们多么秘密地反抗;你原来的东西是从哪里来的? (3.《伦理学形而上学》,JW Semple 译,爱丁堡,1836 年,第 136 页。)

这个伟大的问题已经被许多作家讨论过(4. 贝恩先生列出了一份名单(“心理和道德科学”,1868 年,第 543-725 页),其中列出了 XNUMX 位曾就此主题撰写过文章的英国作家,以及他们的名字每个读者都熟悉;贝恩先生自己的名字,以及莱基先生、沙德沃斯霍奇森先生、J.卢伯克爵士和其他人的名字,可能会加上。)我谈论它的唯一借口是这里不可能忽略它。因为据我所知,没有人专门从自然历史的角度来研究它。这项调查还具有一些独立的兴趣,试图了解对低等动物的研究在多大程度上揭示了人类最高的心理能力之一。

在我看来,以下命题很有可能——即任何动物,无论什么,都具有明显的社会本能(5. B 先生。 布罗迪(Brodie)在观察到人是一种社会性动物后(“心理学探究”,1854 年,第 XNUMX 页)。 192),提出了一个意味深长的问题:“这难道不应该解决有关道德感是否存在的争议问题吗?”许多人可能都曾有过类似的想法,就像很久以前马库斯·奥勒留那样。 先生。 JS 密尔在他的著名著作《功利主义》(1864 年,第 XNUMX 页)中谈到了这一点。 45, 46),将社会情感视为“强大的自然情感”和“功利主义道德情感的自然基础”。他再次说道:“就像上面提到的其他后天获得的能力一样,道德能力即使不是我们本性的一部分,也是自然而然的产物;像他们一样,能力在某种程度上是自发产生的。”但与这一切相反,他还指出,“如果像我自己的信念一样,道德情感不是天生的,而是后天获得的,那么它们也不会因此而变得不那么自然。”我犹豫着不敢与如此深刻的思想家有任何不同,但毫无疑问,社会情感是低等动物的本能或与生俱来的。为什么人类不应该如此呢? 先生。 贝恩(例如,参见“情感与意志”,1865 年,第 XNUMX 页) 481)而其他人则认为道德感是每个人在其一生中获得的。 根据一般进化论,这至少是极不可能的。 在我看来,对所有传承下来的精神品质的忽视今后将被视为先生作品中最严重的缺陷。 密尔),这里包括父母和孝顺的感情,一旦其智力变得像人类一样或几乎一样发达,道德感或良知就不可避免地获得道德感或良心。 因为,首先,社会本能引导动物从同伴的社会中获得乐趣,对他们产生一定程度的同情,并为他们提供各种服务。 这些服务可能具有明确的、明显的本能性质;或者,就像大多数高级社会动物一样,可能只是希望并准备好以某些一般方式帮助它们的同伴。 但这些感受和服务绝不适用于同一物种的所有个体,而仅适用于同一协会的个体。 其次,一旦心智能力变得高度发达,过去所有行为和动机的图像就会不断地在每个人的大脑中闪过:而这种不满,甚至痛苦的感觉,不可避免地会导致,正如我们将在下文中看到的那样任何未满足的本能都会出现,只要人们意识到持久且始终存在的社会本能已经屈服于其他某种本能,这些本能当时更强大,但其本质既不持久,也没有留下非常生动的印象。 显然,许多本能的欲望,例如饥饿的欲望,本质上都是短暂的。满足后,也不容易或生动地回忆起来。 第三,当获得了语言的力量,社会的愿望得以表达后,每个成员应该如何为公共利益而行动的共同意见,自然会在很大程度上成为行动的指南。 但应该记住,无论我们对公众舆论给予多大的重视,我们对同胞的赞成和反对的重视取决于同情心,正如我们将看到的,同情心构成了社会本能的重要组成部分,并且是社会本能的重要组成部分。确实是它的基石。 最后,个人的习惯最终将在指导每个成员的行为中发挥非常重要的作用。因为社会本能和同情心一样,像任何其他本能一样,通过习惯大大加强,因此会服从社会的愿望和判断。

可能首先要假设的是,我不希望认为任何严格的社会动物,如果其智力能力变得像人类一样活跃和高度发达,就会获得与我们完全相同的道德感。就像各种动物都有某种美感一样,尽管它们欣赏的物体截然不同,同样,它们也可能有一种是非感,尽管受其引导而遵循截然不同的行为路线。例如,举个极端的例子,如果男性在与蜂巢蜜蜂完全相同的条件下饲养,那么毫无疑问,我们的未婚女性会像工蜂一样,认为杀死自己的蜜蜂是一项神圣的职责。兄弟们和母亲们会努力杀死她们能生育的女儿;没有人会想到干涉。 (6. H. Sidgwick 先生在关于这个主题的精彩讨论中评论道(《学院》,15 年 1872 月 231 日,第 1872 页),“我们可以肯定,高级蜜蜂会渴望一种更温和的解决方案然而,从许多或大多数野蛮人的习惯来看,人类通过杀女婴、一妻多夫和乱交来解决问题;因此,是否会采取更温和的方法很值得怀疑。科布小姐,在在同一例证上评论(“道德中的达尔文主义”,“神学评论”,188 年 191 月,第 XNUMX-XNUMX 页)说,社会责任的原则将因此被颠倒;我认为,她的意思是,履行社会责任往往会伤害个人;但她忽视了一个事实,她无疑会承认这一事实:蜜蜂的本能是为了社会的利益而获得的。她甚至说,如果本章所提倡的伦理学理论曾经被普遍接受,“我不能不相信,在他们胜利的时刻,将会敲响人类美德的丧钟!”然而,在我们假设的情况下,蜜蜂或任何其他社会动物,在我看来,会获得一些对错的感觉,或者良知。 。因为每个人都会有一种内在的感觉,即拥有某些更强烈或更持久的本能,而另一些则不那么强烈或更持久;因此,人们经常会纠结应该遵循哪种冲动;当过去的印象不断地在头脑中经过时,人们会感到满意、不满意,甚至痛苦。在这种情况下,内部监视器会告诉动物,跟随一种冲动会比跟随另一种冲动更好。其中一种做法应该被遵循,而另一种则不应该被遵循。一个是对的,另一个是错的;但我将重申这些条款。

社交性

许多种类的动物都是群居的。我们甚至发现不同的物种生活在一起;例如,一些美洲猴子;还有成群结队的白嘴鸦、寒鸦和椋鸟。人对狗的强烈爱也表现出同样的感觉,而狗也以兴趣回报。每个人都一定注意到,马、狗、羊等与同伴分开时是多么痛苦,而至少前两种动物在重聚时表现出多么强烈的相互感情。推测一只狗的感受是很奇怪的,它会和主人或家人一起在一个房间里安静地休息几个小时,而不会受到任何人的注意;但如果让他独自呆一小会儿,他就会凄惨地吠叫或嚎叫。我们将把注意力集中在高等社会动物上;并忽略昆虫,尽管其中一些是社会性的,并在许多重要方面互相帮助。高等动物中最常见的相互服务是通过所有的联合感官来警告彼此危险。每个运动员都知道,正如 Jaeger 博士所说(7.《达尔文理论》,第 101 节),接近兽群或群体中的动物是多么困难。我相信野马和牛不会发出任何危险信号;但他们中任何一个第一个发现敌人的人的态度都会警告其他人。兔子用后脚大声跺地作为信号;绵羊和羚羊用前脚做同样的事情,同样发出口哨声。许多鸟类和一些哺乳动物都有哨兵,就海豹而言,据说哨兵通常是雌性(8. R. Brown 先生,《Proc. Zoolog. Soc.》,1868 年,第 409 页)。一群猴子的首领充当哨兵,发出代表危险和安全的叫声。 (9. Brehm, 'Thierleben,' B. i. 1864, s. 52, 79。关于猴子互相拔出荆棘的情况,参见 s. 54。关于狒狒翻转石头,事实是给出(第 76 节),根据阿尔瓦雷斯的证据,布雷姆认为他的观察非常可信。有关老年雄性狒狒攻击狗的案例,请参阅第 79 节;关于鹰,请参阅第 56 节。)动物互相提供许多小服务:马会啃咬对方,牛会互相舔对方任何发痒的地方:猴子会互相寻找外部寄生虫;布雷姆指出,当一群灰绿猴冲过荆棘丛后,每只猴子都会在树枝上伸展身体,另一只猴子坐在旁边,“认真地”检查它的皮毛,并拔掉所有的刺或毛刺。

动物之间还提供更重要的服务:因此狼和其他一些猛兽成群捕猎,并互相帮助攻击受害者。鹈鹕一起捕鱼。狒狒翻石寻找昆虫等;当他们来到一个大的地方时,尽可能多的人能站在周围,一起把它翻过来并分享战利品。社会性动物互相保护。北美的公牛一旦遇到危险,就会把母牛和小牛赶到牛群中间,而它们则保卫外面。我还将在以后的章节中讲述奇灵厄姆的两只年轻野公牛协同攻击一头老公牛,以及两匹种马一起试图从一群母马中赶走第三匹种马的故事。在阿比西尼亚,布雷姆遇到了一大群正在穿越山谷的狒狒:有的已经登上了对面的山,有的还在山谷里;后者遭到了狗的攻击,但老雄立即从岩石上急忙下来,张大嘴巴,发出可怕的咆哮,吓得狗们赶紧退开。他们再次受到鼓舞,发起进攻。但此时,所有的狒狒都重新登上了高处,除了一只大约六个月大的小狒狒,它大声呼救,爬上了一块岩石,并被包围了。现在,其中一只最大的雄性,一个真正的英雄,再次从山上下来,慢慢地走到那只年轻的狗身边,哄骗他,并得意地把他带走——狗们惊呆了,不敢发起攻击。我无法抗拒提供同一位博物学家亲眼目睹的另一个场景;一只老鹰抓住了一只小鹿,它抓住了一根树枝,没有立即被带走。它大声呼救,其他成员哗然,纷纷赶来救援,将老鹰团团围住,拔掉了许多羽毛,老鹰不再考虑猎物,只想着如何逃跑。正如布雷姆所说,这只鹰肯定不会再攻击猴群中的任何一只。 (10. 贝尔特先生讲述了尼加拉瓜的一只蜘蛛猴(Ateles)的例子,人们听到它在森林里尖叫了近两个小时,人们发现一只鹰栖息在它附近。这只鸟显然害怕攻击,因为它被攻击了。只要它们保持面对面的状态;贝尔特先生认为,根据他对这些猴子的习性的观察,它们通过将两三只猴子放在一起来保护自己免受老鹰的袭击。《尼加拉瓜的博物学家》,1874 年,第 118 页。 XNUMX。)

可以肯定的是,有联系的动物彼此之间有一种爱的感觉,这是非社会性成年动物所感受不到的。在大多数情况下,他们实际上在多大程度上同情他人的痛苦和快乐,这是更值得怀疑的,尤其是在快乐方面。然而,巴克斯顿先生拥有出色的观察能力(11.《自然历史年鉴与杂志》,1868 年 382 月,第 12 页),他指出,他的金刚鹦鹉自由生活在诺福克,对它产生了“极大的兴趣”成对有巢;每当雌性离开它时,她就会被一群人包围,“尖叫着向她致敬”。通常很难判断动物是否对其同类的痛苦有任何感情。谁能说清楚当奶牛围住并凝视着垂死或死去的同伴时,它们会作何感想?然而,正如乌佐所说,他们显然并不感到怜悯。毫无疑问,动物有时根本感受不到任何同情心。因为他们会把受伤的动物赶出牛群,或者刺伤或担心它而死。这几乎是自然史上最黑暗的事实,除非所提出的解释确实正确,即它们的本能或理性导致它们驱逐受伤的同伴,以免包括人类在内的猛兽受到诱惑而跟随部队。在这种情况下,他们的行为并不比北美印第安人差多少,印第安人把自己软弱的战友丢在平原上等死。或者斐济人,当他们的父母变老或生病时,他们会把他们活埋。 (2. J. Lubbock 爵士,《史前时代》,第二版,第 446 页。)

然而,许多动物肯定会同情彼此的痛苦或危险。即使对于鸟类也是如此。斯坦斯伯里船长 (13. 正如 LH Morgan 先生所引述的,《美国海狸》,1868 年,第 272 页。斯坦斯伯里船长还有趣地描述了一只非常年轻的鹈鹕被强劲的水流冲走的方式,在六只老鸟的引导和鼓励下,它试图到达岸边。)在犹他州的一个盐湖上发现了一只完全失明的老鹈鹕,它非常肥胖,一定是被他的同伴长时间喂养的。同伴。布莱斯先生告诉我,他看到印度乌鸦正在喂食它们的两三个盲人同伴。我听说过一个关于家养公鸡的类似案例。如果我们选择的话,我们可以将这些行为称为本能;但对于任何特殊本能的发展来说,这种情况太罕见了。 (14. 正如贝恩先生所说,“对患者的有效援助源于真正的同情心:”《心理与​​道德科学》,1868 年,第 245 页。)我自己也见过一只狗,它从未经过一只生病的猫。放在篮子里,是他的好朋友,却没有用舌头舔她几下,这是狗友善感情的最明显标志。

这必须被称为同情心,它会引导一只勇敢的狗向任何攻击他主人的人扑去,而他肯定会这样做。我看到一个人假装殴打一位女士,她的腿上放着一只非常胆小的小狗,以前从未进行过审判;小东西立刻跳开了,但假装殴打结束后,他还坚持舔着情妇的脸,安慰着她,实在是太可怜了。 Brehm(15岁,“Thierleben”,B. 85岁)表示,当一只被监禁的狒狒被追捕并受到惩罚时,其他狒狒试图保护他。一定是出于对上述情况的同情,导致狒狒和鹿皮特西保护他们的年轻同伴免受狗和鹰的侵害。我仅举另一个富有同情心和英勇行为的例子,即一只美国小猴子的例子。几年前,动物园的一位饲养员向我展示了他自己的颈背上有一些很深且几乎没有愈合的伤口,这是他跪在地板上时被一只凶猛的狒狒造成的。这只小美洲猴是这位饲养员的好朋友,住在同一个大隔间里,它非常害怕大狒狒。然而,当他看到他的朋友陷入危险时,他立即赶去营救,并通过尖叫和咬伤分散了狒狒的注意力,最终这名男子得以逃脱,正如外科医生认为的那样,他冒着生命危险。

除了爱和同情之外,动物还表现出与社会本能相关的其他品质,这对我们来说被称为道德;我同意 Agassiz 的观点(16. 'De l'Espèce et de la Classe,' 1869, p. 97.),狗拥有类似良心的东西。

狗拥有一定的自我控制能力,这似乎并不完全是恐惧的结果。正如布劳巴赫(Braubach)(17.《达尔文艺术教育》,1869,第 54 节)所说,在主人不在的情况下,它们不会偷窃食物。长期以来,它们一直被认为是忠诚和服从的典型。但大象同样对他的司机或饲养员非常忠诚,并且可能将他视为象群的领导者。胡克博士告诉我,他在印度骑的一头大象陷入了深深的泥沼,以至于他一直被困住,直到第二天,才被用绳子救出来的人救出来。在这种情况下,大象会用鼻子抓住任何物体,无论是死的还是活的,放在膝盖下,以防止自己在泥里陷得更深。司机非常害怕,生怕这只动物抓住了胡克医生,把他压死了。但正如胡克博士所保证的那样,司机本人没有冒任何风险。对于沉重的动物来说,在如此可怕的紧急情况下的这种忍耐,是高尚忠诚的绝佳证明。 (18.另见胡克的《喜马拉雅日记》,第 ii 卷,1854 年,第 333 页。)

所有生活在一个身体中的动物,如果一致地保卫自己或攻击敌人,确实必须在某种程度上彼此忠诚。追随领导者的人必须在某种程度上服从。当阿比西尼亚的狒狒(19. Brehm,“Thierleben”,B. 76 岁)掠夺花园时,它们会默默地追随它们的首领;如果一只鲁莽的小动物发出声音,其他动物就会打他一巴掌,以教导他保持沉默和服从。高尔顿先生曾有过在南非观察半野生牛的绝佳机会,他说(20。参见他关于“牛和人的群居性”的极其有趣的论文,《麦克米伦杂志》,1871 年 353 月, p. XNUMX.),他们甚至无法忍受与群体短暂的分离。他们本质上是奴隶,接受共同的决心,除了由任何一只有足够自力更生能力接受这一职位的牛领导之外,他们不寻求更好的命运。那些把这些动物驯化为挽具的人,会孜孜不倦地留意那些通过放牧而表现出自力更生性格的动物,并将这些动物训练成前牛。高尔顿先生补充说,此类动物非常稀有且有价值。如果有很多狮子出生,它们很快就会被淘汰,因为狮子总是在寻找从群体中走出来的个体。

关于导致某些动物联合起来并以多种方式互相帮助的冲动,我们可以推断,在大多数情况下,它们受到与执行其他本能行为时所经历的相同的满足感或快乐感的驱使;或者与其他本能行为受到抑制时同样的不满感。我们在无数的例子中看到了这一点,并且我们家养动物的后天本能以惊人的方式说明了这一点。因此,一只年轻的牧羊犬喜欢驱赶羊群,围着羊群奔跑,而不是让它们担心。年轻的猎狐犬喜欢猎杀狐狸,而据我所见,其他一些种类的狗却完全不理会狐狸。多么强烈的内心满足感一定会促使一只如此活跃的鸟儿日复一日地孵蛋。如果候鸟的迁徙被阻止,它们的处境会非常悲惨。也许他们喜欢开始长途飞行;但很难相信,奥杜邦所描述的那只可怜的被钉住的鹅,在适当的时间开始徒步旅行,可能有一千多英里的路程,却能在这样做时感到任何快乐。有些本能仅由痛苦的感觉决定,例如恐惧,这导致自我保护,并且在某些情况下针对特殊的敌人。我认为没有人能够分析快乐或痛苦的感觉。然而,在许多情况下,本能很可能仅仅由于遗传的力量而持续遵循,而没有快乐或痛苦的刺激。一只年轻的指示犬,当它第一次闻到猎物的气味时,显然会情不自禁地指指点点。一只关在笼子里的松鼠拍打它不能吃的坚果,仿佛要把它们埋在地里,很难想象它会这样做,无论是出于快乐还是痛苦。因此,人们的每一个行动都必须受到某种快乐或痛苦的驱使这一普遍假设可能是错误的。尽管一种习惯可能会被盲目地、含蓄地遵循,与当时感受到的任何快乐或痛苦无关,但如果强行地、突然地制止它,通常会产生一种模糊的不满感。

人们常常认为动物首先是社会性的,因此当它们彼此分开时会感到不舒服,而在一起时会感到舒适;但更可能的观点是,这些感觉最初发展起来,是为了那些通过社会生活而受益的动物应该被诱导生活在一起,就像饥饿感和进食的乐趣一样,毫无疑问,先天获得是为了诱导动物进食。来自社会的快乐感可能是父母或孝顺之情的延伸,因为社会本能似乎是由长期与父母呆在一起的年轻人发展起来的;这种延伸可能部分归因于习惯,但主要归因于自然选择。对于那些因密切交往而受益的动物来说,那些在群居中获得最大快乐的个体将最好地逃避各种危险,而那些最不关心同伴、单独生活的个体将会大量死亡。父母之情和孝顺之情显然是社会本能的基础,至于它们的起源,我们不知道它们是通过什么步骤获得的;但我们可以推断,这在很大程度上是通过自然选择实现的。几乎可以肯定的是,最近的亲属之间存在着不寻常的、相反的仇恨情绪,就像工蜂杀死它们的雄蜂兄弟,以及蜂王杀死它们的女蜂王一样。在这种情况下,破坏他们最亲近的关系的愿望是为社区服务。父母之爱,或者某种替代父母之爱的情感,在某些等级极低的动物中已经发展起来,例如海星和蜘蛛。它偶尔也存在于整个动物群中的少数成员中,例如蠼螋属或蠼螋属。

最重要的同情情感不同于爱。一位母亲可能热情地爱着她熟睡、消极的婴儿,但在这种时候,她很难说对婴儿有同情心。人对狗的爱不同于同情,狗对主人的爱也是如此。正如贝恩先生最近所言,亚当·斯密曾经说过,同情心的基础在于我们对以前的痛苦或快乐状态的强烈保留。因此,“看到另一个人忍受饥饿、寒冷、疲劳,我们就会想起这些状态,即使在脑海中也是痛苦的。”因此,我们被迫去减轻他人的痛苦,以便我们自己的痛苦感受也能同时得到减轻。同样,我们也被引导去参与他人的快乐。 (21.参见亚当·斯密《道德情感理论》第一章,也是引人注目的一章。另见《贝恩先生的心理和道德科学》,1868 年,第 244 页和 275-282。贝恩先生指出,“同情心”他指出,“受益者或其他代替他的人可以通过同情和斡旋来弥补所有的牺牲”。但是,如果同情心严格意义上是一种本能,那么,正如我们前面所说的,同情心的运用会带来直接的快乐,就像前面提到的几乎所有其他本能的运用一样。)这种观点解释了这样一个事实:一个被爱的人比一个冷漠的人更能激发同情心。仅仅看到苦难,与爱无关,就足以唤起我们生动的回忆和联想。解释可能在于这样一个事实:对于所有动物来说,同情仅针对同一群体的成员,因此也针对已知的、或多或少受人爱戴的成员,而不是同一物种的所有个体。这一事实并不比许多动物的恐惧应该针对特殊的敌人更令人惊讶。狮子和老虎等非群居物种无疑会同情自己幼崽的痛苦,但不会同情任何其他动物的痛苦。正如贝恩先生所表明的那样,对于人类来说,自私、经验和模仿可能会增加同情的力量。因为我们希望得到好的回报,从而对他人做出富有同情心的善意行为;习惯会增强同情心。无论这种感觉以多么复杂的方式产生,因为它对所有互相帮助和保护的动物来说都是非常重要的,所以它会通过自然选择而增强。因为那些拥有最多数量最有同情心的成员的社区将最繁荣,并养育最多数量的后代。

然而,在许多情况下,我们无法确定某些社会本能是通过自然选择获得的,还是其他本能和能力(如同情心、理性、经验和模仿倾向)的间接结果;又或者,它们是否仅仅是长期习惯的结果。如此显着的本能,如设置哨兵来警告社区危险,不可能是任何这些能力的间接结果;因此,它一定是直接获得的。另一方面,一些群居动物的雄性所遵循的保卫群体、联合攻击敌人或猎物的习惯,也许源于相互同情;但勇气,在大多数情况下,力量,一定是事先获得的,很可能是通过自然选择获得的。

在各种本能和习惯中,有些比其他的强烈得多;也就是说,与其他人相比,有些人要么在他们的表现中给予更多快乐,要么在预防中给予更多痛苦;或者,可能同样重要的是,通过遗传,它们被更持久地遵循,而不会激发任何特殊的快乐或痛苦的感觉。我们自己意识到,有些习惯比其他习惯更难治愈或改变。因此,在动物身上经常可以观察到不同本能之间或本能与某种习惯性倾向之间的斗争。就像一只狗追赶一只野兔,受到斥责,停顿下来,犹豫不决,再次追赶,或者羞愧地回到主人身边;或者就像母狗对她的小狗和她的主人的爱一样,因为她可能会偷偷溜到他们身边,仿佛为不陪伴她的主人而感到羞愧。但据我所知,一种本能战胜另一种本能的最奇怪的例子是迁徙本能战胜母性本能。前者异常强大;后者异常强大。一只被关在笼子里的鸟儿会在适当的季节用自己的胸部敲打笼子的铁丝,直到胸部赤裸、血淋淋的。它会导致幼鲑鱼跳出它们可以继续生存的淡水,从而无意中自杀。大家都知道,母性本能有多么强大,即使是胆小的鸟儿也会面临巨大的危​​险,虽然会犹豫不决,但与自我保护的本能相反。然而,迁徙的本能是如此强大,以至于在深秋,燕子、家燕和雨燕经常抛弃它们幼小的幼崽,让它们在巢中悲惨地死去。 (22. L. Jenyns 牧师指出,这一事实(参见他的《White's Nat. Hist. of Selborne》版本,1853 年,第 204 页)最初是由杰出的 Jenner 在 1824 年的《Phil. Transact》中记录的。 ,并且此后得到了几位观察者的证实,特别是布莱克沃尔先生。这位细心的观察者在深秋检查了两年中的三十六个巢穴;他发现十二个巢中含有死去的幼鸟,五个巢中含有蛋。孵化的点,三个,尚未孵化的蛋。许多鸟,还不够大,无法长时间飞行,同样被遗弃并被抛在后面。参见 Blackwall,“动物学研究”,1834 年,第 108、118 页。一些额外的证据,尽管这不是想要的,请参见 Leroy,“Lettres Phil.”1802 年,第 217 页。对于 Swifts,请参见 Gould 的“Introduction to the Birds of Great Britain”,1823 年,第 5 页。在加拿大,亚当斯先生著;《流行科学评论》,1873 年 283 月,第 XNUMX 页。)

我们可以认识到,如果一种本能冲动比其他本能或相反的本能对一个物种更有利,那么它就会通过自然选择而变得更有效。因为这种能力发展得最强烈的个体将会大量生存。与母性本能相比,迁徙的情况是否如此,可能值得怀疑。前者在一年中的某些季节一整天的巨大持久性或稳定作用可能会在一段时间内赋予它至关重要的力量。

人是社会性动物

每个人都会承认,人是一种社会存在。我们从他对孤独的厌恶以及他对家庭之外的社会的渴望中看到了这一点。单独监禁是可以施加的最严厉的惩罚之一。一些作者认为,人类最初生活在单亲家庭中。但如今,尽管只有一个家庭,或者只有两三个家庭,在一些荒野的荒野中漫步,但据我所知,他们总是与居住在同一地区的其他家庭保持着友好的关系。这些家庭偶尔会开会,团结起来共同保卫家园。毫无疑问,野蛮人是一种社会性动物,居住在邻近地区的部落几乎总是互相交战。因为社会本能永远不会延伸到同一物种的所有个体。从大多数 Quadrumana 的类比来看,人类的早期类人猿祖先很可能同样是社会性的。但这对我们来说并不重要。尽管现在的人类几乎没有什么特殊的本能,而且已经失去了其早期祖先可能拥有的任何本能,但这并不是说他不应该从一个极其遥远的时期开始保留对同胞的某种本能的爱和同情。我们确实都意识到我们确实拥有这种同情心(23.休谟评论(“道德原则的探究”,1751年编辑,第132页),“似乎有必要承认幸福和痛苦其他人的景象对我们来说并非完全无关紧要,而是前者的景象……传达了一种秘密的喜悦;后者的出现……给我们的想象力带来了忧郁的潮湿。”);但我们的意识并不能告诉我们它们是否是本能的,与低等动物一样起源于很久以前,或者它们是否是我们每个人在早年习得的。由于人是一种社会性动物,几乎可以肯定的是,他会继承对同伴忠诚、服从部落首领的倾向。因为这些品质是大多数社会性动物所共有的。因此,他将拥有一定的自我控制能力。他出于一种继承的倾向,愿意与他人合作,保卫他的同胞。并且愿意以任何方式帮助他们,这不会太大地干扰他自己的福利或他自己的强烈愿望。

处于等级底部的社会性动物几乎完全受到引导,而处于等级较高的动物在很大程度上受到特殊本能的引导,它们向同一社区的成员提供帮助;但他们同样在一定程度上受到相互的爱和同情的推动,显然还得到了一定程度的理性的帮助。正如刚才所说,虽然人没有特殊的本能来告诉他如何帮助他的同胞,但他仍然有冲动,而且随着他的智力能力的提高,在这方面自然会受到理性和经验的更多指导。本能的同情心也会使他高度重视同伴的认可。因为,正如贝恩先生所清楚表明的那样(24.《精神与道德科学》,1868 年,第 254 页),对赞美的热爱和强烈的荣耀感,以及对蔑视和耻辱的更强烈的恐惧,“是由于同情心的作用。”因此,人会在很大程度上受到同胞的愿望、认可和责备的影响,这些愿望、赞许和责备都通过他们的手势和语言表达出来。因此,人类在非常粗鲁的状态下获得的社会本能,甚至可能是他早期的类人猿祖先所获得的,仍然为他的一些最佳行为提供了动力;但他的行为在很大程度上是由他的同胞所表达的愿望和判断决定的,不幸的是,他常常是由他自己强烈的自私欲望决定的。但是,随着爱、同情和自我控制通过习惯而得到加强,随着推理的力量变得更加清晰,人们能够公正地评价他人的判断,除了任何短暂的快乐或痛苦之外,他会感到自己被迫去某些行为准则。然后他可能会宣称——任何野蛮人或未开化的人都不会这么想——我是我自己行为的最高法官,用康德的话来说,我不会以我自己的身份侵犯人类的尊严。

更持久的社会本能征服不太持久的本能

然而,我们还没有考虑到从我们目前的观点来看整个道德感问题所转向的要点。为什么一个人应该觉得他应该服从一种本能的欲望而不是另一种?如果他屈服于强烈的自我保护意识,没有冒着生命危险去拯救同胞,为什么他会感到痛苦呢?或者为什么他会后悔因饥饿而偷了食物?

首先,很明显,人类的本能冲动有不同程度的强度。一个野蛮人会冒着生命危险去拯救同一个群体的成员,却会对一个陌生人漠不关心;一个年轻胆怯的母亲在母性本能的驱使下,会毫不犹豫地为她冒最大的危险。自己的婴儿,但不仅仅是一个同胞。然而,许多文明人,甚至是男孩,从来没有为别人冒过生命危险,而是充满勇气和同情心,却无视自我保护的本能,立即跳入洪流去救一个落水的人,尽管陌生人。在这种情况下,人类受到同样本能动机的驱使,这使得先前描述的英勇的小美洲猴通过攻击巨大而可怕的狒狒来拯救他的饲养员。上述行为似乎是社会或母性本能的强大力量的简单结果,而不是任何其他本能或动机的结果;因为它们执行得太突然,无法进行反思,也无法在当时感受到快乐或痛苦;然而,如果因任何原因而被阻止,人们可能会感到痛苦甚至痛苦。另一方面,对于一个胆怯的人来说,自我保护的本能可能非常强烈,以至于他无法强迫自己冒任何这样的风险,甚至可能不会为了自己的孩子。

我知道有些人认为,像上述情况那样的冲动行为不属于道德感的范畴,不能称为道德。 他们将这个术语限定为在战胜对立的欲望之后或在某些崇高动机的推动下故意采取的行动。 但似乎几乎不可能划出这种明确的区分线。 (25。 我在这里指的是所谓物质道德和形式道德之间的区别。 我很高兴发现赫胥黎教授(《批评与演讲》,1873 年,第 XNUMX 页)。 287)在这个问题上与我持相同的观点。 先生。 莱斯利·斯蒂芬 (Leslie Stephen) 评论(《关于自由思想和直言不讳的论文》,1873 年,第 XNUMX 页) 83),“物质道德和形式道德之间的形而上学区别与其他此类区别一样无关紧要。”)就崇高动机而言,有许多关于野蛮人的例子,他们缺乏对人类的任何普遍仁慈的感觉,并且不受任何宗教动机引导,作为囚犯故意牺牲自己的生命(26. 我曾举过一个这样的案例,即三名巴塔哥尼亚印第安人,他们宁愿被枪杀,也不愿背叛战友的计划(《研究杂志》,1845 年,第 XNUMX 页)。 103).),而不是背叛自己的战友;当然,他们的行为应该被视为道德的。 就深思熟虑和战胜对立动机而言,动物在将其后代或同伴从危险中拯救出来时,可能会在对立的本能之间犹豫不决。然而,他们的行为虽然是为了他人的利益,但却不被称为道德。 而且,我们经常做的任何事情,最终都会不假思索、毫不犹豫地去做,这样就很难与本能区分开来了。但肯定没有人会假装这样的行为不再是道德的。 相反,我们都认为,一个行为不能被认为是完美的,或者是以最高尚的方式进行的,除非它是冲动地完成的,没有经过深思熟虑或努力,就像一个具有必要品质的人一样。先天。 然而,在行动之前被迫克服恐惧或缺乏同情心的人,在某种程度上应该比那些天生的性格使他不费吹灰之力就能做好事的人得到更高的荣誉。 由于我们无法区分动机,因此,如果由道德存在执行,我们会将某个阶级的所有行为视为道德行为。 一个有道德的人能够比较他过去和未来的行为或动机,并能够批准或不批准它们。 我们没有理由认为任何低等动物都有这种能力;因此,当一只纽芬兰狗把一个孩子从水中拖出来,或者一只猴子面临危险去营救它的同伴,或者照顾一只孤儿猴子时,我们并不认为它的行为是道德的。

但回到我们更直接的主题。虽然有些本能比其他本能更强大,从而导致相应的行动,但认为人的社会本能(包括喜欢赞扬和害怕责备)拥有更大的力量,或者通过长期的习惯而获得的观点是站不住脚的。比自我保护、饥饿、欲望、复仇等本能更强大的力量。那么,为什么人类会后悔,尽管他试图消除这种遗憾,因为他遵循了一种自然冲动而不是另一种?为什么他进一步觉得他应该为自己的行为感到遗憾?在这方面,人类与低等动物有很大不同。尽管如此,我认为我们可以在一定程度上清楚地看到这种差异的原因。

人从他的心智活动中就无法避免反思:过去的印象和形象不断地、清晰地在他的头脑中闪过。 对于那些永久生活在体内的动物来说,社会本能始终存在并持续存在。 这些动物随时准备发出危险信号,保卫群体,并按照自己的习惯向同伴提供帮助;即使没有任何特殊热情或欲望的刺激,他们始终感受到某种程度的爱和同情;如果与他们长期分离,他们会不高兴,但总是很高兴再次与他们在一起。 我们自己也是如此。 即使当我们非常孤独时,我们是否经常会高兴或痛苦地思考别人对我们的看法——他们想象中的赞同或反对;而这一切都源于同情心,这是社会本能的基本要素。 一个人如果没有这种本能,就会成为一个不自然的怪物。 另一方面,满足饥饿的欲望或任何诸如复仇之类的激情本质上都是暂时的,并且可以暂时得到充分满足。 要完全生动地唤起饥饿的感觉也不是一件容易的事,也许几乎不可能。事实上,正如人们经常提到的那样,也没有任何痛苦。 除非存在危险,否则人们不会感受到自我保护的本能。许多胆小鬼在与敌人面对面之前都认为自己很勇敢。 对他人财产的渴望也许是一种持久的渴望,就像任何可以命名的渴望一样。但即使在这种情况下,实际拥有的满足感通常也比欲望更弱:许多小偷,即使不是习惯性的小偷,在成功之后也会想知道为什么他偷了一些物品。 (27。 敌意或仇恨似乎也是一种高度持久的感觉,也许比任何其他可以命名的感觉都更强烈。 嫉妒被定义为对他人的某些卓越或成功的仇恨;培根坚持认为(散文九),“在所有其他感情中,嫉妒是最重要和最持续的。”狗很容易讨厌陌生人和陌生的狗,特别是当他们住在附近,但不属于同一家庭、部落或氏族时;因此,这种感觉似乎是与生俱来的,而且肯定是一种最持久的感觉。 这似乎是真正的社会本能的补充和逆向。 从我们对野蛮人的了解来看,类似的东西似乎也适用于他们。 如果真是这样,那么,如果一个人伤害了他,并成为了他的敌人,那么,将这种感情转移到同一个部落的任何一个成员身上,这对任何人来说都是一小步。 原始的良知也不可能因为一个人伤害了敌人而责备他。如果他没有为自己报仇的话,它反而会责备他。 行善报恶,爱仇敌,是一种道德的高度,人们可能会怀疑社会本能本身是否会引导我们达到这种高度。

一个人无法阻止过去的印象经常在他的脑海中浮现。因此,他会被迫将过去的饥饿、复仇的满足或以他人为代价避免危险的印象与几乎始终存在的同情本能,以及他对他人认为值得赞扬或应受谴责的早期知识进行比较。这种知识无法从他的头脑中消失,而出于本能的同情心是非常重要的。然后,他会感觉自己似乎无法遵循当前的本能或习惯,这对所有动物来说都会引起不满,甚至痛苦。

上述燕子的例子提供了一个例子,虽然性质相反,但暂时的、强烈持久的本能征服了另一种本能,而另一种本能通常比其他所有本能都占主导地位。在适当的季节,这些鸟似乎整天都渴望迁徙。他们的习惯改变了;它们变得焦躁不安、吵闹并成群结队。当母鸟正在喂食或孵化雏鸟时,母性本能可能比迁徙时更强烈。但更持久的本能获得了胜利,最后,当她的孩子们看不见时,她就逃跑并抛弃了他们。当它到达长途旅行的终点,迁徙的本能不再发挥作用时,如果鸟儿由于具有强大的心理活动能力而不能阻止图像不断地在她的脑海中闪过,那么她会感到多么悔恨的痛苦啊。 ,她的孩子们在寒冷和饥饿的荒凉北方死去。

在采取行动的那一刻,人无疑会倾向于追随更强烈的冲动。尽管这偶尔会促使他做出最高尚的行为,但更常见的是,这会导致他以牺牲他人为代价来满足自己的欲望。但在他们满足之后,当过去的和较弱的印象被永恒的社会本能所判断,以及他对同胞好感的深深尊重时,报应肯定会到来。然后他会感到悔恨、忏悔、遗憾或羞愧;然而,后一种感觉几乎完全与他人的判断有关。因此,他或多或少会坚定地决心为未来采取不同的行动;这就是良心;因为良心回顾过去,并为未来提供指南。

我们称之为遗憾、羞耻、忏悔或悔恨的情感的性质和强度,显然不仅取决于被侵犯的本能的强度,而且部分取决于诱惑的强度,而且往往更多地取决于我们同伴的判断。 每个人在多大程度上重视他人的欣赏,取决于他与生俱来或后天获得的同情心的强度;以及他自己推理出他的行为的遥远后果的能力。 另一个因素是最重要的,尽管不是必要的,那就是对每个人所信仰的诸神或灵魂的敬畏或敬畏:这尤其适用于悔恨的情况。 一些批评者反对说,虽然本章所主张的观点可以解释一些轻微的遗憾或悔恨,但无法解释那种震撼灵魂的悔恨之情。 但我看不出这种反对意见有什么说服力。 我的批评者并没有定义他们所说的悔恨是什么意思,我也找不到任何定义比压倒性的悔改感更能暗示。 悔恨与悔改的关系似乎与愤怒与愤怒、痛苦与痛苦的关系相同。 毫不奇怪的是,像母爱这样强烈而普遍受人尊敬的本能,如果不服从,一旦对过去不服从原因的印象减弱,就会导致最深的痛苦。 即使某个行为并不违背任何特殊的本能,仅仅知道我们的朋友和同等人因此鄙视我们就足以造成巨大的痛苦。 谁能怀疑因恐惧而拒绝决斗已经给许多人带来了羞耻的痛苦呢? 据说,许多印度人因吃了不洁的食物而感到心神不宁。 我认为,这是另一个必须被称为悔恨的例子。 Dr. 兰多 (Landor) 曾担任西澳大利亚的治安法官,并讲述了这一点 (28. “与法律有关的精神错乱”,美国安大略省,1871 年,第 XNUMX 页。 1.),他农场里的一个当地人,在因病失去了一位妻子后,过来说道,“他要去一个遥远的部落,用矛刺杀一个女人,以满足他对妻子的责任感。 我告诉他,如果他这样做,我就会把他判终身监禁。 他在农场呆了几个月,但变得非常瘦弱,并抱怨他无法休息或进食,他妻子的灵魂一直困扰着他,因为他没有夺走她的生命。 我毫不留情地向他保证,如果他这么做了,没有什么能拯救他。”尽管如此,这名男子失踪了一年多,然后又恢复健康。他的另一位妻子告诉博士。 兰多得知她的丈夫夺走了一名来自遥远部落的妇女的生命;但不可能获得该行为的法律证据。 因此,违反部落所奉行的神圣规则,似乎会引起最深的感情——这与社会本能完全不同,除非规则是建立在社区判断的基础上的。 。 我们不知道世界各地是如何出现这么多奇怪的迷信的。我们也无法说明一些真实而严重的罪行,例如乱伦,是如何被最低等的野蛮人所憎恶的(但这种罪行并不十分普遍)。 甚至值得怀疑的是,在某些部落中,乱伦是否会比男人与同名(尽管不是亲戚)的女人结婚更令人恐惧。 “违反这项法律是澳大利亚人最憎恶的犯罪行为,这与北美某些部落的观点完全一致。 当问题出现在任何一个地区时,杀死外来部落的女孩,还是娶自己的女孩更糟糕,都会毫不犹豫地给出与我们相反的答案。” (29. EB 泰勒,《当代评论》,1873 年 XNUMX 月,第 XNUMX 页。 707.)因此,我们可以拒绝一些作家最近坚持的信念,即对乱伦的憎恶是由于我们拥有上帝植入的特殊良知。

人在良心的驱使下,将通过长期的习惯获得如此完美的自我控制,以至于他的欲望和激情最终会立即屈服于他的社会同情心和本能,包括他对同胞判断的感觉,而不需要挣扎。仍然饥饿的人,或者仍然复仇的人,不会想到去偷食物,或者报仇。自我控制的习惯有可能像其他习惯一样被遗传,这一点我们将在下文中看到,甚至很可能。因此,最终,通过后天的、也许是遗传的习惯,人开始感到,最好是服从他更持久的冲动。 “应该”这个专横的词似乎仅仅意味着行为规则的存在的意识,无论它起源于什么。以前一定经常强烈要求受侮辱的绅士应该决斗。我们甚至说指针应该指向,而检索器应该检索游戏。如果他们不这样做,他们就没有履行职责,行为错误。

如果任何导致违背他人利益的行为的欲望或本能仍然出现,当回想起来时,它与社会本能一样强烈,或者比社会本能更强烈,那么一个人不会因为遵循它而感到强烈的遗憾;但他会意识到,如果他的行为被他的同伴知道,就会遭到他们的反对。很少有人如此缺乏同情心,以至于在意识到这一点时不感到不安。如果他没有这样的同情心,如果他当时导致不良行为的欲望很强烈,并且当回想起来时没有被持久的社会本能和他人的判断所过度控制,那么他本质上就是一个坏人(30) Prosper Despine 博士在他的《自然心理学》中,1868 年(tom. ip 243;tom. ii. p. 169)给出了许多最严重的罪犯的奇怪案例,这些罪犯显然完全丧失了良心。);剩下的唯一限制动机是害怕受到惩罚,并坚信从长远来看,考虑别人的利益而不是自己的利益对他自己的私利来说是最好的。

显然,每个人都可以心安理得地满足自己的欲望,只要这些欲望不干扰他的社会本能,即不干扰他人的利益;但为了完全摆脱自责,或者至少摆脱焦虑,他几乎有必要避免同胞的反对,无论合理与否。他也不必打破生活中固定的习惯,特别是如果这些习惯有理性的支持的话;因为如果他这么做了,他肯定会感到不满。同样,他必须避免根据他的知识或迷信所信仰的一位或多位神受到谴责。但在这种情况下,对神圣惩罚的额外恐惧往往随之而来。

首先要严格遵守社会美德

上述关于道德感的起源和性质的观点非常符合我们所看到的这种能力的早期和未发展的状况,道德感告诉我们应该做什么,而良心则在我们不服从它时责备我们。人类。至少在一般情况下,粗鲁的人必须实践的美德,以便他们能够结成一体,这些美德仍然被认为是最重要的。但这些习俗几乎都是针对同一部落的男性。对于其他部落的人来说,他们的对立面不被视为犯罪。如果谋杀、抢劫、背叛等行为普遍存在,任何部落都无法团结起来;因此,在同一部落范围内的此类犯罪行为“会被烙上永久的耻辱”(31。参见《北不列颠评论》中一篇干练的文章,1867 年,第 395 页。另请参见 W. Bagehot 先生关于“犯罪的重要性”的文章) 《对原始人的服从和连贯性》,载于《双周评论》,1867 年,第 529 页,1868 年,第 457 页等);但不要在这些限制之外激起这种情绪。当北美印第安人剥掉另一个部落的人的头皮时,他会感到非常满意,并受到其他人的尊重;戴雅克人会砍下一个无罪之人的头,并将其晒干作为战利品。全世界范围内最大规模的婴儿谋杀案(32)我所见过的最完整的叙述是 Gerland 博士在他的《Ueber den Aussterben der Naturvölker》中,1868 年;但我必须回顾一下杀婴的主题将在以后的章节中讨论。),并且没有受到任何指责;但杀婴,尤其是杀婴,被认为对部落有利,或者至少不会造成伤害。以前的自杀通常不被视为犯罪(33。参见莱基的《欧洲道德史》中关于自杀的非常有趣的讨论,第 i 卷,1869 年,第 223 页。关于野蛮人,温伍德·里德先生告知我知道西非的黑人经常自杀。众所周知,在西班牙征服后,在南美洲悲惨的原住民中自杀是多么普遍。对于新西兰,请参见诺瓦拉号的航行,对于阿留申群岛,穆勒,正如 Houzeau 所引用的,“Les Facultés Mentales”等,tom. ii. p. 136.),而是来自所表现出的勇气,作为一种光荣的行为;一些半文明和未开化的民族仍然在毫无争议地实行这种做法,因为它显然与部落的其他人无关。据记载,一名印度暴徒认真地后悔自己没有像他的父亲那样抢劫和勒死那么多的旅行者。在粗鲁的文明状态下,抢劫陌生人确实通常被认为是光荣的。

奴隶制虽然在某些方面在古代是有益的(34。参见白芝浩先生,“物理学与政治”,1872 年,第 72 页),但却是一种严重的犯罪。然而,直到最近,即使是最文明的国家也才如此重视这一点。情况尤其如此,因为奴隶一般属于与主人不同的种族。由于野蛮人不尊重妇女的意见,妻子通常被当作奴隶对待。大多数野蛮人对陌生人的痛苦完全漠不关心,甚至乐于目睹他们的痛苦。众所周知,北美印第安人的妇女和儿童帮助折磨他们的敌人。一些野蛮人以残酷对待动物为乐(35. 例如,参见汉密尔顿先生对卡菲尔人的描述,《人类学评论》,1870 年,第 xv. 页),而人性是一种未知的美德。然而,除了家庭感情之外,同一部落的成员之间,特别是在生病期间,善意是很常见的,有时甚至超出了这些限度。蒙戈·帕克对内陆黑人妇女对他的善意的感人描述是众所周知的。可以举出许多例子来说明野蛮人对彼此的崇高忠诚,但对陌生人则不然。共同的经验证明了西班牙人的格言:“永远、永远不要相信印度人。”没有真理就不可能有忠诚;没有真理就不可能有忠诚。这种基本美德在同一部落的成员中并不罕见:因此蒙戈帕克听到黑人妇女教导她们的孩子热爱真理。这又是一种深深扎根于人们思想中的美德,以至于野蛮人有时甚至会付出高昂的代价,对陌生人实行这种美德。但对敌人撒谎很少被认为是一种罪过,现代外交史也清楚地表明了这一点。一旦部落有了公认的领袖,不服从就成为犯罪,甚至卑鄙的服从也被视为神圣的美德。

在粗暴的时代,没有勇气,任何人都无法对自己的部落有用或忠诚,因此这种品质普遍被视为最高品质。尽管在文明国家,一个善良而胆怯的人可能比一个勇敢的人对社会更有用,但我们不禁本能地尊重后者,而不是胆小鬼,无论多么仁慈。另一方面,不关心他人福祉的谨慎虽然是一种非常有用的美德,但从未受到高度重视。由于没有自我牺牲、自我控制和忍耐力,任何人都无法实践其部落福祉所必需的美德,因此这些品质在任何时候都受到高度和最公正的重视。美国野蛮人自愿接受最可怕的酷刑,毫无呻吟,以证明和增强他的刚毅和勇气;我们情不自禁地钦佩他,甚至钦佩一位印度托钵僧,他出于愚蠢的宗教动机,用埋在肉里的钩子悬挂着秋千。

其他所谓的自私美德虽然可能确实影响部落的福祉,但显然并没有受到野蛮人的尊重,尽管现在受到文明国家的高度赞赏。最大的不节制就是不责备野蛮人。极度放荡和非自然犯罪盛行到了令人震惊的程度。 (36. M'Lennan 先生(《原始婚姻》,1865 年,第 176 页)就这一问题提供了大量事实。)然而,一旦婚姻,无论是一夫多妻制还是一夫一妻制,变得普遍,嫉妒就会产生。将导致女性美德的灌输;如果得到尊重,这一点将会蔓延到未婚女性身上。我们今天看到,它向男性传播的速度有多慢。贞洁极其需要自我控制。因此,从文明人道德史的早期阶段起,它就受到人们的尊敬。因此,自古以来,毫无意义的独身主义就被视为一种美德。 (38. 莱基,《欧洲道德史》,第 1869 卷,109 年,第 38 页。)对不雅行为的憎恨,在我们看来是如此自然,以至于被认为是与生俱来的,而且对贞洁的帮助是如此宝贵,正如 G. Staunton 爵士所言(348.《驻华使馆》,第二卷,第 XNUMX 页),这是一种现代美德,完全属于文明生活。各个民族的古代宗教仪式、庞贝城墙上的图画以及许多野蛮人的习俗都证明了这一点。

我们现在已经看到,原始人认为行为是好是坏,只是因为它们明显影响了部落的福祉,而不是物种的福祉,也不是原始人的福祉。部落。这个结论与所谓的道德感最初源自社会本能的信念非常吻合,因为两者最初都只与社区相关。

以我们的标准来看,野蛮人道德低下的主要原因,首先是对同一部落的同情。其次,推理能力不足以认识到许多美德,特别是自利美德对部落整体福利的影响。例如,野蛮人无法追踪由于缺乏节制、贞洁等而导致的多重罪恶。第三,自我控制能力薄弱。因为这种力量并没有通过长期延续的、也许是遗传的、习惯、教育和宗教而得到加强。

我已经详细介绍了野蛮人的不道德行为(39。请参阅 J. Lubbock 爵士《文明的起源》,1870 年第七章中关于这一主题的大量证据。),因为一些作者最近采取了高度的态度认为他们的道德本性,或者将他们的大部分罪行归咎于错误的仁慈。 (40. 例如,Lecky,《欧洲道德史》,第 124 卷。)这些作者似乎将他们的结论建立在野蛮人拥有这些美德的基础上,这些美德对于家庭和部落的存在是有用的,甚至是必要的。 ,——他们无疑确实拥有这些品质,而且往往程度很高。

结束语

它以前是由导数哲学家假设的(41。这个术语在《威斯敏斯特评论》的一篇干练的文章中使用,1869 年 498 月,第 17 页。关于“最大幸福原则”,请参见 JS Mill,“功利主义, ” p. 42.) 道德学派认为道德的基础是自私;但最近“最大幸福原则”被突出地提出来。然而,更正确的说法是将后一个原则作为标准,而不是作为行为的动机。然而,我查阅过的所有作者的作品,除了少数例外(422.密尔)以最明确的方式认识到(“逻辑系统”,第 ii 卷,第 1872 页),行动可以通过习惯来执行,而无需预期H. Sidgwick 先生也在他的《关于快乐与欲望的文章》(《当代评论》,671 年 XNUMX 月,第 XNUMX 页)中评论道:“总而言之,与我们有意识的主动冲动是我认为,我们在意识中到处都发现了与快乐无关的冲动,而在许多情况下,这种冲动与自我关注是不相容的。两者并不容易在同一意识时刻共存。”我不得不认为,一种模糊的感觉是我们的冲动并不总是源于任何同时的或预期的快乐,这一直是我们接受道德的直觉理论,以及对功利主义或“最大幸福”理论的拒绝。对于后一种理论,行为的标准和动机无疑经常被混淆,但它们实际上在某种程度上是混合在一起的。),写得好像每一个行为都必须有一个明确的动机,并且这必须是相关的带着一些高兴或不高兴。但人似乎常常出于本能或长期习惯而冲动行事,没有任何快乐的意识,就像蜜蜂或蚂蚁盲目追随本能时的行为一样。在极度危险的情况下,比如在火灾中,当一个人毫不犹豫地努力拯救同胞时,他很难感到快乐;他更没有时间去思考如果他不尝试的话,他随后可能会遇到的不满。如果他事后反省自己的行为,他会感到自己内心深处存在着一种与追求快乐或幸福截然不同的冲动力量;这似乎是根深蒂固的社会本能。

就低等动物而言,谈论它们的社会本能似乎更合适,因为它们的社会本能是为了普遍利益而不是为了物种的普遍幸福而发展的。 “普遍利益”一词可以被定义为在他们所处的条件下培养出最大多数的人,使他们充满活力和健康,使他们的所有能力都完美。由于人类和低等动物的社会本能无疑是通过几乎相同的步骤发展起来的,因此,如果可行的话,建议在这两种情况下使用相同的定义,并将社会的普遍利益或福利,而不是普遍的幸福;但出于政治道德考虑,这一定义可能需要一些限制。

当一个人冒着生命危险去拯救同胞时,更正确的说法是,他的行为是为了公共利益,而不是为了人类的普遍幸福。毫无疑问,个人的福利和幸福通常是一致的。一个满足、快乐的部落会比一个不满、不快乐的部落更加繁荣。我们已经看到,即使在人类历史的早期阶段,共同体所表达的愿望也会自然地在很大程度上影响每个成员的行为;而作为所有人对幸福的渴望,“最大幸福原则”将成为最重要的次要指导和对象;然而,社会本能和同情心(这导致我们对他人的认可和不认可)一起充当了主要的冲动和指导。这样,我们就不再因以自私为基本原则而为我们本性中最高尚的部分奠定基础而受到指责。事实上,除非每一种动物在遵循其适当的本能时所感受到的满足,以及在受到阻止时所感受到的不满,都可以被称为自私。

同一社区成员的愿望和意见,最初是口头表达的,后来也通过书面表达,要么构成我们行为的唯一指南,要么极大地强化了社会本能;然而,这些观点有时具有与这些本能直接相反的倾向。荣誉法很好地说明了后一个事实,即我们平等者而不是我们所有同胞的意见法。违反这条法律,即使已知这种违反严格符合真正的道德,给许多人带来的痛苦比真正的犯罪还要多。我们认识到,我们大多数人在想起无意中违反了一些虽然固定的礼仪规则时,都会感到强烈的羞耻感,即使是在多年之后。社区的判断通常会以一些粗略的经验为指导,这些经验从长远来看对所有成员来说是最好的;但由于无知和推理能力薄弱,这种判断常常会犯错误。因此,与人类真正的福祉和幸福完全相反的最奇怪的习俗和迷信在全世界变得无所不能。我们从一个打破种姓的印度人所感受到的恐惧以及许多其他类似的案例中看到了这一点。很难区分一个印度人在屈服于吃不洁食物的诱惑后所感受到的悔恨与犯下盗窃后的悔恨之情。但前者可能更为严重。

这么多荒唐的行为准则、这么多荒唐的宗教信仰是如何产生的,我们不得而知;也不知道它们是如何在世界各地的人们心中留下如此深刻的印象的;但值得注意的是,在生命早期不断灌输的信念,虽然大脑是难以受影响的,但似乎几乎获得了本能的本质;本能的本质就在于它是独立于理性而被遵循的。我们也不能说为什么某些令人钦佩的美德,例如热爱真理,比其他部落更受一些野蛮部落的赞赏(43. 华莱士先生在《科学观点》,15 年 1869 月 1870 日中给出了很好的例子;更详细的内容参见他的《自然选择理论的贡献》,353 年,第 XNUMX 页。)同样,这也解释了为什么即使在高度文明的国家中也存在类似的差异。知道许多奇怪的习俗和迷信已经变得多么根深蒂固,我们就不会感到惊讶,因为它们是由理性支持的,以自我为中心的美德现在对我们来说是如此自然,以至于被认为是与生俱来的,尽管它们并没有受到人们的重视。处于早期状态的人。

尽管存在许多疑问,但人类通常可以轻松地区分较高和较低的道德规则。更高层次的事物建立在社会本能的基础上,并与他人的福祉相关。他们得到了我们同胞的认可和理性的支持。较低的规则,虽然其中一些意味着自我牺牲,很难被称为较低的规则,但主要与自我有关,源于公众舆论,经过经验和修养而成熟;因为粗鲁的部落不会这样做。

随着人类文明的进步,小部落联合成更大的社区,最简单的理由告诉每个人,他应该将他的社会本能和同情心延伸到同一国家的所有成员,尽管他个人不认识。一旦达到这一点,就只剩下人为的障碍来阻止他向所有国家和种族的人们表达同情。如果这些人确实因外表或习惯的巨大差异而与他分开,不幸的是,经验告诉我们,我们需要多久才能将他们视为我们的同胞。超越人类范围的同情心,即对低等动物的人性,似乎是最新的道德成就之一。野蛮人显然没有感受到这种感觉,除了他们的宠物。古罗马人对这一点知之甚少,从他们令人憎恶的角斗表演就可见一斑。据我观察,人性的概念对于潘帕斯草原上的大多数高乔人来说都是新鲜的。这种美德是人类被赋予的最崇高的美德之一,它似乎是从我们的同情心变得更加温柔和更加广泛传播而偶然产生的,直到它们扩展到所有有情众生。一旦这种美德被少数人尊崇和实践,它就会通过教导和榜样向年轻人传播,并最终融入公众舆论。

道德文化的最高阶段是当我们认识到我们应该控制自己的思想时,“即使在内心深处,也不要再去想那些让过去让我们如此愉快的罪恶”。 (44. 丁尼生,《国王的田园诗》,第 244 页。) 任何使不良行为为人们所熟悉的事物,都会使其表现得更加容易。正如马可·奥勒留很久以前说过的那样:“你的习惯性想法有多大,你的思想性格也将有多大;因为灵魂被思想染色了。” (45.《皇帝 M.奥勒留·安东尼的思想》,英文翻译,第二版,2 年。第 1869 页。马库斯·奥勒留出生于公元 112 年。)

我们伟大的哲学家赫伯特·斯宾塞最近解释了他对道德感的看法。他说(46. 贝恩《心理与道德科学》中给米尔先生的信,1868 年,第 722 页),“我相信,人类过去几代人组织和巩固的功利经验,一直在产生相应的修改,通过不断的传播和积累,已经成为我们某些道德直觉的能力——对正确和错误行为做出反应的某些情感,而这些情感在个人的功利经验中没有明显的基础。”在我看来,美德倾向或多或少是强烈遗传的,这并非是天生不可能的。因为,不说我们许多家畜遗传给后代的各种性情和习惯,我就听说过一些真实的案例,在这些案例中,上层家庭中似乎存在着偷窃的欲望和撒谎的倾向。由于偷窃在富裕阶层中是一种罕见的犯罪行为,我们很难用偶然的巧合来解释同一家庭中两三个成员发生的这种倾向。如果不良倾向被传播,那么良好的倾向也可能同样被传播。大多数患有慢性消化或肝脏紊乱的人都知道,身体的状态通过影响大脑,对道德倾向有很大的影响。 “道德感的扭曲或破坏往往是精神错乱的最早症状之一”(47. Maudsley, 'Body and Mind,' 1870, p. 60.)也证明了同样的事实。众所周知,精神错乱往往是遗传性的。除非通过道德倾向的传递原理,我们无法理解人类不同种族之间在这方面存在的差异。

即使是部分美德倾向的传承,也会对直接或间接源自社会本能的原始冲动产生巨大的帮助。暂时承认美德倾向是遗传的,至少在贞洁、节制、对动物的人道等情况下,它们似乎可能首先通过习惯、指导和榜样在精神组织上留下深刻的印象,这些印象在几个世纪以来一直持续着。在同一个家庭的几代人中,具有这种美德的个人在为生存而奋斗中取得了最大的成功,这种美德处于相当从属的程度,或者根本没有。我对任何此类遗产的怀疑的主要根源在于,毫无意义的习俗、迷信和品味,例如印度人对不洁食物的恐惧,应该按照同样的原则来传承。我没有遇到任何证据支持迷信习俗或无意义习惯的传播,尽管其本身的可能性可能不亚于动物应该遗传对某些食物的口味或对某些敌人的恐惧。

最后,毫无疑问,人类和低等动物为了群体的利益而获得的社会本能,从一开始就会赋予他一些帮助同伴的愿望,一些同情心,并迫使他尊重他人。他们的认可和不认可。这种冲动在很早的时期就作为粗鲁的是非规则为他服务。但随着人类的智力逐渐进步,并能够追踪其行为的更遥远的后果;因为他获得了足够的知识来拒绝有害的习俗和迷信;他越来越关心的不仅是同胞的福祉,还有同胞的幸福。由于习惯,遵循有益的经验、指导和榜样,他的同情心变得更加温柔和广泛传播,延伸到所有种族的人,延伸到低能的、残废的和其他无用的社会成员,最后延伸到低等动物,——那么他的道德水准就会越来越高。派生学派的道德家和一些直觉主义者也承认,道德标准从人类历史的早期阶段就已经提高了。 (48. 《北不列颠评论》(1869 年 531 月,第 143 页)的一位作者非常有能力做出正确的判断,他强烈支持这一结论。莱基先生(《道德史》,第 XNUMX 卷)。 ip XNUMX)似乎在某种程度上与其中一致。)

正如有时可以看到低等动物的各种本能之间正在发生斗争一样,毫不奇怪,人类的社会本能及其派生的美德与他的低等但暂时更强烈的冲动或欲望之间存在着斗争也就不足为奇了。 。正如高尔顿先生(49。见他关于“遗传天才”的杰出著作,1869年,第349页。阿盖尔公爵(“原始人”,1869年,第188页)对人类的竞争有一些很好的评论。 )指出,这一点并不令人惊讶,因为人类是在相对较近的时期内摆脱了野蛮状态的。在屈服于某种诱惑后,我们会感到不满、羞耻、悔恨或悔恨,类似于其他强大的本能或欲望在不满足或受阻时所引起的感觉。我们将过去诱惑所减弱的印象与始终存在的社会本能或习惯进行比较,这些习惯是在青年时期获得的,并在我们的一生中不断加强,直到它们变得几乎与本能一样强大。如果诱惑仍然摆在我们面前,我们还没有屈服,那是因为社会本能或某种习俗目前占主导地位,或者因为我们已经知道,与过去的削弱印象相比,它在以后对我们来说会显得更强烈。诱惑,我们意识到违反它会给我们带来痛苦。展望未来几代人,没有理由担心社会本能会变得更弱,我们可以预期,良好的习惯会变得更强,并可能通过遗传而固定下来。在这种情况下,我们的高级冲动和低级冲动之间的斗争就会不那么激烈,美德就会取得胜利。

最后两章总结

毫无疑问,最低等的人的心灵与最高等的动物的心灵之间的差异是巨大的。一只拟人化的猿,如果他能够冷静地看待自己的情况,就会承认,尽管他可以制定一个巧妙的计划来掠夺花园——尽管他可以使用石头来战斗或敲开坚果,但塑造的想法把石头变成工具完全超出了他的范围。更不用说,正如他承认的那样,他无法遵循一系列形而上学推理,或解决数学问题,或反思上帝,或欣赏宏伟的自然景观。然而,一些猿类可能会宣称,它们可以而且确实欣赏婚姻伴侣的彩色皮肤和皮毛之美。他们承认,虽然他们可以通过哭声让其他猿类理解他们的一些看法和简单的需求,但他们从未想过用明确的声音表达明确的想法。他们可能会坚持说,他们已经准备好以多种方式帮助同一队伍中的猿类同胞,为他们冒着生命危险,并照顾他们的孤儿;但他们将被迫承认,对所有生物的无私的爱是人类最崇高的品质,这是他们完全无法理解的。

然而,人与高等动物之间的心灵差异,尽管很大,但肯定是程度而非种类的差异。我们已经看到,人类所夸耀的感觉和直觉,各种情感和能力,如爱、记忆、注意力、好奇心、模仿、理性等,可能是在萌芽状态中发现的,有时甚至是在井然有序的状态下发现的。 - 低等动物的发育状况。它们也能够进行一些遗传性的改进,正如我们在家狗与狼或豺狼相比中所看到的那样。如果能够证明某些高级心智能力,例如一般概念的形成、自我意识等,绝对是人类所特有的,这似乎是极其令人怀疑的,那么这些品质也并非不可能,只是人类发展的偶然结果。其他高度先进的智力;而这些又主要是持续使用完美语言的结果。新生婴儿在什么年龄才具备抽象的能力,或者变得有自我意识,反思自己的存在?我们无法回答;我们也无法回答有机规模的上升问题。语言的半艺术、半本能仍然带有其逐渐演变的印记。对上帝的高尚信仰并不普遍存在于人类之中。对精神力量的信仰自然源于其他精神力量。道德感也许是人类与低等动物之间最好、最高的区别。但在这个问题上我不需要多说什么,因为我最近一直在努力表明社会本能——人类道德构成的首要原则(50.《马库斯·奥勒留的思想》等,第139页)——借助积极的智力和习惯的影响,自然会导致金科玉律:“你希望人们对你做什么,你就对他们做同样的事情”。这是道德的基础。

在下一章中,我将对人类几种心智和道德能力逐渐进化的可能步骤和方法做一些评论。这种进化至少是可能的,不应该被否认,因为我们每天都看到这些能力在每个婴儿身上不断发展。我们可以从一个比动物低等的白痴的头脑到牛顿的头脑进行完美的分级。

第五章 •8,300字
论原始文明时期智力和道德能力的发展

通过自然选择提高智力——模仿的重要性——社会和道德能力——它们在同一部落范围内的发展——自然选择对文明国家的影响——文明国家曾经是野蛮的证据。

本章要讨论的主题是我最感兴趣的,但我的处理方式并不完善和零散。华莱士先生在之前提到的一篇令人钦佩的论文中(1.人类学评论,1864年XNUMX月,第clviii页)认为,人类在部分获得了区别于低等动物的智力和道德能力之后,会几乎不可能通过自然选择或任何其他方式改变身体。因为人能够通过他的心智能力“以不变的身体与不断变化的宇宙保持和谐”。他有能力使自己的习惯适应新的生活条件。他发明了武器、工具和各种策略来获取食物和保护自己。当他迁移到气候寒冷的地方时,他会穿衣服、搭建棚屋、生火;并借助火来烹饪难以消化的食物。他以多种方式帮助他的同胞,并预测未来的事件。即使在遥远的时期,他也实行了某种劳动分工。

另一方面,低等动物必须改变其身体结构才能在巨大变化的条件下生存。它们必须变得更强,或者获得更有效的牙齿或爪子,以防御新的敌人;或者必须缩小它们的尺寸,以逃避检测和危险。当它们迁徙到气候寒冷的地方时,它们必须穿上更厚的皮毛,或者改变它们的体质。如果它们不能被如此修改,它们将不复存在。

然而,正如华莱士先生公正地坚持的那样,就人类的智力和道德能力而言,情况却大不相同。这些能力是可变的;我们有充分的理由相信这些变异往往是遗传的。因此,如果它们以前对原始人类及其类人猿祖先非常重要,那么它们就会通过自然选择而得到完善或进步。智力的高度重要性是毫无疑问的,因为人类在世界上的主导地位主要归功于智力。我们可以看到,在最原始的社会状态下,那些最有智慧的人,那些发明并使用最好的武器或陷阱,那些最有能力保护自己的人,将会养育出最多数量的后代。这些部落,其中包括最多数量的男性,因此数量将增加并取代其他部落。人数主要取决于生存手段,这部分取决于该国的自然条件,但在更大程度上取决于该国所从事的艺术。当一个部落不断壮大并取得胜利时,它往往会通过吸收其他部落而进一步增加。 (2.一段时间后,被吸收到另一个部落的成员或部落假定,正如亨利·梅因爵士所说(《古代法律》,1861年,第131页),他们是同一祖先的共同后裔。)一个部落的男人的身材和力量对于其成功同样具有一定的重要性,而这些部分取决于可以获得的食物的性质和数量。在欧洲,青铜时期的人类被更强大的种族所取代,从他们的剑柄来看,他们的手更大(3. Morlot, 'Soc. Vaud. Sc. Nat.' 1860, p. 294.) ;但他们的成功可能更多地归功于他们在艺术上的优越性。

我们对野蛮人的了解,或者从他们的传统和古老的纪念碑中推断出来的一切,其历史已被现在的居民所遗忘,都表明,从远古时代开始,成功的部落就取代了其他部落。在地球上的文明地区、美洲的荒野平原以及太平洋的孤岛上都发现了灭绝或被遗忘的部落的遗迹。如今,文明国家到处都在取代野蛮国家,除了气候有致命障碍的地方。他们的成功主要(但并非完全)是通过他们的艺术,而艺术是智力的产物。因此,人类的智力很可能主要是通过自然选择而逐渐完善的。这个结论对于我们的目的来说已经足够了。毫无疑问,追踪每种独立能力从低等动物中存在的状态到人类中存在的状态的发展是很有趣的。但我的能力和知识都不允许这种尝试。

值得注意的是,一旦人类的祖先变得社会化(这可能发生在很早的时期),模仿的原则、理性和经验就会增加,并在某种程度上改变智力,我们只在低等动物身上看到过这种痕迹。猿类非常喜欢模仿,最低等的野蛮人也是如此。前面提到的简单事实,即一段时间后,没有动物会在同一地点被同一种陷阱捕获,这表明动物通过经验学习,并模仿其他动物的谨慎。现在,如果部落中的某个人比其他人更聪明,发明了一种新的圈套或武器,或其他攻击或防御手段,那么最简单的自我利益,无需太多推理能力的帮助,就会促使其他成员模仿他;所有人都会因此受益。每一种新艺术的习惯实践也必须在某种程度上增强智力。如果新发明是一项重要发明,部落的数量就会增加、传播并取代其他部落。在一个数量如此众多的部落中,总会有更大的机会诞生其他优秀和有创造力的成员。如果这些人留下孩子来继承他们的智力优势,那么出生更多聪明成员的机会会更好一些,而且在一个非常小的部落中显然更好。即使他们没有留下孩子,部落仍然会包括他们的血缘关系;农学家已经确定(4.我在《驯养动物的变化》,卷二,第 196 页中给出了实例。)通过保存和繁殖动物家族,在屠宰时发现该动物是有价值,已获得所需的字符。

现在转向社会和道德能力。为了使原始人,或者类人猿的人类祖先变得社会化,他们必须获得同样的本能情感,这种情感促使其他动物生活在一个身体里;毫无疑问,他们都表现出了同样的性格。当他们与战友分开时,他们会感到不安,因为他们对战友会产生某种程度的爱;他们会互相警告危险,并在进攻或防御时互相帮助。所有这些都意味着某种程度的同情、忠诚和勇气。这些社会品质对于低等动物来说具有无可争议的重要性,毫无疑问,人类的祖先以类似的方式获得了这些品质,即通过自然选择,并在遗传习惯的帮助下获得的。当生活在同一个国家的两个原始人类部落发生竞争时,如果(在其他条件相同的情况下)其中一个部落有大量勇敢、富有同情心和忠诚的成员,他们随时准备互相警告危险,为了互相帮助和保卫,这个部落会取得更好的成功并征服另一个部落。请记住,在野蛮人永无休止的战争中,忠诚和勇气是多么重要。纪律严明的士兵相对于散漫的军队的优势主要来自于每个人对战友的信任。服从,正如白芝浩先生所充分展示的那样(5.参见《双周评论》,1867 年 1 月、1868 年 1 月 1869 日、XNUMX 年 XNUMX 月 XNUMX 日出版的关于“物理学和政治”的一系列精彩文章,此后分别出版。 ),具有最高的价值,因为任何形式的政府都比没有政府好。自私和好争吵的人不会团结一致,没有团结一致就什么也做不了。一个富有上述品质的部落将会扩张并战胜其他部落:但从过去的历史来看,随着时间的推移,它会被其他一些更有天赋的部落所征服。因此,社会和道德品质将趋于缓慢进步并传播到世界各地。

但也许有人会问,在同一个部落的范围内,大量的成员是如何首先具备这些社会道德品质的,优秀的标准是如何提高的?具有同情心和仁慈的父母,或者对同伴最忠诚的父母所生出的后代,是否会比同一个部落中自私和奸诈的父母所生出的后代数量更多,这是极其值得怀疑的。那些愿意牺牲自己生命的人,就像许多野蛮人一样,而不是背叛他的同志,往往不会留下任何后代来继承他的高贵本性。最勇敢的人总是愿意在战争中走上前线,并且愿意为他人冒着生命危险,平均而言,他们会比其他人更多地死去。因此,具有这种美德的人的数量,或者他们的卓越标准,可以通过自然选择,即通过适者生存来增加,这似乎不太可能。因为我们在这里谈论的并不是一个部落战胜另一个部落。

尽管导致同一部落内受赠者数量增加的情况过于复杂,无法清楚地追踪,但我们可以追踪一些可能的步骤。首先,随着成员的推理能力和远见的提高,每个人很快就会知道,如果他帮助他的同胞,他通常会得到援助作为回报。由于这种卑鄙的动机,他可能会养成帮助同伴的习惯。行善的习惯必然会增强同情心,而同情心是行善的第一动力。此外,许多代人所遵循的习惯很可能会遗传。

但是,对社会美德的发展来说,另一个更强大的刺激是来自我们同胞的赞扬和指责。正如我们已经看到的,我们习惯性地赞扬和指责他人,这主要是由于同情的本能,而当我们应用于自己时,我们又爱前者,又害怕后者。毫无疑问,这种本能最初是通过自然选择获得的,就像所有其他社会本能一样。我们当然不能说,人类的祖先在其发展过程中多久开始能够感受并受到同胞的赞扬或责备的驱使。但看来即使是狗也喜欢鼓励、赞扬和责备。最粗鲁的野蛮人也感受到了荣耀的感觉,这一点通过他们保存自己英勇的战利品、过度吹嘘的习惯,甚至通过他们对个人外表和装饰的极度关注而清楚地表现出来;因为除非他们考虑同志的意见,否则这些习惯就是毫无意义的。

他们当然对违反一些较小的规则感到羞耻,并且显然感到悔恨,正如澳大利亚人的例子所表明的那样,他变得越来越瘦,为了安抚他死去妻子的灵魂,他无法停止谋杀其他女人。 。虽然我没有遇到过任何其他有记录的案例,但一个野蛮人愿意牺牲自己的生命而不是背叛他的部落,或者一个愿意作为囚犯自首而不是打破假释的人几乎令人难以置信(6. Mr.华莱士在他的《自然选择理论的贡献》,1870 年,第 354 页中给出了案例。),如果他未能履行他认为神圣的职责,他的内心深处不会感到悔恨。

因此我们可以得出这样的结论:原始人在很遥远的时期就受到了同胞的赞扬和指责的影响。显然,同一部落的成员会赞成他们看来有益的行为,并会谴责那些看似邪恶的行为。为他人行善——己所不欲,勿施于人——是道德的基石。因此,在粗鲁时期,爱赞美、怕责备的重要性怎么强调都不为过。一个人如果不是被任何深刻的、本能的情感所驱使,为了他人的利益而牺牲自己的生命,而是被一种荣耀感所唤醒而采取这种行动,那么他就会以自己的榜样激起其他人对荣耀的同样的渴望,并且通过锻炼可以增强崇高的钦佩感。因此,他对部落的好处可能比生下倾向于继承他自己高尚品格的后代要多得多。

随着经验和理性的增加,人们认识到自己行为的更遥远的后果,以及自私的美德,例如节制、贞洁等,正如我们之前所看到的,这些美德在早期被完全忽视。受到高度尊重,甚至被视为神圣。然而,我不需要重复我在第四章中就这个问题所说过的内容。最终,我们的道德感或良心变成了一种高度复杂的情感——起源于社会本能,很大程度上受到同胞认可的指导,受理性、自利的支配,后来受到深刻的宗教情感的支配,并受到指导的确认和习惯。

我们决不能忘记,尽管道德高标准只给每个人及其子女相对于同一部落的其他人带来轻微或没有优势,但是,天赋良好的人的数量增加,进步也随之增加。在道德标准上肯定会给一个部落比另一个部落带来巨大的优势。一个部落的许多成员都具有高度的爱国主义、忠诚、服从、勇气和同情心,随时准备互相帮助,并为了共同利益而牺牲自己,这样,部落就能战胜大多数其他部落。部落;这就是自然选择。世界各地的部落在任何时候都在取代其他部落。由于道德是他们成功的重要因素之一,因此各地的道德水平和有天赋的人的数量都会趋于提高和增加。

然而,很难判断为什么一个特定部落而不是另一个部落取得了成功并在文明规模上得到了提升。许多野蛮人的状况与几个世纪前首次发现时相同。正如白芝浩先生所说,我们倾向于将进步视为人类社会的正常现象;但历史反驳了这一点。古人甚至没有这个想法,现在的东方国家也没有。另一位高级权威亨利·梅因爵士 (Sir Henry Maine) 表示(7.《古代法律》,1861 年,第 22 页。对于白芝浩先生的言论,《双周评论》,1 年 1868 月 452 日,第 8 页。)“人类从未表现出一丝希望改善其公民制度的愿望。”进展似乎取决于许多同时存在的有利条件,而这些条件太复杂而难以遵循。但人们经常指出,凉爽的气候,从工业到各种艺术,都非常有利于这里的发展。迫于生存的压力,爱斯基摩人成功地完成了许多巧妙的发明,但他们的气候过于严酷,无法持续进步。游牧习惯,无论是在广阔的平原上,还是穿过热带茂密的森林,还是沿着海岸,在任何情况下都是非常有害的。在观察火地岛的野蛮居民时,我突然意识到,拥有一定的财产、固定的住所以及在酋长领导下的许多家庭的联合,是文明不可或缺的必要条件。这种习惯几乎需要耕种土地。正如我在其他地方所表明的那样(309.“驯化下的动物和植物的变异”,第 ip XNUMX 卷),栽培的第一步可能是由诸如果树种子掉落在地上的意外事件造成的。一堆垃圾,却产出了异常优良的品种。然而,野蛮人首次迈向文明的问题目前却很难解决。

自然选择影响文明国家

迄今为止,我只考虑了人类从半人状态到现代野蛮状态的进步。但关于自然选择对文明国家的作用的一些评论可能值得补充。 WR Greg 先生巧妙地讨论了这个主题(9.《弗雷泽杂志》,1868 年 353 月,第 3 页。这篇文章似乎引起了很多人的注意,并引起了两篇出色的文章和《弗雷泽杂志》中的反驳。 《旁观者》,17 年 1868 月 1869 日至 152 日。《科学季刊》,1869 年,第 1870 页以及劳森·泰特先生在《都柏林医学科学季刊》,128 月 13 日也对此进行了讨论。 1867 年,E. Ray Lankester 先生在他的《比较长寿》中,10 年,第 1865 页。类似的观点之前出现在 318 年 1870 月 XNUMX 日的《澳大利亚人》中。我借用了其中几位作家的想法。)之前是华莱士先生和高尔顿先生。 (XNUMX. 关于华莱士先生,请参阅《人类学评论》,如前所述。高尔顿先生在《麦克米伦杂志》,XNUMX 年 XNUMX 月,第 XNUMX 页;还有他的伟大著作《遗传性天才》,XNUMX 年。)我的言论摘自这三位作者。对于野蛮人来说,身体或精神上的弱者很快就会被淘汰;那些幸存下来的人通常表现出旺盛的健康状况。另一方面,我们文明人则尽最大努力阻止消除的过程。我们为低能者、伤残者和病人建造庇护所;我们制定济贫法;我们的医务人员竭尽全力挽救每个人的生命,直到最后一刻。我们有理由相信,疫苗接种拯救了成千上万原本因体​​质虚弱而死于天花的人。文明社会的弱者就这样繁衍生息。任何一个参与过家畜饲养的人都不会怀疑这对人类来说一定是一种极大的伤害。令人惊讶的是,缺乏照顾或照顾不当会很快导致家庭种族的退化。但除了人类自己之外,几乎没有人会无知到允许最糟糕的动物繁殖。

我们感到被迫向无助者提供的援助主要是同情本能的偶然结果,同情本能最初是作为社会本能的一部分而获得的,但后来以前面提到的方式变得更加温柔和更广泛地传播。即使在严酷的理由的催促下,我们也无法抑制我们的同情心,而不会使我们本性中最高尚的部分退化。外科医生在进行手术时可能会变得坚强,因为他知道他是为了病人的利益而行事。但如果我们故意忽视弱者和无助者,那只能是为了一时的利益,而带来压倒性的眼前的祸害。因此,我们必须承受弱者生存和繁殖所带来的毫无疑问的坏影响。但稳定的行动似乎至少有一个障碍,即社会中较弱和低等的成员不能像声音那样自由地结婚;身体或精神上的弱者如果不结婚,这种抑制可能会无限期地增加,尽管这比预期的更值得希望。

在每一个拥有庞大常备军的国家,最优秀的年轻人都会被征召入伍或入伍。因此,他们在战争期间很容易英年早逝,经常受到诱惑而犯下恶行,并且在年富力强时无法结婚。另一方面,身材矮小、体质较差的男性则被留在家里,因此有更好的机会结婚和繁衍后代。 (11. H. Fick 教授(“Einfluss der Naturwissenschaft auf das Recht”,1872 年 XNUMX 月)对这个问题以及其他类似观点有一些很好的评论。)

人类积累财产并将其遗赠给他的孩子,因此富人的孩子在成功的竞赛中比穷人具有优势,无论身体或精神是否优越。另一方面,父母寿命短,因此平均缺乏健康和活力,他们的孩子比其他孩子更早获得财产,并且可能更早结婚,并留下更多的财产。后代继承其劣等体质。但继承财产本身并不是一件坏事。因为没有资本的积累,艺术就不可能进步。文明种族主要是通过它们的力量得以扩展,并且现在正在到处扩展它们的范围,以取代低等种族。财富的适度积累也不会干扰选择的过程。当一个穷人变得中等富裕时,他的孩子就会进入那些需要足够奋斗的行业或职业,这样身体和精神上有能力的人才能取得最大的成功。一群受过良好教育的人的存在,他们不必为每日的生计而劳作,其重要性是不容高估的。因为所有高智力工作都是由他们进行的,而各种物质进步主要取决于这些工作,更不用说其他更高的优势了。毫无疑问,当财富非常多时,往往会将人变成无用的无人机,但他们的数量从来都不是很大;这里发生了某种程度的消除,因为我们每天都会看到富人,他们碰巧是傻瓜或挥霍者,挥霍他们的财富。

带有继承财产的长子继承权是一种更直接的罪恶,尽管它以前可能因统治阶级的建立而具有巨大的优势,而且任何政府都比没有政府好。大多数长子虽然身体或精神较弱,但还是会结婚,而小儿子,无论在这些方面多么优秀,一般都不会结婚。拥有继承财产的毫无价值的长子也不能挥霍他们的财富。但在这里,和其他地方一样,文明生活的关系是如此复杂,以至于需要一些补偿性的检查介入。通过长子继承权而富有的男人能够一代又一代地挑选更美丽、更有魅力的女人;这些人通常必须身体健康、思想活跃。不经过任何选择而继续保留同一血统所带来的邪恶后果,可能会受到总是希望增加财富和权力的有地位的人的制止。他们通过与女继承人结婚来实现这一点。但是,正如高尔顿先生(12.《遗传天才》,1870 年,第 132-140 页)所表明的那样,那些生育了独生子女的父母的女儿本身也容易不育。因此,贵族家庭的直系血统不断被切断,他们的财富流向了一些旁路。但不幸的是,这个渠道并不是由任何形式的优势决定的。

尽管文明在许多方面抑制了自然选择的作用,但它显然有利于身体的更好发展,通过良好的食物和摆脱偶尔的困难。这可以从文明人被发现无论在什么方面都比野蛮人身体更强壮来推断。 (13. Quatrefages,《Revue des Cours Scientifiques》,1867-68,第 659 页。)正如许多冒险探险所证明的那样,它们似乎也具有同等的耐力。即使是富人的奢侈享受也无多大害处。因为我们的贵族阶层,无论年龄大小,无论性别,对生活的期望,都比英国下层阶级的健康生活要差得多。 (14. 请参阅 ER Lankester 先生的“比较寿命”,1870 年,第 115 页中给出的表格中的第五和第六栏,这些栏目由权威人士整理。)

现在我们将关注智力。如果社会每个阶层的成员都被分成两个平等的群体,一个包含智力上的优势者,另一个包含智力上的劣者,那么毫无疑问,前者将在所有职业中取得最好的成功,并养育更多的孩子。即使在最底层的行业,技能和能力也必须具有一定的优势;尽管在许多职业中,由于劳动分工很大,但分工很小。因此,在文明国家中,智力人才的数量和水平都会有增加的趋势。但我不想断言,这种趋势可能只能通过其他方式来抵消,例如鲁莽和短视的增加;但即便是这样的人,能力也一定是有一些优势的。

诸如此类的观点经常遭到反对,即有史以来最杰出的人物没有留下任何后代继承他们的伟大智慧。高尔顿先生说:“我很遗憾无法解决这样一个简单的问题:天才的男人和女人是否不育以及在多大程度上不育。然而,我已经表明,杰出人物决不是这样的。” (15.《遗传天才》,1870 年,第 330 页。)伟大的立法者、仁慈宗教的创始人、伟大的哲学家和科学发现者,通过他们的作品比通过留下众多的后代在更大程度上帮助人类进步。 。就物质结构而言,导致物种进步的是对天赋稍佳的个体的选择和天赋稍差的个体的淘汰,而不是对明显标记和罕见异常的保存。 (16.《物种起源》(第五版,1869 年),第 104 页。)智力也是如此,因为社会各个阶层中能力稍强的人比能力较差的人取得的成功要好得多,因此智力也会提高。如果没有其他方式阻止的话,数量上。当任何一个国家的智力水平和知识分子数量有所增加时,我们可以根据偏离平均数的规律预计,正如高尔顿先生所表明的那样,天才的出现会比以前更加频繁。

就道德品质而言,即使在最文明的国家中,对最恶劣性格的某些消除也总是在进行中。犯罪分子会被处决,或者长期监禁,这样他们就不能自由地传播他们的坏品质。忧郁和精神错乱的人会被限制或自杀。暴力和争吵的人往往会以血腥结束。不安分的人不会从事任何稳定的职业——而这种野蛮的遗迹是对文明的巨大阻碍(17.《遗传天才》,1870年,第347页)——移民到新定居的国家;他们被证明是有用的先驱。不节制的破坏力如此之大,以至于不节制的人在13.8岁时的预期寿命只有40.59岁;而英国农村劳动力的同龄人为 18 岁。 (1870. E. Ray Lankester,“比较长寿”,115 年,第 1858 页。不节制者的表格来自 Neison 的“生命统计”。关于挥霍,请参阅 Farr 博士,“婚姻对死亡率的影响”, “国家社会科学促进协会,”XNUMX。)挥霍的女人很少生孩子,挥霍的男人很少结婚。两人都患有疾病。在家畜的饲养过程中,淘汰那些数量虽少但明显劣等的个体,对于成功来说绝不是一个不重要的因素。这尤其适用于那些往往通过回归而重新出现的有害特征,例如绵羊的黑色;对于人类来说,一些最恶劣的性情,偶尔会在没有任何明显原因的情况下出现在家庭中,可能会回归到野蛮状态,而我们几代人都没有摆脱这种状态。这种观点似乎确实被普遍认为是这样的男人是家庭中的害群之马。

对于文明国家来说,就道德标准的提高和相当优秀的人的数量的增加而言,自然选择的影响显然微乎其微。尽管基本的社会本能最初是由此获得的。但是,在谈到低等种族时,关于导致道德进步的原因,即我们同胞的认可——通过习惯加强我们的同情心——榜样和模仿——理性——经验,我已经说得够多了。 ,甚至还有自私——青年时期的教导,以及宗教感情。

格雷格先生和高尔顿先生强烈主张,文明国家中上层阶级人数增加的一个最重要的障碍(19.《弗雷泽杂志》,1868 年 353 月,第 1865 页。《麦克米伦杂志》杂志,”318 年 1870 月,第 264 页。牧师 FW Farrar(“弗雷泽杂志”,20 年 287 月,第 1871 页)持不同观点。),即,事实上,非常贫穷和鲁莽的人,经常因恶习而堕落,几乎总是早婚,而谨慎节俭的人,通常在其他方面都是有道德的,则晚婚,以便他们能够舒适地养活自己和孩子。那些早婚的人在一定时期内不仅会生育更多的后代,而且正如邓肯博士所表明的那样(352.《论妇女生育力的法则》,《皇家学会汇刊》,爱丁堡,第 xxiv 卷,第 357 页;现已单独出版,标题为“Fecundity、Fertility 和 Sterility”,XNUMX 年。另请参阅 Galton 先生,“Hereditary Genius”,第 XNUMX-XNUMX 页,了解对上述内容的观察效应),他们会生育更多的孩子。此外,母亲在壮年时期所生的孩子比其他时期出生的孩子更重、更大,因此可能更有活力。因此,鲁莽的、堕落的、常常邪恶的社会成员,往往比有远见的、普遍有道德的成员以更快的速度增长。或者正如格雷格先生所说:“粗心、卑鄙、缺乏抱负的爱尔兰人像兔子一样繁衍:节俭、有远见、自尊、雄心勃勃的苏格兰人,道德严厉,信仰虔诚,智慧睿智而自律,他在奋斗和独身中度过了他最好的岁月,结婚较晚,身后所剩无几。给定一块土地,最初居住着一千名撒克逊人和一千名凯尔特人,经过十几代,六分之五的人口将是凯尔特人,但六分之五的财产、权力和智力将属于一个人。 -剩下的第六个撒克逊人。在永恒的‘生存斗争’中,占上风的将是劣等的、不受青睐的种族——而且并不是凭借其优良品质,而是凭借其缺点而取得胜利。”

然而,这种下降趋势需要一些控制。我们看到,不节制的人死亡率很高,极度挥霍的人子孙很少。最贫困的阶层涌入城镇,斯塔克博士从苏格兰十年来的统计数据中证明了这一点(21.“苏格兰出生、死亡等第十次年度报告”,1867年,第xxix页)。 ,在所有年龄段,城镇的死亡率都高于农村地区,“在生命的头五年中,城镇死亡率几乎是农村地区的两倍。”由于这些回报既包括富人,也包括穷人,因此,相对于乡村人口来说,城镇中的贫困居民数量无疑需要两倍以上的出生人数来维持。对于女性来说,过早结婚是非常有害的。因为在法国发现,“一年中二十岁以下的妻子死亡人数是同等数量未婚者死亡人数的两倍。”二十岁以下丈夫的死亡率也“过高”(22。这些引文摘自我们在此类问题上的最高权威,即法尔博士,在他的论文《论婚姻对法国人死亡率的影响》中)人们,”在国家社会科学促进协会,1858 年之前读到。),但其原因可能是什么,似乎值得怀疑。最后,如果那些谨慎地推迟结婚直到能够舒适地养家糊口的男人们,像他们经常做的那样,选择正值壮年的女性,那么上层阶级的增长率只会略有下降。

根据 1853 年进行的大量统计数据得出,全法国 1000 岁至 11.3 岁之间的未婚男性的死亡比例远高于已婚男性:例如,每 6.5 名未婚男性中,XNUMX 岁至 XNUMX 岁之间的未婚男性中, XNUMX岁和XNUMX岁的人每年死亡XNUMX人,而已婚者只有XNUMX人死亡。 (23。 Dr. 法尔,同上。 下面给出的引文摘自同一篇引人注目的论文。)事实证明,在 1863 年和 1864 年期间,苏格兰所有 1000 岁以上的人口中,有一个类似的法律是有效的:例如,每 14.97 名未婚男性中就有一个在7.24岁至XNUMX岁之间,每年有XNUMX人死亡,而已婚者中只有XNUMX人死亡,不到一半。 (24。 我采用了 1867 年《苏格兰第十次出生、死亡等年度报告》中给出的五年平均值。 引自Dr. 斯塔克摘自《每日新闻》10 月 17 日的一篇文章。 17 年 1868 日,博士。 法尔认为写得非常仔细。)博士。 斯塔克对此评论说,“单身对生活的破坏性比最不健康的行业,或者居住在一个不健康的房子或地区,而那里从来没有进行过最彻底的卫生改善尝试。”他认为死亡率的降低是“婚姻以及该州更规律的家庭习惯”的直接结果。然而,他承认,那些放荡、挥霍和犯罪的阶层,他们的寿命很短,通常不结婚;他们的寿命很短。同样必须承认的是,体质虚弱、健康不佳或身体或精神有任何严重缺陷的男人往往不愿意结婚,或者会被拒绝。 Dr. 斯塔克似乎得出这样的结论:婚姻本身就是长寿的主要原因,因为他发现年老的已婚男性在这方面仍然比同龄的未婚男性有相当大的优势;但每个人都一定知道这样的例子:年轻时身体虚弱,没有结婚,但到了老年,虽然身体仍然虚弱,但生存或结婚的机会总是减少。 还有另一个值得注意的情况似乎支持博士的观点。 斯塔克的结论是,法国的寡妇和鳏夫与已婚者相比死亡率非常高;但博士。 法尔将其归因于家庭破裂和悲伤所带来的贫困和恶习。 总的来说,我们可以用博士来总结。 法尔认为,已婚男性的死亡率低于未婚男性,这似乎是一个普遍规律,“主要是由于不完美类型的不断消除,以及每一代人中最优秀个体的巧妙选择”;这种选择只与婚姻状态有关,并且作用于所有的身体、智力和道德品质。 (25。 Dr. 邓肯评论(“生育力、生育力等”,1871 年,第 XNUMX 页)

如果最后两段中规定的各种检查,也许还有其他未知的检查,不能阻止鲁莽的、邪恶的和其他低等的社会成员以比上等阶级更快的速度增长,国家就会倒退,正如世界历史上经常发生的那样。我们必须记住,进步并不是一成不变的规则。很难说为什么一个文明国家会比另一个文明国家崛起、变得更加强大、传播得更广泛。或者为什么同一个国家在某个时期比另一个时期进步得更快。我们只能说,这取决于实际人口数量的增长,取决于具有高智商和道德能力的人的数量以及他们的优秀水平。身体结构似乎没有什么影响,除非身体的活力导致心灵的活力。

一些作家极力主张,高智力对一个国家是有利的,古希腊人的智力水平比任何曾经存在的种族都要高(26。参见先生关于这个问题的巧妙而原创的论点)。 .高尔顿,《遗传天才》,第 340-342 页),如果自然选择的力量是真实的,那么规模应该会更大,数量也会增加,并充满整个欧洲。在这里,我们有一个关于肉体结构经常做出的默认假设,即心智和身体存在某种持续发展的内在倾向。但一切事物的发展都依赖于多种有利条件的并存。自然选择只是暂时起作用。个人和种族可能已经获得了某些无可争议的优势,但却因在其他方面的失败而灭亡。希腊人可能因为许多小国之间缺乏一致性、因为整个国家面积狭小、因为奴隶制的实行或因为极端的肉欲而倒退。因为直到“他们变得虚弱、腐败到了最深处”时,他们才屈服。 (27. 格雷格先生,《弗雷泽杂志》,1868 年 357 月,第 XNUMX 页。)欧洲西部国家现在已经远远超越了他们以前的野蛮祖先,并站在文明的顶峰,他们几乎不欠或根本不欠它们的优越性远胜于古希腊人的直接继承,尽管它们在很大程度上要归功于那些优秀民族的书面作品。

谁能肯定地说为什么曾经如此占主导地位的西班牙在比赛中却被拉开距离。欧洲各国从黑暗时代的觉醒是一个更加令人困惑的问题。正如高尔顿先生所说,在那个早期时期,几乎所有性情温和的人,那些致力于冥想或思想文化的人,除了要求独身的教会的怀抱外,没有任何避难所(28.“遗传性天才”) ”,1870 年,第 357-359 页。FW Farrar 牧师(“弗雷泽杂志”,1870 年 257 月,第 1868 页)提出了另一方的论点。C. Lyell 爵士已经(“地质学原理”,第 489 卷) ii. XNUMX 年,第 XNUMX 页),在一段引人注目的段落中,呼吁人们注意神圣宗教裁判所的邪恶影响,因为它通过选拔降低了欧洲的一般情报标准。);这几乎不可能不对每一代人产生日益恶化的影响。在同一时期,神圣宗教裁判所极其谨慎地挑选最自由和最勇敢的人,以便烧死或监禁他们。仅在西班牙,一些最优秀的人——那些怀疑和质疑的人,毫无疑问不可能有任何进步——在三个世纪里以每年一千人的速度被淘汰。天主教会由此造成的罪恶是无法估量的,尽管无疑在一定程度上,也许在很大程度上,以其他方式抵消了;尽管如此,欧洲却以无与伦比的速度取得了进步。

与其他欧洲国家相比,英国作为殖民者所取得的非凡成功被归因于他们的“大胆而持久的活力”。通过比较具有英语和法语血统的加拿大人的进步,可以很好地说明这一结果;但谁能说清英国人是如何获得能量的呢?美国的惊人进步以及人民的性格都是自然选择的结果,这一信念显然是有道理的。因为在过去的十代或十二代人中,来自欧洲各地的更有活力、不安分和勇敢的人们移民到了这个伟大的国家,并在那里取得了最大的成功。 (29. 高尔顿先生,《麦克米伦杂志》,1865 年 325 月,第 1869 页。另见《自然》,《论达尔文主义和国民生活》,184 年 30 月,第 1868 页。)展望遥远的未来,我不要认为津克牧师先生的观点有些夸张(29.《美国的去年冬天》,XNUMX 年,第 XNUMX 页):“所有其他一系列事件——如导致希腊的精神文化,以及导致罗马帝国的文化——只有在与盎格鲁-撒克逊向西方移民的大潮联系起来或者更确切地说是附属于……时才显得具有目的和价值。”尽管文明进步的问题很模糊,但我们至少可以看到,一个在较长时期内培养出最多数量的高智商、精力充沛、勇敢、爱国和仁慈的人的国家,通常会战胜那些不太受宠的国家。

自然选择源于生存斗争。这是快速增长的结果。人不可能不感到痛苦地后悔,但是否明智则是另一个问题,即人类趋于增长的速度。因为这会导致野蛮部落中的杀婴和许多其他罪恶,而在文明国家中则会导致赤贫、独身以及谨慎者的晚婚。但是,由于人类与低等动物一样遭受着同样的身体罪恶,因此他没有权利期望免受生存斗争所带来的罪恶的影响。如果他没有在太古时代经历自然选择,他肯定永远不会达到现在的地位。由于我们在世界许多地方看到了大片最肥沃的土地,能够支撑无数幸福的家园,但居住着的只是少数流浪的野蛮人,因此可以说,生存斗争还没有激烈到足以迫使人类向上发展。达到他的最高标准。从我们对人类和低等动物的了解来看,他们的智力和道德能力始终存在足够的变异性,以便通过自然选择稳步前进。毫无疑问,这种进步需要许多有利的并发环境。但如果增长速度不是很快,以及随之而来的生存斗争极其激烈,最有利的条件是否就足够了,人们很可能会怀疑。甚至从我们所看到的情况来看,例如在南美洲的部分地区,当生活条件非常安逸时,一个可以称为文明的民族,例如西班牙定居者,很容易变得懒惰和倒退。 。对于高度文明的国家来说,持续的进步在一定程度上取决于自然选择。因为这些国家不会像野蛮部落那样互相取代和消灭。然而,从长远来看,同一群体中更聪明的成员会比低等的成员取得更好的成功,并留下更多的后代,这是自然选择的一种形式。进步的更有效原因似乎包括在青年时期接受良好的教育,同时大脑是易受影响的,以及由最有能力和最优秀的人灌输的高标准卓越,体现在国家的法律、习俗和传统中,并且由舆论强制执行。然而,应该记住的是,舆论的执行取决于我们对他人的赞同和反对的理解;这种欣赏是建立在我们的同情心的基础上的,毫无疑问,同情心最初是通过自然选择发展起来的,是社会本能最重要的要素之一。 (31. 我非常感谢约翰·莫利先生对这个主题的一些很好的批评:另见布罗卡,“Les Selections”,“Revue d'Anthropologie”,1872年。)

所有文明国家都曾经是野蛮的证据

J. Lubbock 爵士(32.《论文明的起源》,《民族学学会会议记录》,26 年 1867 月 33 日)以如此全面和令人钦佩的方式处理了当前的主题。 .M'Lennan 和其他人,我在这里只需要给出他们的结果的最简短的总结。阿盖尔公爵最近提出的论点(1869.“原始人”,XNUMX)以及之前由维特利大主教提出的论点,支持这样一种信念:人类作为文明生物来到世上,所有野蛮人都经历了退化,在我看来,与另一边的先进者相比,显得很弱。毫无疑问,许多国家已经在文明中衰落,有些国家可能已经陷入彻底的野蛮状态,尽管我没有找到关于后一个方面的证据。火地岛人可能是被其他征服部落强迫定居在他们不适宜居住的国家,因此他们可能变得更加堕落。但很难证明他们的水平远远低于居住在巴西最美丽地区的博图库多人。

所有文明民族都是野蛮人的后裔的证据,一方面是在至今仍存在的风俗、信仰、语言等方面,带有明显的从前低贱的痕迹;另一方面,证明野蛮人能够独立地将自己提升到文明的水平上,并且实际上已经上升了。第一个方面的证据非常奇怪,但不能在这里给出:我将这种情况称为枚举艺术,正如泰勒先生通过引用某些地方仍在使用的词语清楚地表明的那样,它起源于数手指,首先是一只手,然后是另一只手,最后是脚趾。我们在我们自己的十进制系统和罗马数字中都有这样的痕迹,其中,在 V(应该是人手的缩写图片)之后,我们传递到 VI 等,当另一只手没有时怀疑被使用了。再说一次,“当我们谈到三分和十分时,我们是用二十进制度来计数的,因此每个分数都是理想的,代表 20——正如墨西哥人或加勒比人所说的‘一个人’。” (34.《大不列颠皇家研究所》,15 年 1867 月 1865 日。另外,《人类早期历史研究》,35 年。)根据越来越多的语言学家学派的说法,每种语言都带有其缓慢而缓慢的发展过程的印记。逐渐演变。书写艺术也是如此,因为字母是图形表达的基础。几乎不可能读到 M'Lennan 先生的著作(1865。“原始婚姻”,1869 年。同样,请参阅 1868 年 1869 月的“北不列颠评论”中的一篇出色的文章,显然是同一作者写的。此外, LH Morgan,“阶级起源的猜想解决方案。关系系统”,《美国科学院院刊》,第 vii 卷,373 年 XNUMX 月。Schaaffhausen 教授(《人类学评论》,XNUMX 月) . XNUMX,第XNUMX页)关于“荷马和旧约中发现的活人祭祀的痕迹。”的评论),并且不承认几乎所有文明国家仍然保留着诸如强行俘虏妻子之类的粗鲁习惯的痕迹。正如同一作者所问,哪个古代国家最初是一夫一妻制的?战争法和其他至今仍残留的习俗所表明的原始正义观念同样是最粗鲁的。许多现存的迷信都是以前错误的宗教信仰的残余。宗教的最高形式——上帝恨恶罪恶、热爱公义的宏伟理念——在远古时期是未知的。

转向另一种证据:J.拉伯克爵士已经表明,一些野蛮人最近在一些简单的艺术方面有了一些进步。从他对世界各地野蛮人使用的武器、工具和艺术的极其好奇的描述来看,毫无疑问,这些几乎都是独立的发现,也许除了生火的艺术。 (36. J. Lubbock 爵士,《史前时代》,第 2 版,1869 年,第 xv. 章和第 xvi. 章等。另请参阅泰勒的《人类早期史》,第 9 版,2 年,精彩的第 1870 章。)澳大利亚的回旋镖就是此类独立发现的一个很好的例子。塔希提人第一次来到这里时,在许多方面都超越了大多数其他波利尼西亚岛屿的居民。没有正当理由相信秘鲁人和墨西哥人的高雅文化源自国外(37. F. Müller 博士在《Reise der Novara: Anthropolog. Theil》中对此做了一些很好的评论, Abtheil.iii.1868,第 127 节);那里种植了许多本土植物,驯养了一些本土动物。我们应该记住,从大多数传教士的微小影响来看,来自一些半文明国家的流浪船员如果被冲到美洲海岸,不会对当地人产生任何显着影响,除非他们已经成为有点先进。回顾世界历史上一个非常遥远的时期,我们发现,用 J. Lubbock 爵士的著名术语来说,是旧石器时代和新石器时代。没有人会假装磨削粗糙燧石工具的艺术是借来的。在欧洲各地,远至希腊、巴勒斯坦、印度、日本、新西兰和非洲,包括埃及,都发现了大量的燧石工具;现有居民对它们的使用没有保留任何传统。还有间接证据表明中国人和古代犹太人以前曾使用过它们。因此,毫无疑问,这些国家(几乎包括整个文明世界)的居民曾经处于野蛮状态。相信人类最初是文明的,然后在许多地区遭受了彻底的退化,这就是对人性的低落看法。进步比倒退更为普遍,这显然是一种更真实、更令人高兴的观点。这个人虽然缓慢而断断续续地从卑微的状态上升到了他在知识、道德和宗教方面迄今为止所达到的最高标准。

第六章 •9,100字
论人的亲缘关系和谱系

人在动物系列中的地位——自然系统谱系——无价值的适应性特征——人与夸德鲁马纳之间的各种小相似点——人在自然系统中的地位——人的出生地和古代——缺乏化石连接——人类谱系的较低阶段,首先从他的亲缘关系推断,其次从他的结构——脊椎动物的早期雌雄同体状态——结论。

即使承认人类和他最亲密的盟友之间在物质结构上的差异像一些博物学家所认为的那样巨大,并且尽管我们必须承认他们之间在智力上的差异是巨大的,但前面几章中给出的事实似乎是这样的。以最简单的方式宣告,人是从某种低等形式演化而来的,尽管迄今为止还没有发现任何联系。

与低等动物一样,人类容易受到许多、轻微和多样化的变异的影响,这些变异是由相同的一般原因引起的,并按照相同的一般规律进行控制和传播。人类繁殖得如此之快,以至于他必然要面临生存斗争,从而面临自然选择。他创造了许多种族,其中一些种族彼此之间差异很大,以至于博物学家经常将它们列为不同的物种。他的身体是按照与其他哺乳动物相同的同源计划构建的。他经历了相同的胚胎发育阶段。他保留了许多简陋且无用的建筑,毫无疑问它们曾经是有用的。一些性格偶尔会在他身上重新出现,我们有理由相信这些性格是由他的早期祖先所拥有的。如果人类的起源与所有其他动物完全不同,那么这些不同的外表就只是空洞的欺骗而已;但这样的承认是令人难以置信的。另一方面,如果人类是其他某种未知的低等哺乳动物的共同后代,那么这些表象至少在很大程度上是可以理解的。

一些博物学家对人类的智力和精神力量印象深刻,将整个有机世界分为三个王国:人类、动物和植物,从而给人类一个单独的王国。 (1。 Isidore Geoffroy St.-Hilaire 详细描述了各种博物学家在他们的分类中赋予人类的位置:“Hist”。 纳特。 将军'汤姆。 II。 1859页。 170-189。)自然主义者无法对精神力量进行比较或分类:但他可能会像我所做的那样,努力表明人类和低等动物的心智能力在种类上并没有区别,尽管在程度上存在巨大差异。 程度的差异,无论多么大,都不能证明我们将人类置于一个不同的王国中,这也许可以通过比较两种昆虫的智力来最好地说明,即球虫或介壳虫和蚂蚁,它们无疑属于到同一个班级。 此处的差异比人类与最高等哺乳动物之间的差异更大,尽管在类型上有所不同。 雌性球菌在年轻时,通过其长鼻将自己附着在植物上。吸吮汁液,但不再移动;受精并产卵;这就是它的全部历史。 另一方面,正如皮埃尔·胡贝尔(Pierre Huber)所表明的那样,要描述工蚁的习惯和精神力量,需要大量的资料;不过,我可以简要说明几点。 蚂蚁当然会互相交流信息,并且几只蚂蚁会联合起来从事相同的工作或玩游戏。 几个月后,它们认出了自己的蚂蚁同伴,并对彼此感到同情。 他们建造宏伟的建筑,保持清洁,晚上关门,并设置哨兵。 他们通过粘在一起建造道路和河下隧道,以及河上的临时桥梁。 它们为社区收集食物,当一个太大而无法进入的物体被带到巢穴时,它们会扩大门,然后再次将其建造起来。 它们储存种子,防止种子发芽,如果种子潮湿,就会被带到表面干燥。 他们饲养蚜虫和其他昆虫作为奶牛。 他们定期参加战斗,为了公共利益而自由地牺牲自己的生命。 他们按照事先商定的计划移民。 他们俘虏奴隶。 它们将蚜虫的卵以及自己的卵和茧移到巢穴温暖的地方,以便它们可以快速孵化;类似的事实还有无数个。 (2。 迄今为止发表的有关蚂蚁习性的一些最有趣的事实是由先生提供的。 贝尔特在他的《尼加拉瓜的博物学家》中,1874 年。 另见先生。 莫格里奇令人钦佩的作品《收获蚂蚁》等,1873 年,还有 M.莫格里奇的《昆虫的本能》。 乔治·普切特,《Revue des Deux Mondes》,二月号 1870。 682.) 总体而言,蚂蚁和球虫之间的智力差异是巨大的。然而,没有人梦想过将这些昆虫划分为不同的类别,更不用说划分为不同的王国了。 毫无疑问,这种差异是由其他昆虫弥补的。人类和高等猿类的情况并非如此。

欧文教授主要根据大脑的结构,将哺乳动物系列分为四个亚类。他将其中之一奉献给人类;在另一幅作品中,他同时放置了有袋动物和Monotremata;因此,他使人类与所有其他哺乳动物的区别就如后两个群体的结合一样。据我所知,这一观点还没有被任何能够形成独立判断的博物学家所接受,因此这里不需要进一步考虑。

我们可以理解为什么基于任何单个特征或器官(即使是像大脑这样极其复杂和重要的器官)或基于心智能力的高度发展的分类几乎肯定会被证明是不令人满意的。这个原理确实已经在膜翅目昆虫中进行了尝试。但当按照他们的习惯或本能进行分类时,事实证明这种安排完全是人为的。 (3. Westwood,《昆虫的现代分类》,第 ii 卷,1840 年,第 87 页。)当然,分类可以基于任何特征,例如大小、颜色或栖息的元素;但博物学家长期以来一直坚信存在一个自然系统。现在人们普遍承认,这一系统必须尽可能地按谱系排列,也就是说,同一形式的共同后代必须被保留在一个群体中,而与任何其他形式的共同后代除外。形式;但如果父类有相关性,那么它们的后代也有相关性,这两个群体将形成一个更大的群体。几个类群之间的差异量,即每个类群所经历的修饰量,用属、科、目和纲等术语来表示。由于我们没有血统记录,所以只能通过观察待分类生物之间的相似程度来发现谱系。对于这个物体来说,许多相似点比少数点中的相似或不同点更重要。如果发现两种语言在许多单词和结构点上彼此相似,那么它们将被普遍认为来自共同的来源,尽管它们在一些单词或结构点上存在很大差异。但对于有机生物来说,相似点一定不包括对相似生活习惯的适应:例如,两种动物可能为了在水中生活而改变了它们的整个框架,但它们不会彼此靠近。在自然系统中。因此,我们可以看到,几个不重要的结构、无用的和初级的器官、或者现在功能不活跃的器官、或者胚胎状况的相似性,是迄今为止最适合分类的;因为它们不可能是由于后期的适应造成的;因此,它们揭示了古老的血统或真正的亲缘关系。

我们可以进一步理解为什么对某个特征进行大量修改不应导致我们广泛地区分任何两种生物体。根据进化论,一个已经与其他相关形式的同一部分有很大不同的部分,已经有很大的不同。因此,它(只要有机体仍然暴露在相同的令人兴奋的条件下)就容易遭受同类的进一步变异;如果这些是有益的,就会被保留下来,从而不断得到增强。在许多情况下,例如鸟喙或哺乳动物牙齿的某个部分的持续发育不会帮助该物种获得食物或任何其他目标;但就人类的优势而言,我们可以看到大脑和心智能力的持续发展没有明确的限制。因此,在确定人在自然或谱系系统中的地位时,他大脑的极端发展不应超过其他不太重要或相当不重要的方面的众多相似之处。

更多的博物学家考虑了人类的整体结构,包括他的心智能力,他们追随布卢门巴赫和居维叶,将人类置于一个单独的秩序中,称为比马纳(Bimana),因此与人类平等。最近,我们许多最优秀的博物学家都重新考虑了林奈首先提出的观点,他的睿智非常引人注目,并将人类与四目动物置于同一目中,称为灵长类动物。我们将承认这个结论的正确性:因为首先,我们必须牢记,对人类大脑的巨大发展进行分类相对来说是微不足道的,而且人类的头骨和夸德鲁马纳人的头骨之间存在着显着的差异。 (最近 Bischoff、Aeby 和其他人坚持认为)显然是从他们不同发育的大脑中得出的。其次,我们必须记住,人类和夸德鲁马纳之间几乎所有其他更重要的差异在本质上显然都是适应性的,并且主要与人类的直立位置有关。例如他的手、脚和骨盆的结构,他的脊柱的弯曲度,以及他的头部的位置。海豹家族很好地说明了适应性特征对于分类的重要性。这些动物在身体形式和四肢结构上与所有其他食肉目动物不同,远远超过人类与高等猿类的不同。然而,在大多数系统中,从居维叶的系统到弗劳尔先生最新的系统(4.“动物学学会论文集”,1863 年,第 4 页),海豹仅被列为食肉目中的一个科。如果人不是自己的分类者,他就不会想到为自己的接受建立一个单独的秩序。

即使说出人类与其他灵长类动物相同的无数结构点,也超出了我的极限,也完全超出了我的知识范围。我们伟大的解剖学家和哲学家赫胥黎教授充分讨论了这个主题(5.“关于人类在自然界中的地位的证据”,1863年,第70页,等),并得出结论,人类在其组织的各个部分都不同来自高等猿类的动物比来自同一类群的低等类人猿的动物要少。因此,“没有理由将人置于不同的秩序中”。

在本书的早期部分,我提出了各种事实,表明人类在体质上与高等哺乳动物有多么接近。这种一致必须取决于我们在微小结构和化学成分上的密切相似性。作为例子,我列举了我们对同样的疾病以及相关寄生虫的攻击的责任;我们对相同的兴奋剂有共同的口味,它们以及各种药物产生的相似效果,以及其他类似的事实。

由于人与 Quadrumana 之间微小的、不重要的相似点在系统著作中并不常见,而且当它们数量众多时,它们清楚地揭示了我们的关系,因此我将具体说明一些这样的点。我们五官的相对位置显然是相同的;各种情绪通过几乎相似的肌肉和皮肤运动来表现,主要是眉毛上方和嘴巴周围。确实,有些表情几乎是一样的,就像某种猴子的哭泣和另一些猴子的笑声,嘴角向后拉,下眼睑皱起。外耳惊人地相似。人类的鼻子比大多数猴子的鼻子要突出得多。但我们可以追踪白长臂猿鼻子中鹰嘴曲率的开始;而这在猿猴身上则达到了荒谬的极端。

许多猴子的脸上都装饰着胡须、胡须或小胡子。某些念珠猴物种的头上的毛发会长得很长(6. Isidore Geoffroy St.-Hilaire, 'Hist. Nat. Gen.' tom. ii. 1859, p. 217.);在帽猴(Macacus radiatus)中,它从冠上的一个点呈辐射状,中间有一个分开。人们常说,额头给人一种高贵、知性的感觉。但帽猴头上浓密的毛发突然向下终止,随后的毛发又短又细,以至于在稍远的地方,除了眉毛之外,前额显得完全裸露。有人错误地断言任何猴子都没有眉毛。在刚刚命名的物种中,不同个体的前额裸露程度有所不同。埃施里希特 (Eschricht) 指出(7.“Über die Richtung der Haare”等,Müller 的“Archiv Fur Anat. und Phys.” 1837,第 51 节),在我们的孩子中,毛茸茸的头皮和裸露的前额之间的界限有时是没有明确定义;因此,这里我们似乎有一个回归祖先的微不足道的例子,其中前额还没有变得完全裸露。

众所周知,我们手臂上的毛发往往会从上到下汇聚到肘部的一点。这种奇特的排列与大多数低等哺乳动物的排列不同,但在大猩猩、黑猩猩、红毛猩猩、某些长臂猿物种,甚至少数美洲猴中很常见。但在敏捷长臂猿中,前臂上的毛发通常向下或朝向手腕;在 H. lar 中,它几乎是直立的,只有非常轻微的向前倾斜;因此,在后一个物种中,它处于过渡状态。毫无疑问,对于大多数哺乳动物来说,背部毛发的厚度和方向都适合挡雨。当狗盘成一圈睡觉时,甚至狗前腿上的横向毛发也可以起到这个作用。华莱士先生仔细研究了红毛猩猩的习性,他指出,红毛猩猩手臂上的毛发向肘部会聚,这可能是为了挡雨,因为这种动物在雨天会坐在自己的位置上。手臂弯曲,双手紧握树枝或举过头顶。据利文斯通介绍,这只大猩猩还“坐在倾盆大雨中,双手举过头顶”。 (8. 引自 Reade,《非洲素描书》,第 1873 卷,第 152 页。)如果上述解释正确(看起来很可能),那么我们手臂上毛发的方向就提供了我们的奇怪记录。前状态;因为现在没有人认为它对于驱雨有任何用处。在我们目前的情况下,它也没有适当地用于此目的。

然而,过分相信人类或其早期祖先毛发方向的适应原理是轻率的。因为不可能研究埃施里希特给出的人类胎儿毛发排列的数据(这与成人的毛发排列相同)而不同意这位优秀观察者的观点,即有其他更复杂的原因介入。收敛点似乎与胚胎中在发育过程中最后闭合的那些点存在某种关系。四肢毛发的排列与髓动脉的走向之间似乎也存在某种关系。 (9. 关于 Hylobates 的毛发,参见 CL Martin 所著的《哺乳动物自然史》,1841 年,第 415 页。此外,Isidore Geoffroy 关于美洲猴子和其他物种的研究,《Hist. Nat. Gen.》第二卷. 1859,第 216、243 页。埃施里希特,同上,第 46、55、61 页。欧文,《脊椎动物解剖学》,第三卷,第 619 页。华莱士,《对自然选择理论的贡献》,1870 年,第 344 页。)

决不能认为人类与某些猿类在上述以及许多其他方面的相似之处——例如额头裸露、头上留着长发等——都必然是来自某个物种不间断的遗传的结果。共同的祖先,或随后的回归。许多相似之处更可能是由于类似的变异,正如我在其他地方试图展示的那样(10.“物种起源”,第 5 次编辑。1869 年,第 194 页。“驯化下动物和植物的变异, ' vol. ii. 1868, p. 348.),来自具有相似构成的共同后代生物体,并受到相似原因的作用,诱导相似的修饰。就人类和某些猴子前臂上的毛发方向相似而言,由于这一特征几乎是所有拟人猿所共有的,因此这可能归因于遗传;但这并不确定,因为一些非常独特的美洲猴子具有这样的特征。

尽管正如我们现在所看到的,人没有正当权利为自己的接待而组建一个单独的秩序,但他也许可以要求一个独特的子秩序或家庭。赫胥黎教授在他的最后著作中(11.《动物分类简介》,1869 年,第 99 页)将灵长类动物分为三个亚目:即,猿科(Anthropidae)仅指人类,猿科(Simiadae)包括各种猴子,狐猴科(Lemuridae)包括狐猴的多种属。就结构的某些重要点的差异而言,人类无疑可以正确地主张亚目的等级。如果我们主要看他的智力的话,这个排名太低了。然而,从谱系的角度来看,这个等级似乎太高了,人类应该仅仅组成一个家族,甚至可能只是一个亚科。如果我们想象三个血统来自一个共同的血统,那么很可能其中两个血统在岁月流逝后可能会发生如此微小的变化,以至于仍然保留为同一属的物种,而第三个血统可能会发生如此巨大的变化。被修改为值得被列为一个独特的亚科,家族,甚至秩序。但在这种情况下,几乎可以肯定的是,第三条线仍然会通过继承保留与其他两条线的许多小相似之处。那么,这里就会出现目前无法解决的困难,即我们应该在分类中为某些点上的显着差异赋予多少权重,即所经历的修改量;以及在许多不重要的点上有多少相似之处,例如表明血统或家谱。重视少数但强烈的差异是最明显的,也许也是最安全的做法,尽管高度关注许多微小的相似之处似乎更正确,因为它给出了真正自然的分类。

在对人类这​​个问题做出判断时,我们必须看一下猿科的分类。几乎所有博物学家都将这个家族分为卡他林猴类或旧世界猴类,所有这些猴类的特征(正如它们的名字所表达的)都是鼻孔的特殊结构,并且每个下巴都有四个前臼齿;以及鸭嘴猴类或新大陆猴类(包括两个非常不同的亚类),所有这些猴类的特征都是鼻孔构造不同,并且每个下颌都有六个前臼齿。可能会提到一些其他的小差异。现在,人类在牙列、鼻孔的结构以及其他一些方面无疑属于卡塔林或旧世界的划分;除了少数不太重要且显然具有适应性的角色外,他在任何角色上都不像喀他林族那样更接近扁鼻族。因此,完全不可能认为某些新世界物种以前应该已经变异并产生了类人生物,具有旧世界分类所特有的所有独特特征;同时失去了所有自己独特的特征。因此,毫无疑问,人类是旧大陆猿猴的分支。从谱系学的角度来看,他必须归入卡塔琳家族。 (12. 这与 St. George Mivart 先生临时采用的分类几乎相同(“Transactions,Philosophical Society”,1867 年,第 300 页),他在分离狐猴科之后,将其余的灵长类动物分为人科、猿科,对应于卡塔里科、螽科和哈帕里科,后两个类群对应于鸭嘴兽科。米瓦特先生仍然坚持同样的观点;见《自然》,1871年,第481页。)

大多数博物学家将拟人化的猿类,即大猩猩、黑猩猩、红毛猩猩和长臂猿与其他旧大陆猴类分开,作为一个独特的亚群。我知道Gratiolet依靠大脑的结构不承认这个子群的存在,并且毫无疑问它是一个破碎的子群。因此,正如圣·G·米瓦特先生所说,红毛猩猩“是该组织中最奇特、最异常的形态之一”。 (13. 《Transactions,Zoolog. Soc.》,第 vi 卷,1867 年,第 214 页。) 剩余的非拟人化的旧世界猴子,再次被一些博物学家分为两个或三个较小的亚组;长古猿属(Semnopithecus)因其独特的囊状胃而成为其中一个亚群的类型。但从高德里先生在阿提卡的奇妙发现来看,在中新世时期,那里存在着一种将猿猴和猕猴联系在一起的形式;这可能说明了其他和更高层次的群体曾经混合在一起的方式。

如果拟人猿被承认形成一个自然的亚群,那么作为人类,不仅在他所拥有的与整个卡塔林类群相同的所有特征上,而且在其他奇特特征上都同意它们,例如缺乏尾巴和老茧,以及总体外观,我们可以推断,拟人亚群的某些古代成员孕育了人类。根据相似变异法则,其他低等亚类之一的成员不太可能产生一种在许多方面与高等拟人猿相似的类人生物。毫无疑问,与他的大多数盟友相比,人类已经经历了非凡的改变,这主要是由于他的大脑的巨大发展和他的直立姿势的结果。然而,我们应该记住,他“只是灵长类动物的几种特殊形式之一”。 (14. St. G. Mivart 先生,《哲学会汇刊》,1867 年,第 410 页。)

每一位相信进化原理的博物学家都会承认猿猴科的两个主要分支,即长鼻猴和扁鼻猴及其亚群,都来自某个极其古老的祖先。这个祖先的早期后代,在彼此分化到相当大的程度之前,仍然会形成一个单一的自然群体。但某些物种或早期属已经开始通过其不同的特征来表明卡他林科和阔鼻科未来的独特标志。因此,这个所谓的古老群体的成员在牙列或鼻孔结构上不会像现有的卡塔尼猴和扁鼻猴那样一致,但在这方面可能类似于近亲狐猴科,它们的口吻形状彼此差异很大(15. Murie 和 Mivart 先生关于狐猴总科,“动物学协会交易”,第 vii 卷,1869 年,第 5 页),并且对一个非凡的他们的牙列程度。

狭鼻猴和扁鼻猴在许多特征上是一致的,这从它们毫无疑问属于同一个目就可以看出。它们所拥有的许多共同特征很难由如此多的不同物种独立获得。所以这些性格一定是遗传下来的。但博物学家无疑会将其归为猿或猴子,这是一种古老的形态,具有许多与长鼻猴和扁鼻猴相同的特征,以及处于中间状态的其他特征,也许还有一些与现在在这两个群体中发现的特征不同。由于从谱系学的角度来看,人类属于卡塔琳族或旧世界族,我们必须得出结论,无论这个结论可能多么违背我们的骄傲,我们的早期祖先应该被正确地指定为这样的。 (16. 海克尔也得出了同样的结论。参见 Virchow 的《Sammlung.gemein.wissen.Vorträge》,1868 年,第 61 节中的《Über die Entstehung des Menshengeschlechts》。还有他的《Natürliche Schöpfungsgeschichte》,1868 年,其中他详细给出了他对人类谱系的看法。)但我们绝不能犯这样的错误:认为包括人类在内的整个猿猴种群的早期祖先与任何现有的猿或猴子相同,甚至非常相似。

论人类的诞生地和古代

我们很自然地会问,当我们的祖先从卡他林族中分化出来的那个阶段,人类的出生地在哪里?他们属于这个族群这一事实清楚地表明他们居住在旧世界。但正如我们可以从地理分布规律推断的那样,澳大利亚或任何海洋岛屿都不是。在世界上每个大地区,现存的哺乳动物都与同一地区已灭绝的物种密切相关。因此,非洲以前很可能居住着与大猩猩和黑猩猩关系密切的已灭绝猿类。由于这两个物种现在是人类最亲密的盟友,因此我们的早期祖先生活在非洲大陆的可能性比其他地方更大。但猜测这个问题是没有用的。两到三只拟人猿,其中一只是来自 Lartet 的 Dryopithecus(17. Dr. C. Forsyth Major, 'Sur les Singes Foleses trouvés en Italie:' 'Soc. Ital. des Sc. Nat.' tom. xv. 1872.)几乎与人一样大,并且与许洛贝特关系密切,存在于中新世时期的欧洲;自如此遥远的时期以来,地球确实经历了许多伟大的革命,并且有足够的时间进行最大规模的移民。

当人类第一次失去毛茸茸的覆盖物时,无论何时何地,他可能居住在一个炎热的国家;从类比来看,这种环境有利于他赖以生存的节食饮食。我们根本不知道人类第一次从卡塔林族中分离出来是在多久以前。但它可能发生在始新世这样遥远的时代;早在上中新世时期,高等猿类就已与低等猿类分化,这从森林古猿的存在就可见一斑。我们也完全不知道生物体,无论规模大小,在有利的环境下可以以多快的速度发生改变;然而,我们知道,有些在漫长的时间流逝中仍保留着相同的形式。从我们在驯化过程中所看到的情况来看,我们了解到同一物种的一些共同后代可能根本没有变化,有些变化很小,有些变化很大,都在同一时期。人类可能也是如此,与高等猿类相比,人类在某些特征上经历了巨大的改变。

人类与其最亲近的盟友之间的有机链发生了巨大的断裂,任何灭绝的或现存的物种都无法弥补这一断裂,这常常被认为是对人类是某种低等形式的后裔这一信念的严重反对。但对于那些出于一般原因相信进化论一般原理的人来说,这种反对意见不会显得有多大分量。该系列的所有部分都经常出现断裂,有些是宽阔、尖锐和明确的,有些则不同程度地不那么明显;比如红毛猩猩和它最近的盟友之间——眼镜猴和其他狐猴科之间——大象之间,以及以更引人注目的方式在鸟嘴兽或针鼹和所有其他哺乳动物之间。但这些中断仅仅取决于已经灭绝的相关形式的数量。在未来的某个时期,以几个世纪来衡量并不遥远,人类的文明种族几乎肯定会消灭并取代全世界的野蛮种族。与此同时,正如沙夫豪森教授所说(18.《人类学评论》,1867 年 236 月,第 XNUMX 页),拟人猿无疑将被灭绝。到那时,人类和他最亲近的盟友之间的鸿沟将更加广泛,因为正如我们所希望的那样,它将介入处于更加文明状态的人类和一些低如狒狒的猿类之间,而不是像现在那样介于白种人和黑种人之间。黑人或澳大利亚人和大猩猩。

至于缺乏将人类与其类人猿祖先联系起来的化石遗迹,读过 C. Lyell 爵士的讨论的人不会太强调这一事实(19.《地质学原理》,1865 年,第 583 页) - 585.《人类的古代》,1863 年,第 145 页。),他在其中表明,在所有脊椎动物中,化石遗骸的发现是一个非常缓慢且偶然的过程。也不应该忘记的是,地质学家尚未对那些最有可能发现将人类与某种已灭绝的类人猿生物联系起来的遗迹的地区进行过搜索。

人类谱系的较低阶段

我们已经看到,在西米亚科的卡塔莱因或旧世界分支与新世界分支分离之后,人类似乎又与它们分离。我们现在将努力追踪他的家谱的遥远痕迹,主要相信不同阶级和秩序之间的相互亲缘关系,并稍微参考一下它们在地球上相继出现的时期。狐猴科位于猴科之下且靠近猴科,构成了一个非常独特的灵长类家族,或者根据海克尔等人的说法,构成了一个独特的目。这个群体非常多样化和破碎,并且包括许多异常形式。因此,它可能遭受了很大的灭绝。大多数残余物生存在马达加斯加和马来亚群岛等岛屿上,在那里它们没有像在资源丰富的大陆上那样受到如此激烈的竞争。这个群体同样呈现出许多等级,正如赫胥黎所言(20。“人类在自然界中的地位”,第105页),“不知不觉地从动物创造的顶峰下降到只有一步之遥的生物,看起来,这是胎盘哺乳动物中最低级、最小和最不聪明的。”从这些不同的考虑来看,拟猴科最初很可能是从现有狐猴科的祖先发展而来的。而这些又是哺乳动物系列中地位非常低的形式。

有袋动物在许多重要特征上都低于胎盘哺乳动物。它们出现在更早的地质时期,而且它们的范围以前比现在要广泛得多。因此,胎盘动物通常被认为源自胎盘动物或有袋动物。然而,并非来自与现有有袋动物非常相似的形式,而是来自它们的早期祖先。单孔动物显然与有袋动物有亲缘关系,构成了伟大的哺乳动物系列中的第三个较低的分类。如今,它们的代表仅是鸟嘴龙和针鼹。这两种形式可以被安全地视为一个更大群体的遗物,其中的代表通过一些有利的情况在澳大利亚得以保存。单孔目动物非常有趣,因为它在爬行动物类结构的几个重要点上处于领先地位。

在试图追溯哺乳动物的谱系,从而追溯人类的谱系时,我们陷入了越来越模糊的境地。但正如一位最有能力的法官帕克先生所说,我们有充分的理由相信,没有真正的鸟类或爬行动物介入直接血统。想要了解聪明才智和知识能产生什么效果的人可以查阅海克尔教授的著作。 (21. 详细的表格在他的“Generelle Morphologie”(B. ii. s. cliii. 和 s. 425)中给出;并且在他的“Natürliche Schöpfungsgeschichte” 1868 中更特别地提到了人类。赫胥黎教授在审查时后者的著作(《学院》,1869 年,第 42 页)指出,他认为海克尔对脊椎动物门或脊椎动物的血统进行了令人钦佩的讨论,尽管他在某些观点上存在分歧。他还表达了他的高度评价。对整部作品的总体基调和精神的估计。)我将满足于一些一般性的评论。每一位进化论者都会承认,五大脊椎动物纲,即哺乳动物、鸟类、爬行动物、两栖动物和鱼类,都是某个原型的后裔;它们的原型是脊椎动物。因为它们有很多共同点,尤其是在胚胎阶段。由于鱼类的组织程度最低,并且出现得早于其他鱼类,因此我们可以得出结论,脊椎动物界的所有成员都源自某种类似鱼类的动物。认为猴子、大象、蜂鸟、蛇、青蛙和鱼等如此独特的动物可能都来自同一个父母,对于那些没有注意过的人来说,这种想法会显得很可怕。自然历史的最新进展。因为这种信念意味着以前存在将所有这些形式紧密结合在一起的联系,而现在却完全不同了。

尽管如此,可以肯定的是,动物群体曾经存在,或者现在确实存在,它们或多或少地将几个大型脊椎动物纲紧密地联系在一起。我们已经看到鸟嘴龙逐渐进化为爬行动物。赫胥黎教授发现,并得到科普先生和其他人的证实,恐龙在许多重要特征上介于某些爬行动物和某些鸟类之间——这些鸟类被称为鸵鸟部落(本身显然是一种广泛传播的残余物)一个更大的群体)和始祖鸟,这是一种奇怪的次要鸟类,有一条像蜥蜴一样的长尾巴。再次,根据欧文教授的说法(22.《古生物学》1860,第 199 页),鱼龙类(长有桨的大型海蜥蜴)与鱼类有许多亲缘关系,或者根据赫胥黎的说法,与两栖动物有许多亲缘关系。这一类,包括其最高级别的青蛙和蟾蜍,显然与鳄类鱼类相似。后者的鱼类在早期地质时期成群结队,并建立在所谓的广义类型之上,也就是说,它们与其他生物群体表现出多样化的亲缘关系。鳞甲鱼与两栖动物和鱼类的关系也非常密切,以至于博物学家长期以来一直在争论将其归入这两类中的哪一类。它和一些鳄类鱼类都因栖息在河流中而免遭彻底灭绝,河流是避难港,与大海的关系就像岛屿与大陆的关系一样。

最后,庞大而多样化的鱼类中的一个成员,即文昌鱼或文昌鱼,与所有其他鱼类如此不同,以至于海克尔认为它应该在脊椎动物王国中形成一个独特的类别。 这种鱼因其负面特征而引人注目。很难说它有大脑、脊柱或心脏等;因此,较老的博物学家将其归入蠕虫中。 许多年前,Prof. 古德瑟认为,文昌鱼与海鞘有一些相似之处,海鞘是一种无脊椎动物、雌雄同体、永久附着在支撑物上的海洋生物。 它们看起来不像动物,由一个简单、坚韧的皮革袋组成,有两个小突出的孔。 它们属于赫胥黎的穆鲁斯科亚目(Mulluscoida of Huxley)——伟大的软体动物王国的一个低级分支。但最近一些博物学家将它们归入 Vermes 或蠕虫中。 它们的幼虫形状有点像蝌蚪(23. 1833 年 XNUMX 月,我在福克兰群岛满意地看到了一种复合海鞘的运动幼虫,这种复合海鞘与 Synoicum 关系密切,但显然在总体上与它不同,因此比其他博物学家早了几年。 尾巴大约是椭圆形头部的五倍长,末端有一根非常细的丝。 正如我在简单显微镜下绘制的草图,它被横向不透明的隔板清楚地分开,我认为这代表了科瓦列夫斯基描绘的巨大细胞。 在发育的早期阶段,尾巴紧密地盘绕在幼虫的头部上。),并且具有自由游动的能力。 先生。 科瓦列夫斯基 (24. 《阿卡德回忆录》。 圣科学学院 圣彼得堡,汤姆。 x. 没有 15年1866月XNUMX日。)最近观察到海鞘幼虫在发育方式、神经系统的相对位置以及拥有与脊椎动物的背索非常相似的结构方面与脊椎动物有亲缘关系;此后他的这一点得到了Prof.的证实。 库普弗。 M. 科瓦列夫斯基从那不勒斯给我写信说,他现在进一步推进了这些观察,如果他的结果得到充分证实,整个结果将形成一个具有最大价值的发现。 因此,如果我们可以依靠胚胎学这一最安全的分类指南,那么我们似乎终于获得了脊椎动物起源的线索。 (25。 但我必须补充一点,一些有能力的法官对这一结论提出异议。例如,M. Giard,1872 年《动物学实验档案》中的一系列论文。 然而,这位博物学家评论说,第 17 页。

迄今为止,我们粗鲁地努力借助脊椎动物的相互亲缘关系来追踪脊椎动物的谱系。现在我们将关注人的存在;我认为,我们将能够在连续的时期内部分恢复我们早期祖先的结构,但不是按适当的时间顺序。这可以通过人类仍然保留的基础、通过逆转偶尔出现在他身上的特征以及通过形态学和胚胎学原理的帮助来实现。我将在这里提及的各种事实已在前面的章节中给出。

人类的早期祖先肯定曾经长满头发,男女都有胡须;他们的耳朵可能是尖的,并且能够移动;他们的身体有一条尾巴,有适当的肌肉。他们的四肢和身体也受到许多肌肉的作用,这些肌肉现在只是偶尔重新出现,但通常存在于四肢中。在这个时期或早期,肱骨大动脉和神经穿过髁上孔。肠道产生了比现在大得多的憩室或盲肠。从胎儿大脚趾的状况来看,当时的脚是可以抓握的;毫无疑问,我们的祖先习惯于树栖,经常出没于一些温暖、森林覆盖的土地。雄性有巨大的犬齿,这可以作为强大的武器。在更早的时期,子宫是双的;排泄物通过泄殖腔排出;眼睛受到第三眼睑或瞬膜的保护。在更早的时期,人类的祖先一定已经习惯了水生。因为形态学清楚地告诉我们,我们的肺是由一个改良过的鳔组成的,它曾经用作浮子。人类胚胎颈部的裂缝显示了鳃曾经存在的地方。在我们某些功能的农历或每周循环周期中,我们显然仍然保留着我们原始出生地的痕迹,即被潮汐冲刷的海岸。大约在同一早期时期,真正的肾脏被狼体所取代。心脏作为一个简单的脉动血管而存在。背索取代了脊​​柱。从时间的昏暗深处看来,这些人类早期祖先的组织一定和文昌鱼或文昌鱼一样简单,甚至更简单。

还有一点值得更充分的注意。人们早就知道,在脊椎动物王国中,一种性别具有与生殖系统有关的各种附属部分的雏形,而这些附属部分完全属于异性。现在已经确定,在胚胎的早期阶段,两性都拥有真正的男性和女性腺体。因此,整个脊椎动物界的某些远古祖先似乎是雌雄同体或雌雄同体。 (26. 这是比较解剖学最高权威之一 Gegenbaur 教授的结论:参见“Grundzüge der vergleich. Anat.”1870,第 876 节。该结果主要来自对两栖类的研究;但从 Waldeyer 的研究看来(引自“Journal of Anat. and Phys.” 1869,第 161 页),即使是“高等脊椎动物的性器官,在其早期状态下也是雌雄同体的。”类似的观点长期以来一直被一些作者所持有,尽管直到最近还没有坚实的基础。)但是在这里我们遇到了一个独特的困难。在哺乳动物纲中,雄性在其前列腺囊泡中具有子宫的雏形和邻近的通道。它们还具有妈妈的雏形,一些雄性有袋动物有有袋动物的袋子的痕迹。 (27. 雄性袋狼提供了最好的例子。Owen,《脊椎动物解剖学》,第 771 卷,第 28 页。)可以添加其他类似的事实。那么,我们是否可以假设某种极其古老的哺乳动物在获得了其类别的主要特征并因此与脊椎动物界的较低类别分化之后仍然保持雌雄同体?这似乎不太可能,因为我们必须在所有纲中最低等的鱼类中寻找仍然存在的雌雄同体的形式。 (28. 在几种 Serranus 以及其他一些鱼类中都观察到了雌雄同体,雌雄同体要么是正常且对称的,要么是异常且单侧的。Zouteveen 博士给了我关于这个主题的参考资料,尤其是一篇论文作者:Halbertsma 教授,发表在《荷兰科学院学报》第十六卷中。Gunther 博士对这一事实表示怀疑,但现在它已被太多优秀的观察家记录下来,不再有争议。M 博士.Lessona 写信给我,他已经证实了 Cavolini 对 Serranus 的观察。Ercolani 教授最近表明(“Accad. delle Scienze”,博洛尼亚,1871 年 XNUMX 月 XNUMX 日)鳗鱼是雌雄同体的。)各种附属部分每种性别所特有的器官,在异性身上都处于初级状态,这可能是因为这些器官是由一种性别逐渐获得的,然后以或多或少不完美的状态传递给另一种性别。当我们讨论性选择时,我们会遇到无数这种遗传形式的例子,例如雄性鸟类为战斗或装饰而获得的马刺、羽毛和绚丽的颜色,并由雌性以某种方式遗传。不完美或基本的状况。

雄性哺乳动物拥有功能不完善的乳腺器官,在某些方面尤其令人好奇。单孔目有适当的乳汁分泌腺,有孔,但没有乳头;由于这些动物处于哺乳动物系列的最底层,因此该类的祖先很可能也有泌乳腺,但没有乳头。这一结论得到了其发展方式的已知支持;特纳教授根据科利克和兰格的权威告诉我,在胚胎中,乳头在最不可见之前就可以清楚地追踪到。个体的连续部分的发展通常代表并符合同一血统中连续存在的发展。有袋动物与单孔动物的不同之处在于它们有乳头。因此,这些器官很可能首先由有袋动物获得,在它们与单孔目动物分离并上升到其之上之后,然后被传递给胎盘哺乳动物。 (29. Gegenbaur 教授表明(“Jenäische Zeitschrift”,Bd. vii. p. 212)在几种哺乳动物目中普遍存在两种不同类型的乳头,但是很容易理解这两种类型是如何从乳头衍生出来的后者来自有袋动物。另请参阅 Max Huss 博士关于乳腺的回忆录,同上。B. viii. p. 176。)没有人会认为有袋动物仍然存在雌雄同体,在他们大致获得了目前的结构之后。那么我们该如何解释拥有乳房的雄性哺乳动物呢?它们有可能首先在雌性体内发育,然后转移到雄性体内,但从接下来的情况来看,这几乎是不可能的。

另一种观点认为,在整个哺乳动物的祖先不再是雌雄同体之后很久,两性都会产奶,从而滋养它们的后代。就有袋类动物而言,雌雄都将幼崽放在有袋类动物的麻袋中。如果我们考虑到现有合颌鱼类的雄性在其腹袋中接收雌性的卵,孵化它们,然后,正如一些人所认为的那样,滋养幼鱼(30。洛克伍德先生认为(如引自《科学杂志》,1868 年 269 月,第 15 页),根据他对海马发育的观察,雄性鱼的腹袋壁以某种方式提供营养。参见 Wyman 教授于 1857 年 1 月 1866 日发表在“Proc. Boston Soc. of Nat. Hist”上的一篇非常有趣的论文;还有 Turner 教授发表于“Journal of Anatomy and Physiology”,78 月 31 日的“Journal of Anatomy and Physiology”中。 1870, XNUMX, p. XNUMX. Gunther 博士同样描述了类似的情况。);——某些其他雄鱼在它们的嘴或鳃腔内孵化卵;——某些雄性蟾蜍从雌性蟾蜍那里夺走卵的花环,并且将它们缠绕在自己的大腿上,一直留在那里,直到蝌蚪出生;某些雄性鸟类承担了孵化的全部职责,雄性鸽子和雌性鸽子都用嗉囊中的分泌物喂养雏鸟。但我首先想到上述建议,是因为雄性哺乳动物的乳腺比其他附属生殖部分的雏形发育得更完美,这些附属生殖部分只存在于一种性别中,尽管适合另一种性别。雄性哺乳动物的乳腺和乳头确实很难说是不发达的。它们只是尚未完全发育,并且功能不活跃。他们在某些疾病的影响下会受到交感神经的影响,就像女性的相同器官一样。它们经常在出生时和青春期分泌几滴乳汁:后一个事实发生在前面提到的一个奇怪的案例中,一个年轻人拥有两对妈妈。人们知道,在人类和其他一些雄性哺乳动物中,这些器官在成熟过程中有时会发育得非常好,以产生大量的乳汁。现在,如果我们假设,在过去的很长一段时间内,雄性哺乳动物帮助雌性哺乳它们的后代(XNUMX. Mlle. C. Royer 在她的“Origine de l'homme”等,XNUMX 年中提出了类似的观点),并且后来,由于某种原因(如生育数量减少),雄性不再提供这种帮助,在成熟期间不使用这些器官将导致它们变得不活跃;根据两个众所周知的遗传原理,这种不活跃的状态可能会在相应的成熟年龄传递给雄性。但在较早的年龄,这些器官不会受到影响,因此男女年轻人的这些器官几乎同样发育良好。

结论

冯·贝尔(Von Baer)比任何其他人都更好地定义了有机尺度的进步或进步,因为它取决于一个人的各个部分的分化和专业化程度——当达到成熟时,我应该倾向于补充这一点。现在,随着生物体通过自然选择慢慢适应了多样化的生命线,它们的各个部分将利用生理劳动分工所获得的优势,变得越来越分化和专门化,以实现各种功能。同一部分似乎常常首先为了一个目的而被修改,然后很久之后又为了其他一些完全不同的目的而被修改。因此所有的部分都变得越来越复杂。但每种生物体仍然保留着其最初起源的祖先的一般结构类型。根据这种观点,如果我们转向地质证据,那么该组织总体上是在缓慢而断断续续地在全世界范围内前进的。在脊椎动物这个伟大的王国里,它在人类身上达到了顶峰。然而,我们不能认为有机生物群体一旦产生了其他更完美的群体,就总是会被取代或消失。后者虽然战胜了它们的前辈,但可能并没有更好地适应自然经济中的所有地方。一些古老的形式似乎是从栖息在保护区中幸存下来的,在那里它们没有受到非常激烈的竞争;这些通常可以帮助我们构建我们的家谱,让我们对以前和消失的人口有一个公平的了解。但我们决不能犯这样的错误:将任何组织松散的团体的现有成员视为其古代前辈的完美代表。

我们所能瞥见的脊椎动物王国最古老的祖先显然是由一群海洋动物组成的(32. 海边的居民一定受潮汐的影响很大;生活在平均高水位线附近或平均低水位线附近的动物在两周内经历一个完整的潮汐变化周期。 因此,他们的食物供应将每周发生显着变化。 这些动物在这种条件下生活了很多代,其重要功能几乎不可能每周定期运行。 现在有一个神秘的事实,在高等和现在的陆生脊椎动物中,以及在其他纲中,许多正常和异常的过程都有一个或多个整周作为它们的周期;如果脊椎动物是现有潮汐海鞘动物的后裔,这一点就可以理解了。 这种周期性过程的例子有很多,如哺乳动物的妊娠、发烧的持续时间等。 鸡蛋的孵化也是一个很好的例子,因为据先生说。 巴特利特(《土地与水》,Jan. 7年1871月XNUMX日),鸽子的蛋在两周内孵化;禽类分为三份;鸭子分成四份;鹅的五分;鸵鸟则需要七周的时间。 据我们判断,一个经常性周期,如果大约是任何流程或职能的正确持续时间,一旦获得,就不会轻易改变;因此,它可能会通过几乎任意数量的世代传播。 但如果功能发生变化,周期就必须改变,而且很容易突然改变整整一周。 这个结论如果合理的话,那就是非常了不起的。因为每种哺乳动物的妊娠期、每种鸟蛋的孵化以及许多其他生命过程,都向我们揭示了这些动物的原始出生地。),类似于现有海鞘的幼虫。 这些动物可能产生了一群鱼类,其组织结构与文昌鱼一样低下。伽尼鱼和鳞鱼等其他鱼类必定是从这些鱼类中进化而来的。 从这种鱼出发,只要稍微向前推进一点,我们就可以到达两栖动物。 我们已经看到鸟类和爬行动物曾经紧密地联系在一起。现在,单孔动物在某种程度上将哺乳动物与爬行动物联系起来。 但目前没有人能说清这三个较高级且相关的纲,即哺乳动物、鸟类和爬行动物,是由两个较低级脊椎动物纲,即两栖类和鱼类衍生而来的。 在哺乳动物纲中,从古代单孔动物到古代有袋动物的步骤并不难想象。以及从这些到胎盘哺乳动物的早期祖先。 因此我们可以上升到Lemuridae;而且这些与猿科的间隔并不是很宽。

因此,我们赋予人类一个极其漫长的谱系,但可以说,它的品质并不高尚。人们经常说,世界似乎早已为人类的到来做好了准备:从某种意义上来说,这是完全正确的,因为人类的诞生归功于一长串祖先。如果这条链条中的任何一个环节从未存在过,人类就不会是现在这个样子。除非我们故意闭上眼睛,否则以我们目前的知识,我们可以大致认识到我们的出身;我们也不必为此感到羞耻。最卑微的有机体是比我们脚下的无机尘埃高得多的东西;任何一个头脑不偏不倚的人在研究任何生物时,无论多么卑微,都会对其奇妙的结构和特性感到兴奋。

第七章 •19,000字
关于人类的种族

特定特征的本质和价值——应用于人类种族——支持和反对将所谓的人类种族划分为不同物种的论点——亚种——单性论者和多性论者——性格的趋同性——许多要点人类最独特的种族之间在身体和精神上的相似性——人类第一次在地球上传播时的状态——每个种族都不是一对的后代——种族的灭绝——种族的形成——杂交的影响——生命条件直接作用的轻微影响——自然选择的轻微影响或没有影响——性选择。

我在这里无意描述几个所谓的人类种族;但我要问的是,从分类的角度来看,它们之间的差异有什么价值,以及它们是如何起源的。在确定两种或多种类似形式是否应被列为物种或变种时,博物学家实际上遵循以下考虑因素:即,它们之间的差异程度,以及这些差异是否与少数或许多结构点有关,以及它们是否具有生理重要性;但更特别的是它们是否恒定。性格的恒久是博物学家最看重和追求的。每当可以证明或有可能证明所讨论的形式在很长一段时间内保持独特时,这就成为支持将它们视为物种的重要论据。即使任何两种形式在首次杂交时或其后代中存在轻微的不育性,通常也被认为是对其特定独特性的决定性测试。它们持续存在而不在同一区域内混合,通常被认为是充分的证据,要么是某种程度的相互不育,要么是动物对配对有某种程度的排斥。

与杂交和融合无关,在一个经过充分研究的地区,完全不存在将任何两种密切相关的形式连接在一起的品种,这可能是其特定独特性的所有标准中最重要的。这与单纯的特性恒定性的考虑有些不同,因为两种形式可能变化很大,但不会产生中间变种。地理分布常常是无意识地、有时是有意识地发挥作用;因此,生活在两个相距甚远的地区的形态,其中大多数其他居民都是截然不同的,它们本身通常也被视为截然不同的;但事实上,这并不能帮助区分地理种族和所谓的良种或真正的物种。

现在让我们将这些普遍承认的原则应用到人类身上,以博物学家看待任何其他动物的同样的精神来看待人类。关于种族之间的差异,我们必须考虑到我们通过长期观察自己的习惯而获得的良好辨别能力。正如埃尔芬斯通所言,在印度,尽管新来的欧洲人一开始无法区分不同的本土种族,但他们很快就会在他看来极为不同(1.《印度历史》,1841 年,第 323 卷。Ripa 神父准确地指出对于中国人也有同样的说法。);印度人一开始看不出几个欧洲国家之间有什么区别。即使是最独特的人类种族在形态上也比最初想象的要相似得多。某些黑人部落必须被排除在外,而其他黑人部落,正如罗尔夫斯博士写给我的,以及我自己所看到的,具有白人特征。巴黎人类学博物馆藏品中的法国照片很好地体现了这种普遍的相似性,这些照片中的人属于不同种族,其中大部分可能被误认为是欧洲人,正如我向许多人展示过的那样。然而,如果这些人活着,无疑会显得非常独特,因此,我们的判断显然受到皮肤和头发颜色、特征上的细微差别以及表情的很大影响。

然而,毫无疑问,当仔细比较和测量时,各个种族彼此之间存在很大差异,例如头发的质地、身体各部分的相对比例(2.大量的测量数据) BA Gould 所著的“军事和人类学调查。美国士兵统计”,1869 年,第 298-358 页;“关于肺的容量”,第 471 页. 另请参阅 Weisbach 博士根据 Scherzer 博士和 Schwarz 博士的观察,在“Reise der Novara: Anthropolog. Theil,” 1867 中提供的大量有价值的表格。)和头骨的容量,甚至大脑的回旋。 (3. 例如,请参阅马歇尔先生在《哲学汇刊》,1864 年,第 519 页中对丛林女性大脑的描述。)但是,详细说明众多差异点将是一项无休止的任务。不同种族在体质、适应环境和对某些疾病的易感性方面也存在差异。他们的心理特征同样非常独特。主要表现在他们的情感上,但部分表现在他们的智力上。每一个有机会进行比较的人,一定会对沉默寡言、甚至忧郁的南美原住民与轻松健谈的黑人之间的对比感到震惊。马来人和巴布亚人之间存在几乎相似的对比(4. Wallace,“马来群岛”,第 ii 卷,1869 年,第 178 页。),他们生活在相同的自然条件下,只是彼此分开靠近一片狭窄的海域。

我们将首先考虑可能提出的支持将人类种族划分为不同物种的论点,然后考虑另一方的论点。如果一个以前从未见过黑人、霍屯督人、澳大利亚人或蒙古人的博物学家对他们进行比较,他会立即发现他们在许多特征上存在差异,有些是轻微的,有些是相当重要的。经过询问,他发现他们适应了截然不同的气候条件,在体质和心理素质上也有所不同。如果他随后被告知可以从同一国家带来数百个类似的标本,他肯定会宣称它们与他习惯于附加特定名称的许多物种一样好。一旦他确定这些形式在许多世纪以来都保留了相同的特征,这个结论就会得到极大的加强。黑人显然与现有的黑人相同,至少生活在 4000 年前。 (5. 关于著名的埃及阿布辛贝洞穴中的人物,M. Pouchet 说(“人类的多元性”,英译,1864 年,第 50 页),他远未发现一些作者认为他们可以识别十几个或更多国家的可识别代表。即使是一些最明显的种族也不能以那种程度的一致来识别,而这可能是从有关该主题的文章中所期望的。因此,先生们诺特和格利登(《人类的类型》,第 148 页)指出,拉美西斯二世或大帝具有极好的欧洲特征;而诺克斯,另一位坚信人类种族特殊性的人(《种族的种族》) Man,1850 年,第 201 页)在谈到年轻的门农(正如伯奇先生告诉我的那样,他与拉美西斯二世相同),以最强烈的方式坚持认为他与安特卫普的犹太人在性格上是相同的。 ,当我看着阿穆诺夫三世的雕像时,我同意两位官员(两位都是称职的法官)的观点,即他具有明显的黑人特征;但诺特和格利登先生(同上,第 146 页,图 53)将他描述为一个混血儿,但不是“黑人混血儿”。)他还会听到一位优秀观察家的权威,隆德博士( 6. 正如 Nott 和 Gliddon 所引用的,《人类类型》,1854 年,第 439 页。他们还给出了确凿的证据;但 C. Vogt 认为这个主题需要进一步调查。),在巴西埋藏着许多已灭绝的哺乳动物,它们与现在美洲大陆盛行的哺乳动物属于同一类型。

然后我们的博物学家可能会转向地理分布,他可能会宣称这些形式必须是不同的物种,它们不仅在外观上不同,而且适合炎热、潮湿或干燥的国家以及北极地区。他可能会诉诸这样一个事实:在与人类相邻的群体中,没有一个物种(即夸德鲁马纳人)能够抵抗低温或任何显着的气候变化。即使在欧洲温和的气候下,最接近人类的物种也从未被培育到成熟。阿加西首先注意到的事实给他留下了深刻的印象(7.“人类起源的多样性”,《基督教观察家》,1850 年 XNUMX 月),不同的人类种族分布在世界各地。相同的动物学省份,毫无疑问,它们居住着不同的哺乳动物物种和属。澳大利亚人、蒙古人和黑人的情况显然就是如此。与霍屯督人的关系不太明显;但显然,巴布亚人和马来人,正如华莱士先生所表明的那样,他们之间的界限几乎与划分马来亚和澳大利亚大动物省份的界限相同。美洲原住民遍布整个大陆。乍一看,这似乎与上述规则相反,因为南半球和北半球的大多数产物差异很大:然而,一些少数的生物形式,如负鼠,从一种变化到另一种,就像以前一些巨大的生物一样。埃德塔塔。爱斯基摩人与其他北极动物一样,分布在整个极地地区。值得注意的是,几个动物学省份的哺乳动物之间的差异程度并不与后者之间的分离程度相对应;因此,与非洲和美洲大陆的哺乳动物与其他省份的哺乳动物相比,黑人与其他人类种族的差异更大,而美国人的差异要小得多,这很难被视为异常。还可以补充一点,人类似乎最初并不居住在任何大洋岛屿上。在这方面,他与班上的其他成员很相似。

在确定同一类家畜的假定变种是否应该被归类为这样,或者是否应该被明确区分,即它们中的任何一个是否是不同野生物种的后代时,每个博物学家都会非常重视它们的外部特征这一事实。寄生虫是特别独特的。人们会更加强调这一事实,因为这将是一个特殊的事实。因为丹尼先生告诉我,在英国,最不同种类的狗、家禽和鸽子都感染了同一种虱子。现在,A. Murray 先生仔细检查了在不同国家、不同种族的人类中收集的虱子(8.《爱丁堡皇家学会汇刊》,第 xxii 卷,1861 年,第 567 页);他发现它们不仅颜色不同,爪子和四肢的结构也不同。在获得许多样本的每种情况下,差异都是恒定的。太平洋上一艘捕鲸船的外科医生向我保证,当船上一些三明治岛民聚集的虱子误入英国水手的尸体时,他们在三四天内就死了。这些虱子颜色较深,看起来与南美洲奇洛埃岛原住民特有的虱子不同,他给了我标本。这些虱子又比欧洲虱子更大、更软。穆雷先生从非洲采购了四种,即东西海岸的黑人、霍屯督人和卡菲尔人;两种来自澳大利亚原住民;两个来自北美,两个来自南美。在后一种情况下,可以推测虱子来自居住在不同地区的当地人。对于昆虫来说,轻微的结构差异,如果是恒定的,通常被认为具有特定的价值:而人类的种族被寄生虫感染的事实,似乎是特别不同的,可以合理地作为一个论点来敦促种族本身应该是被归类为不同的物种。

我们所谓的博物学家已经进行了到目前为止的调查,接下来将询问人类种族在杂交时是否具有任何程度的不育性。 他可能会查阅该著作(9. “论人属的杂交现象”,Eng。 译,1864。)布罗卡教授是一位谨慎而富有哲理的观察家,在这本书中,他会找到很好的证据,证明某些种族在一起具有很强的生育能力,但也有证据表明其他种族的性质相反。 因此有人断言,澳大利亚和塔斯马尼亚的土著妇女很少给欧洲男人生孩子; 然而,这方面的证据现在已被证明几乎毫无价值。 混血儿被纯种黑人杀害:最近有报道称,十一名混血儿青年同时被谋杀和烧死,警方发现了他们的遗体。 (10。 请参阅先生的有趣的来信。 TA Murray,《人类学评论》,1868 年 XNUMX 月,第 XNUMX 页。 十三. 在这封信中,斯特泽莱茨基伯爵声称澳大利亚妇女与白人生下孩子之后会与自己的种族不育,这一说法被驳斥了。 M. A. de Quatrefages 还收集了(Revue des Cours Scientifiques,1869 年 XNUMX 月,第 XNUMX 页)。 239),有很多证据表明澳大利亚人和欧洲人在杂交时不会生育。)同样,人们经常说,当混血儿通婚时,他们生下的孩子很少;另一方面,博士。 查尔斯顿的巴赫曼 (11. '教授的考试。 阿加西的《国家素描》。 《动物世界的省份》,查尔斯顿,1855 年,第 XNUMX 页。 44.),积极断言他认识混血儿家庭,这些家庭已经通婚了好几代,并且平均生育能力与纯白人或纯黑人一样。 先前由 C. 爵士提出的查询 莱尔告诉我,在这个问题上,他得出了同样的结论。 (12。 Dr. 罗尔夫斯写信给我说,他发现大撒哈拉地区的混血儿,由阿拉伯人、柏柏尔人和黑人三个部落组成,非常肥沃。 另一方面,先生。 温伍德·里德告诉我,黄金海岸的黑人虽然钦佩白人和混血儿,但有一条格言:混血儿不应该通婚,因为孩子很少而且体弱多病。 这一信念,正如先生所言。 里德的言论值得关注,因为白人已经在黄金海岸居住并居住了四百年,因此当地人有充足的时间通过经验获取知识。)据报道,美国 1854 年的人口普查包括在内给博士。 巴赫曼,405,751 名黑白混血儿;考虑到案件的所有情况,这个数字似乎很小;但其部分原因可能是该阶级地位低下、反常,以及妇女的挥霍无度。 一定程度的黑白混血儿必须一直被黑人吸收;这将导致前者明显减少。 一部值得信赖的著作中谈到了黑白混血儿的低劣活力(13. BA 的“美国士兵的军事和人类学统计” 古尔德,1869,p。 319.)作为一种众所周知的现象;尽管这一点与生育力下降有不同的考虑,但也许可以作为父母种族特定独特性的证据。 毫无疑问,动物和植物的杂交品种,当由极其不同的物种产生时,很容易过早死亡。但混血儿的父母不能归入极其独特的物种类别。

即使以后证明所有人类种族都具有完美的生育能力,但出于其他原因而倾向于将它们列为不同物种的人可能会公正地辩称,生育力和不育性并不是特定区别的安全标准。 我们知道,这些品质很容易受到生活条件变化或近亲杂交的影响,并且它们受到高度复杂的规律的控制,例如,同一两个物种之间逆向杂交的生育力不平等的规律。 对于必须被列为毫无疑问的物种的形式,存在着一个完美的系列,从杂交时绝对不育的品种到几乎或完全可育的品种。 不育的程度并不严格与亲本在外部结构或生活习惯上的差异程度一致。 人类在许多方面都可以与那些长期被驯化的动物进行比较,并且可以提出大量证据来支持帕拉修斯学说(14. “驯化下动植物的变异”,卷。 II。 p. 109. 在这里我要提醒读者,物种杂交时的不育性并不是一种特殊获得的品质,而是像某些树木无法嫁接在一起一样,是其他后天差异的偶然因素。 这些差异的性质尚不清楚,但它们尤其与生殖系统有关,与外部结构或体质的普通差异关系较小。 杂交物种不育的一个重要因素显然在于其中一个或两个已经长期习惯于固定的条件。因为我们知道条件的变化对生殖系统有特殊的影响,并且我们有充分的理由相信(如前所述)驯化条件的波动往往会消除物种在自然状态下普遍存在的不育性,当穿越时。 我在其他地方已经展示过它(同上。 飞行。 II。 p. 185,以及“物种起源”,第五次编辑。 p. 317),杂交物种的不育性并不是通过自然选择获得的:我们可以看到,当两种形式已经变得非常不育时,它们的不育性几乎不可能通过更多和更先进的物种的保存或生存来增强。更多不育个体;因为,随着不育性的增加,产生的用于繁殖的后代会越来越少,最后只会以最稀有的间隔产生单个个体。 但还有比这更高级别的不育。 Gartner 和 Kolreuter 都证明,在包括许多物种在内的植物属中,可以形成一系列植物,从杂交时产生越来越少种子的物种到从不产生单个种子但仍受到花粉影响的物种其他物种的情况,如胚芽的肿胀所示。 在这里,显然不可能选择更不育的个体,因为它们已经停止产生种子。因此,当仅影响生殖细胞时,绝育是不可能通过选择获得的。 这种极端,毫无疑问,其他等级的不育,是杂交物种生殖系统构成中某些未知差异的偶然结果。),驯化往往会消除不育,而这种不育通常是由于不育而造成的。自然状态下的物种杂交。

与生育能力无关,杂交后代所呈现的性状被认为表明了亲本形式是否应该被列为物种或变种。但在仔细研究了证据之后,我得出的结论是,这种一般规则是不可信的。杂交的一般结果是产生混合形式或中间形式。但在某些情况下,一些后代密切关注一种亲本形式,而另一些则密切关注另一种。当父母性格不同时,这种情况尤其容易发生,这些性格差异最初表现为突然的变异或畸形。 (15.《动物的变异》等,第 ii 卷,第 92 页。)我提到这一点,是因为罗尔夫斯博士告诉我,他在非洲经常看到黑人的后代与其他种族的成员杂交。种族,要么全黑,要么全白,或者很少有花斑。另一方面,众所周知,在美国混血儿通常呈现出中间的外观。

我们现在已经看到,博物学家可能会觉得自己完全有理由将人类的种族划分为不同的物种。因为他发现它们在结构和构成上有许多差异,其中一些差异很重要。这些差异在很长一段时间内也几乎保持不变。我们的博物学家在某种程度上会受到人类的巨大范围的影响,如果人类被视为一个单一物种,那么这在哺乳动物类别中是一个巨大的反常现象。他会对几个所谓的种族的分布感到震惊,这与其他毫无疑问不同的哺乳动物物种的分布是一致的。最后,他可能会强调,所有种族的相互生育能力尚未得到充分证明,即使得到证明也不能绝对证明其特定身份。

另一方面,如果我们所谓的博物学家要询问,当人类在同一个国家大量混合在一起时,其形态是否像普通物种一样保持独特,他会立即发现事实并非如此。在巴西,他会看到大量的黑人和葡萄牙人的混血人口。在奇洛埃岛和南美洲的其他地区,他会看到由印第安人和西班牙人组成的整个人口在不同程度上混合在一起。 (16. M. de Quatrefages 给出了(《人类学评论》,1869 年 22 月,第 XNUMX 页),对巴西保利斯塔人的成功和活力进行了有趣的描述,他们是葡萄牙人和印度人的混血种族,在同一片大陆的许多地方,他会遇到黑人、印第安人和欧洲人之间最复杂的杂交;他是其他种族血统的混合物。从植物界来看,这种三重杂交对亲本的互育性提出了最严峻的考验。在太平洋的一个岛屿上,他发现了一小群混有波利尼西亚人和英国人血统的人。在斐济群岛,波利尼西亚人和尼格利托人在不同程度上都有混血。可以添加许多类似的案例;例如,在非洲。因此,人类的种族差异还不足以居住在同一个国家而不发生融合。并且不存在融合提供了特定清晰度的通常且最好的测试。

当我们的博物学家意识到所有种族的独特性状差异很大时,他也会同样感到非常不安。这一事实让每个人第一次看到巴西的黑人奴隶时就感到震惊,他们是从非洲各地进口的。同样的说法也适用于波利尼西亚人和许多其他种族。人们可能会怀疑是否可以命名任何一个种族特有且恒定的特征。野蛮人,即使在同一个部落的范围内,其性格也并不像人们经常断言的那样一致。霍屯督族女性具有某些特征,比任何其他种族中的特征更为明显,但众所周知,这些特征并不经常出现。在美洲的几个部落中,颜色和毛羽差异很大。在非洲黑人中,颜色在一定程度上也是如此,而特征的形状在很大程度上也是如此。一些种族的头骨形状差异很大(17。例如,赫胥黎教授说,美国和澳大利亚的原住民(“Transact.Internat.Congress of Prehist.Arch.”1868,第 105 页),许多南德人和瑞士人的头骨“与鞑靼人的头骨一样短和宽”,等等);其他所有角色也是如此。现在,所有博物学家都通过昂贵的经验了解到,试图借助变化无常的特征来定义物种是多么轻率。

但反对将人类种族视为不同物种的所有论据中最重要的一点是,据我们判断,它们在许多情况下彼此独立地逐渐相互交叉。人类比任何其他动物都得到了更仔细的研究,然而,在有能力的判断者之间存在最大可能的多样性,是否应将人类归类为单一物种或种族,或者作为两个(维雷),作为三个(雅奎诺),作为四个(康德)、五(布鲁门巴赫)、六(布冯)、七(亨特)、八(阿加西)、十一(皮克林)、十五(博里·圣文森特)、十六(德穆兰)、二十二(莫顿)、六十(克劳福德),或者根据伯克的说法是六十三岁。 (18. 请参阅 Waitz 的《人类学导论》,英译本,1863 年,第 198-208 页,第 227 页,对此主题进行了很好的讨论。我从 H. Tuttle 的《起源与古代》中摘录了上述一些陈述of Physical Man,” Boston,1866,第 35 页。)这种判断的多样性并不能证明这些种族不应该被列为物种,但它表明它们逐渐相互融合,并且几乎不可能发现他们之间性格鲜明。

每一个不幸地对一组高度变化的生物体进行描述的博物学家,都遇到过与人类完全相同的情况(我是根据经验说的)。如果他态度谨慎,他最终会将所有相互演化的形式统一在一个物种之下。因为他会对自己说,他无权为他无法定义的物体命名。此类情况发生在包括人类在内的目中,即猴子的某些属中。而在其他属中,如鹿猴属,大多数物种都可以确定。在美洲宿雾属中,一些博物学家将其各种形式列为物种,而另一些博物学家则将其仅仅列为地理种族。现在,如果从南美洲各地收集到大量的塞布斯标本,并且发现那些目前看来特别不同的形式彼此之间的逐步接近,那么它们通常会被列为纯粹的变种或种族;大多数博物学家在研究人类种族时都遵循这一路线。然而,必须承认,至少在植物王国中是有形式的(19. Nageli 教授在他的“Botanische Mittheilungen”,B. ii. 1866,ss. 294-369 中仔细描述了几个引人注目的案例。阿萨·格雷(Asa Gray)对北美菊科的一些中间形式做出了类似的评论。),我们无法避免将它们命名为物种,但它们通过无数的等级连接在一起,独立于交叉。

一些博物学家最近使用“亚种”一词来指称具有真正物种的许多特征的形式,但它们几乎不值得这么高的排名。现在,如果我们反思一下上面给出的关于将人类种族提升到物种尊严的重要论点,以及在定义它们时所面临的难以克服的困难,那么“亚种”一词在这里似乎可以与“亚种”一词一起使用。礼。但从长期的习惯来看,“种族”这个词也许永远都会被使用。术语的选择仅到目前为止是重要的,因为希望尽可能对相同程度的差异使用相同的术语。不幸的是,这很少能做到:因为较大的属通常包括密切相关的形式,很难区分它们,而同一科内的较小的属则包括完全不同的形式;然而,所有物种都必须被平等地列为物种。同样,同一大属内的物种之间的相似程度绝不相同:相反,其中一些物种通常可以排列成围绕其他物种的小群体,就像卫星围绕行星一样。 (20.《物种起源》,第 5 次编辑。第 68 页。)

人类到底是由一个物种还是由多个物种组成的问题近年来被人类学家广泛讨论,人类学家分为单基因论者和多基因论者两个流派。那些不承认进化论原理的人必须将物种视为独立的创造物,或者以某种方式视为不同的实体;他们必须通过与将其他有机生物归类为物种时通常采用的方法进行类比来决定将何种形式的人视为物种。但在“物种”一词的某些定义被普遍接受之前,要确定这一点是无望的。并且定义不得包含不确定因素,例如创造行为。我们不妨尝试在没有任何定义的情况下决定一定数量的房屋是否应该被称为村庄、城镇或城市。我们有一个实际的例证,说明了永无休止的疑问中的困难,即许多密切相关的哺乳动物、鸟类、昆虫和植物,它们分别在北美和欧洲相互代表,是否应该被列为物种或地理种族?对于距离最近的大陆有一段距离的许多岛屿的产品来说,情况也是如此。

另一方面,那些承认进化原理的博物学家,而且现在大多数崛起的人也承认这一点,他们将毫无疑问地感到,所有人类种族都是单一原始血统的后裔。他们是否认为将种族指定为不同的物种是合适的,以便表达他们之间的差异程度。 (21. 见赫胥黎教授在《双周评论》,1865 年,第 275 页中对此的看法。)对于我们的家养动物,不同种族是否起源于一个或多个物种的问题有些不同。虽然可以承认所有的种族以及同一属内的所有自然物种都起源于同一个原始种群,但这仍然是一个合适的讨论主题,例如狗的所有家养种族是否都是如此,自从某些物种首次被人类驯化以来,已经获得了目前的差异程度;或者它们的某些特征是否源于不同物种的遗传,而这些物种在自然状态下已经分化了。对于人来说,不会出现这样的问题,因为不能说他在任何特定时期被驯化了。

在人类种族与共同种族分化的早期阶段,种族及其数量之间的差异一定很小;因此,就他们的显着特征而言,他们比现有的所谓种族更没有资格被列为独特的物种。然而,“物种”这一术语是如此武断,以至于这些早期的种族也许会被一些博物学家列为不同的物种,如果它们的差异虽然极其微小,但比现在更加稳定,并且没有逐步发展为每个物种。其他。

然而,尽管可能性很小,但人类的早期祖先以前可能在性格上有很大差异,直到他们变得比现在存在的任何种族都更加不同。但随后,正如 Vogt (22. 《关于人的讲座》,Eng。 译,1864 年,第 XNUMX 页。 468.),他们在性格上趋同。 当人类为同一物体选择两个不同物种的后代时,就总体外观而言,有时会引起相当大的趋同。 正如 von Nathusius 所表明的那样(23. “Die Rassen des Schweines”,1860 年,s。 46. “Vorstudien für Geschichte”等,Schwenesschädel,1864 年,s。 104. 关于牛,参见 M. de Quatrefages,“Unité de l'Espèce Humaine”,1861 年,第 XNUMX 页。 119.),猪的改良品种,是两个不同物种的后代;改良牛品种的情况则不太明显。 一位伟大的解剖学家格拉蒂奥莱(Gratiolet)认为,拟人猿并不形成一个自然的亚群;但红毛猩猩是一种高度发达的长臂猿或猿猴,黑猩猩是一种高度发达的猕猴,而大猩猩是一种高度发达的山魈。 如果承认这个几乎完全依赖于大脑特征的结论,那么我们至少应该在外部特征上找到趋同的情况,因为拟人猿在许多方面肯定比它们与其他猿类更相似。 所有类比的相似之处,例如鲸鱼与鱼,确实可以说是趋同的例子。但这个术语从未应用于表面的和适应性的相似。 然而,将广泛不同的生物的改良后代中的许多结构点的特征归结为趋同是极其轻率的。 晶体的形式仅由分子力决定,不同的物质有时呈现相同的形式也就不足为奇了。但对于有机生物,我们应该记住,每一种形式都取决于无限的复杂关系,即取决于由于过于复杂而无法遵循的原因而产生的变化,取决于所保留的变化的本质,这些变化取决于物理条件,更重要的是周围相互竞争的有机体,最后,来自无数祖先的遗传(本身就是一个波动的因素),所有这些祖先的形式都是通过同样复杂的关系决定的。 令人难以置信的是,两种生物体的改良后代,如果它们彼此之间存在显着的差异,那么它们后来会如此紧密地融合在一起,从而导致整个组织中的同一性接近接近。 就上述猪的趋同种族而言,根据冯·纳修斯的说法,它们来自两个原始种群的血统证据仍然清楚地保留在它们头骨的某些骨头中。

尽管现有的人类种族在许多方面存在差异,如肤色、头发、头骨形状、身体比例等,但如果考虑到他们的整体结构,就会发现他们在许多方面都非常相似。点。其中许多的性质是如此不重要或如此独特,以至于它们极不可能是由原始不同的物种或种族独立获得的。对于最独特的人类种族之间的许多心理相似点而言,同样的说法具有同等或更强大的力量。美国原住民、黑人和欧洲人在思想上的差异就像任何三个可以命名的种族一样。然而,当我与“小猎犬”号上的火地岛人一起生活时,我不断地被他们的许多性格小特征所震惊,这表明他们的思想与我们的思想是多么相似。我曾经碰巧与一位纯种黑人有过亲密接触,情况也是如此。

他会阅读泰勒先生和 J. 拉伯克爵士的有趣著作(24。泰勒的《人类早期历史》,1865 年:关于手势语言,请参阅第 54 页。拉伯克的《史前时代》,第 2 版。1869 年。 )很难不对所有种族的人在品味、性情和习惯上的密切相似性留下深刻的印象。这一点从他们对舞蹈、粗俗音乐、表演、绘画、纹身和其他装饰自己的乐趣中可见一斑。他们对手势语言的相互理解,通过相同的面部表情,通过相同的口齿不清的哭声,当被相同的情感激发时。与不同种类的猴子的不同表情和叫声相比,这种相似性,或者更确切地说是同一性,是惊人的。有充分的证据表明,弓箭射击的艺术并未从人类的任何共同祖先那里传承下来,但正如韦斯特罗普和尼尔森所说(25.《人类学协会回忆录》中的“论工具的类似形式”)由 HM Westropp 着,“斯堪的纳维亚的原始居民”,英译本,由 J. Lubbock 爵士编辑,1868 年,第 104 页。),石箭头,从世界最遥远的地方带来,并制造在最遥远的时期,几乎是相同的;这一事实只能由具有相似发明力或智力的不同种族来解释。考古学家也做出了同样的观察(26. Westropp“On Cromlechs”等,“Journal of Ethnological Soc.”,《Scientific Opinion》,2 年 1869 月 3 日,第 27 页) -流行的装饰品,如之字形等;以及各种简单的信仰和习俗,例如将死者埋在巨石结构下。我记得在南美洲观察到(46.《研究杂志:“小猎犬”号的航行》,第 XNUMX 页),在那里,就像在世界上许多其他地方一样,人们通常选择高耸的山峰之巅,扔出成堆的石头,要么作为一些非凡事件的记录,要么用于埋葬死者。

现在,当博物学家观察到两个或多个家养种族之间或近亲缘的自然形态之间在习惯、品味和性情的许多小细节上存在密切一致时,他们就用这一事实作为论据,证明他们是来自一个共同祖先的后裔。因而被赋予;因此,所有这些都应该归入同一物种。同样的论点也适用于人类。

由于人类的不同种族之间在身体结构和心智能力上的众多的、不重要的相似点(我在这里不是指相似的习俗)不可能全部都是独立获得的,所以它们一定是从那些拥有相同基因的祖先那里继承下来的。这些相同的字符。因此,我们对人类在地球表面一步步扩张之前的早期状态有了一些了解。毫无疑问,人类向相隔大海的地区扩散之前,几个种族的性格出现了很大的差异。否则,我们有时会在不同的大陆遇到同一种族;但事实并非如此。 J.卢伯克爵士在比较了世界各地现在野蛮人所实践的艺术之后,详细说明了当人类第一次离开自己的出生地时不可能知道的艺术;因为一旦学会它们就永远不会被忘记。 (28.《史前时代》,1869 年,第 574 页。)因此,他表明“长矛只是刀尖的发展,而棍棒只是长锤,是唯一剩下的东西”。 ”。然而,他承认生火的艺术可能已经被发现,因为它是现存所有种族所共有的,并且为欧洲古代洞穴居民所熟知。也许制作简陋的独木舟或木筏的艺术同样为人所知。但由于人类生活在一个遥远的时代,当时许多地方的土地与现在的水平截然不同,因此,即使没有独木舟的帮助,他也能广泛传播。 J. 拉伯克爵士进一步评论说,考虑到现在存在的许多种族都不能超过四个,我们最早的祖先“数到了十个”是多么不可能。然而,在这个早期时期,人类的智力和社会能力几乎不可能比现在最低等的野蛮人所拥有的能力低下任何极端。否则,原始人不可能在生存斗争中取得如此巨大的成功,正如他早期和广泛的传播所证明的那样。

根据某些语言之间的根本差异,一些语言学家推断,当人类最初广泛传播时,他并不是一种会说话的动物;而是一种语言。但人们可能会怀疑,远不如现在所说的完美的语言,在手势的帮助下,可能已经被使用过,但在后来的、更高度发展的语言中却没有留下任何痕迹。如果不使用某些语言,无论多么不完美,人类的智力是否能够达到其早期统治地位所暗示的标准似乎值得怀疑。

原始人,当他所拥有的艺术很少,而且艺术最粗鲁,当他的语言能力极其不完善时,是否值得被称为人,必须取决于我们所采用的定义。在不知不觉中从某种类猿生物演变为现在存在的人类的一系列形式中,不可能确定应该使用“人”一词的任何明确点。但这是一个非常不重​​要的问题。同样,所谓的人类种族是否被如此指定,或被列为物种或亚种,几乎是一个无关紧要的问题;但后一个术语似乎更合适。最后,我们可以得出这样的结论:当进化论原理被普遍接受时(不久之后肯定会如此),单基因论者和多基因论者之间的争论将悄无声息地、不被察觉地消亡。

另外一个问题不应该被忽视,即,是否像有时假设的那样,人类的每个亚种或种族都起源于一对祖先。对于我们的家养动物来说,通过仔细匹配一对不同的后代,甚至是拥有某种新特性的单个个体,可以很容易地形成一个新的种族。但我们的大多数种族并不是有意地由选定的一对组成的,而是无意识地通过许多个体的保存而形成的,这些个体以某种有用或期望的方式发生了变化,无论变化多么微小。如果在一个国家习惯性地偏爱更强壮和更重的马,而在另一个国家习惯性地偏爱更轻和更快的马,那么我们可以确信,随着时间的推移,将会产生两个不同的亚品种,而不会分离和培育任何一对马。来自任一国家。许多种族就这样形成了,其形成方式与自然物种非常相似。我们还知道,被带到福克兰群岛的马经过几代人的努力,变得越来越小、越来越虚弱,而那些在潘帕斯草原上狂奔的马,却长出了更大、更粗的头。这种变化显然不是由于任何一对,而是由于所有个体都处于相同的条件下,或许还得到了回归原理的帮助。在这种情况下,新的亚品种并不是来自任何一对,而是来自许多个体,这些个体在不同程度上有所不同,但总体方式相同;我们可以得出结论,人类的种族也是以类似的方式产生的,这些变化要么是暴露于不同条件的直接结果,要么是某种形式的选择的间接结果。但我们很快就会回到后一个主题。

论人类种族的灭绝

人类许多种族和亚种族的部分或完全灭绝在历史上是众所周知的。洪堡在南美洲看到了一只鹦鹉,它是唯一能说失落部落语言的生物。在世界各地发现的古代纪念碑和石器,目前的居民没有保留任何传统,表明它们已经灭绝。一些小而破碎的部落,前种族的残余,仍然生存在偏僻的山区。根据沙夫豪森(Shaaffhausen)的说法(29.《人类学评论》翻译,1868 年 431 月,第 30 页),在欧洲,古代种族“在规模上比最粗鲁的野蛮人还要低等”。因此,他们一定在某种程度上不同于任何现有的种族。莱艾济斯的布罗卡教授所描述的遗骸,虽然不幸的是它们似乎属于同一个家族,但它们表明了一个种族,具有最独特的低等或愚昧以及高特征的组合。这个种族“与我们听说过的任何其他种族,无论是古代还是现代,都完全不同”。 (1868.《汇刊》,国际史前考古学大会,172 年,第 175-1868 页。另见《人类学评论》中的 Broca (tr.),410 年 XNUMX 月,第 XNUMX 页。)因此,它与第四纪不同。比利时洞穴竞赛。

人可以长期抵抗对他的生存极其不利的条件。 (31. Gerland 博士,“Ueber das Aussterben der Naturvölker”,1868 年,第 82 条。)他长期生活在北方的极端地区,没有木材用于他的独木舟或工具,只有鲸脂作为燃料,并融化雪作为饮料。在美国最南端,火地岛人没有衣服的保护,也没有任何可以称为茅屋的建筑物的保护。在南非,原住民在干旱的平原上漫步,那里充满了危险的野兽。人类可以抵御喜马拉雅山脚下的特莱河和热带非洲沿岸的瘟疫的致命影响。

灭绝主要是由于部落与部落、种族与种族的竞争造成的。各种检查总是在进行,以减少每个野蛮部落的数量,例如周期性的饥荒、游牧习惯和随之而来的婴儿死亡、长时间哺乳、战争、事故、疾病、放荡、偷窃妇女、杀婴,尤其是生育能力下降。如果这些制约中的任何一项力量增加,即使是轻微增加,受影响的部落也会减少;当两个相邻的部落中,一个部落的人数和实力都不如另一个部落时,战争、屠杀、同类相食、奴役和吸收很快就会解决。即使弱小的部落没有被如此突然地消灭,一旦开始减少,一般都会继续减少,直至灭绝。 (32. Gerland(同上,第 12 条)提供了支持这一说法的事实。)

当文明国家与野蛮人接触时,斗争是短暂的,除非致命的气候对本土种族有帮助。文明国家取得胜利的原因,有的简单明了,有的复杂晦涩。我们可以看到,土地的耕种对于野蛮人来说在很多方面都是致命的,因为他们不能也不会改变他们的习惯。新的疾病和恶习在某些情况下被证明具有很强的破坏性;似乎一种新疾病常常会导致大量死亡,直到那些最容易受到其破坏性影响的人被逐渐淘汰(33。参见 H. Holland 爵士的《医学笔记和反思》,1839 年,第 390 页对此的评论。 34。);烈性酒的邪恶影响以及许多野蛮人对烈性酒的强烈嗜好可能也是如此。进一步看来,虽然事实很神秘,但不同且分离的人的第一次相遇会产生疾病。 (435. 我收集了(《研究杂志:“小猎犬号”的航行》,第 8 页)许多与此主题相关的案例;另见 Gerland,同上第 35 节。Poeppig 谈到“文明对于野蛮人来说是有毒的。”)斯普罗特先生在温哥华岛密切关注灭绝问题,他认为欧洲人的到来导致了生活习惯的改变,导致了许多健康问题。他还特别强调了当地人变得“对周围的新生活感到困惑和迟钝”的看似微不足道的原因;他们失去了努力的动力,也没有新的动力来代替。” (1868. 斯普罗特,《野蛮生活的场景与研究》,284 年,第 XNUMX 页。)

他们的文明等级似乎是竞争国家成功的最重要因素。几个世纪前,欧洲担心东方野蛮人的入侵。现在任何这样的恐惧都是荒谬的。正如白芝浩先生所说,一个更奇怪的事实是,野蛮人以前并没有像现在在现代文明国家面前那样在古典民族面前憔悴不堪;相反,他们在现代文明国家面前憔悴不堪。如果他们这样做了,古老的道德家们就会对这件事深思熟虑。但那个时期的任何作家都没有对灭亡的野蛮人表示哀叹。 (36. 白芝浩,《物理学与政治》,《双周刊评论》,1 年 1868 月 455 日,第 XNUMX 页。)在许多情况下,导致灭绝的最有力原因似乎是生育能力下降和健康状况不佳,尤其是在儿童中,这种现象是由于生活条件的改变而产生的,尽管新的条件本身可能并无害处。我非常感谢 HH Howorth 先生引起我对这个主题的关注,并为我提供了有关它的信息。我收集了以下案例。

当塔斯马尼亚首次被殖民时,当地人粗略估计有 7000 人,另一些人估计为 20,000 人。他们的人数很快就大大减少,主要是因为与英国人以及彼此之间的战斗。在所有殖民者进行了著名的狩猎之后,当剩下的土著向政府自首时,他们只有 120 人(37。这里给出的所有陈述均摘自 J. Bonwick 的《最后的塔斯马尼亚人》, 1870 年),他们于 1832 年被运送到弗林德斯岛。这个岛屿位于塔斯马尼亚和澳大利亚之间,长四十英里,宽十二到十八英里:它看起来很健康,当地人也受到了很好的对待。然而,他们的健康却遭受了巨大的痛苦。 1834 年,他们由 250 名成年男性、111 名成年女性和 1835 名儿童组成(Bonwick,第 1847 页),即总共 20 人。 1847 年只剩下一百人。由于它们的数量继续迅速减少,而且它们自己认为在其他地方不应该那么快消亡,因此它们于 38 年被迁移到塔斯马尼亚南部的牡蛎湾。他们当时由十四名男性、二十二名女性和十名儿童组成(1870 年 67 月 1864 日)。 (1869. 这是塔斯马尼亚州州长 W. Denison 爵士的声明,“副王室生活的多样性”,386 年,第 XNUMX 卷。)但是地点的改变并没有带来什么好处。疾病和死亡仍然追随着他们,XNUMX 年,只有一名男子(于 XNUMX 年去世)和三名老年妇女幸存。妇女的不孕症甚至比所有人都面临健康不良和死亡更引人注目的事实。当时牡蛎湾只剩下九名妇女,她们告诉邦威克先生(第 XNUMX 页),只有两人生过孩子:而这两个人总共只生了三个孩子!

关于这种非同寻常的情况的原因,斯托里博士指出,死亡是在对当地人进行文明化的尝试之后发生的。 “如果让他们像往常一样自由地漫游,不受干扰,他们会养育更多的孩子,死亡率也会更低。”另一位细心观察原住民的戴维斯先生评论道:“出生的人很少,死亡的人却很多。这在很大程度上可能是由于他们的生活方式和食物发生了变化。但更重要的是,他们被驱逐出范迪门土地大陆,并随之而来的精神沮丧”(Bonwick,第 388、390 页)。

在澳大利亚两个截然不同的地区也观察到了类似的事实。著名探险家格雷戈里先生告诉邦威克先生,在昆士兰州,“黑人已经感受到了繁衍的需要,甚至在最近定居的地区也是如此,而且这种衰退将会开始。”来自鲨鱼湾的 39 名原住民参观了默奇森河,其中 1870 人在三个月内死于肺结核。 (90. 对于这些案例,请参见 Bonwick 的《塔斯马尼亚人的日常生活》,1870 年,第 386 页:以及《最后的塔斯马尼亚人》,XNUMX 年,第 XNUMX 页。)

新西兰毛利人的减少是由先生仔细调查的。 芬顿在一份令人钦佩的报告中,除一个例外外,以下所有陈述均来自该报告。 (40。 《新西兰原住民观察》,政府出版,1859 年。)自 1830 年以来,包括原住民自己在内的所有人都承认人数减少,而且仍在稳步减少。 尽管迄今为止不可能对当地人进行实际的人口普查,但许多地区的居民都仔细估计了他们的人数。 结果似乎是可信的,并显示在1858年之前的十四年里,下降了19.42%。 经过仔细检查,有些部落居住的距离相距一百英里以上,有些在沿海,有些在内陆;他们的生活资料和生活习惯也有一定的差异(第 17 页)。 28)。 1858年的总人数据信为53,700人,1872年,时隔十四年再次进行人口普查,人数仅为36,359人,减少了32.29%! (41。 亚历克斯的《新西兰》。 肯尼迪,1873 年,p。 47.) 先生。 芬顿详细说明了各种原因的不足,这些原因通常被用来解释这种异常的下降,例如新的疾病、妇女的挥霍、酗酒、战争等,他得出的结论是,这主要取决于妇女的生产力低下,以及幼儿的极高死亡率(第 17 页)。 31,34)。 为了证明这一点,他展示了(第 17 页)。 33) 1844 年,每 2.57 名成人就有 1858 名非成人;而 3.27 年,每 XNUMX 名成人中只有 XNUMX 名非成人。 成虫的死亡率也很大。 他指出,性别不平等现象减少的另一个原因是性别不平等。因为出生的女性比男性少。 对于后一点,也许取决于一个广泛不同的原因,我将在以后的章节中再次讨论。 先生。 芬顿将新西兰的下降与爱尔兰的增长进行了对比,这令人惊讶;这些国家的气候差别不大,而且居民现在的习惯也几乎相似。 毛利人自己(第 17 页) 35)“在某种程度上,将他们的颓废归因于新食物和新衣服的引入,以及随之而来的习惯的改变”;当我们考虑环境变化对生育力的影响时,就会发现它们可能是正确的。 1830 年至 1840 年间,数量开始减少;和先生。 芬顿展示 (p. 40) 大约在 1830 年,人们发现并大量采用了通过长时间浸泡在水中来制造腐烂玉米的技术;这证明,即使在新西兰只有稀少的欧洲人居住时,当地人的习惯已经开始发生变化。

从帕特森主教生平的许多陈述中可以明显看出(42.《JC帕特森的一生》,CM Younge,1874年;尤其参见第530卷。),新赫布里底群岛和邻近群岛的美拉尼西亚人遭受了苦难当他们被转移到新西兰、诺福克岛和其他有益健康的地方,以便接受传教士教育时,他们的健康状况异常严重,并大量死亡。

桑威奇群岛原住民人口的减少与新西兰一样臭名昭著。据最有判断能力的人粗略估计,当库克于 1779 年发现该群岛时,人口约为 300,000 万。根据 1823 年的一项松散人口普查,当时的人口数量为 142,050 人。 1832 年以及随后的几个时期,正式进行了准确的人口普查,但我只能获得以下回报: 本地人口年减少率,假设为(1832 年除外,并且在1836 年,当时进行了几次连续的人口普查;这些人口普查的年份也包括了岛屿上的外国人。)不定期进行。

1832 130,313
4.46
1836 108,579
2.47
1853 71,019
0.81
1860 67,084
2.18
1866 58,765
2.17
1872 51,531

我们在这里看到,在 1832 年至 1872 年间的四十年间,人口减少了不低于百分之六十八! 大多数作家将其归因于妇女的挥霍、以前的血腥战争、强加给被征服部落的繁重劳动以及新引入的疾病,这些疾病在某些情况下具有极大的破坏性。 毫无疑问,这些和其他类似的原因是非常有效的,并且可以解释 1832 年至 1836 年之间的异常下降率;但所有原因中最有力的似乎是生育能力下降。 据博士 美国鲁森伯格 海军于 1835 年至 1837 年间访问了这些岛屿,在夏威夷的一个地区,1134 名男子中只有 637 人,而在另一地区,XNUMX 人中只有 XNUMX 人,而在夏威夷的一个地区,有一个家庭有多达三个孩子。 八十位已婚妇女中,只有三十九人生过孩子; “官方报告显示,全岛每对已婚夫妇平均生育半个孩子。”这几乎与牡蛎湾塔斯马尼亚人的平均水平完全相同。 贾维斯于 1843 年出版了他的《历史》,他说:“拥有三个孩子的家庭可以免除所有税收;那些拥有更多的人会得到土地礼物和其他鼓励。”政府这一无与伦比的法令充分表明了这个种族已经变得多么贫瘠。 牧师 A. 1839年,毕肖普在夏威夷《旁观者》中指出,很大一部分儿童早逝,斯特利主教告诉我,情况仍然如此,就像在新西兰一样。 这被归咎于妇女对孩子的忽视,但这可能在很大程度上是由于孩子先天体质虚弱,与父母生育能力下降有关。 此外,与新西兰的情况还有进一步的相似之处,即出生人口中男性远远多于女性:1872 年的人口普查显示,各个年龄段的男性人口为 31,650 人,女性人口为 25,247 人,也就是说,每个年龄段的男性人口为 125.36 人。 100 名女性;而在所有文明国家,女性都超过男性。 毫无疑问,妇女的挥霍可能是她们生育能力低下的部分原因。但他们生活习惯的改变是一个更有可能的原因,同时也将导致死亡率上升,特别是儿童死亡率的上升。 库克于 1779 年访问过这些岛屿,温哥华于 1794 年访问过这些岛屿,随后捕鲸者也经常访问这些岛屿。 1819年,传教士到达,发现偶像崇拜已经被废除,国王还进行了其他改革。 此后,当地人的几乎所有生活习惯都发生了迅速变化,他们很快就成为“太平洋岛民中最文明的人”。我的一位线人,先生。 出生在岛上的科恩评论说,当地人在五十年的时间里生活习惯发生的变化比英国人在一千年间发生的变化还要大。 从斯塔利主教那里得到的信息来看,尽管引入了许多新的水果种类,而且甘蔗也得到普遍使用,但较贫穷阶层的饮食似乎并没有发生太大改变。 然而,由于热衷于模仿欧洲人,他们很早就改变了自己的着装方式,酒精饮料的使用也变得非常普遍。 尽管这些变化看起来微不足道,但从对动物的了解来看,我完全相信,它们可能足以降低当地人的生育能力。 (43。 上述陈述主要摘自以下著作:贾维斯的《夏威夷群岛历史》,1843 年,第 XNUMX 页。 400-407。 奇弗,《桑威奇群岛的生活》,1851 年,第 XNUMX 页。 277. 邦威克(Bonwick)在《最后的塔斯马尼亚人》(Last of the Tasmanians),1870 年,第 XNUMX 页中引用了鲁森伯格的观点。 378. E爵士引用了毕肖普的话。 贝尔彻,《环游世界》,1843 年,卷。 i. p. 272. 这几年的人口普查工作,多亏了先生的恩情。 应科恩博士的要求 纽约的尤曼斯;在大多数情况下,我都会将尤曼斯的数据与上述几部著作中给出的数据进行比较。

最后,麦克纳马拉先生指出(44。《印度医学公报》,1 年 1871 月 240 日,第 XNUMX 页。)孟加拉湾东侧安达曼群岛的低贱居民是“非常容易受到任何气候变化的影响:事实上,将它们带离岛上的家园,它们几乎肯定会死亡,而且与饮食或外来影响无关。”他进一步指出,夏季极其炎热的尼泊尔山谷的居民以及印度的各个山地部落的居民在平原上都会患上痢疾和发烧。如果他们试图在那里度过一整年,他们就会死。

因此,我们看到,许多野生人类在生活条件或习惯发生变化时,很容易在健康方面受到很大影响,而不仅仅是因为被运送到新的气候。仅仅改变习惯本身似乎并无害处,似乎也会产生同样的效果。在某些情况下,儿童尤其容易遭受苦难。正如麦克纳马拉先生所说,人们常说,人类可以抵抗气候和其他变化的最大差异而不受惩罚;但这仅适用于文明种族。在这方面,处于野外状态的人类似乎与他最亲密的盟友类人猿一样容易受到影响,而类人猿在离开祖国后从未存活过很长时间。

环境变化导致的生育率下降,例如塔斯马尼亚人、毛利人、三明治岛民,显然还有澳大利亚人,这仍然比他们对健康状况不佳和死亡的责任更有趣;因为即使是轻微程度的不孕,再加上那些往往会抑制人口增长的其他原因,迟早会导致灭绝。在某些情况下,生育率的下降可能是由于妇女的挥霍(直到最近的塔希提岛人),但芬顿先生已经表明,这种解释对于新西兰人和塔斯马尼亚人来说都不够。

在上面引用的论文中,麦克纳马拉先生给出了相信疟疾流行地区的居民容易不育的理由;但这不适用于上述几种情况。一些作家认为,岛屿上的原住民由于长期持续的杂交,生育能力和健康状况受到影响。但在上述情况下,不孕症与欧洲人的到来太接近了,我们无法承认这种解释。我们目前也没有任何理由相信人类对杂交的邪恶影响高度敏感,特别是在像新西兰这样大的地区和拥有多样化站点的桑威奇群岛。相反,众所周知,诺福克岛的现有居民几乎都是表兄弟或近亲,印度的托达人以及苏格兰西部一些岛屿的居民也是如此。但他们的生育能力似乎并未受到影响。 (45. 关于诺福克岛民的密切关系,W. Denison 爵士,“Vice-Regal Life”,第 1870 卷,410 年,第 1873 页。关于托达人,请参阅马歇尔上校的著作 110 年,第 1865 页. 对于苏格兰西部群岛,Mitchell 博士,《爱丁堡医学杂志》,XNUMX 年 XNUMX 月至 XNUMX 月。)

低等动物的类比提出了一种更为可能的观点。可以证明,生殖系统对生活条件的变化非常敏感(尽管我们不知道为什么)。这种敏感性既会导致有益的结果,也会导致邪恶的结果。第 46 章提供了有关该主题的大量事实。十八.卷。二.我的《驯化下的动植物的变异》。我在这里只能给出最简短的摘要;对这一主题感兴趣的每个人都可以查阅上述作品。非常轻微的变化会增加大多数或所有有机生物的健康、活力和生育能力,而已知的其他变化会导致大量动物不育。最常见的案例之一是驯服的大象不在印度繁殖。尽管它们经常在阿瓦繁殖,在那里雌性可以在一定程度上在森林中漫步,因此被置于更自然的条件下。各种美洲猴子的例子是一个更恰当的例子,因为它们与人类的关系,它们的雌雄在自己的国家已经被饲养了很多年,但很少或从未繁殖过。值得注意的是,环境条件的微小变化往往会导致野生动物在捕获时不育。更奇怪的是,我们所有的家养动物都比自然状态下的繁殖能力更强。其中一些可以抵抗最不自然的条件而生育力不减。 (111. 有关这一点的证据,请参阅《动物的变异》等,第 ii 卷,第 XNUMX 页。)某些动物群体比其他动物群体更容易受到圈养的影响。一般来说,同一类群的所有物种都以相同的方式受到影响。但有时,群体中的单个物种会变得不育,而其他物种则不然;另一方面,单个物种可能会保留其生育能力,而其他大多数物种则无法繁殖。某些物种的雄性和雌性在被限制或被允许在其祖国几乎但不完全自由地生活时,永远不会结合在一起;其他处于这种情况的动物经常结合在一起,但从未产生后代;其他人再次产生一些后代,但比自然状态下要少;就上述人类情况而言,重要的是要指出,年轻人容易体弱多病,或畸形,并早逝。

鉴于生殖系统对生活条件变化的敏感性的这一规律是多么普遍,并且它适用于我们最近的盟友,Quadrumana,我几乎不怀疑它适用于处于原始状态的人类。因此,如果任何种族的野蛮人突然改变他们的生活习惯,他们就会或多或少地变得不育,而他们的后代也会因同样的原因而健康受损,就像大象和猎豹一样。印度、美国的许多猴子以及许多各种动物,都脱离了自然条件。

我们可以理解,为什么长期居住在岛屿上、长期暴露在几乎统一的条件下的原住民,应该特别受到他们习惯的任何变化的影响,情况似乎就是如此。文明种族当然比野蛮人更能抵抗各种变化。在这方面,它们类似于家养动物,因为尽管后者有时会出现健康问题(例如印度的欧洲狗),但它们很少会不育,尽管有一些这样的例子。 (47.《动物的变异》等,第 ii 卷,第 16 页。)文明种族和驯养动物的免疫力可能是由于他们受到更大程度的影响,因此变得更加习惯,比大多数野生动物适应多样化或变化的条件;以及他们以前移民或被从一个国家带到另一个国家,以及不同的家庭或亚种族之间的交叉。看来,与文明种族的杂交立即赋予了原住民种族免受环境变化带来的邪恶后果的免疫力。因此,大溪地人和英国人的杂交后代在皮特凯恩岛定居后,数量迅速增加,以致该岛很快就出现了过剩。 1856 年 60 月,他们被转移到诺福克岛。当时,他们包括 134 名已婚人士和 194 名儿童,总数为 1859 人。在这里,他们同样迅速增加,尽管其中 1868 人于 300 年返回皮特凯恩岛,但到 194 年 300 月人数已达 120 人;男性和女性的数量完全相等。这个案例与塔斯马尼亚人的案例形成了多么鲜明的对比?诺福克岛居民在短短十二年半的时间里就从 46 人增加到 48 人;而塔斯马尼亚人在十五年间从 1870 人减少到 29 人,其中只有 1863 人是儿童。 (XNUMX. 这些细节取自 Belcher 夫人 XNUMX 年所著的《“赏金叛变者”》;以及下议院 XNUMX 年 XNUMX 月 XNUMX 日下令印制的《皮特凯恩岛》。三明治岛民来自《檀香山公报》和科恩先生。)

因此,在 1866 年至 1872 年的人口普查期间,桑威奇群岛的纯血统土著减少了 8081 人,而被认为更健康的混血种姓则增加了 847 人;但我不知道后一个数字是包括混血种姓的后代,还是只包括第一代混血种姓。

我在这里给出的案例都与原住民有关,他们由于文明人的移民而受到新的条件的影响。但是,如果野蛮人由于任何原因(例如征服部落的入侵)而被迫放弃家园并改变他们的习惯,那么不育和健康状况不佳可能会随之而来。有趣的是,对野生动物驯化的主要限制,这意味着它们在第一次被捕获时可以自由繁殖的力量,而对野人在接触文明时生存并形成文明种族的主要限制是同样的,即生活条件改变导致的不育。

最后,尽管人类种族的逐渐减少和最终灭绝是一个非常复杂的问题,取决于不同地点和不同时间的多种原因;这与一种高等动物的灭绝所带来的问题是一样的,例如化石马,它从南美洲消失,不久之后在同一地区被无数的西班牙马群所取代。这位新西兰人似乎意识到了这种相似性,因为他将自己未来的命运与现在几乎被欧洲老鼠消灭的本土老鼠的命运进行了比较。虽然这个困难对我们的想象来说是巨大的,而且确实是巨大的,但如果我们希望确定确切的原因及其作用方式,那么对我们的理性来说就不应该如此,只要我们牢记在心,每个物种和每个种族不断地以各种方式进行检查;因此,如果增加任何新的检查,即使是轻微的检查,比赛的数量肯定会减少;数量的减少迟早会导致灭绝;在大多数情况下,结局是由征服部落的入侵迅速决定的。

论人类种族的形成

在某些情况下,不同种族的交叉导致了新种族的形成。一个奇怪的事实是,欧洲人和印度人属于同一雅利安人,说的语言基本相同,但在外观上差异很大,而欧洲人与属于闪米特人的犹太人几乎没有什么不同,说的是完全不同的语言,已被布罗卡(49.“论人类学”,翻译,“人类学评论”,1868 年 38 月,第 50 页)解释为,通过某些雅利安分支在其广泛传播期间很大程度上被土著部落跨越。当两个密切接触的种族杂交时,第一个结果是异质混合物:因此亨特先生在描述印度的桑塔利或山地部落时说,“从印度的黑人、矮胖部落”可以追溯到数百个难以察觉的等级。山峦高大,橄榄色的婆罗门,有着智慧的眉毛,平静的眼睛,高而窄的头”;因此,法庭有必要询问证人是桑塔利斯人还是印度人。 (1868.《孟加拉农村年鉴》,134 年,第 51 页。)异质民族,例如某些波利尼西亚岛屿的居民,是否由两个不同种族杂交形成,只剩下很少或没有纯粹的成员,是否会变得同质,无法从直接证据中得知。但是,与我们驯养的动物一样,通过仔细选择,杂交品种肯定可以固定并使其统一(95.“驯化下动物和植物的变异”,第 ii 卷,第 XNUMX 页)。几代人之后,我们可以推断,在漫长的下降过程中,异质混合物的自由交叉将提供选择的位置,并克服任何回归的趋势;因此,杂交的种族最终将变得同质,尽管它可能不会同等程度地分享两个亲本种族的特征。

在人类种族之间的所有差异中,肤色是最显着的,也是最明显的差异之一。以前人们认为这种差异可能是由于长期暴露在不同的气候下造成的。但帕拉斯首先表明这是站不住脚的,此后几乎所有人类学家都追随他。 (52. Pallas,“Act. Acad. St. Petersburg”,1780 年,第二部分,第 69 页。鲁道夫紧随其后,在他的“Beytrage zur Anthropologie”中,1812 年。Godron 对证据进行了出色的总结。 ,“De l'Espèce”,1859 年,第 ii 卷,第 246 页等)这种观点被拒绝,主要是因为不同肤色的种族的分布不一致,其中大多数人肯定长期居住在他们现在的家园。并伴有相应的气候差异。荷兰家庭的案例可能受到一些重视,正如我们从权威那里听到的那样(53.安德鲁·史密斯爵士,诺克斯引用的《人类的种族》,1850年,第473页),在南非居住了三个世纪后,颜色没有发生丝毫变化。同一方的论点同样可以从吉普赛人和犹太人在世界各地的统一外观中得出,尽管后者的统一性有些被夸大了。 (54. 参见 De Quatrefages 关于这一点的内容,“Revue des Cours Scientifiques”,17 年 1868 月 731 日,第 55 页。)人们认为,非常潮湿或非常干燥的空气对改变皮肤的颜色更有影响力。不仅仅是热量;但正如南美洲的多比尼和非洲的利文斯通对于潮湿和干燥得出了截然相反的结论一样,任何关于这个问题的结论都必须被认为是非常值得怀疑的。 (1857. 利文斯通的《南非旅行与研究》,338 年,第 339、266 页。多比尼,戈德隆引用,《De l'Espece》,第二卷,第 XNUMX 页。)

我在其他地方给出的各种事实证明,皮肤和头发的颜色有时以令人惊讶的方式与对某些植物毒物的作用和某些寄生虫的攻击的完全免疫力相关。因此,我想到,黑人和其他黑人种族可能是在漫长的几代人的时间里,由于深色个体逃离了祖国瘴气的致命影响而获得了深色肤色。

后来我发现,威尔斯博士也曾有过同样的想法。 (56. 参见 1813 年皇家学会宣读的一篇论文,并于 1818 年发表在他的论文中。我已在《物种起源》的《历史概述》(第 xvi 页)中阐述了威尔斯博士的观点” 在我的《驯化下的动物和植物的变化》,第 ii 卷,第 227、335 页中给出了与体质特征相关的各种颜色案例。)人们早就知道,黑人,甚至黑白混血儿,几乎完全是免受黄热病的影响,黄热病在美洲热带地区具有严重的破坏性。 (57. 例如,参见 Nott 和 Gliddon,《Types of Mankind》,第 68 页。)他们同样在很大程度上避免了致命的间歇性发烧,这种发烧在非洲海岸至少 2600 英里的范围内盛行,并且每年都会导致五分之一的白人定居者死亡,还有五分之一的人因残疾而返回家乡。 (58. Tulloch 少校,20 年 1840 月 1840 日在统计学会前宣读的一篇论文,并在《雅典娜神庙》,353 年,第 59 页中给出。)黑人的这种免疫力似乎部分是固有的,取决于一些未知的因素。体质的特殊性,部分是适应环境的结果。 Pouchet(1864。“人类的多元化”(翻译),60 年,第 60 页。)指出,在苏丹附近招募的黑人军团,并从埃及总督借来参加墨西哥战争,逃脱了黄-发烧几乎与最初从非洲各地带来并习惯了西印度群岛气候的黑人一样。黑人在寒冷气候中居住一段时间后变得有些容易患热带热病的许多案例表明了这种适应作用。 (1861. Quatrefages, 'Unité de l'Espèce Humaine,' 205, p. 1863. Waitz, 'Introduction to Anthropology,' translat., vol. i. 124, p. 1837. 利文斯通在他的《游记》中给出了类似的案例。 ’)白人长期居住的气候性质同样对他们有一定的影响; XNUMX 年,在德梅拉拉可怕的黄热病流行期间,布莱尔博士发现移民的死亡率与他们来自国家的纬度成正比。对于黑人来说,免疫力,就其适应环境的结果而言,意味着在相当长的时间内暴露在外。对于自古以来就居住在那里的热带美洲原住民来说,也不能幸免于黄热病; HB·崔斯特瑞姆牧师指出,北非有些地区的原住民每年都被迫离开,但黑人可以安全地留下来。

黑人的免疫力在某种程度上与他的皮肤颜色相关只是一种推测:它可能与他的血液、神经系统或其他组织的某些差异有关。 然而,根据上述事实,以及肤色和消费倾向之间明显存在的某种联系,我认为这个猜想并非不可能。 因此我努力了,但收效甚微(61. 1862年春,我获得陆军医疗部部长的许可,向驻外各团的外科医生转交了一张空白表格,附有以下附注,但我没有收到任何回复。 “我们家畜的皮肤附属器的颜色与体质之间的关系已被记录在案,有几个明显的案例;众所周知,人类的肤色与其居住的气候之间存在某种有限的关系。以下调查似乎值得考虑。 也就是说,欧洲人的头发颜色与他们患热带国家疾病的可能性之间是否存在任何关系。 如果几个团的外科医生在驻扎在卫生条件差的热带地区时,首先统计一下,在抽出病人的部队中,有多少人是深色和浅色头发,作为比较的标准。 ,以及中等或可疑色调的头发;如果同一位医学先生对所有患有疟疾、黄热病或痢疾的人进行类似的记录,那么在将数千例病例制成表格后,很快就会发现,这些疾病之间是否存在任何关系。头发的颜色和热带疾病的体质倾向。 也许不会发现这样的关系,但调查是非常值得进行的。 如果获得任何积极的结果,它可能对选择从事任何特定服务的人员有一些实际用途。 从理论上讲,这一结果会引起人们的极大兴趣,因为它表明,居住在遥远时期、不健康的热带气候下的一个种族,可能通过一种方式,通过在一段时期内更好地保存黑发或黑肤色的个体而变得深色。世代相传。”),以确定它的适用范围。 已故的博士 长期居住在非洲西海岸的丹尼尔告诉我,他不相信有任何这样的关系。 他本人异常英俊,并且以一种奇妙的方式经受住了气候的考验。 当他还是个孩子的时候,第一次来到海岸时,一位经验丰富的年长黑人酋长从他的外表上预测,这将证明这一点。 Dr. 安提瓜岛的尼科尔森在讨论完这个问题后写信给我,深色肤色的欧洲人比浅色肤色的欧洲人更容易逃脱黄热病。 先生。 JM 哈里斯完全否认黑头发的欧洲人比其他男人更能承受炎热的气候:相反,经验告诉他,在挑选前往非洲海岸服役的男人时,要选择红头发的人。 (62。 《人类学评论》,一月。 1866。 二十一。 Dr. 夏普还说,关于印度(“人类是一种特殊的创造”,1873 年,第 XNUMX 页) 118),“一些医务人员注意到,浅色头发和红润肤色的欧洲人比深色头发和蜡黄肤色的人患热带国家的疾病要少;而且,据我所知,这一言论似乎有充分的理由。”另一方面,先生。 来自塞拉利昂的赫德尔“因西非海岸的气候(W. 里德,《非洲素描书》,卷。 II。 p. 522),持有完全相反的观点,船长也是如此。

夏普博士评论道(63。《人类是一种特殊的创造》,1873 年,第 119 页),热带阳光会灼伤白色皮肤并起泡,但不会伤害黑色皮肤。他补充说,这并不是个人习惯造成的,因为只有六、八个月大的孩子经常被赤身裸体地抱在身边,并且不受影响。一位医生向我保证,几年前,每年夏天,但不是冬天,他的手上都会出现浅棕色斑块,虽然比雀斑大,但这些斑块从未受到晒伤的影响,而他皮肤的白色部分曾多次严重发炎并起水泡。对于低等动物来说,长有白毛的皮肤部分和其他部分对阳光照射的敏感性也存在本质上的差异。 (64.“驯化下的动物和植物的变异”,第 ii 卷,第 336、337 页。)保存皮肤免遭烧伤是否对于解释人类逐渐获得深色色调具有足够的重要性通过自然选择,我无法判断。如果是这样,我们就不得不假设热带美洲原住民在那里生活的时间比非洲的黑人或马来群岛南部的巴布亚人短得多,就像肤色较浅的印度人在那里生活的时间一样。与半岛中部和南部的肤色较深的原住民相比,他们在印度居住的时间较短。

尽管以我们目前的知识,我们无法通过由此获得的任何优势或气候的直接作用来解释人类种族中的肤色差异;然而,我们不能完全忽视后一种作用,因为有充分的理由相信,某些遗传效应是由此产生的。 (65. 例如,参见 Quatrefages(“Revue des Cours Scientifiques”,10 年 1868 月 724 日,第 1865 页),了解居住在阿比西尼亚和阿拉伯半岛的影响以及其他类似案例。Rolle 博士(“Der Mensch, Seine Abstammung 等,99 年,第 XNUMX 条)根据哈尼科夫的权威指出,定居在格鲁吉亚的大量德国家庭在两代人的过程中都获得了黑头发和黑眼睛。D.福布斯先生告诉我安第斯山脉的盖丘亚人的颜色差异很大,具体取决于他们居住的山谷的位置。)

我们在第二章中已经看到,生活条件直接影响身体框架的发展,并且这种影响是传递的。因此,正如人们普遍承认的那样,在美国的欧洲定居者经历了轻微但异常迅速的外貌变化。他们的身体和四肢变得拉长;我从伯尼斯上校那里听说,在美国战争后期,德国军团穿着为美国市场制造的成衣,所呈现的可笑外表就证明了这一事实。从各方面来说,对男人来说都太长了。还有大量证据表明,在南方各州,第三代房奴的外貌与田地奴隶明显不同。 (66. Harlan,《医学研究》,第 532 页。Quatrefages(《Unité de l'Espèce Humaine》,1861 年,第 128 页)收集了许多关于这一点的证据。)

然而,如果我们观察分布在世界各地的人类种族,我们就必须推断,即使在接触了很长一段时间之后,他们的特征差异也不能用不同生活条件的直接作用来解释。爱斯基摩人完全靠动物性食物为生。他们穿着厚厚的毛皮,暴露在严寒和长时间的黑暗中。然而,他们与中国南方的居民没有任何极端的区别,中国南方的居民完全以蔬菜为生,几乎赤身裸体地暴露在炎热、刺眼的气候下。赤身露体的火地岛人靠其荒凉海岸的海产品为生。巴西的博图库多人在内陆炎热的森林中游荡,主要以蔬菜为生。然而,这些部落彼此非常相似,以至于“小猎犬”号上的火地岛人被一些巴西人误认为是博托库多人。博托库多人和热带美洲的其他居民一样,与居住在大西洋彼岸的黑人完全不同,他们的气候几乎相似,生活习惯也几乎相同。

人类种族之间的差异也不能通过零件使用增加或减少的遗传效应来解释,除非程度相当微不足道。习惯于独木舟生活的人,双腿可能有些发育不良;居住在高处的人,胸部可能会扩大;那些经常使用某些感觉器官的人可能会发现它们所在的空腔尺寸有所增加,因此他们的特征也略有改变。在文明国家中,由于减少使用而导致下颌尺寸减小(不同肌肉习惯性地发挥作用来表达不同的情绪),以及由于更多的智力活动而导致大脑尺寸增大,与比较相比,这些因素共同对他们的整体外观产生了相当大的影响。与野蛮人。 (67. 参见 Schaaffhausen 教授翻译,《人类学评论》,1868 年 429 月,第 XNUMX 页。)身体身高的增加,而大脑尺寸没有任何相应的增加,可能(从之前举出的案例来看)兔子),给某些种族带来了长头型的细长头骨。

最后,鲜为人知的相关发育原理有时会发挥作用,例如肌肉发达和眶上脊强烈突出的情况。皮肤和头发的颜色明显相关,北美曼丹人的头发质地和颜色也是如此。 (68.卡特林先生指出(“北美印第安人”,第 3 版,1842 年,第 ip 49 卷),在曼丹人的整个部落中,大约十分之一或十二个成员,无论年龄大小,男女都有明亮的银灰色头发,这是遗传的。现在这种头发像马鬃毛一样粗糙而粗糙,而其他颜色的头发则细而柔软。)还有皮肤的颜色和散发的气味通过它,同样以某种方式连接起来。羊的品种与特定空间内的毛发数量和排泄孔的数量有关。 (69. 关于皮肤的气味,Godron,'Sur l'Espèce,' tom. ii. p. 217。关于皮肤的毛孔,Dr. Wilckens,'Die Aufgaben der Landwirth. Zootechnik,' 1869,s 7.) 如果我们可以从我们的家养动物的类比来判断,人类结构的许多改变可能都属于这种相关发展的原则。

我们现在已经看到,人类种族之间的外部特征差异不能以令人满意的方式通过生活条件的直接作用、部分的持续使用的影响或通过相关原理来解释。因此,我们不禁要问,人类极有可能造成的微小个体差异,在漫长的世代中是否通过自然选择而得以保留和扩大。但在这里我们立刻遇到了反对意见,认为只有有益的变异才能被保留下来。就我们所能判断的而言,尽管在这个问题上总是容易犯错,但人类种族之间的差异对人类来说没有任何直接或特殊的帮助。当然,智力和道德或社会能力必须排除在这一评论之外。人类种族之间所有外部差异的巨大差异同样表明它们不可能有多大重要性。因为如果它们很重要,那么它们早就被修复和保留,或者被消除了。在这方面,人类类似于那些被自然主义者称为千变万化或多态的形式,这些形式一直保持着极大的可变性,因为看起来,这些变化具有无关紧要的性质,并且因此逃脱了自然选择的作用。

迄今为止,我们在解释人类种族之间差异的所有尝试中都遇到了困惑。但仍然存在一个重要的机构,即性选择,它似乎对人类产生了强大的作用,就像对许多其他动物一样。我并不打算断言性选择会解释种族之间的所有差异。留下了无法解释的残余物,对此,我们只能说,出于我们的无知,随着个体不断出生,例如,头部稍圆或更窄,鼻子稍长或更短,这些细微的差异可能会变得固定如果诱导它们的未知机构在长期持续的交叉的帮助下以更恒定的方式行动,那么它们是统一的。这种变化属于临时类别,在我们的第二章中提到过,由于缺乏更好的术语,临时类别通常被称为自发的。我也不假装性选择的影响可以用科学精确的方式表明。但可以证明的是,如果人类没有被这个似乎对无数动物产生了强大作用的机构改造,这将是一个令人费解的事实。还可以进一步证明,人类种族之间的差异,如肤色、毛羽、特征形状等,可能是受到性选择影响的。但为了正确对待这个主题,我发现有必要通过整个动物界的审查。因此,我将其作为本书的第二部分。最后,我将回到人类,并在试图表明性选择对人类的改变程度之后,将对第一部分的各章进行简要总结。

赫胥黎教授关于人类和猿类大脑结构和发育的相似性和差异的注释

关于人类和猿类大脑结构差异的性质和程度的争论大约十五年前发生,至今尚未结束,尽管目前争论的主题是:和以前完全不一样了。人们最初以一种独特的执着断言和重申,所有猿类的大脑,甚至是最高等的猿类,都与人类的大脑不同,因为它们不存在像大脑半球后叶这样的显着结构,侧脑室角和小海马,包含在这些叶中,这在人类中非常明显。

但事实是,猿类的这三种结构与人类的大脑一样发达,甚至更好;所有灵长类动物(如果我们排除狐猴)的特征是这些部分发育良好,目前与比较解剖学中的任何命题一样有可靠的基础。此外,近年来,许多解剖学家都特别关注人类和高等猿类大脑半球表面出现的复杂脑沟和脑回的排列,他们都承认,他们的性格和他身上的模式一模一样。黑猩猩大脑中的每一个主回和沟都清晰地体现在人类大脑中,因此适用于其中一个的术语可以解释另一个。在这一点上没有任何意见分歧。几年后,Bischoff 教授出版了一本关于人和猿的大脑回旋的回忆录(70. 'Die Grosshirn-Windungen des Menschen;' 'Abhandlungen der K. Bayerischen Akademie,' B. x. 1868.);由于我这位博学的同事的目的当然不是要削弱猿类与人类在这方面的差异的价值,所以我很高兴引用他的话。

“猿类,尤其是红毛猩猩、黑猩猩和大猩猩,其组织结构与人类非常接近,比任何其他动物都更接近,这是众所周知的事实,没有人对此提出异议。仅从组织的角度来看这个问题,可能没有人会质疑林奈的观点,即人类应该仅仅作为一种特殊的物种而被置于哺乳动物和类​​人猿的首位。两者在所有器官中都表现出如此密切的亲和力,以至于需要最精确的解剖学研究才能证明这些差异确实存在。大脑也是如此。人类、红毛猩猩、黑猩猩、大猩猩的大脑,尽管存在所有重要差异,但彼此非常接近”(loc. cit. p. 101)。

因此,关于猿的大脑和人类的大脑在基本特征上的相似性,仍然没有任何争议;对于黑猩猩、猩猩和人类之间的惊人相似性,甚至在脑回和脑沟的排列细节上,也没有任何争议。大脑半球的。转向最高等猿类和人类大脑之间的差异,这些差异的性质和程度也不存在任何严重的问题。人们承认,人类的大脑半球绝对且相对地大于猩猩和黑猩猩的大脑半球;他的额叶较少被眼眶顶部向上突出所挖掘;一般来说,他的脑回和脑沟的分布不太对称,并且存在更多的继发性皱襞。人们承认,一般来说,人类的颞枕裂或“外垂直”裂,通常在猿类的大脑中非常明显地被标记出来,但标记却很微弱。但同样清楚的是,这些差异都不构成人类大脑和猿类大脑之间的明显界限。以人类大脑中的 Gratiolet 外部垂直裂隙为例,特纳教授评论道:(71.“从地形角度考虑人类大脑的卷积”,1866 年,第 12 页。)

“在一些大脑中,它看起来只是半球边缘的一个凹痕,但在另一些大脑中,它或多或少横向向外延伸了一段距离。我看到它在女性大脑的右半球向外移动超过两英寸;在另一个标本上,也是右半球,它向外行进十分之四英寸,然后向下延伸,直到半球外表面的下边缘。与大多数 Quadrumana 大脑中的显着差异相比,大多数人类大脑中这条裂缝的定义并不完美,这是由于前者存在某些表面的、明显的次级回旋,这些回旋将其桥接在连接顶叶和枕叶。第一个桥回离纵裂越近,顶枕外裂就越短”(loc. cit. p. 12)。

因此,Gratiolet 外部垂直裂隙的消失并不是人类大脑的一个恒定特征。另一方面,高等猿脑的全面发展并不是一个恒定的特征。因为,在黑猩猩中,一侧或另一侧的“桥接回旋”或多或少广泛地消除了外部垂直沟,这一点已被罗尔斯顿教授、马歇尔先生、布罗卡先生和特纳教授。在关于这个主题的一篇特别论文的结论中,后者写道:(72。特别是关于黑猩猩大脑中的桥接卷积的注释,“爱丁堡皇家学会论文集”,1865-6。)

“刚刚描述的黑猩猩大脑的三个样本证明,格拉蒂奥莱试图得出的概括是,第一个连接卷积完全不存在,第二个连接卷积被隐藏,这是黑猩猩大脑的本质特征。动物,绝不是普遍适用的。在这些细节中,只有一个样本的大脑遵循格拉蒂奥莱所表达的法则。至于上级桥接卷积的存在,我倾向于认为它已经存在于一个半球中,至少存在于这种动物的大部分大脑中,到目前为止,这些大脑已经被描绘或描述过。第二个桥接卷积的表面位置显然不太常见,并且我相信迄今为止仅在本次通信中记录的大脑(A)中看到过。先前的观察者在他们的描述中提到过两个半球盘旋的不对称排列,这在这些标本中也得到了很好的说明”(第 8、9 页)。

即使颞枕沟或外部垂直沟的存在是高等猿类和人类之间的区别标志,但由于扁鼻猿的大脑结构,这种独特特征的价值会变得非常值得怀疑。事实上,虽然颞枕骨是卡他林类人猿或旧大陆类人猿中最恒定的脑沟之一,但在新大陆类人猿中,颞枕骨从来没有非常发达。较小的扁鼻鱼则没有这种特征; Pithecia 的初级版本(73. Flower,“On the Anatomy of Pithecia Monachus”,“Proceedings of the Zoological Society”,1862 年);并且或多或少被 Ateles 中的桥接卷积所消除。

因此,在单个类群范围内可变的性状不可能具有很大的分类学价值。

进一步证实,人脑两侧卷积的不对称程度存在很大的个体差异;并且,在那些经过检查的布须曼人种个体中,两个半球的脑回和脑沟比欧洲人的大脑要简单得多,而且更加对称,而在黑猩猩的一些个体中,它们的复杂性和不对称性变得更加复杂和对称。值得注意的。在布罗卡(M. Broca)研究的年轻雄性黑猩猩的大脑中,情况尤其如此。 (《灵长类动物勋章》,第 165 页,图 11。)

再次,关于绝对大小的问题,可以确定最大和最小的健康人类大脑之间的差异大于最小的健康人类大脑和最大的黑猩猩或猩猩的大脑之间的差异。

此外,在一种情况下,红毛猩猩和黑猩猩的大脑与人类的大脑相似,但又不同于低等猿类,那就是存在两个白体,而犬类只有一个。

鉴于这些事实,我在 1874 年毫不犹豫地重复并坚持我在 1863 年阐明的主张:(74。“人类在自然中的地位”,第 102 页。)

“因此,就大脑结构而言,很明显,人类与黑猩猩或红毛猩猩的差异甚至比猴子与黑猩猩的差异还要小,而且与人类大脑相比,黑猩猩和人类大脑之间的差异几乎微不足道。介于黑猩猩大脑和狐猴大脑之间。”

在我提到的那篇论文中,比肖夫教授并没有否认这一说法的第二部分,但他首先发表了一句无关紧要的话:如果猩猩和狐猴的大脑有很大不同,那并不奇怪;其次,继续断言,“如果我们依次将人的大脑与猩猩的大脑进行比较;这个大脑和黑猩猩的大脑一样;与大猩猩、长臂猿、长臂猿、犬头猿、鹿猿、猕猴、Cebus、Callithrix、狐猴、Stenops、Hapale 等动物相比,我们不会遇到更大的、甚至同样大的突破。正如我们在人类大脑和猩猩或黑猩猩大脑之间发现的那样,卷积的发展程度。”

对此,我首先回答,无论这个断言是真是假,它与“人在自然中的地位”中阐明的命题没有任何关系,该命题不仅仅指的是卷积的发展,而是指的是整个大脑。如果 Bischoff 教授不厌其烦地参考第 96 页。事实上,在他批评的著作第XNUMX页中,他会发现以下段落:“这是一个值得注意的情况,尽管就我们目前的知识而言,在猿猴大脑的一系列形式中存在一个真正的结构断裂,这种差距并不存在于人类和类人猿之间,而是存在于低等和最低等猿猴之间,或者换句话说,存在于新旧大陆猿类、猴子和狐猴之间。事实上,每只经过检查的狐猴,从上方都可以看到部分小脑。及其后叶,以及包含的后角和小海马,或多或少是不完整的。相反,每只狨猴、美洲猴、东大陆猴、狒狒或类人猿的小脑完全被大脑叶隐藏在后面,并拥有一个大的后角和发育良好的小海马体。

该声明严格准确地描述了其发表时已知的情况;在我看来,后来发现合趾猴和嚎叫猴的后叶发育相对较小,这一点并没有明显减弱。尽管这两个物种的后叶非常短暂,但没有人会假装它们的大脑在某种程度上与狐猴的大脑相似。如果我们不像比肖夫教授最不负责任的做法那样将哈帕勒从其自然位置中剔除,而是写下他选择提及的一系列动物,如下:智人、猿猴、穴居人、长臂猿、长猿猴、犬头猴、鹿猴、猕猴、 Cebus、Callithrix、Hapale、Lemur、Stenops,我冒昧地重申,这个系列中的伟大突破发生在 Hapale 和 Lemur 之间,并且这个突破比该系列中任何其他两个学期之间的突破要大得多。毕肖夫教授忽略了这样一个事实:早在他写作之前,格拉蒂奥莱特就曾建议将狐猴与其他灵长类动物区分开来,因为它们的大脑特征存在差异。弗劳尔教授在描述爪哇懒猴的大脑过程中做出了以下观察:(75.《动物学会汇刊》,第 1862 卷。)

“尤其值得注意的是,在后叶的发育过程中,在那些通常被认为在其他方面接近这个家族的猴子中,并没有类似于狐猴的短半球大脑,即。阔叶草族的低等成员。”

就成人大脑的结构而言,在过去的十年里,通过如此众多的研究者的研究,我们的知识有了非常可观的补充,这完全证明了我在 1863 年所做的陈述。但有人说,尽管承认人类和猿类的成年大脑之间存在相似性,但实际上它们还是有很大不同,因为它们在发育模式上表现出根本的差异。如果这种发展的根本差异确实存在的话,没有人会比我更愿意承认这一论点的力量。但我否认它们确实存在。相反,人类和猿类的大脑发育具有根本的一致性。

格拉蒂奥莱特提出了这样一种说法:猿类的大脑发育与人类的大脑发育存在根本性的差异,即:在猿类中,首先出现的脑沟位于大脑半球的后部区域,而在人类胎儿中,脑沟首先在额叶上可见。 (76. Chez tous les singes, les plis postérieurs sedevelopmentpent les primes; les plis antérieurs sedevelopmentpent plus tard, aussi la vertèbre occipitale et la parietale sont-ellesrelativement tres-grandes chez le foetus. L'Homme présente une excerptable quant a l'époque de l'apparition des plis frontaux, qui sont les primes indiqués; mais le développement General du lobe frontal, 设想与子卷融洽的关系,适合 les mêmes lois que dans les singes: Gratiolet, 'Mémoire sur les plis cérèbres de l'Homme et des Primateaux,第 39 页,表 iv,图 3。)

这一一般性陈述基于两项观察,其中一项是对即将出生的长臂猿的观察,其中后回“发育良好”,而额叶的那些“几乎没有指示”(77。Gratiolet 的话是(loc) . 引文第 39 页):“Dans le fetus dont il s'agit les plis cérébraux posterieurs sont biendevelopmentpés, tandis que les plis du lobe frontal sont a peine indiqués。”然而,这个数字(图四,图 3) ),清楚地显示了罗兰多的裂隙和额沟之一。尽管如此,阿利克斯先生在他的“Notice sur les travaux anthropologiques de Gratiolet”(“Mem. de la Societé d'Anthropologie de Paris”,1868)中,第 32 页),这样写道:“Gratiolet a eu entre les mains le cerveau d'un fetus de Gibbon, single eminemment superérieur, ettellement rapproché de l'orang, que des natureistes tres-compétents l'ont range parmi les anthropoides. M . Huxley, par example, n'hesite pas sur ce point. Eh bien, c'est sur le cerveau d'un fetus de Gibbon que Gratiolet a vu LES CIRCONVOLUTIONS DU LOBE TEMPORO-SPHENOIDAL DÉJÀ DEVELOPPÉES LORSQU'IL N'EXISTENT PAS ENCORE DE PLIS sur le Lobe Frontal。 Il etait donc bien autorisé a dire que, chez l'homme les cirvolvs apparaissent d'a en w, tandis que chez les singes elles se developmentpent d'w en a.”),另一个是人类胎儿在 22 号或子宫妊娠第 23 周,Gratiolet 注意到岛叶被暴露,但尽管如此,“des incisures sement de lobe anterieur, une scissure peu profonde indique la seperation du lobe occipital, tres-reduit, d'ailleurs dès cette époque”。 Le Reste de la Surface Cérébrale est encore Absolument lisse。”

图 1 中给出了该大脑的三个视图。引用的作品的第 2、3、XNUMX 部分显示了半球的上视图、侧视图和下视图,但没有显示内视图。值得注意的是,该图决不能证实格拉蒂奥莱的描述,因为半球面部后半部分的裂痕(前颞裂)比前半部分模糊显示的裂痕更加明显。如果这个数字是正确的,它绝不能证明格拉蒂奥莱的结论是正确的:“Il ya donc entre ces cerveaux [Callithrix 和 Gibbon 的那些] et celui du fetus human une différence foldamental。 Chez celui-ci,longtemps avant que les plis temporaux apparaissent,les plis frontaux,ESSAYENT d'exister。”

然而,自 Gratiolet 时代以来,Schmidt、Bischoff、Pansch (78. 'Ueber dietypysche Anordnung der Furchen und Windungen auf den Grosshirn-Hemisphären des Menschen und der Affen,“Archiv für Anthropologie”,iii. 1868.),尤其是埃克(79.“Zur Entwicklungs Geschichte der Furchen und Windungen der Grosshirn- Hemisphären im Fetus des Menschen”,“Archiv für Anthropologie”,iii.)。 1868),他的作品不仅是关于这个主题的最新回忆录,而且是迄今为止最完整的回忆录。

他们的调查最终结果可归纳如下:

1. 在人类胎儿中,侧裂是在子宫妊娠的第三个月过程中形成的。在这个阶段,以及第四个月,大脑半球光滑且圆形(侧裂凹陷除外),并且向后突出远远超过小脑。

2. 脑沟,确切地说,是在胎儿生命的第四个月末到第六个月月初之间开始出现的,但埃克小心地指出,不仅是时间,而且是顺序,他们的外表存在很大的个体差异。然而,无论如何,额沟或颞沟都不是最早的。

事实上,第一个出现的,位于半球的内表面(因此毫无疑问,格拉蒂奥莱,他似乎没有检查过他胎儿的那张脸,忽略了它),并且要么是内垂线(枕顶骨),要么是内垂线(枕顶骨),或距状沟,这两者靠得很近,最终彼此相遇。一般来说,枕顶叶是两者中较早的一个。

3. 在这个时期的后半部分,另一个沟,即“后顶叶”或“罗兰多裂”发育出来,随后在第六个月的过程中,额叶的另一个主沟发育出来。 、顶叶、颞叶和枕叶。然而,没有明确的证据表明其中一个经常出现在另一个之前。值得注意的是,在埃克描述和描绘的时期的大脑中(loc.cit.pp.212-213,Taf.II,图1、2、3、4),前颞沟(剪状)平行脑裂)是猿类大脑的特征,即使不是比罗兰多裂更发达,也比罗兰多裂更明显,而且比额沟明显得多。

就目前的事实而言,在我看来,胎儿大脑中脑沟和脑回的出现顺序与一般进化论完全一致,并且认为人类是从某些物种进化而来的。类似猿的形态;尽管毫无疑问,这种形态在许多方面都不同于现存的灵长类动物。

半个世纪前,冯·贝尔告诉我们,在它们的发展过程中,同类动物首先表现出它们所属的更大群体的特征,然后逐渐呈现出那些限制它们的特征。它们的科、属和种;同时,他证明了高等动物的发育阶段与任何低等动物的成年状况都不相同。说青蛙经历了鱼的状况是完全正确的,因为蝌蚪在其生命的某个时期具有鱼的所有特征,如果再进一步,就必须归入鱼类之中。但同样真实的是,蝌蚪与任何已知的鱼类都非常不同。

同样,第五个月的人类胎儿的大脑可以正确地说,不仅是猿的大脑,而且是Arctopithecine或类狨猴的大脑;因为它的半球有巨大的后龙虾,除了侧裂和距状沟外没有脑沟,呈现出仅在大猩猩灵长类群体中发现的特征。但正如格拉蒂奥莱特所说,同样正确的是,在其广泛开放的侧裂中,它与任何实际狨猴的大脑都不同。毫无疑问,它与狨猴高级胎儿的大脑更加相似。但我们对狨猴大脑的发育一无所知。在扁鼻属本体中,我所熟悉的唯一观察结果来自潘什(Pansch),他在胎儿 Cebus Apella 的大脑中发现,除了外侧裂和深距裂之外,只有一条非常浅的前颞裂( Gratiolet 的剪刀平行线)。

现在,这一事实,再加上前颞沟存在于像赛米尔这样的扁鼻类动物中,而这些扁鼻动物的大脑半球外部的前半部仅存在颞沟的痕迹,或者根本没有,毫无疑问,因此,就目前而言,这为支持格拉蒂奥莱的假设提供了合理的证据,即在扁鼻类动物的大脑中,后脑沟出现在前脑沟之前。但是,这绝不意味着适用于扁鼻科的规则也适用于狭鼻科。我们没有任何关于犬类大脑发育的信息;至于拟人类,除了已经提到过的长臂猿出生时大脑的描述外,什么也没有。目前,没有任何证据表明黑猩猩或猩猩大脑的脑沟与人类大脑的脑沟排列顺序不同。

格拉蒂奥莱以格言开头:“Il estangereux dans les sciences de conclure trop vite”。我担心,当他在自己的著作中讨论人类和猿类之间的差异时,他一定已经忘记了这条听起来很合理的格言。毫无疑问,这位为正确理解哺乳动物大脑作出的最杰出贡献之一的杰出作者,如果他能从探究的进步中受益的话,他会是第一个承认他的数据不足的人。不幸的是,他的结论被那些没有能力理解其基础的人所利用,作为支持蒙昧主义的论据。 (80. 例如,M. l'Abbe Lecomte 在他的可怕的小册子《Le Darwinisme et l'origine de l'Homme》中,1873 年。)

但值得注意的是,无论格拉蒂奥莱关于颞沟和额沟出现的相对顺序的假设是对还是错,事实仍然存在;在颞沟或额沟出现之前,人类胎儿大脑呈现出仅在最低等灵长类动物中发现的特征(狐猴除外);如果人类是由与其他灵长类动物相同的形态逐渐变化而来的,那么这正是我们所期望的情况。

第二部分 • 性选择

第八章 •25,400字
性选择原理

第二性特征——性选择——行动方式——雄性过多——一夫多妻制——通常只有雄性通过性选择而改变——雄性的渴望——雄性的变异性——雌性的选择——性选择与自然选择的比较——遗传,生命相应时期、一年中相应季节,并受性别限制——几种遗传形式之间的关系——一性和幼体不通过性选择而改变的原因——两性比例数的补充整个动物界——与自然选择相关的性别比例。

对于雌雄分离的动物来说,雄性的生殖器官必然与雌性不同。这些是主要的性特征。但两性在亨特所谓的第二性征上常常有所不同,这些特征与繁殖行为没有直接关系。例如,雄性拥有某些感觉或运动器官,而雌性则完全缺乏这些器官,或者具有更高度发达的器官,以便他可以轻松地找到或接近她;或者,雄性有特殊的抓握器官来牢牢地抓住她。后面这些器官的种类无限多样,逐渐发展为通常被列为初级的器官,在某些情况下几乎无法与它们区分开来。我们在雄性昆虫腹部顶端的复杂附肢中看到了这种情况的例子。除非我们确实将“主要”一词限制在生殖腺上,否则几乎不可能决定哪个应该被称为主要的,哪个应该被称为次要的。

雌性与雄性的不同之处通常在于其拥有滋养或保护幼崽的器官,例如哺乳动物的乳腺和有袋动物的腹袋。在某些情况下,雄性也拥有雌性所缺乏的相似器官,例如某些雄性鱼的卵子容器,以及某些雄性青蛙暂时发育的器官。大多数雌性蜜蜂都有一种特殊的装置来收集和携带花粉,它们的产卵器被改造成刺,以保护幼虫和群体。类似的例子还有很多,但这里与我们无关。然而,还有其他性别差异与主要生殖器官完全无关,而我们更特别关心的是这些差异,例如男性的体型更大、力量更大、好斗性、进攻武器或防御手段对抗对手,他华丽的色彩和各种装饰,他的歌曲力量,以及其他类似的角色。

除了上述的第一性和第二性差异之外,一些动物的雄性和雌性在结构上存在差异,这些差异与不同的生活习性有关,而与生殖功能完全无关或仅间接有关。因此,某些苍蝇(库蚊科和虻科)的雌性是吸血动物,而以花为食的雄性则没有下颌骨。 (1. Westwood,《现代昆虫分类》,第 ii 卷,1840 年,第 541 页。对于下面提到的关于 Tanais 的陈述,我感谢 Fritz Muller。)某些飞蛾和某些甲壳类动物的雄性(例如Tanais)有不完美的、闭合的嘴,并且不能进食。某些蔓足类的互补雄性以雌性或雌雄同体的形式像附生植物一样生活,并且没有嘴和可抓握的四肢。在这些情况下,雄性已被改造,并失去了雌性拥有的某些重要器官。在其他情况下,是雌性失去了这些部分。例如,雌性萤火虫没有翅膀,许多雌性飞蛾也是如此,其中一些从不离开茧。许多雌性寄生甲壳类动物失去了游泳腿。在某些象甲虫(象甲科)中,雄性和雌性的喙或口鼻部的长度存在很大差异(2. Kirby 和 Spence,“昆虫学导论”,第 iii 卷,1826 年,第 309 页。) ;但这一点以及许多类似差异的含义根本不被理解。与不同生活习惯相关的两性结构差异通常仅限于低等动物;但有少数鸟类的雄性喙与雌性不同。在新西兰的胡亚族中,这种差异非常大,我们从布勒博士那里听到(3.“新西兰鸟类”,1872年,第66页),雄性用他强壮的喙将昆虫幼虫凿出来雌性用她更长、更弯曲、更柔韧的喙探测较软的部分:因此它们互相帮助。在大多数情况下,两性之间的结构差异或多或少与物种的繁殖直接相关:因此,雌性需要滋养大量卵子,比雄性需要更多的食物,因此需要特殊的手段来获取食物。它。雄性动物的寿命很短,可能会因为不使用而失去获取食物的器官,但不会造成任何损害;但他会保持自己的运动器官处于完美状态,以便能够接触到雌性。另一方面,如果雌性逐渐养成使这些能力变得无用的习惯,她可能会安全地失去飞行、游泳或行走的器官。

然而,我们在这里只关心性选择。这取决于某些个体仅在繁殖方面相对于同性别和同物种的其他个体的优势。正如上述情况,当两种性别在结构上与不同的生活习惯有关时,它们无疑是通过自然选择和仅限于同一性别的遗传而改变的。因此,主要性器官以及那些用于滋养或保护幼体的器官也受到同样的影响。因为那些在其他条件不变的情况下,那些最能生育或养育后代的人,会留下最多的人来继承他们的优势。而那些未能很好地生育或养育后代的人,却很少会留下来继承他们较弱的力量。由于雄性必须找到雌性,因此他需要感觉和运动器官,但如果这些器官对于生命的其他目的是必需的(通常情况如此),那么它们将是通过自然选择而发展起来的。当雄性找到雌性时,有时他绝对需要抓握器官来抓住她。因此,华莱士博士告诉我,某些飞蛾的雄性如果跗骨或脚被折断,就无法与雌性结合。许多海洋甲壳类动物的雄性在成年后,其腿和触角都会以一种特殊的方式进行改造,以便抓住雌性。因此,我们可能怀疑,正是因为这些动物受到公海波浪的冲刷,它们才需要这些器官来繁殖它们的种类,如果是这样,它们的发育就是普通或自然选择的结果。出于同样的目的,一些等级极低的动物已被改造。因此,某些寄生蠕虫的雄性在完全长大后,其身体末端部分的下表面像锉刀一样粗糙,因此它们盘绕并永久地固定住雌性。 (4. M. Perrier 提出这一案例(《科学评论》,1 年 1873 月 865 日,第 XNUMX 页)作为对性选举信仰的致命一击,因为他认为我将性别之间的所有差异归因于性选择。因此,这位杰出的博物学家,像许多其他法国人一样,甚至没有费力去理解性选择的首要原则。一位英国博物学家坚持认为,某些雄性动物的扣子不可能是通过性选择的选择而发展出来的。女性!如果我没有听到这句话,我就不会认为有人读过这一章,也不会认为我认为女性的选择与抓握器官的发育有关。男性。)

当两性的生活习惯完全相同,并且男性的感觉器官或运动器官比女性更加发达时,这些器官的完善可能对于男性寻找女性来说是必不可少的;但在绝大多数情况下,它们只会让一只雄性比另一只雄性更具优势,因为只要有足够的时间,天赋较差的雄性就会成功与雌性配对。从女性的结构来看,她们在所有其他方面都同样能够很好地适应她们的日常生活习惯。因为在这种情况下,雄性获得了目前的结构,不是因为在生存斗争中更适合生存,而是因为获得了相对于其他雄性的优势,并且将这种优势仅传递给了它们的雄性后代,所以性选择必须这里已经开始行动了。正是这种区别的重要性使我将这种选择形式称为性选择。同样,如果雄性的抓握器官为雄性提供的主要服务是在其他雄性到达之前或在受到其他雄性攻击时防止雌性逃跑,那么这些器官将通过性选择而完善,即通过性选择某些个人相对于其竞争对手获得的优势。但在大多数情况下,不可能区分自然选择和性选择的影响。整章都充满了关于两性在感觉、运动和抓握器官方面差异的细节。然而,由于这些结构并不比其他适合日常生活目的的结构更有趣,因此我将几乎完全忽略它们,只在每个类别下给出几个实例。

还有许多其他的结构和本能,一定是通过性选择而发展起来的——比如雄性与对手战斗和赶走对手的进攻武器和防御手段——它们的勇气和好斗性——它们的各种装饰品——它们的发明创造。用于产生声乐或器乐的腺体,以及用于散发气味的腺体,后者中的大多数结构仅用于引诱或兴奋雌性。很明显,这些特征是性的结果,而不是普通选择的结果,因为没有武装、没有装饰或没有吸引力的雄性在生命之战中同样会取得成功,并留下大量后代,但如果没有更优秀的雄性存在的话。我们可以推断,情况确实如此,因为雌性没有武装,没有任何装饰,能够生存并繁衍后代。刚才提到的第二性特征,将在接下来的章节中进行充分讨论,因为在许多方面都很有趣,但尤其取决于任一性别个体的意愿、选择和竞争。当我们看到两只雄鸟争夺雌鸟的占有权,或者几只雄鸟展示它们华丽的羽毛,在一群雌鸟面前表演奇怪的滑稽动作时,我们不能怀疑,尽管它们受到本能的引导,但它们知道自己在做什么,并有意识地发挥自己的精神和体力。

正如人类可以通过选择在驾驶舱中获胜的鸟类来改进斗鸡的品种一样,最强壮、最有活力的雄性,或者那些拥有最好武器的雄性,似乎在自然界中占了上风。导致了自然品种或物种的改良。在反复的致命竞争中,轻微程度的变异会带来一些优势,无论多么轻微,对于性选择的工作来说就足够了。可以肯定的是,第二性征是非常多变的。正如人类可以根据自己的品味标准,赋予雄性家禽美丽,或者更严格地说,可以修改其亲本物种最初获得的美丽,可以赋予塞布赖特矮脚鸡一种新的、优雅的羽毛,一种直立而奇特的姿态。 ——因此,在自然状态下,雌鸟似乎会通过长期选择更具吸引力的雄鸟,增加它们的美丽或其他吸引人的品质。毫无疑问,这意味着女性具有辨别力和品味,这乍一看似乎是极不可能的。但我希望通过下文所列举的事实,能够证明女性确实拥有这些力量。然而,当说低等动物有美感时,我们决不能认为这种美感可以与有教养的人的美感相提并论,因为他的思想多种多样、复杂。更公正的比较是动物对美的品味和最低级野蛮人的审美品味,后者欣赏并用任何辉煌、闪闪发光或好奇的物体来装饰自己。

由于我们对几个问题的无知,性选择起作用的确切方式有些不确定。尽管如此,如果那些已经相信物种可变性的博物学家阅读以下章节,我想他们会同意我的观点,即性选择在有机世界的历史中发挥了重要作用。可以肯定的是,几乎所有的动物中,雄性之间都会为了占有雌性而进行斗争。这个事实是如此臭名昭著,以至于没有必要举例。因此,雌性有机会从数名雄性中选择一个,前提是她们的智力足以做出选择。在许多情况下,特殊情况往往会使雄性之间的斗争变得特别激烈。因此,候鸟中的雄性通常会先于雌性到达繁殖地,因此许多雄性都准备好争夺每一个雌性。詹纳·威尔先生告诉我,捕鸟者声称夜莺和黑帽总是如此,对于后者,他本人可以证实这一说法。

布莱顿的斯韦斯兰先生在过去四十年里一直习惯于在候鸟首次抵达时捕捉它们,他从未见过任何物种的雌性先于雄性到达。有一年春天,他射杀了三十九只雄性雷鹡鸰(Budytes Raii),然后才看到一只雌性。古尔德先生通过解剖那些最先到达这个国家的鹬,确定雄性先于雌性出现。同样的情况也适用于美国的大多数候鸟。 (5. JA Allen,关于“佛罗里达州的哺乳动物和冬季鸟类”,《比较动物学通报》,哈佛大学,第 268 页。)我们河流中的大多数雄性鲑鱼在从海里上来时,已经准备好在雌性之前繁殖。青蛙和蟾蜍似乎也是如此。在所有昆虫大纲中,雄性几乎总是最先从蛹状态中出来,因此,在看到雌性之前,它们通常会大量繁殖一段时间。 (6. 即使对于那些雌雄分离的植物,雄花通常也先于雌花成熟。正如 CK Sprengel 首先表明的那样,许多雌雄同体植物是雌雄同体的;也就是说,它们的雄性和雌性器官在成熟时还没有准备好。在这种花中,花粉通常在柱头之前成熟,但也有雌性器官先于雌性器官成熟的特殊情况。) 造成雄性和雌性之间这种差异的原因雌性在到达和成熟时期的表现是非常明显的。那些每年首先迁徙到任何国家的雄性,或者在春天最先准备好繁殖的雄性,或者最渴望繁殖的雄性,将留下最多数量的后代;这些人往往会继承相似的本能和体质。必须牢记的是,不可能对雌性性成熟的时间进行实质性改变,同时又不干扰幼体的生产时期——这一时期必须由季节决定。今年的。总的来说,毫无疑问,对于几乎所有雌雄分离的动物来说,雄性之间为了占有雌性而不断发生斗争。

我们在性选择方面的困难在于理解,那些征服了其他雄性的雄性,或者那些对雌性最具吸引力的雄性,是如何比那些被击败的、吸引力较差的竞争对手留下更多数量的后代来继承自己的优越性的。除非这个结果确实成立,否则赋予某些雄性相对于其他雄性的优势的特征就无法通过性选择来完善和增强。当两性数量完全相等时,天赋最差的雄性(除非一夫多妻制盛行)最终会找到雌性,并留下与天赋最好的雄性一样多的后代,这些后代也适合他们的一般生活习惯。根据各种事实和考虑,我以前推断,对于大多数第二性征发育良好的动物来说,雄性的数量大大超过雌性;但这并不总是正确的。如果雄性与雌性的比例是二比一,或者三比二,甚至更低一些,那么整个事情就简单了;因为装备更好或更有吸引力的雄性会留下最多数量的后代。但在尽可能地调查了男女人数比例后,我认为一般不存在人数上的严重不平等。在大多数情况下,性选择似乎通过以下方式发挥了作用。

让我们以任何物种为例,例如一只鸟,将居住在一个地区的雌性分成两个相等的身体,一个由较有活力和营养较好的个体组成,另一个由较不活跃和健康的个体组成。毫无疑问,前者将在春天先于其他物种准备好繁殖。这是多年来密切关注鸟类习性的詹纳·威尔先生的观点。毫无疑问,最有活力、营养最好、最早的繁殖者平均会成功地养育出最多数量的优秀后代。 (7. 这是一位经验丰富的鸟类学家提供的有关后代性格的极好证据。JA Allen 先生在谈到意外破坏后的后来的雏鸟时(“佛罗里达州东部的哺乳动物和冬季鸟类”,第 229 页)第一个的研究人员说,这些“被发现比本季节早些时候孵化的鸟更小,颜色更浅。在每年饲养几窝的情况下,作为一般规则,早期窝的鸟在各方面似乎都一样最完美、最有活力。”)正如我们所见,雄性通常比雌性先准备好繁殖;最强壮的,在某些物种中是武装最精良的雄性,赶走较弱的;然后前者会与更有活力、营养更好的雌性结合,因为它们是最先繁殖的。 (8. 赫尔曼·穆勒(Hermann Müller)对每年第一个从蛹中破茧而出的雌性蜜蜂也得出了同样的结论。请参阅他的杰出文章“Anwendung der Darwin'schen Lehre auf Bienen”,“Verh. d.”。 V. Jahrg.' xxix. p. 45.) 如此精力充沛的配对肯定会比迟钝的雌性养育更多数量的后代,假设两性在数量上是平等的,那么雌性将被迫与被征服的、实力较弱的雄性联合起来。这就是在连续几代人的过程中想要增加男性的体型、力量和勇气,或者改进他们的武器的全部内容。

但在很多情况下,征服了对手的雄性并没有获得雌性的占有,无论后者的选择如何。动物的求爱绝非想象中那么简单和短暂。雌性最兴奋,或者更喜欢与那些装饰性更强的雄性,或者那些唱歌最好的,或者表演最好滑稽动作的雄性配对;但很明显,它们同时更喜欢精力充沛、活泼的雄性,这一点在某些情况下已被实际观察所证实。 (9. 关于家禽,我已经收到了这方面的信息,下文将予以提供。即使是终生配对的鸟类,例如鸽子,正如我从詹纳·威尔先生那里听到的那样,雌性也会抛弃她如果他受伤或变得虚弱,就交配。)因此,最先繁殖的更有活力的雌性将有许多雄性的选择;尽管他们可能并不总是选择最强壮或武装最好的人,但他们会选择那些精力充沛、武装精良、在其他方面最有吸引力的人。因此,如上所述,这种早期配对的两性在抚养后代方面都比其他性别更有优势。显然,在漫长的世代中,这不仅足以增加雄性的力量和战斗力,而且还增加了它们的各种装饰品或其他吸引力。

在雄性选择特定雌性的相反且更为罕见的情况下,很明显,那些最有活力并征服了其他雌性的雌性将拥有最自由的选择;而那些雄性选择特定雌性的情况则更为罕见。几乎可以肯定,他们会选择精力充沛且有吸引力的女性。这样的配对在抚养后代方面将具有优势,尤其是如果雄性有能力在交配季节像某些高等动物那样保护雌性,或者帮助雌性抚养幼崽。如果每个性别都偏爱并选择某些异性,同样的原则也适用。假设他们不仅选择了更有魅力的人,而且还选择了更有活力的人。

两性人口比例

我说过,如果雄性的数量比雌性多得多,性选择就会是一件简单的事情。因此,我被引导尽可能多地调查动物的两种性别之间的比例。但材料匮乏。我在这里仅对结果进行简要摘要,保留细节以供补充讨论,以免干扰我的论证过程。只有家养动物才能提供确定出生比例的方法;但没有为此目的专门保存任何记录。然而,通过间接的方式,我收集了大量的统计数据,从中看来,我们大多数家养动物的性别在出生时几乎是平等的。因此,在 25,560 年里记录了 99.7 匹赛马的出生,其中雄性出生与雌性出生的比例为 100:6878。在灵缇犬中,这种不平等比任何其他动物都更大,在 110.1 年内出生了 100 匹赛马。 ,男性生育数与女性生育数为 104.5 比 108.9。然而,在某种程度上,推断自然条件下的这一比例与驯化条件下的这一比例是否相同,在某种程度上是值得怀疑的。因为条件的微小且未知的差异会影响性别比例。因此,就人类而言,英国的男性出生率为 120,俄罗斯为 100,利沃尼亚的犹太人为 90,女性出生率为 99。但我将在本章的补充中再次讨论男性出生过多这一奇怪的问题。然而,在好望角,几年来出生的欧洲血统男孩的比例在 100 到 XNUMX 比 XNUMX 之间。

就我们目前的目的而言,我们不仅关心出生时的性别比例,而且还关心成熟时的性别比例,这又增加了另一个怀疑因素。因为众所周知的事实是,对于男性来说,在出生前或出生期间以及婴儿期头两年内死亡的男性人数远远多于女性。几乎可以肯定,雄性羔羊也是如此,其他一些动物也可能如此。有些物种的雄性通过打斗互相残杀;或者他们互相驱赶,直到变得非常憔悴。它们还必须经常面临各种危险,同时四处游荡,热切地寻找雌性。在许多鱼类中,雄性比雌性小得多,人们相信它们经常被雌性或其他鱼类吞食。有些鸟类的雌性似乎比雄性更早死亡。它们也可能在筑巢或照顾幼崽时被摧毁。对于昆虫来说,雌性幼虫通常比雄性幼虫大,因此更容易被吃掉。在某些情况下,成熟的雌性比雄性更不活跃,动作也更慢,无法很好地逃离危险。因此,对于处于自然状态的动物,我们只能依靠单纯的估计来判断成熟时的性别比例;除非不平等现象非常明显,否则这种说法不太可信。然而,就可以形成的判断而言,我们可以从补充中给出的事实得出结论,一些少数哺乳动物、许多鸟类、一些鱼类和昆虫的雄性数量远多于雌性。

性别比例在连续几年中略有波动:因此,对于赛马来说,每 100 匹母马出生的公马从一年的 107.1 匹到另一年的 92.6 匹不等,而灵缇犬则从 116.3 匹到 95.3 匹不等。但如果在比英格兰更广阔的地区统计出更多的数字,这些波动可能就会消失;即使如此,也不足以在自然状态下产生有效的性选择。然而,就少数野生动物而言,如补充材料所示,这些比例似乎在不同季节或不同地点的波动程度足以导致这种选择。因为应该指出的是,那些能够征服竞争对手或对雌性最具吸引力的雄性在某些年份或某些地点获得的任何优势都可能会遗传给后代,而不会随后被继承。被淘汰。在随后的季节里,由于性别平等,每个雄性都能够获得雌性,先前产生的更强壮或更具吸引力的雄性仍然至少有与较弱或不太有吸引力的雄性一样好的留下后代的机会。

一夫多妻制

一夫多妻制的做法所导致的结果与性别数量实际不平等所产生的结果相同;因为如果每个雄性都拥有两个或更多雌性,许多雄性就无法配对;而后者肯定会是较弱或较不有吸引力的个体。许多哺乳动物和少数鸟类是一夫多妻制的,但对于属于下层阶级的动物,我没有发现这种习惯的证据。这些动物的智力也许不足以引导它们收集和守护一窝雌性。一夫多妻制与第二性征的发展之间存在着某种关系,这似乎几乎是肯定的。这支持了这样一种观点,即雄性的数量优势将非常有利于性选择的作用。然而,许多严格实行一夫一妻制的动物,尤其是鸟类,表现出强烈的第二性征。而一些一夫多妻制的动物则不具有这样的特征。

我们将首先简要介绍哺乳动物,然后转向鸟类。 大猩猩似乎是一夫多妻制,雄性与雌性有很大不同。一些狒狒也是如此,它们生活在群体中,成年雌性狒狒的数量是雄性狒狒的两倍。 在南美洲,Mycetes caraya 在颜色、胡须和发声器官方面表现出明显的性别差异;雄性通常与两到三个妻子生活在一起:雄性 Cebus capucinus 与雌性有所不同,似乎是一夫多妻制。 (10。 关于大猩猩、萨维奇和怀曼,《波士顿自然历史杂志》,卷。 v. 1845-47,第。 423. 关于犬头蛇,Brehm,“Thierleben”,B. i. 1864,第 77. 关于霉菌,Rengger,“Naturgeschichte der Säugethiere von Paraguay”,1830 年,ss。 14,20。 关于塞布斯,布雷姆,同上。 s. 108.) 对于大多数其他猴子来说,人们对这个头知之甚少,但有些物种是严格的一夫一妻制。 反刍动物是一夫多妻制的动物,它们比几乎所有其他哺乳动物群体更频繁地表现出性别差异。这一点很适用,尤其是在他们的武器上,而且在其他角色上也是如此。 大多数鹿、牛和羊都是一夫多妻制。大多数羚羊也是如此,尽管有些羚羊是一夫一妻制的。 安德鲁·史密斯爵士在谈到南非的羚羊时表示,在大约十几只羚羊群中,很少有超过一只成熟的雄性羚羊。 亚洲羚羊赛加羚羊似乎是世界上最无节制的一夫多妻制。对于帕拉斯 (11. 帕拉斯,“Spiilegia Zoolog.,Fasc.”十二. 1777。 29. 安德鲁·史密斯爵士,《S 动物学插图》 非洲,1849 年,图版。 29日,在Kobus上。 欧文,在他的《脊椎动物解剖学》(第一卷)中。 III。 1868。 633)给出了一张表格,顺便显示了哪种羚羊是群居的。)指出雄性羚羊赶走了所有竞争对手,并聚集了一群大约一百只雌性和孩子在一起;雌性无角,毛发较柔软,但在其他方面与雄性没有太大区别。 福克兰群岛和西部北部各州的野马。 美国实行一夫多妻制,但除了体型较大和身体比例较大外,与母马的区别不大。 野猪在其巨大的獠牙和其他一些特征上表现出明显的性特征。 在欧洲和印度,除繁殖季节外,他过着独居的生活。但正如 W. 艾略特在印度有很多机会观察这种动物,他在这个季节与几只雌性交配。 这在欧洲是否有效尚存疑问,但有一些证据支持。 成年雄性印度象和野猪一样,大部分时间都是在孤独中度过。但作为博士 坎贝尔表示,与其他人在一起时,“很少会发现不止一只雄性与一整群雌性在一起”;较大的雄性会驱逐或杀死较小和较弱的雄性。 雄性与雌性的不同之处在于其巨大的獠牙、更大的体型、力量和耐力。这些方面的差异如此之大,以至于雄性捕获后的价值比雌性高五分之一。 (12。 Dr. 坎贝尔,在“Proc。 动物园。 苏格拉底。” 1869,p。 138. 另请参阅 Lieut 的一篇有趣的论文。 约翰斯通,《孟加拉亚洲学会会议记录》,1868 年 XNUMX 月。)其他厚皮动物的性别差异很小或根本没有差异,而且据所知,它们不是一夫多妻制的。 我也没有听说过耳翅目、齿目、食虫目和啮齿目中的任何物种是一夫多妻制的,除了啮齿目动物中,根据一些捕鼠者的说法,普通老鼠与几只雌性生活在一起。 然而,一些树懒(Edentata)的两性在其肩部某些毛发的特征和颜色上有所不同。 (13。 Dr. 格雷,《自然历史年鉴和杂志》,1871 年,第 XNUMX 页。 302.) 许多种类的蝙蝠(蝙蝠目)都表现出明显的性别差异,主要是雄性拥有有气味的腺体和育儿袋,而且它们的颜色较浅。 (14。 见博士。 多布森 (Dobson) 在《动物学会学报》上发表的优秀论文,1873 年,第 XNUMX 页。

据我从安德鲁史密斯爵士那里听说,南非的狮子有时与一只雌性狮子生活在一起,但通常与更多雌性狮子生活在一起,在一个案例中,发现了多达五只雌性狮子;所以他是一夫多妻的。据我所知,他是所有陆地食肉动物中唯一的一夫多妻制,而且只有他表现出明显的性特征。然而,如果我们转向海洋食肉目,正如我们将在下文中看到的那样,情况就大不相同了。许多海豹物种都具有非凡的性别差异,而且它们是一夫多妻制的。因此,根据庇隆的说法,南大洋的雄性海象总是拥有几只雌性,而福斯特的海狮据说周围有二十到三十只雌性。在北方,雄性北海熊身边有更多的雌性海熊。这是一个有趣的事实,正如吉尔博士所说(15.《耳海豹》,《美国博物学家》,第 iv 卷,1871 年 XNUMX 月),在一夫一妻制的物种中,“或者那些生活在小群落中的物种,几乎没有雄性和雌性之间的体型差异;在社会物种中,或者更确切地说,在雄性有后宫的物种中,雄性比雌性大得多。”

在鸟类中,许多性别差异很大的物种无疑是一夫一妻制的。在英国,我们看到了明显的性别差异,例如,与单一雌性配对的野鸭、常见的黑鸟和据说终身配对的红腹灰雀。华莱士先生告诉我,南美洲的喋喋不休鸟或燕雀科以及许多其他鸟类也是如此。在几个群体中,我无法确定该物种是一夫多妻制还是一夫一妻制。莱瑟斯说,天堂鸟的性别差异如此显着,它们是一夫多妻制的,但华莱士先生怀疑他是否有足够的证据。萨尔文先生告诉我,他被引导相信蜂鸟是一夫多妻制的。雄性寡妇鸟因其尾部羽毛而引人注目,显然是一夫多妻制。 (16.“The Ibis”,第 1861 卷,133 年,第 1860 页,关于 Progne Widow-bird。另见 Vidua axillaris,同上,第 211 卷,1867 年,第 19 页。关于 Capercailzie 的一夫多妻制和大鸨,参见 L. Lloyd,《瑞典的猎鸟》,182 年,第 XNUMX 页和 XNUMX。蒙塔古和塞尔比说黑松鸡是一夫多妻制,而红松鸡是一夫一妻制。)我已得到先生的保证。 Jenner Weir 和其他人认为,三只椋鸟经常光顾同一个巢穴是很常见的;但这究竟是一夫多妻制还是一妻多夫制尚未确定。

鸡科动物表现出几乎与天堂鸟或蜂鸟一样强烈的性别差异,而且众所周知,许多物种都是一夫多妻制的。其他人则严格实行一夫一妻制。一夫多妻制的孔雀或雉鸡与一夫一妻制的珍珠鸡或鹧鸪之间的性别形成了多么鲜明的对比啊!可以举出许多类似的例子,例如在松鸡部落中,一夫多妻制的松鸡和黑雄鸡的雄性与雌性有很大不同。而一夫一妻制的红松鸡和雷鸟的性别差异很小。在库索雷族中,除了鸨之外,很少有物种具有明显的性别差异,而大鸨(Otis tarda)据说是一夫多妻制的。就 Grallatores 而言,极少有性别差异的物种,但 ruff (Machetes pugnax) 是一个明显的例外,蒙塔古认为该物种是一夫多妻制的。因此,在鸟类中,一夫多妻制与明显的性别差异的发展之间往往存在着密切的关系。我问动物园的巴特利特先生,他对鸟类有丰富的经验,雄性角雉(鸡科动物之一)是否是一夫多妻制,他的回答令我震惊:“我不知道,但应该认为所以从他绚丽的色彩来看。”

值得注意的是,与单一雌性交配的本能在驯化过程中很容易丧失。野鸭是严格的一夫一妻制,而家鸭则是高度的一夫多妻制。 WD Fox牧师告诉我,在他家附近的一个大池塘里,有一些半驯化的野鸭,有很多野鸭被猎场看守人射杀,以至于每七八只雌性野鸭就只剩下一只;然而,却养育了异常大的幼崽。珍珠鸡严格实行一夫一妻制。但狐狸先生发现,当他将一只公鸡与两到三只母鸡放在一起时,他的鸽子会取得最好的成功。金丝雀鸟在自然状态下配对,但英国的饲养员成功地将一只雄性与四到五只雌性配对。我注意到这些情况,因为野生一夫一妻制物种很可能很容易变成暂时或永久的一夫多妻制。

我们对爬行动物和鱼类的习性知之甚少,无法谈论它们的婚姻安排。然而,据说棘鱼 (Gasterosteus) 是一夫多妻制的 (17. Noel Humphreys, 'River Gardens,' 1857.);繁殖季节的雄性与雌性有明显不同。

总结一下,据我们判断,性选择导致第二性征发展的方式。事实证明,最强壮、武装最好的雄性(在与其他雄性的竞争中获胜)与最有活力、营养最好的雌性(最先在该地区繁殖)配对,将繁育出最多数量的精力充沛的后代。春天。如果这些雌性选择更具吸引力、同时精力充沛的雄性,它们将比智力低下的雌性生育更多的后代,后者必须与活力较弱、吸引力较差的雄性配对。如果更有活力的雄性选择更有魅力、同时又健康、有活力的雌性,情况也会如此。如果雄性保护雌性并帮助为幼崽提供食物,这一点尤其有效。更有活力的配对在养育更多数量的后代方面所获得的优势显然足以使性选择变得有效。但男性在人数上相对女性而言仍会更有效率。优势是否只是偶然的、局部的,还是永久的;无论是在出生时发生,还是在雌性遭受更大破坏后发生;或者它是否间接源于一夫多妻制的做法。

男性通常比女性更修饰

在整个动物王国中,当性别在外观上有所不同时,除了极少数例外,雄性的变化更大;因为一般来说,雌性与其同类的幼体以及同一群体的其他成年成员保持着更接近的相似性。其原因似乎在于几乎所有动物的雄性都比雌性有更强烈的激情。于是,雄性就一起战斗,在雌性面前刻意展示自己的魅力;胜利者将他们的优越感传递给他们的男性后代。为什么两性都没有因此获得其父亲的性格,我们将在下文中讨论。所有哺乳动物中的雄性都热切地追求雌性,这是每个人都知道的。鸟类也是如此。但许多公鸡并不那么追逐母鸡,而是展示它们的羽毛,表演奇怪的滑稽动作,并在母鸡面前倾诉它们的歌声。在观察到的少数几条鱼中,雄性似乎比雌性更加渴望。短吻鳄也是如此,显然巴特拉奇亚目也是如此。正如柯比所说,在昆虫这个庞大的类别中,“法则是雄性必须寻找雌性。” (18. Kirby 和 Spence,《昆虫学导论》,第 iii 卷,1826 年,第 342 页。)两位优秀的权威人士,Blackwall 先生和 C. Spence Bate 先生,告诉我蜘蛛和甲壳类动物的雄性更与雌性相比,它们的习惯更活跃且更不稳定。当昆虫和甲壳类动物的一种性别存在感觉或运动器官而另一种性别不存在时,或者当一种性别的感觉或运动器官比另一种性别更发达时(通常是这种情况),据我所知,几乎总是男性保留了这些器官,或者说它们最发达。这表明雄性在两性求爱中是更积极的成员。 (19. 一种寄生膜翅目昆虫(Westwood,《现代昆虫纲》,第 ii 卷,第 160 页)是该规则的一个例外,因为雄性具有发育不全的翅膀,并且永远不会离开它出生的细胞奥杜安认为,该物种的雌性是由与它们出生在同一细胞中的雄性受孕的;但雌性更有可能访问其他细胞,因此雌性之间的密切关系-因此避免了繁殖。我们将在以后的各个类别中遇到,其中有一些例外的情况,其中雌性而不是雄性是寻求者和求爱者。)

另一方面,除了极少数例外,雌性不如雄性那么渴望。正如著名的亨特(20.《随笔与观察》,欧文编辑,第 1861 卷,194 年,第 XNUMX 页)很久以前所观察到的那样,她通常“需要被求爱”;她很腼腆,经常会被看到长时间试图逃离雄性。每一个观察动物习性的人都能想起这样的例子。下文给出的各种事实以及相当可归因于性选择的结果表明,雌性虽然相对被动,但通常会做出某种选择并优先接受一个雄性。或者,正如外表有时会让我们相信的那样,她可能接受的不是对她最有吸引力的男性,而是最不令人反感的男性。女性做出某种选择的努力似乎与男性的渴望一样普遍。

我们很自然地会问,为什么在如此众多、如此不同的阶级中,雄性比雌性变得更加渴望,以至于他寻找她,并在求爱中发挥更积极的作用。如果两性都去寻找另一性,那不但没有任何优势,反而会损失一些力量。但为什么男性几乎总是寻找者呢?受精后的植物胚珠需要一段时间的滋养;因此,花粉必然被带到雌性器官——通过昆虫或风,或通过雄蕊的自发运动,被放置在柱头上;在藻类等中,通过类虫的运动力。对于组织低下的水生动物来说,它们永久固定在同一个地方,并且雌性分开,雄性元素总是被带到雌性身上。由此我们可以看出原因,因为即使卵子在受精前分离,并且不需要随后的滋养或保护,运输它们也会比雄性元素更困难,因为它们比后者大,它们的产量要少得多。因此,许多低等动物在这方面与植物类似。 (21. Sachs 教授(‘Lehrbuch der Botanik’,1870,S. 633)在谈到男性和女性生殖细胞时,评论道:“verhält sich die eine bei der Vereinigung activ,…die andere erscheint bei der Vereinigung passiv。 ”)固定动物和水生动物的雄性已被引导以这种方式释放其受精元素,很自然,它们的任何后代,在规模上上升并成为机车,应该保留相同的习惯;它们会尽可能靠近雌性,以免冒着在长时间的水中移动时失去受精元素的风险。对于一些低等动物来说,只有雌性是固定的,而这些动物中的雄性一定是探索者。但很难理解,为什么在祖先原本是自由的物种中,雄性总是会养成接近雌性的习惯,而不是被雌性接近。但无论如何,为了使男性能够有效地寻求,他们必须被赋予强烈的激情;渴望获得这种激情的人自然会比不那么渴望的人留下更多的后代。

因此,雄性的强烈渴望间接导致了它们比雌性更频繁地出现第二性征。但是,如果雄性比雌性更容易发生变化(正如我在对家养动物进行长期研究后得出的结论那样),那么这些性格的发展将会有很大帮助。拥有丰富经验的冯·纳修斯 (Von Nathusius) 也强烈同意这一观点。 (22.“Vorträge uber Viehzucht”,1872 年,第 63 页。)通过比较人类的两性,可以得出同样支持这一结论的良好证据。在诺瓦拉探险期间(23. 'Reise der Novara: Anthropolog. Theil,' 1867, ss. 216-269。结果由 Weisbach 博士根据 K. Scherzer 和 Schwarz 博士的测量结果计算得出。家养动物的雄性,请参阅我的《驯化下的动物和植物的变化》,第 ii 卷,1868 年,第 75 页。)对不同种族的身体各个部位进行了大量的测量,并且几乎在所有情况下都发现比女性表现出更大范围的变异;但我将不得不在以后的章节中再次讨论这个主题。 J. Wood 先生(第 24 卷《英国皇家学会学报》,第十六卷,1868 年 519 月,第 524 和 102 页)仔细研究了人体肌肉的变化,用斜体字得出以下结论: “每个受试者中发现的异常数量最多的是男性。”他此前曾表示,“在 25 名受试者中,发现冗余的种类又是女性的一半,这与之前描述的女性更高的缺陷频率形成鲜明对比。”麦卡利斯特教授同样评论道(1868.《爱尔兰皇家学院院报》,第 x 卷,123 年,第 26 页),肌肉的变化“在男性中可能比女性更常见”。某些人类通常不存在的肌肉在男性中也比在女性中更常见,尽管据说存在例外情况。 Burt Wilder 博士(3.《马萨诸塞州医学会》,第 ii 卷,第 1868 期,9 年,第 152 页)列出了 86 例多指病例,其中 39 例为男性,27 例或更少超过一半是女性,其余 27 名性别不明。然而,不应忽视的是,女性比男性更频繁地试图掩盖这种畸形。 L. Meyer 博士再次断言,男性耳朵的形状比女性耳朵的变化更大。 (1871.“ArchivfurPath.Anat.undPhys.”488,第28页。)最后,男性的体温比女性的变化更大。 (1. J. Stockton Hough 博士最近得出的关于人体体温的结论见《流行科学评论》,1874 年 97 月 XNUMX 日,第 XNUMX 页。)

男性比女性普遍变异性更大的原因尚不清楚,除非第二性征异常多变,并且通常仅限于男性。正如我们即将看到的,这一事实在某种程度上是可以理解的。通过性选择和自然选择的作用,雄性动物在很多情况下都与雌性动物截然不同。但与选择无关,两种性别由于体质不同,往往会以某种不同的方式发生变化。雌性在卵子的形成过程中需要消耗大量的有机物质,而雄性则在与竞争对手的激烈竞争、四处游荡寻找雌性、发出声音、排出有气味的分泌物等方面消耗大量的力量:而且这种支出一般集中在短期内。雄性在爱情季节的巨大活力似乎常常会增强他的色彩,与雌性没有任何明显的差异。 (29. 曼特加扎教授倾向于相信(“Lettera a Carlo Darwin”,“Archivio per l'Anthropologia”,1871 年,第 306 页)许多雄性动物中常见的鲜艳颜色是由于雄性动物的存在和它们保留了精液;但事实并非如此;对于许多雄性鸟类,例如雏雉,它们在第一年的秋天就变得颜色鲜艳。)在人类中,甚至在有机尺度上也是如此与鳞翅目动物一样,雄性的体温高于雌性,并且男性的脉搏较慢。 (30. 对于人类,参见 J. Stockton Hough 博士,其结论发表于《大众科学评论》,1874 年,第 97 页。参见吉拉德对鳞翅目的观察,发表于《动物学记录》,1869 年, p. 347。) 总体而言,两性消耗的物质和力量可能几乎相等,尽管其影响方式和速度不同。

从刚才指出的原因来看,两性在体质上不可能不存在一些差异,至少在繁殖季节是这样。而且,尽管它们可能处于完全相同的条件下,但它们往往会以不同的方式变化。如果这种变异对任何性别都没有帮助,它们就不会通过性选择或自然选择而积累和增加。然而,如果令人兴奋的原因永久起作用,它们可能会成为永久性的;根据常见的遗传形式,它们可能会仅遗传给它们最初出现的性别。在这种情况下,两种性别将呈现出永久但不重要的性格差异。例如,艾伦先生表示,美国北部和南部栖息着大量鸟类,南部的标本颜色比北部的要深;而这似乎是两个地区之间温度、光照等差异的直接结果。现在,在少数情况下,同一物种的两种性别似乎受到了不同的影响。在南方的Agelaeus phoeniceus中,雄性的颜色大大增强。而对于弗吉尼亚枢机主教来说,受到影响的是雌性;对于 Quiscalus Major,雌性的颜色变化极大,而雄性则几乎保持一致。 (31.“佛罗里达州东部的哺乳动物和鸟类”,第 234、280、295 页。)

一些特殊情况发生在不同类别的动物中,其中雌性而不是雄性获得了明显的第二性特征,例如更鲜艳的颜色、更大的体型、力量或好斗性。对于鸟类来说,有时每种性别所特有的普通特征会完全互换。雌性在求爱方面变得更加渴望,而雄性则相对被动,但显然会选择更具吸引力的雌性,正如我们从结果中推断的那样。因此,某些母鸡的颜色或装饰变得更加鲜艳,并且比公鸡更加强大和好斗。这些特征仅遗传给雌性后代。

可以认为,在某些情况下进行了双重选择过程;雄性选择了更有吸引力的雌性,而后者则选择了更有吸引力的雄性。然而,这一过程虽然可能会导致两性的改变,但不会使一种性别与另一种性别不同,除非他们对美的品味确实不同。但对于除了人类以外的任何动物来说,这种假设太不可能了,不值得考虑。然而,有许多动物的性别彼此相似,都配备有相同的装饰物,这种类比会让我们将其归因于性选择的作用。在这种情况下,可以更合理地表明存在双重或相互的性选择过程。更有活力和早熟的雌性选择更有吸引力和更有活力的雄性,后者拒绝除了更有吸引力的雌性之外的所有雄性。但从我们对动物习性的了解来看,这种观点几乎不可能,因为雄性通常渴望与任何雌性交配。更有可能的是,两性共有的装饰品是由一种性别(通常是男性)获得的,然后传给两性的后代。事实上,如果在一个延长的时期内,任何物种的雄性在数量上大大超过雌性,然后在另一个延长的时期内,但在不同的条件下,就会发生相反的情况,一个双重但不是同时发生的性过程选择很容易进行,通过这种选择,两种性别可能会产生很大的差异。

我们将在下文中看到,存在着许多动物,它们的性别都没有绚丽的色彩,也没有特殊的装饰,但两性或单一性别的成员可能通过性选择获得了简单的颜色,例如白色或黑色。缺乏明亮的色彩或其他装饰可能是由于从未发生过正确种类的变化,或者是动物本身更喜欢纯黑色或白色。出于保护目的,自然选择往往会产生暗淡的色彩,而通过性选择获得的显眼颜色有时似乎可以避免由此产生的危险。但在其他情况下,雄性在漫长的岁月中可能会为了对雌性的占有而共同奋斗,但不会产生任何效果,除非更成功的雄性留下比雌性更多的后代来继承其优势。不太成功:正如前面所示,这取决于许多复杂的突发事件。

性选择的行为方式不如自然选择严格。后者的影响取决于各个年龄段或多或少成功的个人的生或死。事实上,雄性之间的冲突导致死亡的情况并不罕见。但通常情况下,不太成功的雄性只是无法获得雌性,或者在季节后期获得一只迟钝且缺乏活力的雌性,或者,如果是一夫多妻制,获得的雌性较少;以至于它们留下的后代数量更少、活力更弱,甚至没有。对于通过普通或自然选择获得的结构,在大多数情况下,只要生命条件保持不变,对某些特殊目的的有利改变的数量就受到限制;但是,对于使一个雄性战胜另一个雄性的结构,无论是在战斗还是在迷惑雌性方面,有利修改的数量没有明确的限制;因此,只要出现适当的变异,性选择的工作就会继续下去。这种情况可能部分解释了第二性征频繁且异常多变的原因。然而,自然选择将决定胜利的雄性不会获得这些特征,如果它们具有高度伤害性,或者通过消耗过多的生命力,或者通过使它们暴露于任何巨大的危险中。然而,某些结构的发展——例如某些雄鹿的角——已经达到了奇妙的极限。在某些情况下,就一般生活条件而言,达到极端程度,必定会对男性造成轻微伤害。从这个事实我们了解到,从长远来看,受青睐的雄性在战斗或求爱中征服其他雄性并因此留下大量后代所获得的优势,比更完美地适应其生活条件所获得的优势更大。我们将进一步看到,这是永远无法预料到的,迷惑女性的力量有时比在战斗中征服其他男性的力量更重要。

继承法

为了了解性选择如何作用于许多类别的许多动物,并在漫长的岁月中产生显着的结果,有必要牢记已知的遗传规律。 “继承”一词包含两个不同的要素——性格的传承和发展;但由于这些通常是结合在一起的,因此它们之间的区别常常被忽视。 我们在那些在生命早期遗传下来但只有在成熟或老年时才发展起来的性格中看到了这种区别。 我们更清楚地看到第二性征的相同区别,因为这些特征是通过两性传播的,尽管是单独发展的。 当具有强烈明显性特征的两个物种杂交时,它们在两性中都存在,这是显而易见的,因为每个物种都将适合其自身男性和女性性别的特征传递给任一性别的杂交后代。 同样的事实也很明显,当雌性年老或患病时,偶尔会发展出雄性特有的特征,例如,当普通母鸡呈现出飘逸的尾羽时——羽毛、鬃毛、鸡冠、马刺、声音,甚至还有公鸡的好斗性。 相反,对于阉割的男性来说,同样的情况或多或少是明显的。 同样,与年老或疾病无关,性状偶尔会从雄性转移到雌性,就像在某些品种的家禽中,骨刺经常出现在年轻和健康的雌性身上。 但事实上,它们只是在女性身上发育出来的。因为在每个品种中,骨刺结构的每个细节都会通过雌性传递给其雄性后代。 Many cases will hereafter be given, where the female exhibits, more or less perfectly, characters proper to the male, in whom they must have been first developed, and then transferred to the female. The converse case of the first development of characters in the female and of transference to the male, is less frequent; it will therefore be well to give one striking instance. With bees the pollen- collecting apparatus is used by the female alone for gathering pollen for the larvae, yet in most of the species it is partially developed in the males to whom it is quite useless, and it is perfectly developed in the males of Bombus or the humble-bee. (32。 H. Muller, ‘Anwendung der Darwin’schen Lehre,’ etc., Verh. d. n. V. Jahrg., xxix. p. 42.) As not a single other Hymenopterous insect, not even the wasp, which is closely allied to the bee, is provided with a pollen-collecting apparatus, we have no grounds for supposing that male bees primordially collected pollen as well as the females; although we have some reason to suspect that male mammals primordially suckled their young as well as the females. Lastly, in all cases of reversion, characters are transmitted through two, three, or many more generations, and are then developed under certain unknown favourable conditions. This important distinction between transmission and development will be best kept in mind by the aid of the hypothesis of pangenesis. According to this hypothesis, every unit or cell of the body throws off gemmules or undeveloped atoms, which are transmitted to the offspring of both sexes, and are multiplied by self-division.

Inheritance at Corresponding Periods of Life

This tendency is well established. A new character, appearing in a young animal, whether it lasts throughout life or is only transient, will, in general, reappear in the offspring at the same age and last for the same time. If, on the other hand, a new character appears at maturity, or even during old age, it tends to reappear in the offspring at the same advanced age. When deviations from this rule occur, the transmitted characters much oftener appear before, than after the corresponding age. As I have dwelt on this subject sufficiently in another work (33. The ‘Variation of Animals and Plants under Domestication,’ vol. ii. 1868, p. 75. In the last chapter but one, the provisional hypothesis of pangenesis, above alluded to, is fully explained.), I will here merely give two or three instances, for the sake of recalling the subject to the reader’s mind. In several breeds of the Fowl, the down-covered chickens, the young birds in their first true plumage, and the adults differ greatly from one another, as well as from their common parent-form, the Gallus bankiva; and these characters are faithfully transmitted by each breed to their offspring at the corresponding periods of life. For instance, the chickens of spangled Hamburgs, whilst covered with down, have a few dark spots on the head and rump, but are not striped longitudinally, as in many other breeds; in their first true plumage, “they are beautifully pencilled,” that is each feather is transversely marked by numerous dark bars; but in their second plumage the feathers all become spangled or tipped with a dark round spot. (34. These facts are given on the high authority of a great breeder, Mr. Teebay; see Tegetmeier’s ‘Poultry Book,’ 1868, p. 158. On the characters of chickens of different breeds, and on the breeds of the pigeon, alluded to in the following paragraph, see ‘Variation of Animals,’ etc., vol. i. pp. 160, 249; vol. ii. p. 77.) Hence in this breed variations have occurred at, and been transmitted to, three distinct periods of life. The Pigeon offers a more remarkable case, because the aboriginal parent species does not undergo any change of plumage with advancing age, excepting that at maturity the breast becomes more iridescent; yet there are breeds which do not acquire their characteristic colours until they have moulted two, three, or four times; and these modifications of plumage are regularly transmitted.

Inheritance at Corresponding Seasons of the Year

With animals in a state of nature, innumerable instances occur of characters appearing periodically at different seasons. We see this in the horns of the stag, and in the fur of Arctic animals which becomes thick and white during the winter. Many birds acquire bright colours and other decorations during the breeding-season alone. Pallas states (35. ‘Novae species Quadrupedum e Glirium ordine,’ 1778, p. 7. On the transmission of colour by the horse, see ‘Variation of Animals and Plants under Domestication,’ vol. i. p. 51. Also vol. ii. p. 71, for a general discussion on ‘Inheritance as limited by Sex.’), that in Siberia domestic cattle and horses become lighter-coloured during the winter; and I have myself observed, and heard of similar strongly marked changes of colour, that is, from brownish cream-colour or reddish-brown to a perfect white, in several ponies in England. Although I do not know that this tendency to change the colour of the coat during different seasons is transmitted, yet it probably is so, as all shades of colour are strongly inherited by the horse. Nor is this form of inheritance, as limited by the seasons, more remarkable than its limitation by age or sex.

Inheritance as Limited by Sex

The equal transmission of characters to both sexes is the commonest form of inheritance, at least with those animals which do not present strongly- marked sexual differences, and indeed with many of these. But characters are somewhat commonly transferred exclusively to that sex, in which they first appear. Ample evidence on this head has been advanced in my work on ‘Variation under Domestication,’ but a few instances may here be given. There are breeds of the sheep and goat, in which the horns of the male differ greatly in shape from those of the female; and these differences, acquired under domestication, are regularly transmitted to the same sex. As a rule, it is the females alone in cats which are tortoise-shell, the corresponding colour in the males being rusty-red. With most breeds of the fowl, the characters proper to each sex are transmitted to the same sex alone. So general is this form of transmission that it is an anomaly when variations in certain breeds are transmitted equally to both sexes. There are also certain sub-breeds of the fowl in which the males can hardly be distinguished from one another, whilst the females differ considerably in colour. The sexes of the pigeon in the parent-species do not differ in any external character; nevertheless, in certain domesticated breeds the male is coloured differently from the female. (36. Dr. Chapuis, ‘Le Pigeon Voyageur Belge,’ 1865, p. 87. Boitard et Corbie, ‘Les Pigeons de Volière,’ etc., 1824, p. 173. See, also, on similar differences in certain breeds at Modena, ‘Le variazioni dei Colombi domestici,’ del Paolo Bonizzi, 1873.) The wattle in the English Carrier pigeon, and the crop in the Pouter, are more highly developed in the male than in the female; and although these characters have been gained through long-continued selection by man, the slight differences between the sexes are wholly due to the form of inheritance which has prevailed; for they have arisen, not from, but rather in opposition to, the wish of the breeder.

Most of our domestic races have been formed by the accumulation of many slight variations; and as some of the successive steps have been transmitted to one sex alone, and some to both sexes, we find in the different breeds of the same species all gradations between great sexual dissimilarity and complete similarity. Instances have already been given with the breeds of the fowl and pigeon, and under nature analogous cases are common. With animals under domestication, but whether in nature I will not venture to say, one sex may lose characters proper to it, and may thus come somewhat to resemble the opposite sex; for instance, the males of some breeds of the fowl have lost their masculine tail-plumes and hackles. On the other hand, the differences between the sexes may be increased under domestication, as with merino sheep, in which the ewes have lost their horns. Again, characters proper to one sex may suddenly appear in the other sex; as in those sub-breeds of the fowl in which the hens acquire spurs whilst young; or, as in certain Polish sub-breeds, in which the females, as there is reason to believe, originally acquired a crest, and subsequently transferred it to the males. All these cases are intelligible on the hypothesis of pangenesis; for they depend on the gemmules of certain parts, although present in both sexes, becoming, through the influence of domestication, either dormant or developed in either sex.

There is one difficult question which it will be convenient to defer to a future chapter; namely, whether a character at first developed in both sexes, could through selection be limited in its development to one sex alone. If, for instance, a breeder observed that some of his pigeons (of which the characters are usually transferred in an equal degree to both sexes) varied into pale blue, could he by long-continued selection make a breed, in which the males alone should be of this tint, whilst the females remained unchanged? I will here only say, that this, though perhaps not impossible, would be extremely difficult; for the natural result of breeding from the pale-blue males would be to change the whole stock of both sexes to this tint. If, however, variations of the desired tint appeared, which were from the first limited in their development to the male sex, there would not be the least difficulty in making a breed with the two sexes of a different colour, as indeed has been effected with a Belgian breed, in which the males alone are streaked with black. In a similar manner, if any variation appeared in a female pigeon, which was from the first sexually limited in its development to the females, it would be easy to make a breed with the females alone thus characterised; but if the variation was not thus originally limited, the process would be extremely difficult, perhaps impossible. (37. Since the publication of the first edition of this work, it has been highly satisfactory to me to find the following remarks (the ‘Field,’ Sept. 1872) from so experienced a breeder as Mr. Tegetmeier. After describing some curious cases in pigeons, of the transmission of colour by one sex alone, and the formation of a sub- breed with this character, he says: “It is a singular circumstance that Mr. Darwin should have suggested the possibility of modifying the sexual colours of birds by a course of artificial selection. When he did so, he was in ignorance of these facts that I have related; but it is remarkable how very closely he suggested the right method of procedure.”)

On the Relation Between the Period of Development of a Character and Its Transmission to One Sex or to Both Sexes

Why certain characters should be inherited by both sexes, and other characters by one sex alone, namely by that sex in which the character first appeared, is in most cases quite unknown. We cannot even conjecture why with certain sub-breeds of the pigeon, black striae, though transmitted through the female, should be developed in the male alone, whilst every other character is equally transferred to both sexes. Why, again, with cats, the tortoise-shell colour should, with rare exceptions, be developed in the female alone. The very same character, such as deficient or supernumerary digits, colour-blindness, etc., may with mankind be inherited by the males alone of one family, and in another family by the females alone, though in both cases transmitted through the opposite as well as through the same sex. (38. References are given in my ‘Variation of Animals and Plants under Domestication,’ vol. ii. p. 72.) Although we are thus ignorant, the two following rules seem often to hold good—that variations which first appear in either sex at a late period of life, tend to be developed in the same sex alone; whilst variations which first appear early in life in either sex tend to be developed in both sexes. I am, however, far from supposing that this is the sole determining cause. As I have not elsewhere discussed this subject, and it has an important bearing on sexual selection, I must here enter into lengthy and somewhat intricate details.

It is in itself probable that any character appearing at an early age would tend to be inherited equally by both sexes, for the sexes do not differ much in constitution before the power of reproduction is gained. On the other hand, after this power has been gained and the sexes have come to differ in constitution, the gemmules (if I may again use the language of pangenesis) which are cast off from each varying part in the one sex would be much more likely to possess the proper affinities for uniting with the tissues of the same sex, and thus becoming developed, than with those of the opposite sex.

I was first led to infer that a relation of this kind exists, from the fact that whenever and in whatever manner the adult male differs from the adult female, he differs in the same manner from the young of both sexes. The generality of this fact is quite remarkable: it holds good with almost all mammals, birds, amphibians, and fishes; also with many crustaceans, spiders, and some few insects, such as certain orthoptera and libellulae. In all these cases the variations, through the accumulation of which the male acquired his proper masculine characters, must have occurred at a somewhat late period of life; otherwise the young males would have been similarly characterised; and conformably with our rule, the variations are transmitted to and developed in the adult males alone. When, on the other hand, the adult male closely resembles the young of both sexes (these, with rare exceptions, being alike), he generally resembles the adult female; and in most of these cases the variations through which the young and old acquired their present characters, probably occurred, according to our rule, during youth. But there is here room for doubt, for characters are sometimes transferred to the offspring at an earlier age than that at which they first appeared in the parents, so that the parents may have varied when adult, and have transferred their characters to their offspring whilst young. There are, moreover, many animals, in which the two sexes closely resemble each other, and yet both differ from their young: and here the characters of the adults must have been acquired late in life; nevertheless, these characters, in apparent contradiction to our rule, are transferred to both sexes. We must not however, overlook the possibility or even probability of successive variations of the same nature occurring, under exposure to similar conditions, simultaneously in both sexes at a rather late period of life; and in this case the variations would be transferred to the offspring of both sexes at a corresponding late age; and there would then be no real contradiction to the rule that variations occurring late in life are transferred exclusively to the sex in which they first appeared. This latter rule seems to hold true more generally than the second one, namely, that variations which occur in either sex early in life tend to be transferred to both sexes. As it was obviously impossible even to estimate in how large a number of cases throughout the animal kingdom these two propositions held good, it occurred to me to investigate some striking or crucial instances, and to rely on the result.

An excellent case for investigation is afforded by the Deer family. In all the species, but one, the horns are developed only in the males, though certainly transmitted through the females, and capable of abnormal development in them. In the reindeer, on the other hand, the female is provided with horns; so that in this species, the horns ought, according to our rule, to appear early in life, long before the two sexes are mature and have come to differ much in constitution. In all the other species the horns ought to appear later in life, which would lead to their development in that sex alone, in which they first appeared in the progenitor of the whole Family. Now in seven species, belonging to distinct sections of the family and inhabiting different regions, in which the stags alone bear horns, I find that the horns first appear at periods, varying from nine months after birth in the roebuck, to ten, twelve or even more months in the stags of the six other and larger species. (39. I am much obliged to Mr. Cupples for having made enquiries for me in regard to the Roebuck and Red Deer of Scotland from Mr. Robertson, the experienced head-forester to the Marquis of Breadalbane. In regard to Fallow-deer, I have to thank Mr. Eyton and others for information. For the Cervus alces of N. America, see ‘Land and Water,’ 1868, pp. 221 and 254; and for the C. Virginianus and strongyloceros of the same continent, see J.D. Caton, in ‘Ottawa Acad. of Nat. Sc.’ 1868, p. 13. For Cervus Eldi of Pegu, see Lieut. Beaven, ‘Proccedings of the Zoological Society,’ 1867, p. 762.) But with the reindeer the case is widely different; for, as I hear from Prof. Nilsson, who kindly made special enquiries for me in Lapland, the horns appear in the young animals within four or five weeks after birth, and at the same time in both sexes. So that here we have a structure, developed at a most unusually early age in one species of the family, and likewise common to both sexes in this one species alone.

In several kinds of antelopes, only the males are provided with horns, whilst in the greater number both sexes bear horns. With respect to the period of development, Mr. Blyth informs me that there was at one time in the Zoological Gardens a young koodoo (Ant. strepsiceros), of which the males alone are horned, and also the young of a closely-allied species, the eland (Ant. oreas), in which both sexes are horned. Now it is in strict conformity with our rule, that in the young male koodoo, although ten months old, the horns were remarkably small, considering the size ultimately attained by them; whilst in the young male eland, although only three months old, the horns were already very much larger than in the koodoo. It is also a noticeable fact that in the prong-horned antelope (40. Antilocapra Americana. I have to thank Dr. Canfield for information with respect to the horns of the female: see also his paper in ‘Proceedings of the Zoological Society,’ 1866, p. 109. Also Owen, ‘Anatomy of Vertebrates,’ vol. III。 p. 627), only a few of the females, about one in five, have horns, and these are in a rudimentary state, though sometimes above four inches long: so that as far as concerns the possession of horns by the males alone, this species is in an intermediate condition, and the horns do not appear until about five or six months after birth. Therefore in comparison with what little we know of the development of the horns in other antelopes, and from what we do know with respect to the horns of deer, cattle, etc., those of the prong-horned antelope appear at an intermediate period of life,—that is, not very early, as in cattle and sheep, nor very late, as in the larger deer and antelopes. The horns of sheep, goats, and cattle, which are well developed in both sexes, though not quite equal in size, can be felt, or even seen, at birth or soon afterwards. (41。 I have been assured that the horns of the sheep in North Wales can always be felt, and are sometimes even an inch in length, at birth. Youatt says (‘Cattle,’ 1834, p. 277), that the prominence of the frontal bone in cattle penetrates the cutis at birth, and that the horny matter is soon formed over it.) Our rule, however, seems to fail in some breeds of sheep, for instance merinos, in which the rams alone are horned; for I cannot find on enquiry (42. I am greatly indebted to Prof. Victor Carus for having made enquiries for me, from the highest authorities, with respect to the merino sheep of Saxony. On the Guinea coast of Africa there is, however, a breed of sheep in which, as with merinos, the rams alone bear horns; and Mr. Winwood Reade informs me that in one case observed by him, a young ram, born on Feb. 10th, first shewed horns on March 6th, so that in this instance, in conformity with rule, the development of the horns occurred at a later period of life than in Welsh sheep, in which both sexes are horned.), that the horns are developed later in life in this breed than in ordinary sheep in which both sexes are horned.

Dr. W. Marshall has lately made a special study of the protuberances so common on the heads of birds (43. ‘Über die knochernen Schädelhöcker der Vögel,’ in the ‘Niederland. Archiv fur Zoologie,’ B.i. Heft 2, 1872.), and he comes to the following conclusion:—that with those species in which they are confined to the males, they are developed late in life; whereas with those species in which they are common to the two sexes, they are developed at a very early period. This is certainly a striking confirmation of my two laws of inheritance.

In most of the species of the splendid family of the Pheasants, the males differ conspicuously from the females, and they acquire their ornaments at a rather late period of life. The eared pheasant (Crossoptilon auritum), however, offers a remarkable exception, for both sexes possess the fine caudal plumes, the large ear-tufts and the crimson velvet about the head; I find that all these characters appear very early in life in accordance with rule. The adult male can, however, be distinguished from the adult female by the presence of spurs; and conformably with our rule, these do not begin to be developed before the age of six months, as I am assured by Mr. Bartlett, and even at this age, the two sexes can hardly be distinguished. (44。 In the common peacock (Pavo cristatus) the male alone possesses spurs, whilst both sexes of the Java Peacock (P. muticus) offer the unusual case of being furnished with spurs. Hence I fully expected that in the latter species they would have been developed earlier in life than in the common peacock; but M. Hegt of Amsterdam informs me, that with young birds of the previous year, of both species, compared on April 23rd, 1869, there was no difference in the development of the spurs. The spurs, however, were as yet represented merely by slight knobs or elevations. I presume that I should have been informed if any difference in the rate of development had been observed subsequently.) The male and female Peacock differ conspicuously from each other in almost every part of their plumage, except in the elegant head-crest, which is common to both sexes; and this is developed very early in life, long before the other ornaments, which are confined to the male. The wild-duck offers an analogous case, for the beautiful green speculum on the wings is common to both sexes, though duller and somewhat smaller in the female, and it is developed early in life, whilst the curled tail-feathers and other ornaments of the male are developed later. (45。 In some other species of the Duck family the speculum differs in a greater degree in the two sexes; but I have not been able to discover whether its full development occurs later in life in the males of such species, than in the male of the common duck, as ought to be the case according to our rule. With the allied Mergus cucullatus we have, however, a case of this kind: the two sexes differ conspicuously in general plumage, and to a considerable degree in the speculum, which is pure white in the male and greyish-white in the female. Now the young males at first entirely resemble the females, and have a greyish-white speculum, which becomes pure white at an earlier age than that at which the adult male acquires his other and more strongly-marked sexual differences: see Audubon, ‘Ornithological Biography,’ vol. III。 1835页。

As most insects emerge from the pupal state in a mature condition, it is doubtful whether the period of development can determine the transference of their characters to one or to both sexes. But we do not know that the coloured scales, for instance, in two species of butterflies, in one of which the sexes differ in colour, whilst in the other they are alike, are developed at the same relative age in the cocoon. Nor do we know whether all the scales are simultaneously developed on the wings of the same species of butterfly, in which certain coloured marks are confined to one sex, whilst others are common to both sexes. A difference of this kind in the period of development is not so improbable as it may at first appear; for with the Orthoptera, which assume their adult state, not by a single metamorphosis, but by a succession of moults, the young males of some species at first resemble the females, and acquire their distinctive masculine characters only at a later moult. Strictly analogous cases occur at the successive moults of certain male crustaceans.

We have as yet considered the transference of characters, relatively to their period of development, only in species in a natural state; we will now turn to domesticated animals, and first touch on monstrosities and diseases. The presence of supernumerary digits, and the absence of certain phalanges, must be determined at an early embryonic period—the tendency to profuse bleeding is at least congenital, as is probably colour-blindness— yet these peculiarities, and other similar ones, are often limited in their transmission to one sex; so that the rule that characters, developed at an early period, tend to be transmitted to both sexes, here wholly fails. But this rule, as before remarked, does not appear to be nearly so general as the converse one, namely, that characters which appear late in life in one sex are transmitted exclusively to the same sex. From the fact of the above abnormal peculiarities becoming attached to one sex, long before the sexual functions are active, we may infer that there must be some difference between the sexes at an extremely early age. With respect to sexually-limited diseases, we know too little of the period at which they originate, to draw any safe conclusion. Gout, however, seems to fall under our rule, for it is generally caused by intemperance during manhood, and is transmitted from the father to his sons in a much more marked manner than to his daughters.

In the various domestic breeds of sheep, goats, and cattle, the males differ from their respective females in the shape or development of their horns, forehead, mane, dewlap, tail, and hump on the shoulders; and these peculiarities, in accordance with our rule, are not fully developed until a rather late period of life. The sexes of dogs do not differ, except that in certain breeds, especially in the Scotch deer-hound, the male is much larger and heavier than the female; and, as we shall see in a future chapter, the male goes on increasing in size to an unusually late period of life, which, according to rule, will account for his increased size being transmitted to his male offspring alone. On the other hand, the tortoise- shell colour, which is confined to female cats, is quite distinct at birth, and this case violates the rule. There is a breed of pigeons in which the males alone are streaked with black, and the streaks can be detected even in the nestlings; but they become more conspicuous at each successive moult, so that this case partly opposes and partly supports the rule. With the English Carrier and Pouter pigeons, the full development of the wattle and the crop occurs rather late in life, and conformably with the rule, these characters are transmitted in full perfection to the males alone. The following cases perhaps come within the class previously alluded to, in which both sexes have varied in the same manner at a rather late period of life, and have consequently transferred their new characters to both sexes at a corresponding late period; and if so, these cases are not opposed to our rule:—there exist sub-breeds of the pigeon, described by Neumeister (46. ‘Das Ganze der Taubenzucht,’ 1837, ss. 21, 24. For the case of the streaked pigeons, see Dr. Chapuis, ‘Le pigeon voyageur Belge,’ 1865, p. 87.), in which both sexes change their colour during two or three moults (as is likewise the case with the Almond Tumbler); nevertheless, these changes, though occurring rather late in life, are common to both sexes. One variety of the Canary-bird, namely the London Prize, offers a nearly analogous case.

With the breeds of the Fowl the inheritance of various characters by one or both sexes, seems generally determined by the period at which such characters are developed. Thus in all the many breeds in which the adult male differs greatly in colour from the female, as well as from the wild parent-species, he differs also from the young male, so that the newly- acquired characters must have appeared at a rather late period of life. On the other hand, in most of the breeds in which the two sexes resemble each other, the young are coloured in nearly the same manner as their parents, and this renders it probable that their colours first appeared early in life. We have instances of this fact in all black and white breeds, in which the young and old of both sexes are alike; nor can it be maintained that there is something peculiar in a black or white plumage, which leads to its transference to both sexes; for the males alone of many natural species are either black or white, the females being differently coloured. With the so-called Cuckoo sub-breeds of the fowl, in which the feathers are transversely pencilled with dark stripes, both sexes and the chickens are coloured in nearly the same manner. The laced plumage of the Sebright bantam is the same in both sexes, and in the young chickens the wing- feathers are distinctly, though imperfectly laced. Spangled Hamburgs, however, offer a partial exception; for the two sexes, though not quite alike, resemble each other more closely than do the sexes of the aboriginal parent-species; yet they acquire their characteristic plumage late in life, for the chickens are distinctly pencilled. With respect to other characters besides colour, in the wild-parent species and in most of the domestic breeds, the males alone possess a well-developed comb; but in the young of the Spanish fowl it is largely developed at a very early age, and, in accordance with this early development in the male, it is of unusual size in the adult female. In the Game breeds pugnacity is developed at a wonderfully early age, of which curious proofs could be given; and this character is transmitted to both sexes, so that the hens, from their extreme pugnacity, are now generally exhibited in separate pens. With the Polish breeds the bony protuberance of the skull which supports the crest is partially developed even before the chickens are hatched, and the crest itself soon begins to grow, though at first feebly (47. For full particulars and references on all these points respecting the several breeds of the Fowl, see ‘Variation of Animals and Plants under Domestication,’ vol. i. pp. 250, 256. In regard to the higher animals, the sexual differences which have arisen under domestication are described in the same work under the head of each species.); and in this breed the adults of both sexes are characterised by a great bony protuberance and an immense crest.

Finally, from what we have now seen of the relation which exists in many natural species and domesticated races, between the period of the development of their characters and the manner of their transmission—for example, the striking fact of the early growth of the horns in the reindeer, in which both sexes bear horns, in comparison with their much later growth in the other species in which the male alone bears horns—we may conclude that one, though not the sole cause of characters being exclusively inherited by one sex, is their development at a late age. And secondly, that one, though apparently a less efficient cause of characters being inherited by both sexes, is their development at an early age, whilst the sexes differ but little in constitution. It appears, however, that some difference must exist between the sexes even during a very early embryonic period, for characters developed at this age not rarely become attached to one sex.

Summary and Concluding Remarks

From the foregoing discussion on the various laws of inheritance, we learn that the characters of the parents often, or even generally, tend to become developed in the offspring of the same sex, at the same age, and periodically at the same season of the year, in which they first appeared in the parents. But these rules, owing to unknown causes, are far from being fixed. Hence during the modification of a species, the successive changes may readily be transmitted in different ways; some to one sex, and some to both; some to the offspring at one age, and some to the offspring at all ages. Not only are the laws of inheritance extremely complex, but so are the causes which induce and govern variability. The variations thus induced are preserved and accumulated by sexual selection, which is in itself an extremely complex affair, depending, as it does, on the ardour in love, the courage, and the rivalry of the males, as well as on the powers of perception, the taste, and will of the female. Sexual selection will also be largely dominated by natural selection tending towards the general welfare of the species. Hence the manner in which the individuals of either or both sexes have been affected through sexual selection cannot fail to be complex in the highest degree.

When variations occur late in life in one sex, and are transmitted to the same sex at the same age, the other sex and the young are left unmodified. When they occur late in life, but are transmitted to both sexes at the same age, the young alone are left unmodified. Variations, however, may occur at any period of life in one sex or in both, and be transmitted to both sexes at all ages, and then all the individuals of the species are similarly modified. In the following chapters it will be seen that all these cases frequently occur in nature.

Sexual selection can never act on any animal before the age for reproduction arrives. From the great eagerness of the male it has generally acted on this sex and not on the females. The males have thus become provided with weapons for fighting with their rivals, with organs for discovering and securely holding the female, and for exciting or charming her. When the sexes differ in these respects, it is also, as we have seen, an extremely general law that the adult male differs more or less from the young male; and we may conclude from this fact that the successive variations, by which the adult male became modified, did not generally occur much before the age for reproduction. Whenever some or many of the variations occurred early in life, the young males would partake more or less of the characters of the adult males; and differences of this kind between the old and young males may be observed in many species of animals.

It is probable that young male animals have often tended to vary in a manner which would not only have been of no use to them at an early age, but would have been actually injurious—as by acquiring bright colours, which would render them conspicuous to their enemies, or by acquiring structures, such as great horns, which would expend much vital force in their development. Variations of this kind occurring in the young males would almost certainly be eliminated through natural selection. With the adult and experienced males, on the other hand, the advantages derived from the acquisition of such characters, would more than counterbalance some exposure to danger, and some loss of vital force.

As variations which give to the male a better chance of conquering other males, or of finding, securing, or charming the opposite sex, would, if they happened to arise in the female, be of no service to her, they would not be preserved in her through sexual selection. We have also good evidence with domesticated animals, that variations of all kinds are, if not carefully selected, soon lost through intercrossing and accidental deaths. Consequently in a state of nature, if variations of the above kind chanced to arise in the female line, and to be transmitted exclusively in this line, they would be extremely liable to be lost. If, however, the females varied and transmitted their newly acquired characters to their offspring of both sexes, the characters which were advantageous to the males would be preserved by them through sexual selection, and the two sexes would in consequence be modified in the same manner, although such characters were of no use to the females: but I shall hereafter have to recur to these more intricate contingencies. Lastly, the females may acquire, and apparently have often acquired by transference, characters from the male sex.

As variations occurring later in life, and transmitted to one sex alone, have incessantly been taken advantage of and accumulated through sexual selection in relation to the reproduction of the species; therefore it appears, at first sight, an unaccountable fact that similar variations have not frequently been accumulated through natural selection, in relation to the ordinary habits of life. If this had occurred, the two sexes would often have been differently modified, for the sake, for instance, of capturing prey or of escaping from danger. Differences of this kind between the two sexes do occasionally occur, especially in the lower classes. But this implies that the two sexes follow different habits in their struggles for existence, which is a rare circumstance with the higher animals. The case, however, is widely different with the reproductive functions, in which respect the sexes necessarily differ. For variations in structure which are related to these functions, have often proved of value to one sex, and from having arisen at a late period of life, have been transmitted to one sex alone; and such variations, thus preserved and transmitted, have given rise to secondary sexual characters.

In the following chapters, I shall treat of the secondary sexual characters in animals of all classes, and shall endeavour in each case to apply the principles explained in the present chapter. The lowest classes will detain us for a very short time, but the higher animals, especially birds, must be treated at considerable length. It should be borne in mind that for reasons already assigned, I intend to give only a few illustrative instances of the innumerable structures by the aid of which the male finds the female, or, when found, holds her. On the other hand, all structures and instincts by the aid of which the male conquers other males, and by which he allures or excites the female, will be fully discussed, as these are in many ways the most interesting.

Supplement on the Proportional Numbers of the Two Sexes in Animals Belonging to Various Classes

As no one, as far as I can discover, has paid attention to the relative numbers of the two sexes throughout the animal kingdom, I will here give such materials as I have been able to collect, although they are extremely imperfect. They consist in only a few instances of actual enumeration, and the numbers are not very large. As the proportions are known with certainty only in mankind, I will first give them as a standard of comparison.

男人

In England during ten years (from 1857 to 1866) the average number of children born alive yearly was 707,120, in the proportion of 104.5 males to 100 females. But in 1857 the male births throughout England were as 105.2, and in 1865 as 104.0 to 100. Looking to separate districts, in Buckinghamshire (where about 5000 children are annually born) the MEAN proportion of male to female births, during the whole period of the above ten years, was as 102.8 to 100; whilst in N. Wales (where the average annual births are 12,873) it was as high as 106.2 to 100. Taking a still smaller district, viz., Rutlandshire (where the annual births average only 739), in 1864 the male births were as 114.6, and in 1862 as only 97.0 to 100; but even in this small district the average of the 7385 births during the whole ten years, was as 104.5 to 100: that is in the same ratio as throughout England. (48. ‘Twenty-ninth Annual Report of the Registrar- General for 1866.’ In this report (p. xii.) a special decennial table is given.) The proportions are sometimes slightly disturbed by unknown causes; thus Prof. Faye states “that in some districts of Norway there has been during a decennial period a steady deficiency of boys, whilst in others the opposite condition has existed.” In France during forty-four years the male to the female births have been as 106.2 to 100; but during this period it has occurred five times in one department, and six times in another, that the female births have exceeded the males. In Russia the average proportion is as high as 108.9, and in Philadelphia in the United States as 110.5 to 100. (49. For Norway and Russia, see abstract of Prof. Faye’s researches, in ‘British and Foreign Medico-Chirurg. Review,’ April 1867, pp. 343, 345. For France, the ‘Annuaire pour l’An 1867,’ p. 213. For Philadelphia, Dr. Stockton Hough, ‘Social Science Assoc.’ 1874. For the Cape of Good Hope, Quetelet as quoted by Dr. H.H. Zouteveen, in the Dutch Translation of this work (vol. i. p. 417), where much information is given on the proportion of the sexes.) The average for Europe, deduced by Bickes from about seventy million births, is 106 males to 100 females. On the other hand, with white children born at the Cape of Good Hope, the proportion of males is so low as to fluctuate during successive years between 90 and 99 males for every 100 females. It is a singular fact that with Jews the proportion of male births is decidedly larger than with Christians: thus in Prussia the proportion is as 113, in Breslau as 114, and in Livonia as 120 to 100; the Christian births in these countries being the same as usual, for instance, in Livonia as 104 to 100. (50. In regard to the Jews, see M. Thury, ‘La Loi de Production des Sexes,’ 1863, p. 25.)

Prof. Faye remarks that “a still greater preponderance of males would be met with, if death struck both sexes in equal proportion in the womb and during birth. But the fact is, that for every 100 still-born females, we have in several countries from 134.6 to 144.9 still-born males. During the first four or five years of life, also, more male children die than females, for example in England, during the first year, 126 boys die for every 100 girls—a proportion which in France is still more unfavourable.” (51. ‘British and Foreign Medico-Chirurg. Review,’ April 1867, p. 343. Dr. Stark also remarks (‘Tenth Annual Report of Births, Deaths, etc., in Scotland,’ 1867, p. xxviii.) that “These examples may suffice to show that, at almost every stage of life, the males in Scotland have a greater liability to death and a higher death-rate than the females. The fact, however, of this peculiarity being most strongly developed at that infantile period of life when the dress, food, and general treatment of both sexes are alike, seems to prove that the higher male death-rate is an impressed, natural, and constitutional peculiarity due to sex alone.”) Dr. Stockton Hough accounts for these facts in part by the more frequent defective development of males than of females. We have before seen that the male sex is more variable in structure than the female; and variations in important organs would generally be injurious. But the size of the body, and especially of the head, being greater in male than female infants is another cause: for the males are thus more liable to be injured during parturition. Consequently the still-born males are more numerous; and, as a highly competent judge, Dr. Crichton Browne (52. ‘West Riding Lunatic Asylum Reports,’ vol. i. 1871, p. 8. Sir J. Simpson has proved that the head of the male infant exceeds that of the female by 3/8ths of an inch in circumference, and by 1/8th in transverse diameter. Quetelet has shewn that woman is born smaller than man; see Dr. Duncan, ‘Fecundity, Fertility, and Sterility,’ 1871, p. 382.), believes, male infants often suffer in health for some years after birth. Owing to this excess in the death-rate of male children, both at birth and for some time subsequently, and owing to the exposure of grown men to various dangers, and to their tendency to emigrate, the females in all old-settled countries, where statistical records have been kept, are found to preponderate considerably over the males. (53. With the savage Guaranys of Paraguay, according to the accurate Azara (‘Voyages dans l’Amerique merid.’ tom. ii. 1809, pp. 60, 179), the women are to the men in the proportion of 14 to 13.)

It seems at first sight a mysterious fact that in different nations, under different conditions and climates, in Naples, Prussia, Westphalia, Holland, France, England and the United States, the excess of male over female births is less when they are illegitimate than when legitimate. (54. Babbage, ‘Edinburgh Journal of Science,’ 1829, vol. i. p. 88; also p. 90, on still-born children. On illegitimate children in England, see ‘Report of Registrar-General for 1866,’ p. xv.) This has been explained by different writers in many different ways, as from the mothers being generally young, from the large proportion of first pregnancies, etc. But we have seen that male infants, from the large size of their heads, suffer more than female infants during parturition; and as the mothers of illegitimate children must be more liable than other women to undergo bad labours, from various causes, such as attempts at concealment by tight lacing, hard work, distress of mind, etc., their male infants would proportionably suffer. And this probably is the most efficient of all the causes of the proportion of males to females born alive being less amongst illegitimate children than amongst the legitimate. With most animals the greater size of the adult male than of the female, is due to the stronger males having conquered the weaker in their struggles for the possession of the females, and no doubt it is owing to this fact that the two sexes of at least some animals differ in size at birth. Thus we have the curious fact that we may attribute the more frequent deaths of male than female infants, especially amongst the illegitimate, at least in part to sexual selection.

It has often been supposed that the relative age of the two parents determine the sex of the offspring; and Prof. Leuckart (55. Leuckart, in Wagner ‘Handwörterbuch der Phys.’ B. iv. 1853, s. 774.) has advanced what he considers sufficient evidence, with respect to man and certain domesticated animals, that this is one important though not the sole factor in the result. So again the period of impregnation relatively to the state of the female has been thought by some to be the efficient cause; but recent observations discountenance this belief. According to Dr. Stockton Hough (56. ‘Social Science Association of Philadelphia,’ 1874.), the season of the year, the poverty or wealth of the parents, residence in the country or in cities, the crossing of foreign immigrants, etc., all influence the proportion of the sexes. With mankind, polygamy has also been supposed to lead to the birth of a greater proportion of female infants; but Dr. J. Campbell (57. ‘Anthropological Review,’ April 1870, p. cviii.) carefully attended to this subject in the harems of Siam, and concludes that the proportion of male to female births is the same as from monogamous unions. Hardly any animal has been rendered so highly polygamous as the English race-horse, and we shall immediately see that his male and female offspring are almost exactly equal in number. I will now give the facts which I have collected with respect to the proportional numbers of the sexes of various animals; and will then briefly discuss how far selection has come into play in determining the result.

马匹

Mr. Tegetmeier has been so kind as to tabulate for me from the ‘Racing Calendar’ the births of race-horses during a period of twenty-one years, viz., from 1846 to 1867; 1849 being omitted, as no returns were that year published. The total births were 25,560 (58. During eleven years a record was kept of the number of mares which proved barren or prematurely slipped their foals; and it deserves notice, as shewing how infertile these highly- nurtured and rather closely-interbred animals have become, that not far from one-third of the mares failed to produce living foals. Thus during 1866, 809 male colts and 816 female colts were born, and 743 mares failed to produce offspring. During 1867, 836 males and 902 females were born, and 794 mares failed.), consisting of 12,763 males and 12,797 females, or in the proportion of 99.7 males to 100 females. As these numbers are tolerably large, and as they are drawn from all parts of England, during several years, we may with much confidence conclude that with the domestic horse, or at least with the race-horse, the two sexes are produced in almost equal numbers. The fluctuations in the proportions during successive years are closely like those which occur with mankind, when a small and thinly-populated area is considered; thus in 1856 the male horses were as 107.1, and in 1867 as only 92.6 to 100 females. In the tabulated returns the proportions vary in cycles, for the males exceeded the females during six successive years; and the females exceeded the males during two periods each of four years; this, however, may be accidental; at least I can detect nothing of the kind with man in the decennial table in the Registrar’s Report for 1866.

小狗

During a period of twelve years, from 1857 to 1868, the births of a large number of greyhounds, throughout England, were sent to the ‘Field’ newspaper; and I am again indebted to Mr. Tegetmeier for carefully tabulating the results. The recorded births were 6878, consisting of 3605 males and 3273 females, that is, in the proportion of 110.1 males to 100 females. The greatest fluctuations occurred in 1864, when the proportion was as 95.3 males, and in 1867, as 116.3 males to 100 females. The above average proportion of 110.1 to 100 is probably nearly correct in the case of the greyhound, but whether it would hold with other domesticated breeds is in some degree doubtful. Mr. Cupples has enquired from several great breeders of dogs, and finds that all without exception believe that females are produced in excess; but he suggests that this belief may have arisen from females being less valued, and from the consequent disappointment producing a stronger impression on the mind.

The sexes of sheep are not ascertained by agriculturists until several months after birth, at the period when the males are castrated; so that the following returns do not give the proportions at birth. Moreover, I find that several great breeders in Scotland, who annually raise some thousand sheep, are firmly convinced that a larger proportion of males than of females die during the first year or two. Therefore the proportion of males would be somewhat larger at birth than at the age of castration. This is a remarkable coincidence with what, as we have seen, occurs with mankind, and both cases probably depend on the same cause. I have received returns from four gentlemen in England who have bred Lowland sheep, chiefly Leicesters, during the last ten to sixteen years; they amount altogether to 8965 births, consisting of 4407 males and 4558 females; that is in the proportion of 96.7 males to 100 females. With respect to Cheviot and black-faced sheep bred in Scotland, I have received returns from six breeders, two of them on a large scale, chiefly for the years 1867-1869, but some of the returns extend back to 1862. The total number recorded amounts to 50,685, consisting of 25,071 males and 25,614 females or in the proportion of 97.9 males to 100 females. If we take the English and Scotch returns together, the total number amounts to 59,650, consisting of 29,478 males and 30,172 females, or as 97.7 to 100. So that with sheep at the age of castration the females are certainly in excess of the males, but probably this would not hold good at birth. (59. I am much indebted to Mr. Cupples for having procured for me the above returns from Scotland, as well as some of the following returns on cattle. Mr. R. Elliot, of Laighwood, first called my attention to the premature deaths of the males, —a statement subsequently confirmed by Mr. Aitchison and others. To this latter gentleman, and to Mr. Payan, I owe my thanks for large returns as to sheep.)

Of CATTLE I have received returns from nine gentlemen of 982 births, too few to be trusted; these consisted of 477 bull-calves and 505 cow-calves; i.e., in the proportion of 94.4 males to 100 females. The Rev. W.D. Fox informs me that in 1867 out of 34 calves born on a farm in Derbyshire only one was a bull. Mr. Harrison Weir has enquired from several breeders of PIGS, and most of them estimate the male to the female births as about 7 to 6. This same gentleman has bred RABBITS for many years, and has noticed that a far greater number of bucks are produced than does. But estimations are of little value.

Of mammalia in a state of nature I have been able to learn very little. In regard to the common rat, I have received conflicting statements. Mr. R. Elliot, of Laighwood, informs me that a rat-catcher assured him that he had always found the males in great excess, even with the young in the nest. In consequence of this, Mr. Elliot himself subsequently examined some hundred old ones, and found the statement true. Mr. F. Buckland has bred a large number of white rats, and he also believes that the males greatly exceed the females. In regard to Moles, it is said that “the males are much more numerous than the females” (60. Bell, ‘History of British Quadrupeds,’ p. 100.): and as the catching of these animals is a special occupation, the statement may perhaps be trusted. Sir A. Smith, in describing an antelope of S. Africa (61. ‘Illustrations of the Zoology of S. Africa,’ 1849, pl. 29.) (Kobus ellipsiprymnus), remarks, that in the herds of this and other species, the males are few in number compared with the females: the natives believe that they are born in this proportion; others believe that the younger males are expelled from the herds, and Sir A. Smith says, that though he has himself never seen herds consisting of young males alone, others affirm that this does occur. It appears probable that the young when expelled from the herd, would often fall a prey to the many beasts of prey of the country.

鸟类

With respect to the FOWL, I have received only one account, namely, that out of 1001 chickens of a highly-bred stock of Cochins, reared during eight years by Mr. Stretch, 487 proved males and 514 females; i.e., as 94.7 to 100. In regard to domestic pigeons there is good evidence either that the males are produced in excess, or that they live longer; for these birds invariably pair, and single males, as Mr. Tegetmeier informs me, can always be purchased cheaper than females. Usually the two birds reared from the two eggs laid in the same nest are a male and a female; but Mr. Harrison Weir, who has been so large a breeder, says that he has often bred two cocks from the same nest, and seldom two hens; moreover, the hen is generally the weaker of the two, and more liable to perish.

With respect to birds in a state of nature, Mr. Gould and others (62. Brehm (‘Thierleben,’ B. IV。 s. 990) comes to the same conclusion.) are convinced that the males are generally the more numerous; and as the young males of many species resemble the females, the latter would naturally appear to be the more numerous. Large numbers of pheasants are reared by Mr. Baker of Leadenhall from eggs laid by wild birds, and he informs Mr. Jenner Weir that four or five males to one female are generally produced. An experienced observer remarks (63. On the authority of L. Lloyd, ‘Game Birds of Sweden,’ 1867, pp. 12, 132.), that in Scandinavia the broods of the capercailzie and black-cock contain more males than females; and that with the Dal-ripa (a kind of ptarmigan) more males than females attend the leks or places of courtship; but this latter circumstance is accounted for by some observers by a greater number of hen birds being killed by vermin. From various facts given by White of Selborne (64. ‘Nat. 历史。 of Selborne,’ letter xxix. 编辑。 of 1825, vol. i. p. 139.), it seems clear that the males of the partridge must be in considerable excess in the south of England; and I have been assured that this is the case in Scotland. 先生。 Weir on enquiring from the dealers, who receive at certain seasons large numbers of ruffs (Machetes pugnax), was told that the males are much the more numerous. This same naturalist has also enquired for me from the birdcatchers, who annually catch an astonishing number of various small species alive for the London market, and he was unhesitatingly answered by an old and trustworthy man, that with the chaffinch the males are in large excess: he thought as high as 2 males to 1 female, or at least as high as 5 to 3. (65。 先生。 Jenner Weir received similar information, on making enquiries during the following year. To shew the number of living chaffinches caught, I may mention that in 1869 there was a match between two experts, and one man caught in a day 62, and another 40, male chaffinches. The greatest number ever caught by one man in a single day was 70.) The males of the blackbird, he likewise maintained, were by far the more numerous, whether caught by traps or by netting at night. These statements may apparently be trusted, because this same man said that the sexes are about equal with the lark, the twite (Linaria montana), and goldfinch. On the other hand, he is certain that with the common linnet, the females preponderate greatly, but unequally during different years; during some years he has found the females to the males as four to one. It should, however, be borne in mind, that the chief season for catching birds does not begin till September, so that with some species partial migrations may have begun, and the flocks at this period often consist of hens alone. 先生。 Salvin paid particular attention to the sexes of the humming-birds in Central America, and is convinced that with most of the species the males are in excess; thus one year he procured 204 specimens belonging to ten species, and these consisted of 166 males and of only 38 females. With two other species the females were in excess: but the proportions apparently vary either during different seasons or in different localities; for on one occasion the males of Campylopterus hemileucurus were to the females as 5 to 2, and on another occasion (66. ‘Ibis,’ vol. II。 p. 260, as quoted in Gould’s ‘Trochilidae,’ 1861, p. 52. For the foregoing proportions, I am indebted to Mr. Salvin for a table of his results.) in exactly the reversed ratio. As bearing on this latter point, I may add, that Mr. Powys found in Corfu and Epirus the sexes of the chaffinch keeping apart, and “the females by far the most numerous”; whilst in Palestine Mr. Tristram found “the male flocks appearing greatly to exceed the female in number.” (67. ‘Ibis,’ 1860, p. 137; and 1867, p. 369.) So again with the Quiscalus major, Mr. G. Taylor says, that in Florida there were “very few females in proportion to the males,” (68. ‘Ibis,’ 1862, p.

With fish the proportional numbers of the sexes can be ascertained only by catching them in the adult or nearly adult state; and there are many difficulties in arriving at any just conclusion. (69. Leuckart quotes Bloch (Wagner, ‘Handwörterbuch der Phys.’ B. iv. 1853, s. 775), that with fish there are twice as many males as females.) Infertile females might readily be mistaken for males, as Dr. Gunther has remarked to me in regard to trout. With some species the males are believed to die soon after fertilising the ova. With many species the males are of much smaller size than the females, so that a large number of males would escape from the same net by which the females were caught. M. Carbonnier (70. Quoted in the ‘Farmer,’ March 18, 1869, p. 369.), who has especially attended to the natural history of the pike (Esox lucius), states that many males, owing to their small size, are devoured by the larger females; and he believes that the males of almost all fish are exposed from this same cause to greater danger than the females. Nevertheless, in the few cases in which the proportional numbers have been actually observed, the males appear to be largely in excess. Thus Mr. R. Buist, the superintendent of the Stormontfield experiments, says that in 1865, out of 70 salmon first landed for the purpose of obtaining the ova, upwards of 60 were males. In 1867 he again “calls attention to the vast disproportion of the males to the females. We had at the outset at least ten males to one female.” Afterwards females sufficient for obtaining ova were procured. He adds, “from the great proportion of the males, they are constantly fighting and tearing each other on the spawning-beds.” (71. ‘The Stormontfield Piscicultural Experiments,’ 1866, p. 23. The ‘Field’ newspaper, June 29, 1867.) This disproportion, no doubt, can be accounted for in part, but whether wholly is doubtful, by the males ascending the rivers before the females. Mr. F. Buckland remarks in regard to trout, that “it is a curious fact that the males preponderate very largely in number over the females. It INVARIABLY happens that when the first rush of fish is made to the net, there will be at least seven or eight males to one female found captive. I cannot quite account for this; either the males are more numerous than the females, or the latter seek safety by concealment rather than flight.” He then adds, that by carefully searching the banks sufficient females for obtaining ova can be found. (72. ‘Land and Water,’ 1868, p. 41.) Mr. H. Lee informs me that out of 212 trout, taken for this purpose in Lord Portsmouth’s park, 150 were males and 62 females.

The males of the Cyprinidae likewise seem to be in excess; but several members of this Family, viz., the carp, tench, bream and minnow, appear regularly to follow the practice, rare in the animal kingdom, of polyandry; for the female whilst spawning is always attended by two males, one on each side, and in the case of the bream by three or four males. This fact is so well known, that it is always recommended to stock a pond with two male tenches to one female, or at least with three males to two females. With the minnow, an excellent observer states, that on the spawning-beds the males are ten times as numerous as the females; when a female comes amongst the males, “she is immediately pressed closely by a male on each side; and when they have been in that situation for a time, are superseded by other two males.” (73. Yarrell, ‘Hist. British Fishes,’ vol. i. 1826, p. 307; on the Cyprinus carpio, p. 331; on the Tinca vulgaris, p. 331; on the Abramis brama, p. 336. See, for the minnow (Leuciscus phoxinus), ‘Loudon’s Magazine of Natural History,’ vol. v. 1832, p. 682.)

昆虫

In this great Class, the Lepidoptera almost alone afford means for judging of the proportional numbers of the sexes; for they have been collected with special care by many good observers, and have been largely bred from the egg or caterpillar state. I had hoped that some breeders of silk-moths might have kept an exact record, but after writing to France and Italy, and consulting various treatises, I cannot find that this has ever been done. The general opinion appears to be that the sexes are nearly equal, but in Italy, as I hear from Professor Canestrini, many breeders are convinced that the females are produced in excess. This same naturalist, however, informs me, that in the two yearly broods of the Ailanthus silk-moth (Bombyx cynthia), the males greatly preponderate in the first, whilst in the second the two sexes are nearly equal, or the females rather in excess.

In regard to Butterflies in a state of nature, several observers have been much struck by the apparently enormous preponderance of the males. (74. Leuckart quotes Meinecke (Wagner, ‘Handwörterbuch der Phys.’ B. iv. 1853, s. 775) that the males of Butterflies are three or four times as numerous as the females.) Thus Mr. Bates (75. ‘The Naturalist on the Amazons,’ vol. ii. 1863, pp. 228, 347.), in speaking of several species, about a hundred in number, which inhabit the upper Amazons, says that the males are much more numerous than the females, even in the proportion of a hundred to one. In North America, Edwards, who had great experience, estimates in the genus Papilio the males to the females as four to one; and Mr. Walsh, who informed me of this statement, says that with P. turnus this is certainly the case. In South Africa, Mr. R. Trimen found the males in excess in 19 species (76. Four of these cases are given by Mr. Trimen in his ‘Rhopalocera Africae Australis.’); and in one of these, which swarms in open places, he estimated the number of males as fifty to one female. With another species, in which the males are numerous in certain localities, he collected only five females during seven years. In the island of Bourbon, M. Maillard states that the males of one species of Papilio are twenty times as numerous as the females. (77. Quoted by Trimen, ‘Transactions of the Ent. Society,’ vol. v. part iv. 1866, p. 330.) Mr. Trimen informs me that as far as he has himself seen, or heard from others, it is rare for the females of any butterfly to exceed the males in number; but three South African species perhaps offer an exception. Mr. Wallace (78. ‘Transactions, Linnean Society,’ vol. xxv. p. 37.) states that the females of Ornithoptera croesus, in the Malay archipelago, are more common and more easily caught than the males; but this is a rare butterfly. I may here add, that in Hyperythra, a genus of moths, Guenee says, that from four to five females are sent in collections from India for one male.

When this subject of the proportional numbers of the sexes of insects was brought before the Entomological Society (79. ‘Proceedings, Entomological Society,’ Feb. 17, 1868.), it was generally admitted that the males of most Lepidoptera, in the adult or imago state, are caught in greater numbers than the females: but this fact was attributed by various observers to the more retiring habits of the females, and to the males emerging earlier from the cocoon. This latter circumstance is well known to occur with most Lepidoptera, as well as with other insects. So that, as M. Personnat remarks, the males of the domesticated Bombyx Yamamai, are useless at the beginning of the season, and the females at the end, from the want of mates. (80. Quoted by Dr. Wallace in ‘Proceedings, Entomological Society,’ 3rd series, vol. v. 1867, p. 487.) I cannot, however, persuade myself that these causes suffice to explain the great excess of males, in the above cases of certain butterflies which are extremely common in their native countries. Mr. Stainton, who has paid very close attention during many years to the smaller moths, informs me that when he collected them in the imago state, he thought that the males were ten times as numerous as the females, but that since he has reared them on a large scale from the caterpillar state, he is convinced that the females are the more numerous. Several entomologists concur in this view. Mr. Doubleday, however, and some others, take an opposite view, and are convinced that they have reared from the eggs and caterpillars a larger proportion of males than of females.

Besides the more active habits of the males, their earlier emergence from the cocoon, and in some cases their frequenting more open stations, other causes may be assigned for an apparent or real difference in the proportional numbers of the sexes of Lepidoptera, when captured in the imago state, and when reared from the egg or caterpillar state. I hear from Professor Canestrini, that it is believed by many breeders in Italy, that the female caterpillar of the silk-moth suffers more from the recent disease than the male; and Dr. Staudinger informs me that in rearing Lepidoptera more females die in the cocoon than males. With many species the female caterpillar is larger than the male, and a collector would naturally choose the finest specimens, and thus unintentionally collect a larger number of females. Three collectors have told me that this was their practice; but Dr. Wallace is sure that most collectors take all the specimens which they can find of the rarer kinds, which alone are worth the trouble of rearing. Birds when surrounded by caterpillars would probably devour the largest; and Professor Canestrini informs me that in Italy some breeders believe, though on insufficient evidence, that in the first broods of the Ailanthus silk-moth, the wasps destroy a larger number of the female than of the male caterpillars. Dr. Wallace further remarks that female caterpillars, from being larger than the males, require more time for their development, and consume more food and moisture: and thus they would be exposed during a longer time to danger from ichneumons, birds, etc., and in times of scarcity would perish in greater numbers. Hence it appears quite possible that in a state of nature, fewer female Lepidoptera may reach maturity than males; and for our special object we are concerned with their relative numbers at maturity, when the sexes are ready to propagate their kind.

The manner in which the males of certain moths congregate in extraordinary numbers round a single female, apparently indicates a great excess of males, though this fact may perhaps be accounted for by the earlier emergence of the males from their cocoons. Mr. Stainton informs me that from twelve to twenty males, may often be seen congregated round a female Elachista rufocinerea. It is well known that if a virgin Lasiocampa quercus or Saturnia carpini be exposed in a cage, vast numbers of males collect round her, and if confined in a room will even come down the chimney to her. Mr. Doubleday believes that he has seen from fifty to a hundred males of both these species attracted in the course of a single day by a female in confinement. In the Isle of Wight Mr. Trimen exposed a box in which a female of the Lasiocampa had been confined on the previous day, and five males soon endeavoured to gain admittance. In Australia, Mr. Verreaux, having placed the female of a small Bombyx in a box in his pocket, was followed by a crowd of males, so that about 200 entered the house with him. (81. Blanchard, ‘Metamorphoses, Moeurs des Insectes,’ 1868, pp. 225-226.)

Mr. Doubleday has called my attention to M. Staudinger’s (82. ‘Lepidopteren-Doubletten Liste,’ Berlin, No. x. 1866.) list of Lepidoptera, which gives the prices of the males and females of 300 species or well- marked varieties of butterflies (Rhopalocera). The prices for both sexes of the very common species are of course the same; but in 114 of the rarer species they differ; the males being in all cases, excepting one, the cheaper. On an average of the prices of the 113 species, the price of the male to that of the female is as 100 to 149; and this apparently indicates that inversely the males exceed the females in the same proportion. About 2000 species or varieties of moths (Heterocera) are catalogued, those with wingless females being here excluded on account of the difference in habits between the two sexes: of these 2000 species, 141 differ in price according to sex, the males of 130 being cheaper, and those of only 11 being dearer than the females. The average price of the males of the 130 species, to that of the females, is as 100 to 143. With respect to the butterflies in this priced list, Mr. Doubleday thinks (and no man in England has had more experience), that there is nothing in the habits of the species which can account for the difference in the prices of the two sexes, and that it can be accounted for only by an excess in the number of the males. But I am bound to add that Dr. Staudinger informs me, that he is himself of a different opinion. He thinks that the less active habits of the females and the earlier emergence of the males will account for his collectors securing a larger number of males than of females, and consequently for the lower prices of the former. With respect to specimens reared from the caterpillar-state, Dr. Staudinger believes, as previously stated, that a greater number of females than of males die whilst confined to the cocoons. He adds that with certain species one sex seems to preponderate over the other during certain years.

Of direct observations on the sexes of Lepidoptera, reared either from eggs or caterpillars, I have received only the few following cases: (See following table.)

So that in these eight lots of cocoons and eggs, males were produced in excess. Taken together the proportion of males is as 122.7 to 100 females. But the numbers are hardly large enough to be trustworthy.

On the whole, from these various sources of evidence, all pointing in the same direction, I infer that with most species of Lepidoptera, the mature males generally exceed the females in number, whatever the proportions may be at their first emergence from the egg.

Males Females
The Rev. J. Hellins* of Exeter reared, during
1868, imagos of 73 species, which
consisted of 153 137

Mr. Albert Jones of Eltham reared, during 1868, imagos of 9 species, which consisted of 159 126

During 1869 he reared imagos from 4 species consisting of 114 112

Mr. Buckler of Emsworth, Hants, during 1869, reared imagos from 74 species, consisting of 180 169

Dr. Wallace of Colchester reared from one
brood of Bombyx cynthia 52 48

Dr. Wallace raised, from cocoons of Bombyx
Pernyi sent from China, during 1869 224 123

Dr. Wallace raised, during 1868 and 1869, from
two lots of cocoons of Bombyx yamamai 52 46

总计934

(*83. This naturalist has been so kind as to send me some results from former years, in which the females seemed to preponderate; but so many of the figures were estimates, that I found it impossible to tabulate them.)

With reference to the other Orders of insects, I have been able to collect very little reliable information. With the stag-beetle (Lucanus cervus) “the males appear to be much more numerous than the females”; but when, as Cornelius remarked during 1867, an unusual number of these beetles appeared in one part of Germany, the females appeared to exceed the males as six to one. With one of the Elateridae, the males are said to be much more numerous than the females, and “two or three are often found united with one female (84. Gunther’s ‘Record of Zoological Literature,’ 1867, p. 260. On the excess of female Lucanus, ibid, p. 250. On the males of Lucanus in England, Westwood,’ ‘Modern Classification of Insects,’ vol. i. p. 187. On the Siagonium, ibid. p. 172.); so that here polyandry seems to prevail.” With Siagonium (Staphylinidae), in which the males are furnished with horns, “the females are far more numerous than the opposite sex.” Mr. Janson stated at the Entomological Society that the females of the bark feeding Tomicus villosus are so common as to be a plague, whilst the males are so rare as to be hardly known.

It is hardly worth while saying anything about the proportion of the sexes in certain species and even groups of insects, for the males are unknown or very rare, and the females are parthenogenetic, that is, fertile without sexual union; examples of this are afforded by several of the Cynipidae. (85。 Walsh in ‘The American Entomologist,’ vol. i. 1869。 103. F. Smith, ‘Record of Zoological Lit.’ 1867, p. 328.) In all the gall-making Cynipidae known to Mr. Walsh, the females are four or five times as numerous as the males; and so it is, as he informs me, with the gall-making Cecidomyiidae (Diptera). With some common species of Saw-flies (Tenthredinae) Mr. F. Smith has reared hundreds of specimens from larvae of all sizes, but has never reared a single male; on the other hand, Curtis says (86. ‘Farm Insects,’ pp. 45-46.), that with certain species (Athalia), bred by him, the males were to the females as six to one; whilst exactly the reverse occurred with the mature insects of the same species caught in the fields. In the family of bees, Hermann Müller (87. ‘Anwendung der Darwin’schen Lehre,’ Verh. d. n. Jahrg., xxiv.), collected a large number of specimens of many species, and reared others from the cocoons, and counted the sexes. He found that the males of some species greatly exceeded the females in number; in others the reverse occurred; and in others the two sexes were nearly equal. But as in most cases the males emerge from the cocoons before the females, they are at the commencement of the breeding-season practically in excess. Müller also observed that the relative number of the two sexes in some species differed much in different localities. But as H. Müller has himself remarked to me, these remarks must be received with some caution, as one sex might more easily escape observation than the other. Thus his brother Fritz Müller has noticed in Brazil that the two sexes of the same species of bee sometimes frequent different kinds of flowers. With respect to the Orthoptera, I know hardly anything about the relative number of the sexes: Korte (88. ‘Die Strich, Zug oder Wanderheuschrecke,’ 1828, p. 20.), however, says that out of 500 locusts which he examined, the males were to the females as five to six. With the Neuroptera, Mr. Walsh states that in many, but by no means in all the species of the Odonatous group, there is a great overplus of males: in the genus Hetaerina, also, the males are generally at least four times as numerous as the females. In certain species in the genus Gomphus the males are equally in excess, whilst in two other species, the females are twice or thrice as numerous as the males. In some European species of Psocus thousands of females may be collected without a single male, whilst with other species of the same genus both sexes are common. (89。 ‘Observations on N. American Neuroptera,’ by H. Hagen and B.D. Walsh, ‘Proceedings, Ent. SOC。 Philadelphia,’ Oct. 1863页。 168, 223, 239.) In England, Mr. MacLachlan has captured hundreds of the female Apatania muliebris, but has never seen the male; and of Boreus hyemalis only four or five males have been seen here. (90。 ‘Proceedings, Ent. SOC。 London,’ Feb.

In the other classes of the Articulata I have been able to collect still less information. With spiders, Mr. Blackwall, who has carefully attended to this class during many years, writes to me that the males from their more erratic habits are more commonly seen, and therefore appear more numerous. This is actually the case with a few species; but he mentions several species in six genera, in which the females appear to be much more numerous than the males. (91. Another great authority with respect to this class, Prof. Thorell of Upsala (‘On European Spiders,’ 1869-70, part i. p. 205), speaks as if female spiders were generally commoner than the males.) The small size of the males in comparison with the females (a peculiarity which is sometimes carried to an extreme degree), and their widely different appearance, may account in some instances for their rarity in collections. (92. See, on this subject, Mr. O.P. Cambridge, as quoted in ‘Quarterly Journal of Science,’ 1868, page 429.)

Some of the lower Crustaceans are able to propagate their kind sexually, and this will account for the extreme rarity of the males; thus von Siebold (93. ‘Beiträge zur Parthenogenesis,’ p. 174.) carefully examined no less than 13,000 specimens of Apus from twenty-one localities, and amongst these he found only 319 males. With some other forms (as Tanais and Cypris), as Fritz Müller informs me, there is reason to believe that the males are much shorter-lived than the females; and this would explain their scarcity, supposing the two sexes to be at first equal in number. On the other hand, Müller has invariably taken far more males than females of the Diastylidae and of Cypridina on the shores of Brazil: thus with a species in the latter genus, 63 specimens caught the same day included 57 males; but he suggests that this preponderance may be due to some unknown difference in the habits of the two sexes. With one of the higher Brazilian crabs, namely a Gelasimus, Fritz Müller found the males to be more numerous than the females. According to the large experience of Mr. C. Spence Bate, the reverse seems to be the case with six common British crabs, the names of which he has given me.

The Proportion of the Sexes in Relation to Natural Selection

There is reason to suspect that in some cases man has by selection indirectly influenced his own sex-producing powers. Certain women tend to produce during their whole lives more children of one sex than of the other: and the same holds good of many animals, for instance, cows and horses; thus Mr. Wright of Yeldersley House informs me that one of his Arab mares, though put seven times to different horses, produced seven fillies. Though I have very little evidence on this head, analogy would lead to the belief, that the tendency to produce either sex would be inherited like almost every other peculiarity, for instance, that of producing twins; and concerning the above tendency a good authority, Mr. J. Downing, has communicated to me facts which seem to prove that this does occur in certain families of short-horn cattle. Col. Marshall (94. ‘The Todas,’ 1873, pp. 100, 111, 194, 196.) has recently found on careful examination that the Todas, a hill-tribe of India, consist of 112 males and 84 females of all ages—that is in a ratio of 133.3 males to 100 females. The Todas, who are polyandrous in their marriages, during former times invariably practised female infanticide; but this practice has now been discontinued for a considerable period. Of the children born within late years, the males are more numerous than the females, in the proportion of 124 to 100. Colonel Marshall accounts for this fact in the following ingenious manner. “Let us for the purpose of illustration take three families as representing an average of the entire tribe; say that one mother gives birth to six daughters and no sons; a second mother has six sons only, whilst the third mother has three sons and three daughters. The first mother, following the tribal custom, destroys four daughters and preserves two. The second retains her six sons. The third kills two daughters and keeps one, as also her three sons. We have then from the three families, nine sons and three daughters, with which to continue the breed. But whilst the males belong to families in which the tendency to produce sons is great, the females are of those of a converse inclination. Thus the bias strengthens with each generation, until, as we find, families grow to have habitually more sons than daughters.”

That this result would follow from the above form of infanticide seems almost certain; that is if we assume that a sex-producing tendency is inherited. But as the above numbers are so extremely scanty, I have searched for additional evidence, but cannot decide whether what I have found is trustworthy; nevertheless the facts are, perhaps, worth giving. The Maories of New Zealand have long practised infanticide; and Mr. Fenton (95. ‘Aboriginal Inhabitants of New Zealand: Government Report,’ 1859, p. 36.) states that he “has met with instances of women who have destroyed four, six, and even seven children, mostly females. However, the universal testimony of those best qualified to judge, is conclusive that this custom has for many years been almost extinct. Probably the year 1835 may be named as the period of its ceasing to exist.” Now amongst the New Zealanders, as with the Todas, male births are considerably in excess. Mr. Fenton remarks (p. 30), “One fact is certain, although the exact period of the commencement of this singular condition of the disproportion of the sexes cannot be demonstratively fixed, it is quite clear that this course of decrease was in full operation during the years 1830 to 1844, when the non-adult population of 1844 was being produced, and has continued with great energy up to the present time.” The following statements are taken from Mr. Fenton (p. 26), but as the numbers are not large, and as the census was not accurate, uniform results cannot be expected. It should be borne in mind in this and the following cases, that the normal state of every population is an excess of women, at least in all civilised countries, chiefly owing to the greater mortality of the male sex during youth, and partly to accidents of all kinds later in life. In 1858, the native population of New Zealand was estimated as consisting of 31,667 males and 24,303 females of all ages, that is in the ratio of 130.3 males to 100 females. But during this same year, and in certain limited districts, the numbers were ascertained with much care, and the males of all ages were here 753 and the females 616; that is in the ratio of 122.2 males to 100 females. It is more important for us that during this same year of 1858, the NON-ADULT males within the same district were found to be 178, and the NON-ADULT females 142, that is in the ratio of 125.3 to 100. It may be added that in 1844, at which period female infanticide had only lately ceased, the NON-ADULT males in one district were 281, and the NON- ADULT females only 194, that is in the ratio of 144.8 males to 100 females.

In the Sandwich Islands, the males exceed the females in number. Infanticide was formerly practised there to a frightful extent, but was by no means confined to female infants, as is shewn by Mr. Ellis (96. ‘Narrative of a Tour through Hawaii,’ 1826, p. 298.), and as I have been informed by Bishop Staley and the Rev. Mr. Coan. Nevertheless, another apparently trustworthy writer, Mr. Jarves (97. ‘History of the Sandwich Islands,’ 1843, p. 93.), whose observations apply to the whole archipelago, remarks:—”Numbers of women are to be found, who confess to the murder of from three to six or eight children,” and he adds, “females from being considered less useful than males were more often destroyed.” From what is known to occur in other parts of the world, this statement is probable; but must be received with much caution. The practice of infanticide ceased about the year 1819, when idolatry was abolished and missionaries settled in the Islands. A careful census in 1839 of the adult and taxable men and women in the island of Kauai and in one district of Oahu (Jarves, p. 404), gives 4723 males and 3776 females; that is in the ratio of 125.08 to 100. At the same time the number of males under fourteen years in Kauai and under eighteen in Oahu was 1797, and of females of the same ages 1429; and here we have the ratio of 125.75 males to 100 females.

In a census of all the islands in 1850 (98. This is given in the Rev. H.T. Cheever’s ‘Life in the Sandwich Islands,’ 1851, p. 277.), the males of all ages amount to 36,272, and the females to 33,128, or as 109.49 to 100. The males under seventeen years amounted to 10,773, and the females under the same age to 9593, or as 112.3 to 100. From the census of 1872, the proportion of males of all ages (including half-castes) to females, is as 125.36 to 100. It must be borne in mind that all these returns for the Sandwich Islands give the proportion of living males to living females, and not of the births; and judging from all civilised countries the proportion of males would have been considerably higher if the numbers had referred to births. (99. Dr. Coulter, in describing (‘Journal R. Geograph. Soc.’ vol. v. 1835, p. 67) the state of California about the year 1830, says that the natives, reclaimed by the Spanish missionaries, have nearly all perished, or are perishing, although well treated, not driven from their native land, and kept from the use of spirits. He attributes this, in great part, to the undoubted fact that the men greatly exceed the women in number; but he does not know whether this is due to a failure of female offspring, or to more females dying during early youth. The latter alternative, according to all analogy, is very improbable. He adds that “infanticide, properly so called, is not common, though very frequent recourse is had to abortion.” If Dr. Coulter is correct about infanticide, this case cannot be advanced in support of Colonel Marshall’s view. From the rapid decrease of the reclaimed natives, we may suspect that, as in the cases lately given, their fertility has been diminished from changed habits of life.

I had hoped to gain some light on this subject from the breeding of dogs; inasmuch as in most breeds, with the exception, perhaps, of greyhounds, many more female puppies are destroyed than males, just as with the Toda infants. Mr. Cupples assures me that this is usual with Scotch deer- hounds. Unfortunately, I know nothing of the proportion of the sexes in any breed, excepting greyhounds, and there the male births are to the females as 110.1 to 100. Now from enquiries made from many breeders, it seems that the females are in some respects more esteemed, though otherwise troublesome; and it does not appear that the female puppies of the best- bred dogs are systematically destroyed more than the males, though this does sometimes take place to a limited extent. Therefore I am unable to decide whether we can, on the above principles, account for the preponderance of male births in greyhounds. On the other hand, we have seen that with horses, cattle, and sheep, which are too valuable for the young of either sex to be destroyed, if there is any difference, the females are slightly in excess.)

From the several foregoing cases we have some reason to believe that infanticide practised in the manner above explained, tends to make a male- producing race; but I am far from supposing that this practice in the case of man, or some analogous process with other species, has been the sole determining cause of an excess of males. There may be some unknown law leading to this result in decreasing races, which have already become somewhat infertile. Besides the several causes previously alluded to, the greater facility of parturition amongst savages, and the less consequent injury to their male infants, would tend to increase the proportion of live-born males to females. There does not, however, seem to be any necessary connection between savage life and a marked excess of males; that is if we may judge by the character of the scanty offspring of the lately existing Tasmanians and of the crossed offspring of the Tahitians now inhabiting Norfolk Island.

As the males and females of many animals differ somewhat in habits and are exposed in different degrees to danger, it is probable that in many cases, more of one sex than of the other are habitually destroyed. But as far as I can trace out the complication of causes, an indiscriminate though large destruction of either sex would not tend to modify the sex-producing power of the species. With strictly social animals, such as bees or ants, which produce a vast number of sterile and fertile females in comparison with the males, and to whom this preponderance is of paramount importance, we can see that those communities would flourish best which contained females having a strong inherited tendency to produce more and more females; and in such cases an unequal sex-producing tendency would be ultimately gained through natural selection. With animals living in herds or troops, in which the males come to the front and defend the herd, as with the bisons of North America and certain baboons, it is conceivable that a male- producing tendency might be gained by natural selection; for the individuals of the better defended herds would leave more numerous descendants. In the case of mankind the advantage arising from having a preponderance of men in the tribe is supposed to be one chief cause of the practice of female infanticide.

In no case, as far as we can see, would an inherited tendency to produce both sexes in equal numbers or to produce one sex in excess, be a direct advantage or disadvantage to certain individuals more than to others; for instance, an individual with a tendency to produce more males than females would not succeed better in the battle for life than an individual with an opposite tendency; and therefore a tendency of this kind could not be gained through natural selection. Nevertheless, there are certain animals (for instance, fishes and cirripedes) in which two or more males appear to be necessary for the fertilisation of the female; and the males accordingly largely preponderate, but it is by no means obvious how this male-producing tendency could have been acquired. I formerly thought that when a tendency to produce the two sexes in equal numbers was advantageous to the species, it would follow from natural selection, but I now see that the whole problem is so intricate that it is safer to leave its solution for the future.

第九章 •5,800字
动物王国下层阶级的第二性征

These characters absent in the lowest classes—Brilliant colours—Mollusca —Annelids—Crustacea, secondary sexual characters strongly developed; dimorphism; colour; characters not acquired before maturity—Spiders, sexual colours of; stridulation by the males—Myriapoda.

With animals belonging to the lower classes, the two sexes are not rarely united in the same individual, and therefore secondary sexual characters cannot be developed. In many cases where the sexes are separate, both are permanently attached to some support, and the one cannot search or struggle for the other. Moreover it is almost certain that these animals have too imperfect senses and much too low mental powers to appreciate each other’s beauty or other attractions, or to feel rivalry.

Hence in these classes or sub-kingdoms, such as the Protozoa, Coelenterata, Echinodermata, Scolecida, secondary sexual characters, of the kind which we have to consider, do not occur: and this fact agrees with the belief that such characters in the higher classes have been acquired through sexual selection, which depends on the will, desire, and choice of either sex. Nevertheless some few apparent exceptions occur; thus, as I hear from Dr. Baird, the males of certain Entozoa, or internal parasitic worms, differ slightly in colour from the females; but we have no reason to suppose that such differences have been augmented through sexual selection. Contrivances by which the male holds the female, and which are indispensable for the propagation of the species, are independent of sexual selection, and have been acquired through ordinary selection.

Many of the lower animals, whether hermaphrodites or with separate sexes, are ornamented with the most brilliant tints, or are shaded and striped in an elegant manner; for instance, many corals and sea-anemones (Actiniae), some jelly-fish (Medusae, Porpita, etc.), some Planariae, many star-fishes, Echini, Ascidians, etc.; but we may conclude from the reasons already indicated, namely, the union of the two sexes in some of these animals, the permanently affixed condition of others, and the low mental powers of all, that such colours do not serve as a sexual attraction, and have not been acquired through sexual selection. It should be borne in mind that in no case have we sufficient evidence that colours have been thus acquired, except where one sex is much more brilliantly or conspicuously coloured than the other, and where there is no difference in habits between the sexes sufficient to account for their different colours. But the evidence is rendered as complete as it can ever be, only when the more ornamented individuals, almost always the males, voluntarily display their attractions before the other sex; for we cannot believe that such display is useless, and if it be advantageous, sexual selection will almost inevitably follow. We may, however, extend this conclusion to both sexes, when coloured alike, if their colours are plainly analogous to those of one sex alone in certain other species of the same group.

How, then, are we to account for the beautiful or even gorgeous colours of many animals in the lowest classes? It appears doubtful whether such colours often serve as a protection; but that we may easily err on this head, will be admitted by every one who reads Mr. Wallace’s excellent essay on this subject. It would not, for instance, at first occur to any one that the transparency of the Medusae, or jelly-fish, is of the highest service to them as a protection; but when we are reminded by Haeckel that not only the Medusae, but many floating Mollusca, crustaceans, and even small oceanic fishes partake of this same glass-like appearance, often accompanied by prismatic colours, we can hardly doubt that they thus escape the notice of pelagic birds and other enemies. M. Giard is also convinced (1. ‘Archives de Zoolog. Exper.’ Oct. 1872, p. 563.) that the bright tints of certain sponges and ascidians serve as a protection. Conspicuous colours are likewise beneficial to many animals as a warning to their would-be devourers that they are distasteful, or that they possess some special means of defence; but this subject will be discussed more conveniently hereafter.

We can, in our ignorance of most of the lowest animals, only say that their bright tints result either from the chemical nature or the minute structure of their tissues, independently of any benefit thus derived. Hardly any colour is finer than that of arterial blood; but there is no reason to suppose that the colour of the blood is in itself any advantage; and though it adds to the beauty of the maiden’s cheek, no one will pretend that it has been acquired for this purpose. So again with many animals, especially the lower ones, the bile is richly coloured; thus, as I am informed by Mr. Hancock, the extreme beauty of the Eolidae (naked sea-slugs) is chiefly due to the biliary glands being seen through the translucent integuments—this beauty being probably of no service to these animals. The tints of the decaying leaves in an American forest are described by every one as gorgeous; yet no one supposes that these tints are of the least advantage to the trees. Bearing in mind how many substances closely analogous to natural organic compounds have been recently formed by chemists, and which exhibit the most splendid colours, it would have been a strange fact if substances similarly coloured had not often originated, independently of any useful end thus gained, in the complex laboratory of living organisms.

The Sub-Kingdom of the Mollusca

Throughout this great division of the animal kingdom, as far as I can discover, secondary sexual characters, such as we are here considering, never occur. Nor could they be expected in the three lowest classes, namely, in the Ascidians, Polyzoa, and Brachiopods (constituting the Molluscoida of some authors), for most of these animals are permanently affixed to a support or have their sexes united in the same individual. In the Lamellibranchiata, or bivalve shells, hermaphroditism is not rare. In the next higher class of the Gasteropoda, or univalve shells, the sexes are either united or separate. But in the latter case the males never possess special organs for finding, securing, or charming the females, or for fighting with other males. As I am informed by Mr. Gwyn Jeffreys, the sole external difference between the sexes consists in the shell sometimes differing a little in form; for instance, the shell of the male periwinkle (Littorina littorea) is narrower and has a more elongated spire than that of the female. But differences of this nature, it may be presumed, are directly connected with the act of reproduction, or with the development of the ova.

The Gasteropoda, though capable of locomotion and furnished with imperfect eyes, do not appear to be endowed with sufficient mental powers for the members of the same sex to struggle together in rivalry, and thus to acquire secondary sexual characters. Nevertheless with the pulmoniferous gasteropods, or land-snails, the pairing is preceded by courtship; for these animals, though hermaphrodites, are compelled by their structure to pair together. Agassiz remarks, “Quiconque a eu l’occasion d’observer les amours des limaçons, ne saurait mettre en doute la séduction deployée dans les mouvements et les allures qui préparent et accomplissent le double embrassement de ces hermaphrodites.” (2. ‘De l’Espèce et de la Class.’ etc., 1869, p. 106.) These animals appear also susceptible of some degree of permanent attachment: an accurate observer, Mr. Lonsdale, informs me that he placed a pair of land-snails, (Helix pomatia), one of which was weakly, into a small and ill-provided garden. After a short time the strong and healthy individual disappeared, and was traced by its track of slime over a wall into an adjoining well-stocked garden. Mr. Lonsdale concluded that it had deserted its sickly mate; but after an absence of twenty-four hours it returned, and apparently communicated the result of its successful exploration, for both then started along the same track and disappeared over the wall.

Even in the highest class of the Mollusca, the Cephalopoda or cuttle- fishes, in which the sexes are separate, secondary sexual characters of the present kind do not, as far as I can discover, occur. This is a surprising circumstance, as these animals possess highly-developed sense-organs and have considerable mental powers, as will be admitted by every one who has watched their artful endeavours to escape from an enemy. (3. See, for instance, the account which I have given in my ‘Journal of Researches,’ 1845, p. 7.) Certain Cephalopoda, however, are characterised by one extraordinary sexual character, namely that the male element collects within one of the arms or tentacles, which is then cast off, and clinging by its sucking-discs to the female, lives for a time an independent life. So completely does the cast-off arm resemble a separate animal, that it was described by Cuvier as a parasitic worm under the name of Hectocotyle. But this marvellous structure may be classed as a primary rather than as a secondary sexual character.

Although with the Mollusca sexual selection does not seem to have come into play; yet many univalve and bivalve shells, such as volutes, cones, scallops, etc., are beautifully coloured and shaped. The colours do not appear in most cases to be of any use as a protection; they are probably the direct result, as in the lowest classes, of the nature of the tissues; the patterns and the sculpture of the shell depending on its manner of growth. The amount of light seems to be influential to a certain extent; for although, as repeatedly stated by Mr. Gwyn Jeffreys, the shells of some species living at a profound depth are brightly coloured, yet we generally see the lower surfaces, as well as the parts covered by the mantle, less highly-coloured than the upper and exposed surfaces. (4. I have given (‘Geological Observations on Volcanic Islands,’ 1844, p. 53) a curious instance of the influence of light on the colours of a frondescent incrustation, deposited by the surf on the coast-rocks of Ascension and formed by the solution of triturated sea-shells.) In some cases, as with shells living amongst corals or brightly-tinted seaweeds, the bright colours may serve as a protection. (5. Dr. Morse has lately discussed this subject in his paper on the ‘Adaptive Coloration of Mollusca,’ ‘Proc. Boston Soc. of Nat. Hist.’ vol. xiv. April 1871.) But that many of the nudibranch Mollusca, or sea-slugs, are as beautifully coloured as any shells, may be seen in Messrs. Alder and Hancock’s magnificent work; and from information kindly given me by Mr. Hancock, it seems extremely doubtful whether these colours usually serve as a protection. With some species this may be the case, as with one kind which lives on the green leaves of algae, and is itself bright-green. But many brightly-coloured, white, or otherwise conspicuous species, do not seek concealment; whilst again some equally conspicuous species, as well as other dull-coloured kinds live under stones and in dark recesses. So that with these nudibranch molluscs, colour apparently does not stand in any close relation to the nature of the places which they inhabit.

These naked sea-slugs are hermaphrodites, yet they pair together, as do land-snails, many of which have extremely pretty shells. It is conceivable that two hermaphrodites, attracted by each other’s greater beauty, might unite and leave offspring which would inherit their parents’ greater beauty. But with such lowly-organised creatures this is extremely improbable. Nor is it at all obvious how the offspring from the more beautiful pairs of hermaphrodites would have any advantage over the offspring of the less beautiful, so as to increase in number, unless indeed vigour and beauty generally coincided. We have not here the case of a number of males becoming mature before the females, with the more beautiful males selected by the more vigorous females. If, indeed, brilliant colours were beneficial to a hermaphrodite animal in relation to its general habits of life, the more brightly-tinted individuals would succeed best and would increase in number; but this would be a case of natural and not of sexual selection.

Sub-Kingdom of the Vermes: Class, Annelida (Or Sea-Worms)

In this class, although the sexes, when separate, sometimes differ from each other in characters of such importance that they have been placed under distinct genera or even families, yet the differences do not seem of the kind which can be safely attributed to sexual selection. These animals are often beautifully coloured, but as the sexes do not differ in this respect, we are but little concerned with them. Even the Nemertians, though so lowly organised, “vie in beauty and variety of colouring with any other group in the invertebrate series”; yet Dr. McIntosh (6. See his beautiful monograph on ‘British Annelids,’ part i. 1873, p. 3.) cannot discover that these colours are of any service. The sedentary annelids become duller-coloured, according to M. Quatrefages (7. See M. Perrier: ‘L’Origine de l’Homme d’après Darwin,’ ‘Revue Scientifique’, Feb. 1873, p. 866.), after the period of reproduction; and this I presume may be attributed to their less vigorous condition at that time. All these worm- like animals apparently stand too low in the scale for the individuals of either sex to exert any choice in selecting a partner, or for the individuals of the same sex to struggle together in rivalry.

Sub-Kingdom of the Arthropoda: Class, Crustacea

In this great class we first meet with undoubted secondary sexual characters, often developed in a remarkable manner. Unfortunately the habits of crustaceans are very imperfectly known, and we cannot explain the uses of many structures peculiar to one sex. With the lower parasitic species the males are of small size, and they alone are furnished with perfect swimming-legs, antennae and sense-organs; the females being destitute of these organs, with their bodies often consisting of a mere distorted mass. But these extraordinary differences between the two sexes are no doubt related to their widely different habits of life, and consequently do not concern us. In various crustaceans, belonging to distinct families, the anterior antennae are furnished with peculiar thread-like bodies, which are believed to act as smelling-organs, and these are much more numerous in the males than in the females. As the males, without any unusual development of their olfactory organs, would almost certainly be able sooner or later to find the females, the increased number of the smelling-threads has probably been acquired through sexual selection, by the better provided males having been the more successful in finding partners and in producing offspring. Fritz Müller has described a remarkable dimorphic species of Tanais, in which the male is represented by two distinct forms, which never graduate into each other. In the one form the male is furnished with more numerous smelling-threads, and in the other form with more powerful and more elongated chelae or pincers, which serve to hold the female. Fritz Müller suggests that these differences between the two male forms of the same species may have originated in certain individuals having varied in the number of the smelling-threads, whilst other individuals varied in the shape and size of their chelae; so that of the former, those which were best able to find the female, and of the latter, those which were best able to hold her, have left the greatest number of progeny to inherit their respective advantages. (8. ‘Facts and Arguments for Darwin,’ English translat., 1869, p. 20. See the previous discussion on the olfactory threads. Sars has described a somewhat analogous case (as quoted in ‘Nature,’ 1870, p. 455) in a Norwegian crustacean, the Pontoporeia affinis.)

[Fig.4. Labidocera Darwinii (from Lubbock). Labelled are: a. Part of right anterior antenna of male, forming a prehensile organ. b. Posterior pair of thoracic legs of male. c. Ditto of female.]

In some of the lower crustaceans, the right anterior antenna of the male differs greatly in structure from the left, the latter resembling in its simple tapering joints the antennae of the female. In the male the modified antenna is either swollen in the middle or angularly bent, or converted (Fig. 4) into an elegant, and sometimes wonderfully complex, prehensile organ. (9. See Sir J. Lubbock in ‘Annals and Mag. of Nat. Hist.’ vol. xi. 1853, pl. i. and x.; and vol. xii. (1853), pl. vii. See also Lubbock in ‘Transactions, Entomological Society,’ vol. iv. new series, 1856-1858, p. 8. With respect to the zigzagged antennae mentioned below, see Fritz Müller, ‘Facts and Arguments for Darwin,’ 1869, p. 40, foot- note.) It serves, as I hear from Sir J. Lubbock, to hold the female, and for this same purpose one of the two posterior legs (b) on the same side of the body is converted into a forceps. In another family the inferior or posterior antennae are “curiously zigzagged” in the males alone.

[Fig. 5. Anterior part of body of Callianassa (from Milne-Edwards), showing the unequal and differently-constructed right and left-hand chelae of the male. N.B.—The artist by mistake has reversed the drawing, and made the left-hand chela the largest.

Fig. 6. Second leg of male Orchestia Tucuratinga (from Fritz Müller).

Fig. 7. Ditto of female.]

In the higher crustaceans the anterior legs are developed into chelae or pincers; and these are generally larger in the male than in the female,—so much so that the market value of the male edible crab (Cancer pagurus), according to Mr. C. Spence Bate, is five times as great as that of the female. In many species the chelae are of unequal size on the opposite side of the body, the right-hand one being, as I am informed by Mr. Bate, generally, though not invariably, the largest. This inequality is also often much greater in the male than in the female. The two chelae of the male often differ in structure (Figs. 5, 6, and 7), the smaller one resembling that of the female. What advantage is gained by their inequality in size on the opposite sides of the body, and by the inequality being much greater in the male than in the female; and why, when they are of equal size, both are often much larger in the male than in the female, is not known. As I hear from Mr. Bate, the chelae are sometimes of such length and size that they cannot possibly be used for carrying food to the mouth. In the males of certain fresh-water prawns (Palaemon) the right leg is actually longer than the whole body. (10. See a paper by Mr. C. Spence Bate, with figures, in ‘Proceedings, Zoological Society,’ 1868, p. 363; and on the nomenclature of the genus, ibid. p. 585. I am greatly indebted to Mr. Spence Bate for nearly all the above statements with respect to the chelae of the higher crustaceans.) The great size of the one leg with its chelae may aid the male in fighting with his rivals; but this will not account for their inequality in the female on the opposite sides of the body. In Gelasimus, according to a statement quoted by Milne Edwards (11. ‘Hist. Nat. des Crust.’ tom. ii. 1837, p. 50.), the male and the female live in the same burrow, and this shews that they pair; the male closes the mouth of the burrow with one of its chelae, which is enormously developed; so that here it indirectly serves as a means of defence. Their main use, however, is probably to seize and to secure the female, and this in some instances, as with Gammarus, is known to be the case. The male of the hermit or soldier crab (Pagurus) for weeks together, carries about the shell inhabited by the female. (12. Mr. C. Spence Bate, ‘British Association, Fourth Report on the Fauna of S. Devon.’) The sexes, however, of the common shore-crab (Carcinus maenas), as Mr. Bate informs me, unite directly after the female has moulted her hard shell, when she is so soft that she would be injured if seized by the strong pincers of the male; but as she is caught and carried about by the male before moulting, she could then be seized with impunity.

[Fig.8. Orchestia Darwinii (from Fritz Müller), showing the differently- constructed chelae of the two male forms.]

Fritz Müller states that certain species of Melita are distinguished from all other amphipods by the females having “the coxal lamellae of the penultimate pair of feet produced into hook-like processes, of which the males lay hold with the hands of the first pair.” The development of these hook-like processes has probably followed from those females which were the most securely held during the act of reproduction, having left the largest number of offspring. Another Brazilian amphipod (see Orchestia darwinii, Fig. 8) presents a case of dimorphism, like that of Tanais; for there are two male forms, which differ in the structure of their chelae. (13. Fritz Müller, ‘Facts and Arguments for Darwin,’ 1869, pp. 25-28.) As either chela would certainly suffice to hold the female,—for both are now used for this purpose,—the two male forms probably originated by some having varied in one manner and some in another; both forms having derived certain special, but nearly equal advantages, from their differently shaped organs.

It is not known that male crustaceans fight together for the possession of the females, but it is probably the case; for with most animals when the male is larger than the female, he seems to owe his greater size to his ancestors having fought with other males during many generations. In most of the orders, especially in the highest or the Brachyura, the male is larger than the female; the parasitic genera, however, in which the sexes follow different habits of life, and most of the Entomostraca must be excepted. The chelae of many crustaceans are weapons well adapted for fighting. Thus when a Devil-crab (Portunus puber) was seen by a son of Mr. Bate fighting with a Carcinus maenas, the latter was soon thrown on its back, and had every limb torn from its body. When several males of a Brazilian Gelasimus, a species furnished with immense pincers, were placed together in a glass vessel by Fritz Müller, they mutilated and killed one another. Mr. Bate put a large male Carcinus maenas into a pan of water, inhabited by a female which was paired with a smaller male; but the latter was soon dispossessed. Mr. Bate adds, “if they fought, the victory was a bloodless one, for I saw no wounds.” This same naturalist separated a male sand-skipper (so common on our sea-shores), Gammarus marinus, from its female, both of whom were imprisoned in the same vessel with many individuals of the same species. The female, when thus divorced, soon joined the others. After a time the male was put again into the same vessel; and he then, after swimming about for a time, dashed into the crowd, and without any fighting at once took away his wife. This fact shews that in the Amphipoda, an order low in the scale, the males and females recognise each other, and are mutually attached.

The mental powers of the Crustacea are probably higher than at first sight appears probable. Any one who tries to catch one of the shore-crabs, so common on tropical coasts, will perceive how wary and alert they are. There is a large crab (Birgus latro), found on coral islands, which makes a thick bed of the picked fibres of the cocoa-nut, at the bottom of a deep burrow. It feeds on the fallen fruit of this tree by tearing off the husk, fibre by fibre; and it always begins at that end where the three eye-like depressions are situated. It then breaks through one of these eyes by hammering with its heavy front pincers, and turning round, extracts the albuminous core with its narrow posterior pincers. But these actions are probably instinctive, so that they would be performed as well by a young animal as by an old one. The following case, however, can hardly be so considered: a trustworthy naturalist, Mr. Gardner (14. ‘Travels in the Interior of Brazil,’ 1846, p. 111. I have given, in my ‘Journal of Researches,’ p. 463, an account of the habits of the Birgus.), whilst watching a shore-crab (Gelasimus) making its burrow, threw some shells towards the hole. One rolled in, and three other shells remained within a few inches of the mouth. In about five minutes the crab brought out the shell which had fallen in, and carried it away to a distance of a foot; it then saw the three other shells lying near, and evidently thinking that they might likewise roll in, carried them to the spot where it had laid the first. It would, I think, be difficult to distinguish this act from one performed by man by the aid of reason.

Mr. Bate does not know of any well-marked case of difference of colour in the two sexes of our British crustaceans, in which respect the sexes of the higher animals so often differ. In some cases, however, the males and females differ slightly in tint, but Mr. Bate thinks not more than may be accounted for by their different habits of life, such as by the male wandering more about, and being thus more exposed to the light. Dr. Power tried to distinguish by colour the sexes of the several species which inhabit the Mauritius, but failed, except with one species of Squilla, probably S. stylifera, the male of which is described as being “of a beautiful bluish-green,” with some of the appendages cherry-red, whilst the female is clouded with brown and grey, “with the red about her much less vivid than in the male.” (15. Mr. Ch. Fraser, in ‘Proc. Zoolog. Soc.’ 1869, p. 3. I am indebted to Mr. Bate for Dr. Power’s statement.) In this case, we may suspect the agency of sexual selection. From M. Bert’s observations on Daphnia, when placed in a vessel illuminated by a prism, we have reason to believe that even the lowest crustaceans can distinguish colours. With Saphirina (an oceanic genus of Entomostraca), the males are furnished with minute shields or cell-like bodies, which exhibit beautiful changing colours; these are absent in the females, and in both sexes of one species. (16. Claus, ‘Die freilebenden Copepoden,’ 1863, s. 35.) It would, however, be extremely rash to conclude that these curious organs serve to attract the females. I am informed by Fritz Müller, that in the female of a Brazilian species of Gelasimus, the whole body is of a nearly uniform greyish-brown. In the male the posterior part of the cephalo- thorax is pure white, with the anterior part of a rich green, shading into dark brown; and it is remarkable that these colours are liable to change in the course of a few minutes—the white becoming dirty grey or even black, the green “losing much of its brilliancy.” It deserves especial notice that the males do not acquire their bright colours until they become mature. They appear to be much more numerous than the females; they differ also in the larger size of their chelae. In some species of the genus, probably in all, the sexes pair and inhabit the same burrow. They are also, as we have seen, highly intelligent animals. From these various considerations it seems probable that the male in this species has become gaily ornamented in order to attract or excite the female.

It has just been stated that the male Gelasimus does not acquire his conspicuous colours until mature and nearly ready to breed. This seems a general rule in the whole class in respect to the many remarkable structural differences between the sexes. We shall hereafter find the same law prevailing throughout the great sub-kingdom of the Vertebrata; and in all cases it is eminently distinctive of characters which have been acquired through sexual selection. Fritz Müller (17. ‘Facts and Arguments,’ etc., p. 79.) gives some striking instances of this law; thus the male sand-hopper (Orchestia) does not, until nearly full grown, acquire his large claspers, which are very differently constructed from those of the female; whilst young, his claspers resemble those of the female.

Class, Arachnida (Spiders)

The sexes do not generally differ much in colour, but the males are often darker than the females, as may be seen in Mr. Blackwall’s magnificent work. (18. ‘A History of the Spiders of Great Britain,’ 1861-64. For the following facts, see pp. 77, 88, 102.) In some species, however, the difference is conspicuous: thus the female of Sparassus smaragdulus is dullish green, whilst the adult male has the abdomen of a fine yellow, with three longitudinal stripes of rich red. In certain species of Thomisus the sexes closely resemble each other, in others they differ much; and analogous cases occur in many other genera. It is often difficult to say which of the two sexes departs most from the ordinary coloration of the genus to which the species belong; but Mr. Blackwall thinks that, as a general rule, it is the male; and Canestrini (19. This author has recently published a valuable essay on the ‘Caratteri sessuali secondarii degli Arachnidi,’ in the ‘Atti della Soc. Veneto-Trentina di Sc. Nat. Padova,’ vol. i. Fasc. 3, 1873.) remarks that in certain genera the males can be specifically distinguished with ease, but the females with great difficulty. I am informed by Mr. Blackwall that the sexes whilst young usually resemble each other; and both often undergo great changes in colour during their successive moults, before arriving at maturity. In other cases the male alone appears to change colour. Thus the male of the above bright-coloured Sparassus at first resembles the female, and acquires his peculiar tints only when nearly adult. Spiders are possessed of acute senses, and exhibit much intelligence; as is well known, the females often shew the strongest affection for their eggs, which they carry about enveloped in a silken web. The males search eagerly for the females, and have been seen by Canestrini and others to fight for possession of them. This same author says that the union of the two sexes has been observed in about twenty species; and he asserts positively that the female rejects some of the males who court her, threatens them with open mandibles, and at last after long hesitation accepts the chosen one. From these several considerations, we may admit with some confidence that the well-marked differences in colour between the sexes of certain species are the results of sexual selection; though we have not here the best kind of evidence,— the display by the male of his ornaments. From the extreme variability of colour in the male of some species, for instance of Theridion lineatum, it would appear that these sexual characters of the males have not as yet become well fixed. Canestrini draws the same conclusion from the fact that the males of certain species present two forms, differing from each other in the size and length of their jaws; and this reminds us of the above cases of dimorphic crustaceans.

The male is generally much smaller than the female, sometimes to an extraordinary degree (20. Aug. Vinson (‘Araneides des Iles de la Reunion,’ pl. vi. figs. 1 and 2) gives a good instance of the small size of the male, in Epeira nigra. In this species, as I may add, the male is testaceous and the female black with legs banded with red. Other even more striking cases of inequality in size between the sexes have been recorded (‘Quarterly Journal of Science,’ July 1868, p. 429); but I have not seen the original accounts.), and he is forced to be extremely cautious in making his advances, as the female often carries her coyness to a dangerous pitch. De Geer saw a male that “in the midst of his preparatory caresses was seized by the object of his attentions, enveloped by her in a web and then devoured, a sight which, as he adds, filled him with horror and indignation.” (21. Kirby and Spence, ‘Introduction to Entomology,’ vol. i. 1818, p. 280.) The Rev. O.P. Cambridge (22. ‘Proceedings, Zoological Society,’ 1871, p. 621.) accounts in the following manner for the extreme smallness of the male in the genus Nephila. “M. Vinson gives a graphic account of the agile way in which the diminutive male escapes from the ferocity of the female, by gliding about and playing hide and seek over her body and along her gigantic limbs: in such a pursuit it is evident that the chances of escape would be in favour of the smallest males, while the larger ones would fall early victims; thus gradually a diminutive race of males would be selected, until at last they would dwindle to the smallest possible size compatible with the exercise of their generative functions,— in fact, probably to the size we now see them, i.e., so small as to be a sort of parasite upon the female, and either beneath her notice, or too agile and too small for her to catch without great difficulty.”

Westring has made the interesting discovery that the males of several species of Theridion (23. Theridion (Asagena, Sund.) serratipes, 4- punctatum et guttatum; see Westring, in Kroyer, ‘Naturhist. Tidskrift,’ vol. iv. 1842-1843, p. 349; and vol. ii. 1846-1849, p. 342. See, also, for other species, ‘Araneae Suecicae,’ p. 184.) have the power of making a stridulating sound, whilst the females are mute. The apparatus consists of a serrated ridge at the base of the abdomen, against which the hard hinder part of the thorax is rubbed; and of this structure not a trace can be detected in the females. It deserves notice that several writers, including the well-known arachnologist Walckenaer, have declared that spiders are attracted by music. (24. Dr. H.H. van Zouteveen, in his Dutch translation of this work (vol. i. p. 444), has collected several cases.) From the analogy of the Orthoptera and Homoptera, to be described in the next chapter, we may feel almost sure that the stridulation serves, as Westring also believes, to call or to excite the female; and this is the first case known to me in the ascending scale of the animal kingdom of sounds emitted for this purpose. (25. Hilgendorf, however, has lately called attention to an analogous structure in some of the higher crustaceans, which seems adapted to produce sound; see ‘Zoological Record,’ 1869, p. 603.)

Class, Myriapoda

In neither of the two orders in this class, the millipedes and centipedes, can I find any well-marked instances of such sexual differences as more particularly concern us. In Glomeris limbata, however, and perhaps in some few other species, the males differ slightly in colour from the females; but this Glomeris is a highly variable species. In the males of the Diplopoda, the legs belonging either to one of the anterior or of the posterior segments of the body are modified into prehensile hooks which serve to secure the female. In some species of Iulus the tarsi of the male are furnished with membranous suckers for the same purpose. As we shall see when we treat of Insects, it is a much more unusual circumstance, that it is the female in Lithobius, which is furnished with prehensile appendages at the extremity of her body for holding the male. (26. Walckenaer et P. Gervais, ‘Hist. Nat. des Insectes: Apteres,’ tom. iv. 1847, pp. 17, 19, 68.)

第十章 •12,800字
昆虫的第二性征

Diversified structures possessed by the males for seizing the females— Differences between the sexes, of which the meaning is not understood— Difference in size between the sexes—Thysanura—Diptera—Hemiptera— Homoptera, musical powers possessed by the males alone—Orthoptera, musical instruments of the males, much diversified in structure; pugnacity; colours—Neuroptera, sexual differences in colour—Hymenoptera, pugnacity and odours—Coleoptera, colours; furnished with great horns, apparently as an ornament; battles, stridulating organs generally common to both sexes.

In the immense class of insects the sexes sometimes differ in their locomotive-organs, and often in their sense-organs, as in the pectinated and beautifully plumose antennae of the males of many species. In Chloeon, one of the Ephemerae, the male has great pillared eyes, of which the female is entirely destitute. (1。 J爵士 Lubbock, ‘Transact. Linnean Soc.’ vol. xxv, 1866, p. 484. With respect to the Mutillidae see Westwood, ‘Modern Class. of Insects,’ vol. II。 p. 213.) The ocelli are absent in the females of certain insects, as in the Mutillidae; and here the females are likewise wingless. But we are chiefly concerned with structures by which one male is enabled to conquer another, either in battle or courtship, through his strength, pugnacity, ornaments, or music. The innumerable contrivances, therefore, by which the male is able to seize the female, may be briefly passed over. Besides the complex structures at the apex of the abdomen, which ought perhaps to be ranked as primary organs (2. These organs in the male often differ in closely-allied species, and afford excellent specific characters. But their importance, from a functional point of view, as Mr. R. MacLachlan has remarked to me, has probably been overrated. It has been suggested, that slight differences in these organs would suffice to prevent the intercrossing of well-marked varieties or incipient species, and would thus aid in their development. That this can hardly be the case, we may infer from the many recorded cases (see, for instance, Bronn, ‘Geschichte der Natur,’ B. II。 1843,第 164; and Westwood, ‘Transact. Ent。 Soc.’ vol. III。 1842。 195) of distinct species having been observed in union. 先生。 MacLachlan informs me (vide ‘Stett. Ent。 Zeitung,’ 1867, s. 155) that when several species of Phryganidae, which present strongly-pronounced differences of this kind, were confined together by Dr. 八月 Meyer, THEY COUPLED, and one pair produced fertile ova.), “it is astonishing,” as Mr. BD Walsh (3. ‘The Practical Entomologist,’ Philadelphia, vol. II。 1867 年 XNUMX 月,第 XNUMX 页。 88.) has remarked, “how many different organs are worked in by nature for the seemingly insignificant object of enabling the male to grasp the female firmly.” The mandibles or jaws are sometimes used for this purpose; thus the male Corydalis cornutus (a neuropterous insect in some degree allied to the Dragon flies, etc.) has immense curved jaws, many times longer than those of the female; and they are smooth instead of being toothed, so that he is thus enabled to seize her without injury. (4。 先生。 Walsh, ibid. p. 107.) One of the stag-beetles of North America (Lucanus elaphus) uses his jaws, which are much larger than those of the female, for the same purpose, but probably likewise for fighting. In one of the sand- wasps (Ammophila) the jaws in the two sexes are closely alike, but are used for widely different purposes: the males, as Professor Westwood observes, “are exceedingly ardent, seizing their partners round the neck with their sickle-shaped jaws” (5. ‘Modern Classification of Insects,’ vol. II。 1840页。 205,206。 先生。

[Fig. 9. Crabro cribrarius. Upper figure, male; lower figure, female.]

The tarsi of the front-legs are dilated in many male beetles, or are furnished with broad cushions of hairs; and in many genera of water-beetles they are armed with a round flat sucker, so that the male may adhere to the slippery body of the female. It is a much more unusual circumstance that the females of some water-beetles (Dytiscus) have their elytra deeply grooved, and in Acilius sulcatus thickly set with hairs, as an aid to the male. The females of some other water-beetles (Hydroporus) have their elytra punctured for the same purpose. (6. We have here a curious and inexplicable case of dimorphism, for some of the females of four European species of Dytiscus, and of certain species of Hydroporus, have their elytra smooth; and no intermediate gradations between the sulcated or punctured, and the quite smooth elytra have been observed. See Dr. H. Schaum, as quoted in the ‘Zoologist,’ vols. v.-vi. 1847-48, p. 1896. Also Kirby and Spence, ‘Introduction to Entomology,’ vol. iii. 1826, p. 305.) In the male of Crabro cribrarius (Fig. 9), it is the tibia which is dilated into a broad horny plate, with minute membraneous dots, giving to it a singular appearance like that of a riddle. (7. Westwood, ‘Modern Class.’ vol. ii. p. 193. The following statement about Penthe, and others in inverted commas, are taken from Mr. Walsh, ‘Practical Entomologist,’ Philadelphia, vol. iii. p. 88.) In the male of Penthe (a genus of beetles) a few of the middle joints of the antennae are dilated and furnished on the inferior surface with cushions of hair, exactly like those on the tarsi of the Carabidae, “and obviously for the same end.” In male dragon-flies, “the appendages at the tip of the tail are modified in an almost infinite variety of curious patterns to enable them to embrace the neck of the female.” Lastly, in the males of many insects, the legs are furnished with peculiar spines, knobs or spurs; or the whole leg is bowed or thickened, but this is by no means invariably a sexual character; or one pair, or all three pairs are elongated, sometimes to an extravagant length. (8. Kirby and Spence, ‘Introduct.’ etc., vol. iii. pp. 332-336.)

[Fig. 10. Taphroderes distortus (much enlarged). Upper figure, male; lower figure, female.]

The sexes of many species in all the orders present differences, of which the meaning is not understood. One curious case is that of a beetle (Fig. 10), the male of which has left mandible much enlarged; so that the mouth is greatly distorted. In another Carabidous beetle, Eurygnathus (9. ‘Insecta Maderensia,’ 1854, page 20.), we have the case, unique as far as known to Mr. Wollaston, of the head of the female being much broader and larger, though in a variable degree, than that of the male. Any number of such cases could be given. They abound in the Lepidoptera: one of the most extraordinary is that certain male butterflies have their fore-legs more or less atrophied, with the tibiae and tarsi reduced to mere rudimentary knobs. The wings, also, in the two sexes often differ in neuration (10. E. Doubleday, ‘Annals and Mag. of Nat. Hist.’ vol. i. 1848, p. 379. I may add that the wings in certain Hymenoptera (see Shuckard, ‘Fossorial Hymenoptera,’ 1837, pp. 39-43) differ in neuration according to sex.), and sometimes considerably in outline, as in the Aricoris epitus, which was shewn to me in the British Museum by Mr. A. Butler. The males of certain South American butterflies have tufts of hair on the margins of the wings, and horny excrescences on the discs of the posterior pair. (11. H.W. Bates, in ‘Journal of Proc. Linn. Soc.’ vol. vi. 1862, p. 74. Mr. Wonfor’s observations are quoted in ‘Popular Science Review,’ 1868, p. 343.) In several British butterflies, as shewn by Mr. Wonfor, the males alone are in parts clothed with peculiar scales.

The use of the bright light of the female glow-worm has been subject to much discussion. The male is feebly luminous, as are the larvae and even the eggs. It has been supposed by some authors that the light serves to frighten away enemies, and by others to guide the male to the female. At last, Mr. Belt (12. ‘The Naturalist in Nicaragua,’ 1874, pp. 316-320. On the phosphorescence of the eggs, see ‘Annals and Magazine of Natural History,’ Nov. 1871, p. 372.) appears to have solved the difficulty: he finds that all the Lampyridae which he has tried are highly distasteful to insectivorous mammals and birds. Hence it is in accordance with Mr. Bates’ view, hereafter to be explained, that many insects mimic the Lampyridae closely, in order to be mistaken for them, and thus to escape destruction. He further believes that the luminous species profit by being at once recognised as unpalatable. It is probable that the same explanation may be extended to the Elaters, both sexes of which are highly luminous. It is not known why the wings of the female glow-worm have not been developed; but in her present state she closely resembles a larva, and as larvae are so largely preyed on by many animals, we can understand why she has been rendered so much more luminous and conspicuous than the male; and why the larvae themselves are likewise luminous.

Difference in Size Between the Sexes

With insects of all kinds the males are commonly smaller than the females; and this difference can often be detected even in the larval state. So considerable is the difference between the male and female cocoons of the silk-moth (Bombyx mori), that in France they are separated by a particular mode of weighing. (13. Robinet, ‘Vers a Soie,’ 1848, p. 207.) In the lower classes of the animal kingdom, the greater size of the females seems generally to depend on their developing an enormous number of ova; and this may to a certain extent hold good with insects. But Dr. Wallace has suggested a much more probable explanation. He finds, after carefully attending to the development of the caterpillars of Bombyx cynthia and yamamai, and especially to that of some dwarfed caterpillars reared from a second brood on unnatural food, “that in proportion as the individual moth is finer, so is the time required for its metamorphosis longer; and for this reason the female, which is the larger and heavier insect, from having to carry her numerous eggs, will be preceded by the male, which is smaller and has less to mature.” (14. ‘Transact. Ent. Soc.’ 3rd series, vol. v. p. 486.) Now as most insects are short-lived, and as they are exposed to many dangers, it would manifestly be advantageous to the female to be impregnated as soon as possible. This end would be gained by the males being first matured in large numbers ready for the advent of the females; and this again would naturally follow, as Mr. A.R. Wallace has remarked (15. ‘Journal of Proc. Ent. Soc.’ Feb. 4, 1867, p. lxxi.), through natural selection; for the smaller males would be first matured, and thus would procreate a large number of offspring which would inherit the reduced size of their male parents, whilst the larger males from being matured later would leave fewer offspring.

There are, however, exceptions to the rule of male insects being smaller than the females: and some of these exceptions are intelligible. Size and strength would be an advantage to the males, which fight for the possession of the females; and in these cases, as with the stag-beetle (Lucanus), the males are larger than the females. There are, however, other beetles which are not known to fight together, of which the males exceed the females in size; and the meaning of this fact is not known; but in some of these cases, as with the huge Dynastes and Megasoma, we can at least see that there would be no necessity for the males to be smaller than the females, in order to be matured before them, for these beetles are not short-lived, and there would be ample time for the pairing of the sexes. So again, male dragon-flies (Libellulidae) are sometimes sensibly larger, and never smaller, than the females (16. For this and other statements on the size of the sexes, see Kirby and Spence, ibid. vol. iii. p. 300; on the duration of life in insects, see p. 344.); and as Mr. MacLachlan believes, they do not generally pair with the females until a week or fortnight has elapsed, and until they have assumed their proper masculine colours. But the most curious case, shewing on what complex and easily-overlooked relations, so trifling a character as difference in size between the sexes may depend, is that of the aculeate Hymenoptera; for Mr. F. Smith informs me that throughout nearly the whole of this large group, the males, in accordance with the general rule, are smaller than the females, and emerge about a week before them; but amongst the Bees, the males of Apis mellifica, Anthidium manicatum, and Anthophora acervorum, and amongst the Fossores, the males of the Methoca ichneumonides, are larger than the females. The explanation of this anomaly is that a marriage flight is absolutely necessary with these species, and the male requires great strength and size in order to carry the female through the air. Increased size has here been acquired in opposition to the usual relation between size and the period of development, for the males, though larger, emerge before the smaller females.

We will now review the several Orders, selecting such facts as more particularly concern us. The Lepidoptera (Butterflies and Moths) will be retained for a separate chapter.

Order, Thysanura

The members of this lowly organised order are wingless, dull-coloured, minute insects, with ugly, almost misshapen heads and bodies. Their sexes do not differ, but they are interesting as shewing us that the males pay sedulous court to the females even low down in the animal scale. Sir J. Lubbock (17. ‘Transact. Linnean Soc.’ vol. xxvi. 1868, p. 296.) says: “it is very amusing to see these little creatures (Smynthurus luteus) coquetting together. The male, which is much smaller than the female, runs round her, and they butt one another, standing face to face and moving backward and forward like two playful lambs. Then the female pretends to run away and the male runs after her with a queer appearance of anger, gets in front and stands facing her again; then she turns coyly round, but he, quicker and more active, scuttles round too, and seems to whip her with his antennae; then for a bit they stand face to face, play with their antennae, and seem to be all in all to one another.”

Order, Diptera (Flies)

The sexes differ little in colour. The greatest difference, known to Mr. F. Walker, is in the genus Bibio, in which the males are blackish or quite black, and the females obscure brownish-orange. The genus Elaphomyia, discovered by Mr. Wallace (18. ‘The Malay Archipelago,’ vol. ii. 1869, p. 313.) in New Guinea, is highly remarkable, as the males are furnished with horns, of which the females are quite destitute. The horns spring from beneath the eyes, and curiously resemble those of a stag, being either branched or palmated. In one of the species, they equal the whole body in length. They might be thought to be adapted for fighting, but as in one species they are of a beautiful pink colour, edged with black, with a pale central stripe, and as these insects have altogether a very elegant appearance, it is perhaps more probable that they serve as ornaments. That the males of some Diptera fight together is certain; Prof. Westwood (19. ‘Modern Classification of Insects,’ vol. ii. 1840, p. 526.) has several times seen this with the Tipulae. The males of other Diptera apparently try to win the females by their music: H. Müller (20. ‘Anwendung,’ etc., ‘Verh. d. n. V. Jahrg.’ xxix. p. 80. Mayer, in ‘American Naturalist,’ 1874, p. 236.) watched for some time two males of an Eristalis courting a female; they hovered above her, and flew from side to side, making a high humming noise at the same time. Gnats and mosquitoes (Culicidae) also seem to attract each other by humming; and Prof. Mayer has recently ascertained that the hairs on the antennae of the male vibrate in unison with the notes of a tuning-fork, within the range of the sounds emitted by the female. The longer hairs vibrate sympathetically with the graver notes, and the shorter hairs with the higher ones. Landois also asserts that he has repeatedly drawn down a whole swarm of gnats by uttering a particular note. It may be added that the mental faculties of the Diptera are probably higher than in most other insects, in accordance with their highly- developed nervous system. (21. See Mr. B.T. Lowne’s interesting work, ‘On the Anatomy of the Blow-fly, Musca vomitoria,’ 1870, p. 14. He remarks (p. 33) that, “the captured flies utter a peculiar plaintive note, and that this sound causes other flies to disappear.”)

Order, Hemiptera (Field-Bugs)

Mr. J.W. Douglas, who has particularly attended to the British species, has kindly given me an account of their sexual differences. The males of some species are furnished with wings, whilst the females are wingless; the sexes differ in the form of their bodies, elytra, antennae and tarsi; but as the signification of these differences are unknown, they may be here passed over. The females are generally larger and more robust than the males. With British, and, as far as Mr. Douglas knows, with exotic species, the sexes do not commonly differ much in colour; but in about six British species the male is considerably darker than the female, and in about four other species the female is darker than the male. Both sexes of some species are beautifully coloured; and as these insects emit an extremely nauseous odour, their conspicuous colours may serve as a signal that they are unpalatable to insectivorous animals. In some few cases their colours appear to be directly protective: thus Prof. Hoffmann informs me that he could hardly distinguish a small pink and green species from the buds on the trunks of lime-trees, which this insect frequents.

Some species of Reduvidae make a stridulating noise; and, in the case of Pirates stridulus, this is said (22. Westwood, ‘Modern Classification of Insects,’ vol. ii. p. 473.) to be effected by the movement of the neck within the pro-thoracic cavity. According to Westring, Reduvius personatus also stridulates. But I have no reason to suppose that this is a sexual character, excepting that with non-social insects there seems to be no use for sound-producing organs, unless it be as a sexual call.

Order: Homoptera

Every one who has wandered in a tropical forest must have been astonished at the din made by the male Cicadae. The females are mute; as the Grecian poet Xenarchus says, “Happy the Cicadas live, since they all have voiceless wives.” The noise thus made could be plainly heard on board the “Beagle,” when anchored at a quarter of a mile from the shore of Brazil; and Captain Hancock says it can be heard at the distance of a mile. The Greeks formerly kept, and the Chinese now keep these insects in cages for the sake of their song, so that it must be pleasing to the ears of some men. (23. These particulars are taken from Westwood’s ‘Modern Classification of Insects,’ vol. ii. 1840, p. 422. See, also, on the Fulgoridae, Kirby and Spence, ‘Introduct.’ vol. ii. p. 401.) The Cicadidae usually sing during the day, whilst the Fulgoridae appear to be night-songsters. The sound, according to Landois (24. ‘Zeitschrift für wissenschaft. Zoolog.’ B. xvii. 1867, ss. 152-158.), is produced by the vibration of the lips of the spiracles, which are set into motion by a current of air emitted from the tracheae; but this view has lately been disputed. Dr. Powell appears to have proved (25. ‘Transactions of the New Zealand Institute,’ vol. v. 1873, p. 286.) that it is produced by the vibration of a membrane, set into action by a special muscle. In the living insect, whilst stridulating, this membrane can be seen to vibrate; and in the dead insect the proper sound is heard, if the muscle, when a little dried and hardened, is pulled with the point of a pin. In the female the whole complex musical apparatus is present, but is much less developed than in the male, and is never used for producing sound.

With respect to the object of the music, Dr. Hartman, in speaking of the Cicada septemdecim of the United States, says (26. I am indebted to Mr. Walsh for having sent me this extract from ‘A Journal of the Doings of Cicada septemdecim,’ by Dr. Hartman.), “the drums are now (June 6th and 7th, 1851) heard in all directions. This I believe to be the marital summons from the males. Standing in thick chestnut sprouts about as high as my head, where hundreds were around me, I observed the females coming around the drumming males.” He adds, “this season (Aug. 1868) a dwarf pear-tree in my garden produced about fifty larvae of Cic. pruinosa; and I several times noticed the females to alight near a male while he was uttering his clanging notes.” Fritz Müller writes to me from S. Brazil that he has often listened to a musical contest between two or three males of a species with a particularly loud voice, seated at a considerable distance from each other: as soon as one had finished his song, another immediately began, and then another. As there is so much rivalry between the males, it is probable that the females not only find them by their sounds, but that, like female birds, they are excited or allured by the male with the most attractive voice.

I have not heard of any well-marked cases of ornamental differences between the sexes of the Homoptera. Mr. Douglas informs me that there are three British species, in which the male is black or marked with black bands, whilst the females are pale-coloured or obscure.

Order, Orthoptera (Crickets and Grasshoppers)

The males in the three saltatorial families in this Order are remarkable for their musical powers, namely the Achetidae or crickets, the Locustidae for which there is no equivalent English name, and the Acridiidae or grasshoppers. The stridulation produced by some of the Locustidae is so loud that it can be heard during the night at the distance of a mile (27. L. Guilding, ‘Transactions of the Linnean Society,’ vol. xv. p. 154.); and that made by certain species is not unmusical even to the human ear, so that the Indians on the Amazons keep them in wicker cages. All observers agree that the sounds serve either to call or excite the mute females. With respect to the migratory locusts of Russia, Korte has given (28. I state this on the authority of Koppen, ‘Über die Heuschrecken in Südrussland,’ 1866, p. 32, for I have in vain endeavoured to procure Korte’s work.) an interesting case of selection by the female of a male. The males of this species (Pachytylus migratorius) whilst coupled with the female stridulate from anger or jealousy, if approached by other males. The house-cricket when surprised at night uses its voice to warn its fellows. (29. Gilbert White, ‘Natural History of Selborne,’ vol. ii. 1825, p. 262.) In North America the Katy-did (Platyphyllum concavum, one of the Locustidae) is described (30. Harris, ‘Insects of New England,’ 1842, p. 128.) as mounting on the upper branches of a tree, and in the evening beginning “his noisy babble, while rival notes issue from the neighbouring trees, and the groves resound with the call of Katy-did-she- did the live-long night.” Mr. Bates, in speaking of the European field- cricket (one of the Achetidae), says “the male has been observed to place himself in the evening at the entrance of his burrow, and stridulate until a female approaches, when the louder notes are succeeded by a more subdued tone, whilst the successful musician caresses with his antennae the mate he has won.” (31. ‘The Naturalist on the Amazons,’ vol. i. 1863, p. 252. Mr. Bates gives a very interesting discussion on the gradations in the musical apparatus of the three families. See also Westwood, ‘Modern Classification of Insects,’ vol. ii. pp. 445 and 453.) Dr. Scudder was able to excite one of these insects to answer him, by rubbing on a file with a quill. (32. ‘Proceedings of the Boston Society of Natural History,’ vol. xi. April 1868.) In both sexes a remarkable auditory apparatus has been discovered by Von Siebold, situated in the front legs. (33. ‘Nouveau Manuel d’Anat. Comp.’ (French translat.), tom. 1, 1850, p. 567.)

[Fig.11. Gryllus campestris (from Landois).
Right-hand figure, under side of part of a wing-nervure, much magnified,
showing the teeth, st.
Left-hand figure, upper surface of wing-cover, with the projecting, smooth
nervure, r, across which the teeth (st) are scraped.

Fig.12. Teeth of Nervure of Gryllus domesticus (from Landois).]

In the three Families the sounds are differently produced. In the males of the Achetidae both wing-covers have the same apparatus; and this in the field-cricket (see Gryllus campestris, Fig. 11) consists, as described by Landois (34. ‘Zeitschrift für wissenschaft. Zoolog.’ B. xvii. 1867, s. 117.), of from 131 to 138 sharp, transverse ridges or teeth (st) on the under side of one of the nervures of the wing-cover. This toothed nervure is rapidly scraped across a projecting, smooth, hard nervure (r) on the upper surface of the opposite wing. First one wing is rubbed over the other, and then the movement is reversed. Both wings are raised a little at the same time, so as to increase the resonance. In some species the wing-covers of the males are furnished at the base with a talc-like plate. (35. Westwood, ‘Modern Classification of Insects,’ vol. i. p. 440.) I here give a drawing (Fig. 12) of the teeth on the under side of the nervure of another species of Gryllus, viz., G. domesticus. With respect to the formation of these teeth, Dr. Gruber has shewn (36. ‘Ueber der Tonapparat der Locustiden, ein Beitrag zum Darwinismus,’ ‘Zeitschrift für wissenschaft. Zoolog.’ B. xxii. 1872, p. 100.) that they have been developed by the aid of selection, from the minute scales and hairs with which the wings and body are covered, and I came to the same conclusion with respect to those of the Coleoptera. But Dr. Gruber further shews that their development is in part directly due to the stimulus from the friction of one wing over the other.

[Fig.13. Chlorocoelus Tanana (from Bates). a,b. Lobes of opposite wing-covers.]

In the Locustidae the opposite wing-covers differ from each other in structure (Fig. 13), and the action cannot, as in the last family, be reversed. The left wing, which acts as the bow, lies over the right wing which serves as the fiddle. One of the nervures (a) on the under surface of the former is finely serrated, and is scraped across the prominent nervures on the upper surface of the opposite or right wing. In our British Phasgonura viridissima it appeared to me that the serrated nervure is rubbed against the rounded hind-corner of the opposite wing, the edge of which is thickened, coloured brown, and very sharp. In the right wing, but not in the left, there is a little plate, as transparent as talc, surrounded by nervures, and called the speculum. In Ephippiger vitium, a member of this same family, we have a curious subordinate modification; for the wing-covers are greatly reduced in size, but “the posterior part of the pro-thorax is elevated into a kind of dome over the wing-covers, and which has probably the effect of increasing the sound.” (37. Westwood ‘Modern Classification of Insects,’ vol. i. p. 453.)

We thus see that the musical apparatus is more differentiated or specialised in the Locustidae (which include, I believe, the most powerful performers in the Order), than in the Achetidae, in which both wing-covers have the same structure and the same function. (38. Landois, ‘Zeitschrift für wissenschaft. Zoolog.’ B. xvii. 1867, ss. 121, 122.) Landois, however, detected in one of the Locustidae, namely in Decticus, a short and narrow row of small teeth, mere rudiments, on the inferior surface of the right wing-cover, which underlies the other and is never used as the bow. I observed the same rudimentary structure on the under side of the right wing-cover in Phasgonura viridissima. Hence we may infer with confidence that the Locustidae are descended from a form, in which, as in the existing Achetidae, both wing-covers had serrated nervures on the under surface, and could be indifferently used as the bow; but that in the Locustidae the two wing-covers gradually became differentiated and perfected, on the principle of the division of labour, the one to act exclusively as the bow, and the other as the fiddle. Dr. Gruber takes the same view, and has shewn that rudimentary teeth are commonly found on the inferior surface of the right wing. By what steps the more simple apparatus in the Achetidae originated, we do not know, but it is probable that the basal portions of the wing- covers originally overlapped each other as they do at present; and that the friction of the nervures produced a grating sound, as is now the case with the wing-covers of the females. (39. Mr. Walsh also informs me that he has noticed that the female of the Platyphyllum concavum, “when captured makes a feeble grating noise by shuffling her wing-covers together.”) A grating sound thus occasionally and accidentally made by the males, if it served them ever so little as a love-call to the females, might readily have been intensified through sexual selection, by variations in the roughness of the nervures having been continually preserved.

[Fig.14. Hind-leg of Stenobothrus pratorum: r, the stridulating ridge; lower figure, the teeth forming the ridge, much magnified (from Landois).

Fig.15. Pneumora (from specimens in the British Museum). Upper figure, male; lower figure, female.]

In the last and third family, namely the Acridiidae or grasshoppers, the stridulation is produced in a very different manner, and according to Dr. Scudder, is not so shrill as in the preceding Families. The inner surface of the femur (Fig. 14, r) is furnished with a longitudinal row of minute, elegant, lancet-shaped, elastic teeth, from 85 to 93 in number (40. Landois, ibid. s. 113.); and these are scraped across the sharp, projecting nervures on the wing-covers, which are thus made to vibrate and resound. Harris (41. ‘Insects of New England,’ 1842, p. 133.) says that when one of the males begins to play, he first “bends the shank of the hind-leg beneath the thigh, where it is lodged in a furrow designed to receive it, and then draws the leg briskly up and down. He does not play both fiddles together, but alternately, first upon one and then on the other.” In many species, the base of the abdomen is hollowed out into a great cavity which is believed to act as a resounding board. In Pneumora (Fig. 15), a S. African genus belonging to the same family, we meet with a new and remarkable modification; in the males a small notched ridge projects obliquely from each side of the abdomen, against which the hind femora are rubbed. (42. Westwood, ‘Modern Classification,’ vol i. p. 462.) As the male is furnished with wings (the female being wingless), it is remarkable that the thighs are not rubbed in the usual manner against the wing-covers; but this may perhaps be accounted for by the unusually small size of the hind-legs. I have not been able to examine the inner surface of the thighs, which, judging from analogy, would be finely serrated. The species of Pneumora have been more profoundly modified for the sake of stridulation than any other orthopterous insect; for in the male the whole body has been converted into a musical instrument, being distended with air, like a great pellucid bladder, so as to increase the resonance. Mr. Trimen informs me that at the Cape of Good Hope these insects make a wonderful noise during the night.

In the three foregoing families, the females are almost always destitute of an efficient musical apparatus. But there are a few exceptions to this rule, for Dr. Gruber has shewn that both sexes of Ephippiger vitium are thus provided; though the organs differ in the male and female to a certain extent. Hence we cannot suppose that they have been transferred from the male to the female, as appears to have been the case with the secondary sexual characters of many other animals. They must have been independently developed in the two sexes, which no doubt mutually call to each other during the season of love. In most other Locustidae (but not according to Landois in Decticus) the females have rudiments of the stridulatory organs proper to the male; from whom it is probable that these have been transferred. Landois also found such rudiments on the under surface of the wing-covers of the female Achetidae, and on the femora of the female Acridiidae. In the Homoptera, also, the females have the proper musical apparatus in a functionless state; and we shall hereafter meet in other divisions of the animal kingdom with many instances of structures proper to the male being present in a rudimentary condition in the female.

Landois has observed another important fact, namely, that in the females of the Acridiidae, the stridulating teeth on the femora remain throughout life in the same condition in which they first appear during the larval state in both sexes. In the males, on the other hand, they become further developed, and acquire their perfect structure at the last moult, when the insect is mature and ready to breed.

From the facts now given, we see that the means by which the males of the Orthoptera produce their sounds are extremely diversified, and are altogether different from those employed by the Homoptera. (43. Landois has recently found in certain Orthoptera rudimentary structures closely similar to the sound-producing organs in the Homoptera; and this is a surprising fact. See ‘Zeitschrift für wissenschaft, Zoolog.’ B. xxii. Heft 3, 1871, p. 348.) But throughout the animal kingdom we often find the same object gained by the most diversified means; this seems due to the whole organisation having undergone multifarious changes in the course of ages, and as part after part varied different variations were taken advantage of for the same general purpose. The diversity of means for producing sound in the three families of the Orthoptera and in the Homoptera, impresses the mind with the high importance of these structures to the males, for the sake of calling or alluring the females. We need feel no surprise at the amount of modification which the Orthoptera have undergone in this respect, as we now know, from Dr. Scudder’s remarkable discovery (44. ‘Transactions, Entomological Society,’ 3rd series, vol. ii. (‘Journal of Proceedings,’ p. 117).), that there has been more than ample time. This naturalist has lately found a fossil insect in the Devonian formation of New Brunswick, which is furnished with “the well-known tympanum or stridulating apparatus of the male Locustidae.” The insect, though in most respects related to the Neuroptera, appears, as is so often the case with very ancient forms, to connect the two related Orders of the Neuroptera and Orthoptera.

I have but little more to say on the Orthoptera. Some of the species are very pugnacious: when two male field-crickets (Gryllus campestris) are confined together, they fight till one kills the other; and the species of Mantis are described as manoeuvring with their sword-like front-limbs, like hussars with their sabres. The Chinese keep these insects in little bamboo cages, and match them like game-cocks. (45. Westwood, ‘Modern Classification of Insects,’ vol. i. p. 427; for crickets, p. 445.) With respect to colour, some exotic locusts are beautifully ornamented; the posterior wings being marked with red, blue, and black; but as throughout the Order the sexes rarely differ much in colour, it is not probable that they owe their bright tints to sexual selection. Conspicuous colours may be of use to these insects, by giving notice that they are unpalatable. Thus it has been observed (46. Mr. Ch. Horne, in ‘Proceedings of the Entomological Society,’ May 3, 1869, p. xii.) that a bright-coloured Indian locust was invariably rejected when offered to birds and lizards. Some cases, however, are known of sexual differences in colour in this Order. The male of an American cricket (47. The Oecanthus nivalis, Harris, ‘Insects of New England,’ 1842, p. 124. The two sexes of OE. pellucidus of Europe differ, as I hear from Victor Carus, in nearly the same manner.) is described as being as white as ivory, whilst the female varies from almost white to greenish-yellow or dusky. Mr. Walsh informs me that the adult male of Spectrum femoratum (one of the Phasmidae) “is of a shining brownish-yellow colour; the adult female being of a dull, opaque, cinereous brown; the young of both sexes being green.” Lastly, I may mention that the male of one curious kind of cricket (48. Platyblemnus: Westwood, ‘Modern Classification,’ vol. i. p. 447.) is furnished with “a long membranous appendage, which falls over the face like a veil;” but what its use may be, is not known.

Order, Neuroptera

Little need here be said, except as to colour. In the Ephemeridae the sexes often differ slightly in their obscure tints (49. B.D. Walsh, the ‘Pseudo-neuroptera of Illinois,’ in ‘Proceedings of the Entomological Society of Philadelphia,’ 1862, p. 361.); but it is not probable that the males are thus rendered attractive to the females. The Libellulidae, or dragon-flies, are ornamented with splendid green, blue, yellow, and vermilion metallic tints; and the sexes often differ. Thus, as Prof. Westwood remarks (50. ‘Modern Classification,’ vol. ii. p. 37.), the males of some of the Agrionidae, “are of a rich blue with black wings, whilst the females are fine green with colourless wings.” But in Agrion Ramburii these colours are exactly reversed in the two sexes. (51. Walsh, ibid. p. 381. I am indebted to this naturalist for the following facts on Hetaerina, Anax, and Gomphus.) In the extensive N. American genus of Hetaerina, the males alone have a beautiful carmine spot at the base of each wing. In Anax junius the basal part of the abdomen in the male is a vivid ultramarine blue, and in the female grass-green. In the allied genus Gomphus, on the other hand, and in some other genera, the sexes differ but little in colour. In closely-allied forms throughout the animal kingdom, similar cases of the sexes differing greatly, or very little, or not at all, are of frequent occurrence. Although there is so wide a difference in colour between the sexes of many Libellulidae, it is often difficult to say which is the more brilliant; and the ordinary coloration of the two sexes is reversed, as we have just seen, in one species of Agrion. It is not probable that their colours in any case have been gained as a protection. Mr. MacLachlan, who has closely attended to this family, writes to me that dragon-flies—the tyrants of the insect-world—are the least liable of any insect to be attacked by birds or other enemies, and he believes that their bright colours serve as a sexual attraction. Certain dragon-flies apparently are attracted by particular colours: Mr. Patterson observed (52. ‘Transactions, Ent. Soc.’ vol. i. 1836, p. lxxxi.) that the Agrionidae, of which the males are blue, settled in numbers on the blue float of a fishing line; whilst two other species were attracted by shining white colours.

It is an interesting fact, first noticed by Schelver, that, in several genera belonging to two sub-families, the males on first emergence from the pupal state, are coloured exactly like the females; but that their bodies in a short time assume a conspicuous milky-blue tint, owing to the exudation of a kind of oil, soluble in ether and alcohol. Mr. MacLachlan believes that in the male of Libellula depressa this change of colour does not occur until nearly a fortnight after the metamorphosis, when the sexes are ready to pair.

Certain species of Neurothemis present, according to Brauer (53. See abstract in the ‘Zoological Record’ for 1867, p. 450.), a curious case of dimorphism, some of the females having ordinary wings, whilst others have them “very richly netted, as in the males of the same species.” Brauer “explains the phenomenon on Darwinian principles by the supposition that the close netting of the veins is a secondary sexual character in the males, which has been abruptly transferred to some of the females, instead of, as generally occurs, to all of them.” Mr. MacLachlan informs me of another instance of dimorphism in several species of Agrion, in which some individuals are of an orange colour, and these are invariably females. This is probably a case of reversion; for in the true Libellulae, when the sexes differ in colour, the females are orange or yellow; so that supposing Agrion to be descended from some primordial form which resembled the typical Libellulae in its sexual characters, it would not be surprising that a tendency to vary in this manner should occur in the females alone.

Although many dragon-flies are large, powerful, and fierce insects, the males have not been observed by Mr. MacLachlan to fight together, excepting, as he believes, in some of the smaller species of Agrion. In another group in this Order, namely, the Termites or white ants, both sexes at the time of swarming may be seen running about, “the male after the female, sometimes two chasing one female, and contending with great eagerness who shall win the prize.” (54. Kirby and Spence, ‘Introduction to Entomology,’ vol. ii. 1818, p. 35.) The Atropos pulsatorius is said to make a noise with its jaws, which is answered by other individuals. (55. Houzeau, ‘Les Facultés Mentales,’ etc. Tom. i. p. 104.)

Order, Hymenoptera

That inimitable observer, M. Fabre (56. See an interesting article, ‘The Writings of Fabre,’ in ‘Nat. Hist. Review,’ April 1862, p. 122.), in describing the habits of Cerceris, a wasp-like insect, remarks that “fights frequently ensue between the males for the possession of some particular female, who sits an apparently unconcerned beholder of the struggle for supremacy, and when the victory is decided, quietly flies away in company with the conqueror.” Westwood (57. ‘Journal of Proceedings of Entomological Society,’ Sept. 7, 1863, p. 169.) says that the males of one of the saw-flies (Tenthredinae) “have been found fighting together, with their mandibles locked.” As M. Fabre speaks of the males of Cerceris striving to obtain a particular female, it may be well to bear in mind that insects belonging to this Order have the power of recognising each other after long intervals of time, and are deeply attached. For instance, Pierre Huber, whose accuracy no one doubts, separated some ants, and when, after an interval of four months, they met others which had formerly belonged to the same community, they recognised and caressed one another with their antennae. Had they been strangers they would have fought together. Again, when two communities engage in a battle, the ants on the same side sometimes attack each other in the general confusion, but they soon perceive their mistake, and the one ant soothes the other. (58. P. Huber, ‘Recherches sur les Moeurs des Fourmis,’ 1810, pp. 150, 165.)

In this Order slight differences in colour, according to sex, are common, but conspicuous differences are rare except in the family of Bees; yet both sexes of certain groups are so brilliantly coloured—for instance in Chrysis, in which vermilion and metallic greens prevail—that we are tempted to attribute the result to sexual selection. In the Ichneumonidae, according to Mr. Walsh (59. ‘Proceedings of the Entomological Society of Philadelphia,’ 1866, pp. 238, 239.), the males are almost universally lighter-coloured than the females. On the other hand, in the Tenthredinidae the males are generally darker than the females. In the Siricidae the sexes frequently differ; thus the male of Sirex juvencus is banded with orange, whilst the female is dark purple; but it is difficult to say which sex is the more ornamented. In Tremex columbae the female is much brighter coloured than the male. I am informed by Mr. F. Smith, that the male ants of several species are black, the females being testaceous.

In the family of Bees, especially in the solitary species, as I hear from the same entomologist, the sexes often differ in colour. The males are generally the brighter, and in Bombus as well as in Apathus, much more variable in colour than the females. In Anthophora retusa the male is of a rich fulvous-brown, whilst the female is quite black: so are the females of several species of Xylocopa, the males being bright yellow. On the other hand the females of some species, as of Andraena fulva, are much brighter coloured than the males. Such differences in colour can hardly be accounted for by the males being defenceless and thus requiring protection, whilst the females are well defended by their stings. H. Müller (60. ‘Anwendung der Darwinschen Lehre auf Bienen,’ Verh. d. n. V. Jahrg. xxix.), who has particularly attended to the habits of bees, attributes these differences in colour in chief part to sexual selection. That bees have a keen perception of colour is certain. He says that the males search eagerly and fight for the possession of the females; and he accounts through such contests for the mandibles of the males being in certain species larger than those of the females. In some cases the males are far more numerous than the females, either early in the season, or at all times and places, or locally; whereas the females in other cases are apparently in excess. In some species the more beautiful males appear to have been selected by the females; and in others the more beautiful females by the males. Consequently in certain genera (Müller, p. 42), the males of the several species differ much in appearance, whilst the females are almost indistinguishable; in other genera the reverse occurs. H. Müller believes (p. 82) that the colours gained by one sex through sexual selection have often been transferred in a variable degree to the other sex, just as the pollen-collecting apparatus of the female has often been transferred to the male, to whom it is absolutely useless. (61。 M. Perrier in his article ‘la Selection sexuelle d’après Darwin’ (‘Revue Scientifique,’ Feb. 1873。 868), without apparently having reflected much on the subject, objects that as the males of social bees are known to be produced from unfertilised ova, they could not transmit new characters to their male offspring. This is an extraordinary objection. A female bee fertilised by a male, which presented some character facilitating the union of the sexes, or rendering him more attractive to the female, would lay eggs which would produce only females; but these young females would next year produce males; and will it be pretended that such males would not inherit the characters of their male grandfathers? To take a case with ordinary animals as nearly parallel as possible: if a female of any white quadruped or bird were crossed by a male of a black breed, and the male and female offspring were paired together, will it be pretended that the grandchildren would not inherit a tendency to blackness from their male grandfather?

Mutilla Europaea makes a stridulating noise; and according to Goureau (62. Quoted by Westwood, ‘Modern Classification of Insects,’ vol. ii. p. 214.) both sexes have this power. He attributes the sound to the friction of the third and preceding abdominal segments, and I find that these surfaces are marked with very fine concentric ridges; but so is the projecting thoracic collar into which the head articulates, and this collar, when scratched with the point of a needle, emits the proper sound. It is rather surprising that both sexes should have the power of stridulating, as the male is winged and the female wingless. It is notorious that Bees express certain emotions, as of anger, by the tone of their humming; and according to H. Müller (p. 80), the males of some species make a peculiar singing noise whilst pursuing the females.

Order, Coleoptera (Beetles)

Many beetles are coloured so as to resemble the surfaces which they habitually frequent, and they thus escape detection by their enemies. Other species, for instance diamond-beetles, are ornamented with splendid colours, which are often arranged in stripes, spots, crosses, and other elegant patterns. Such colours can hardly serve directly as a protection, except in the case of certain flower-feeding species; but they may serve as a warning or means of recognition, on the same principle as the phosphorescence of the glow-worm. As with beetles the colours of the two sexes are generally alike, we have no evidence that they have been gained through sexual selection; but this is at least possible, for they have been developed in one sex and then transferred to the other; and this view is even in some degree probable in those groups which possess other well- marked secondary sexual characters. Blind beetles, which cannot of course behold each other’s beauty, never, as I hear from Mr. Waterhouse, jun., exhibit bright colours, though they often have polished coats; but the explanation of their obscurity may be that they generally inhabit caves and other obscure stations.

Some Longicorns, especially certain Prionidae, offer an exception to the rule that the sexes of beetles do not differ in colour. Most of these insects are large and splendidly coloured. The males in the genus Pyrodes (63. Pyrodes pulcherrimus, in which the sexes differ conspicuously, has been described by Mr. Bates in ‘Transact. Ent. Soc.’ 1869, p. 50. I will specify the few other cases in which I have heard of a difference in colour between the sexes of beetles. Kirby and Spence (‘Introduct. to Entomology,’ vol. iii. p. 301) mention a Cantharis, Meloe, Rhagium, and the Leptura testacea; the male of the latter being testaceous, with a black thorax, and the female of a dull red all over. These two latter beetles belong to the family of Longicorns. Messrs. R. Trimen and Waterhouse, jun., inform me of two Lamellicorns, viz., a Peritrichia and Trichius, the male of the latter being more obscurely coloured than the female. In Tillus elongatus the male is black, and the female always, as it is believed, of a dark blue colour, with a red thorax. The male, also, of Orsodacna atra, as I hear from Mr. Walsh, is black, the female (the so- called O. ruficollis) having a rufous thorax.), which I saw in Mr. Bates’s collection, are generally redder but rather duller than the females, the latter being coloured of a more or less splendid golden-green. On the other hand, in one species the male is golden-green, the female being richly tinted with red and purple. In the genus Esmeralda the sexes differ so greatly in colour that they have been ranked as distinct species; in one species both are of a beautiful shining green, but the male has a red thorax. On the whole, as far as I could judge, the females of those Prionidae, in which the sexes differ, are coloured more richly than the males, and this does not accord with the common rule in regard to colour, when acquired through sexual selection.

[Fig.16. Chalcosoma atlas. Upper figure, male (reduced); lower figure, female (nat. size).

Fig. 17. Copris isidis.

Fig. 18. Phanaeus faunus.

Fig. 19. Dipelicus cantori.

Fig. 20. Onthophagus rangifer, enlarged.
(In Figs. 17 to 20 the left-hand figures are males.)]

A most remarkable distinction between the sexes of many beetles is presented by the great horns which rise from the head, thorax, and clypeus of the males; and in some few cases from the under surface of the body. These horns, in the great family of the Lamellicorns, resemble those of various quadrupeds, such as stags, rhinoceroses, etc., and are wonderful both from their size and diversified shapes. Instead of describing them, I have given figures of the males and females of some of the more remarkable forms. (Figs. 16 to 20.) The females generally exhibit rudiments of the horns in the form of small knobs or ridges; but some are destitute of even the slightest rudiment. On the other hand, the horns are nearly as well developed in the female as in the male Phanaeus lancifer; and only a little less well developed in the females of some other species of this genus and of Copris. I am informed by Mr. Bates that the horns do not differ in any manner corresponding with the more important characteristic differences between the several subdivisions of the family: thus within the same section of the genus Onthophagus, there are species which have a single horn, and others which have two.

In almost all cases, the horns are remarkable from their excessive variability; so that a graduated series can be formed, from the most highly developed males to others so degenerate that they can barely be distinguished from the females. Mr. Walsh (64. ‘Proceedings of the Entomological Society of Philadephia,’ 1864, p. 228.) found that in Phanaeus carnifex the horns were thrice as long in some males as in others. Mr. Bates, after examining above a hundred males of Onthophagus rangifer (Fig. 20), thought that he had at last discovered a species in which the horns did not vary; but further research proved the contrary.

The extraordinary size of the horns, and their widely different structure in closely-allied forms, indicate that they have been formed for some purpose; but their excessive variability in the males of the same species leads to the inference that this purpose cannot be of a definite nature. The horns do not shew marks of friction, as if used for any ordinary work. Some authors suppose (65. Kirby and Spence, ‘Introduction to Entomology,’ vol. iii. p. 300.) that as the males wander about much more than the females, they require horns as a defence against their enemies; but as the horns are often blunt, they do not seem well adapted for defence. The most obvious conjecture is that they are used by the males for fighting together; but the males have never been observed to fight; nor could Mr. Bates, after a careful examination of numerous species, find any sufficient evidence, in their mutilated or broken condition, of their having been thus used. If the males had been habitual fighters, the size of their bodies would probably have been increased through sexual selection, so as to have exceeded that of the females; but Mr. Bates, after comparing the two sexes in above a hundred species of the Copridae, did not find any marked difference in this respect amongst well-developed individuals. In Lethrus, moreover, a beetle belonging to the same great division of the Lamellicorns, the males are known to fight, but are not provided with horns, though their mandibles are much larger than those of the female.

The conclusion that the horns have been acquired as ornaments is that which best agrees with the fact of their having been so immensely, yet not fixedly, developed,—as shewn by their extreme variability in the same species, and by their extreme diversity in closely-allied species. This view will at first appear extremely improbable; but we shall hereafter find with many animals standing much higher in the scale, namely fishes, amphibians, reptiles and birds, that various kinds of crests, knobs, horns and combs have been developed apparently for this sole purpose.

[Fig.21. Onitis furcifer, male viewed from beneath.

Fig.22. Onitis furcifer. Left-hand figure, male, viewed laterally. Right-hand figure, female. a. Rudiment of cephalic horn. b. Trace of thoracic horn or crest.]

The males of Onitis furcifer (Fig. 21), and of some other species of the genus, are furnished with singular projections on their anterior femora, and with a great fork or pair of horns on the lower surface of the thorax. Judging from other insects, these may aid the male in clinging to the female. Although the males have not even a trace of a horn on the upper surface of the body, yet the females plainly exhibit a rudiment of a single horn on the head (Fig. 22, a), and of a crest (b) on the thorax. That the slight thoracic crest in the female is a rudiment of a projection proper to the male, though entirely absent in the male of this particular species, is clear: for the female of Bubas bison (a genus which comes next to Onitis) has a similar slight crest on the thorax, and the male bears a great projection in the same situation. So, again, there can hardly be a doubt that the little point (a) on the head of the female Onitis furcifer, as well as on the head of the females of two or three allied species, is a rudimentary representative of the cephalic horn, which is common to the males of so many Lamellicorn beetles, as in Phanaeus (Fig. 18).

The old belief that rudiments have been created to complete the scheme of nature is here so far from holding good, that we have a complete inversion of the ordinary state of things in the family. We may reasonably suspect that the males originally bore horns and transferred them to the females in a rudimentary condition, as in so many other Lamellicorns. Why the males subsequently lost their horns, we know not; but this may have been caused through the principle of compensation, owing to the development of the large horns and projections on the lower surface; and as these are confined to the males, the rudiments of the upper horns on the females would not have been thus obliterated.

[Fig. 23. Bledius taurus, magnified. Left-hand figure, male; right-hand figure, female.]

The cases hitherto given refer to the Lamellicorns, but the males of some few other beetles, belonging to two widely distinct groups, namely, the Curculionidae and Staphylinidae, are furnished with horns—in the former on the lower surface of the body (66. Kirby and Spence, ‘Introduction to Entomology,’ vol. iii. p. 329.), in the latter on the upper surface of the head and thorax. In the Staphylinidae, the horns of the males are extraordinarily variable in the same species, just as we have seen with the Lamellicorns. In Siagonium we have a case of dimorphism, for the males can be divided into two sets, differing greatly in the size of their bodies and in the development of their horns, without intermediate gradations. In a species of Bledius (Fig. 23), also belonging to the Staphylinidae, Professor Westwood states that, “male specimens can be found in the same locality in which the central horn of the thorax is very large, but the horns of the head quite rudimental; and others, in which the thoracic horn is much shorter, whilst the protuberances on the head are long.” (67. ‘Modern Classification of Insects,’ vol. i. p. 172: Siagonium, p. 172. In the British Museum I noticed one male specimen of Siagonium in an intermediate condition, so that the dimorphism is not strict.) Here we apparently have a case of compensation, which throws light on that just given, of the supposed loss of the upper horns by the males of Onitis.

Law of Battle

Some male beetles, which seem ill-fitted for fighting, nevertheless engage in conflicts for the possession of the females. Mr. Wallace (68. ‘The Malay Archipelago,’ vol. ii. 1869, p. 276. Riley, Sixth ‘Report on Insects of Missouri,’ 1874, p. 115.) saw two males of Leptorhynchus angustatus, a linear beetle with a much elongated rostrum, “fighting for a female, who stood close by busy at her boring. They pushed at each other with their rostra, and clawed and thumped, apparently in the greatest rage.” The smaller male, however, “soon ran away, acknowledging himself vanquished.” In some few cases male beetles are well adapted for fighting, by possessing great toothed mandibles, much larger than those of the females. This is the case with the common stag-beetle (Lucanus cervus), the males of which emerge from the pupal state about a week before the other sex, so that several may often be seen pursuing the same female. At this season they engage in fierce conflicts. When Mr. A.H. Davis (69. ‘Entomological Magazine,’ vol. i. 1833, p. 82. See also on the conflicts of this species, Kirby and Spence, ibid. vol. iii. p. 314; and Westwood, ibid. vol. i. p. 187.) enclosed two males with one female in a box, the larger male severely pinched the smaller one, until he resigned his pretensions. A friend informs me that when a boy he often put the males together to see them fight, and he noticed that they were much bolder and fiercer than the females, as with the higher animals. The males would seize hold of his finger, if held in front of them, but not so the females, although they have stronger jaws. The males of many of the Lucanidae, as well as of the above-mentioned Leptorhynchus, are larger and more powerful insects than the females. The two sexes of Lethrus cephalotes (one of the Lamellicorns) inhabit the same burrow; and the male has larger mandibles than the female. If, during the breeding-season, a strange male attempts to enter the burrow, he is attacked; the female does not remain passive, but closes the mouth of the burrow, and encourages her mate by continually pushing him on from behind; and the battle lasts until the aggressor is killed or runs away. (70. Quoted from Fischer, in ‘Dict. Class. d’Hist. Nat.’ tom. x. p. 324.) The two sexes of another Lamellicorn beetle, the Ateuchus cicatricosus, live in pairs, and seem much attached to each other; the male excites the females to roll the balls of dung in which the ova are deposited; and if she is removed, he becomes much agitated. If the male is removed the female ceases all work, and as M. Brulerie believes, would remain on the same spot until she died. (71. ‘Ann. Soc. Entomolog. France,’ 1866, as quoted in ‘Journal of Travel,’ by A. Murray, 1868, p. 135.)

[Fig. 24. Chiasognathus Grantii, reduced. Upper figure, male; lower figure, female.]

The great mandibles of the male Lucanidae are extremely variable both in size and structure, and in this respect resemble the horns on the head and thorax of many male Lamellicorns and Staphylinidae. A perfect series can be formed from the best-provided to the worst-provided or degenerate males. Although the mandibles of the common stag-beetle, and probably of many other species, are used as efficient weapons for fighting, it is doubtful whether their great size can thus be accounted for. We have seen that they are used by the Lucanus elaphus of N. America for seizing the female. As they are so conspicuous and so elegantly branched, and as owing to their great length they are not well adapted for pinching, the suspicion has crossed my mind that they may in addition serve as an ornament, like the horns on the head and thorax of the various species above described. The male Chiasognathus grantii of S. Chile—a splendid beetle belonging to the same family—has enormously developed mandibles (Fig. 24); he is bold and pugnacious; when threatened he faces round, opens his great jaws, and at the same time stridulates loudly. But the mandibles were not strong enough to pinch my finger so as to cause actual pain.

Sexual selection, which implies the possession of considerable perceptive powers and of strong passions, seems to have been more effective with the Lamellicorns than with any other family of beetles. With some species the males are provided with weapons for fighting; some live in pairs and shew mutual affection; many have the power of stridulating when excited; many are furnished with the most extraordinary horns, apparently for the sake of ornament; and some, which are diurnal in their habits, are gorgeously coloured. Lastly, several of the largest beetles in the world belong to this family, which was placed by Linnaeus and Fabricius as the head of the Order. (72. Westwood, ‘Modern Classification,’ vol. i. p. 184.)

Stridulating Organs

Beetles belonging to many and widely distinct families possess these organs. The sound thus produced can sometimes be heard at the distance of several feet or even yards (73. Wollaston, ‘On Certain Musical Curculionidae,’ ‘Annals and Mag. of Nat. Hist.’ vol. vi. 1860, p. 14.), but it is not comparable with that made by the Orthoptera. The rasp generally consists of a narrow, slightly-raised surface, crossed by very fine, parallel ribs, sometimes so fine as to cause iridescent colours, and having a very elegant appearance under the microscope. In some cases, as with Typhoeus, minute, bristly or scale-like prominences, with which the whole surrounding surface is covered in approximately parallel lines, could be traced passing into the ribs of the rasp. The transition takes place by their becoming confluent and straight, and at the same time more prominent and smooth. A hard ridge on an adjoining part of the body serves as the scraper for the rasp, but this scraper in some cases has been specially modified for the purpose. It is rapidly moved across the rasp, or conversely the rasp across the scraper.

[Fig.25. Necrophorus (from Landois). r. The two rasps. Left-hand figure, part of the rasp highly magnified.]

These organs are situated in widely different positions. In the carrion- beetles (Necrophorus) two parallel rasps (r, Fig. 25) stand on the dorsal surface of the fifth abdominal segment, each rasp (74. Landois, ‘Zeitschrift fur wissenschaft Zoolog.’ B. xvii. 1867, s. 127.) consisting of 126 to 140 fine ribs. These ribs are scraped against the posterior margins of the elytra, a small portion of which projects beyond the general outline. In many Crioceridae, and in Clythra 4-punctata (one of the Chrysomelidae), and in some Tenebrionidae, etc. (75. I am greatly indebted to Mr. G.R. Crotch for having sent me many prepared specimens of various beetles belonging to these three families and to others, as well as for valuable information. He believes that the power of stridulation in the Clythra has not been previously observed. I am also much indebted to Mr. E.W. Janson, for information and specimens. I may add that my son, Mr. F. Darwin, finds that Dermestes murinus stridulates, but he searched in vain for the apparatus. Scolytus has lately been described by Dr. Chapman as a stridulator, in the ‘Entomologist’s Monthly Magazine,’ vol. vi. p. 130.), the rasp is seated on the dorsal apex of the abdomen, on the pygidium or pro-pygidium, and is scraped in the same manner by the elytra. In Heterocerus, which belongs to another family, the rasps are placed on the sides of the first abdominal segment, and are scraped by ridges on the femora. (76. Schiodte, translated, in ‘Annals and Magazine of Natural History,’ vol. xx. 1867, p. 37.) In certain Curculionidae and Carabidae (77. Westring has described (Kroyer, ‘Naturhist. Tidskrift,’ B. ii. 1848- 49, p. 334) the stridulating organs in these two, as well as in other families. In the Carabidae I have examined Elaphrus uliginosus and Blethisa multipunctata, sent to me by Mr. Crotch. In Blethisa the transverse ridges on the furrowed border of the abdominal segment do not, as far as I could judge, come into play in scraping the rasps on the elytra.), the parts are completely reversed in position, for the rasps are seated on the inferior surface of the elytra, near their apices, or along their outer margins, and the edges of the abdominal segments serve as the scrapers. In Pelobius Hermanni (one of Dytiscidae or water-beetles) a strong ridge runs parallel and near to the sutural margin of the elytra, and is crossed by ribs, coarse in the middle part, but becoming gradually finer at both ends, especially at the upper end; when this insect is held under water or in the air, a stridulating noise is produced by the extreme horny margin of the abdomen being scraped against the rasps. In a great number of long-horned beetles (Longicornia) the organs are situated quite otherwise, the rasp being on the meso-thorax, which is rubbed against the pro-thorax; Landois counted 238 very fine ribs on the rasp of Cerambyx heros.

[Fig.26. Hind-leg of Geotrupes stercorarius (from Landois). r. Rasp. c. Coxa. f. Femur. t. Tibia. tr. Tarsi.]

Many Lamellicorns have the power of stridulating, and the organs differ greatly in position. Some species stridulate very loudly, so that when Mr. F. Smith caught a Trox sabulosus, a gamekeeper, who stood by, thought he had caught a mouse; but I failed to discover the proper organs in this beetle. In Geotrupes and Typhoeus, a narrow ridge runs obliquely across (r, Fig. 26) the coxa of each hind-leg (having in G. stercorarius 84 ribs), which is scraped by a specially projecting part of one of the abdominal segments. In the nearly allied Copris lunaris, an excessively narrow fine rasp runs along the sutural margin of the elytra, with another short rasp near the basal outer margin; but in some other Coprini the rasp is seated, according to Leconte (78. I am indebted to Mr. Walsh, of Illinois, for having sent me extracts from Leconte’s ‘Introduction to Entomology,’ pp. 101, 143.), on the dorsal surface of the abdomen. In Oryctes it is seated on the pro-pygidium; and, according to the same entomologist, in some other Dynastini, on the under surface of the elytra. Lastly, Westring states that in Omaloplia brunnea the rasp is placed on the pro-sternum, and the scraper on the meta-sternum, the parts thus occupying the under surface of the body, instead of the upper surface as in the Longicorns.

We thus see that in the different coleopterous families the stridulating organs are wonderfully diversified in position, but not much in structure. Within the same family some species are provided with these organs, and others are destitute of them. This diversity is intelligible, if we suppose that originally various beetles made a shuffling or hissing noise by the rubbing together of any hard and rough parts of their bodies, which happened to be in contact; and that from the noise thus produced being in some way useful, the rough surfaces were gradually developed into regular stridulating organs. Some beetles as they move, now produce, either intentionally or unintentionally, a shuffling noise, without possessing any proper organs for the purpose. Mr. Wallace informs me that the Euchirus longimanus (a Lamellicorn, with the anterior legs wonderfully elongated in the male) “makes, whilst moving, a low hissing sound by the protrusion and contraction of the abdomen; and when seized it produces a grating sound by rubbing its hind-legs against the edges of the elytra.” The hissing sound is clearly due to a narrow rasp running along the sutural margin of each elytron; and I could likewise make the grating sound by rubbing the shagreened surface of the femur against the granulated margin of the corresponding elytron; but I could not here detect any proper rasp; nor is it likely that I could have overlooked it in so large an insect. After examining Cychrus, and reading what Westring has written about this beetle, it seems very doubtful whether it possesses any true rasp, though it has the power of emitting a sound.

From the analogy of the Orthoptera and Homoptera, I expected to find the stridulating organs in the Coleoptera differing according to sex; but Landois, who has carefully examined several species, observed no such difference; nor did Westring; nor did Mr. G.R. Crotch in preparing the many specimens which he had the kindness to send me. Any difference in these organs, if slight, would, however, be difficult to detect, on account of their great variability. Thus, in the first pair of specimens of Necrophorus humator and of Pelobius which I examined, the rasp was considerably larger in the male than in the female; but not so with succeeding specimens. In Geotrupes stercorarius the rasp appeared to me thicker, opaquer, and more prominent in three males than in the same number of females; in order, therefore, to discover whether the sexes differed in their power of stridulating, my son, Mr. F. Darwin, collected fifty-seven living specimens, which he separated into two lots, according as they made a greater or lesser noise, when held in the same manner. He then examined all these specimens, and found that the males were very nearly in the same proportion to the females in both the lots. Mr. F. Smith has kept alive numerous specimens of Monoynchus pseudacori (Curculionidae), and is convinced that both sexes stridulate, and apparently in an equal degree.

Nevertheless, the power of stridulating is certainly a sexual character in some few Coleoptera. Mr. Crotch discovered that the males alone of two species of Heliopathes (Tenebrionidae) possess stridulating organs. I examined five males of H. gibbus, and in all these there was a well- developed rasp, partially divided into two, on the dorsal surface of the terminal abdominal segment; whilst in the same number of females there was not even a rudiment of the rasp, the membrane of this segment being transparent, and much thinner than in the male. In H. cribratostriatus the male has a similar rasp, excepting that it is not partially divided into two portions, and the female is completely destitute of this organ; the male in addition has on the apical margins of the elytra, on each side of the suture, three or four short longitudinal ridges, which are crossed by extremely fine ribs, parallel to and resembling those on the abdominal rasp; whether these ridges serve as an independent rasp, or as a scraper for the abdominal rasp, I could not decide: the female exhibits no trace

of this latter structure.

Again, in three species of the Lamellicorn genus Oryctes, we have a nearly parallel case. In the females of O. gryphus and nasicornis the ribs on the rasp of the pro-pygidium are less continuous and less distinct than in the males; but the chief difference is that the whole upper surface of this segment, when held in the proper light, is seen to be clothed with hairs, which are absent or are represented by excessively fine down in the males. It should be noticed that in all Coleoptera the effective part of the rasp is destitute of hairs. In O. senegalensis the difference between the sexes is more strongly marked, and this is best seen when the proper abdominal segment is cleaned and viewed as a transparent object. In the female the whole surface is covered with little separate crests, bearing spines; whilst in the male these crests in proceeding towards the apex, become more and more confluent, regular, and naked; so that three-fourths of the segment is covered with extremely fine parallel ribs, which are quite absent in the female. In the females, however, of all three species of Oryctes, a slight grating or stridulating sound is produced, when the abdomen of a softened specimen is pushed backwards and forwards.

In the case of the Heliopathes and Oryctes there can hardly be a doubt that the males stridulate in order to call or to excite the females; but with most beetles the stridulation apparently serves both sexes as a mutual call. Beetles stridulate under various emotions, in the same manner as birds use their voices for many purposes besides singing to their mates. The great Chiasognathus stridulates in anger or defiance; many species do the same from distress or fear, if held so that they cannot escape; by striking the hollow stems of trees in the Canary Islands, Messrs. Wollaston and Crotch were able to discover the presence of beetles belonging to the genus Acalles by their stridulation. Lastly, the male Ateuchus stridulates to encourage the female in her work, and from distress when she is removed. (79. M. P. de la Brulerie, as quoted in ‘Journal of Travel,’ A. Murray, vol. i. 1868, p. 135.) Some naturalists believe that beetles make this noise to frighten away their enemies; but I cannot think that a quadruped or bird, able to devour a large beetle, would be frightened by so slight a sound. The belief that the stridulation serves as a sexual call is supported by the fact that death-ticks (Anobium tessellatum) are well known to answer each other’s ticking, and, as I have myself observed, a tapping noise artificially made. Mr. Doubleday also informs me that he has sometimes observed a female ticking (80. According to Mr. Doubleday, “the noise is produced by the insect raising itself on its legs as high as it can, and then striking its thorax five or six times, in rapid succession, against the substance upon which it is sitting.” For references on this subject see Landois, ‘Zeitschrift für wissen. Zoolog.’ B. xvii. s. 131. Olivier says (as quoted by Kirby and Spence, ‘Introduction to Entomology,’ vol. ii. p. 395) that the female of Pimelia striata produces a rather loud sound by striking her abdomen against any hard substance, “and that the male, obedient to this call, soon attends her, and they pair.”), and in an hour or two afterwards has found her united with a male, and on one occasion surrounded by several males. Finally, it is probable that the two sexes of many kinds of beetles were at first enabled to find each other by the slight shuffling noise produced by the rubbing together of the adjoining hard parts of their bodies; and that as those males or females which made the greatest noise succeeded best in finding partners, rugosities on various parts of their bodies were gradually developed by means of sexual selection into true stridulating organs.

第十一章 •10,700字
昆虫(续)——鳞翅目。 (蝴蝶和飞蛾)

Courtship of butterflies—Battles—Ticking noise—Colours common to both

sexes, or more brilliant in the males—Examples—Not due to the direct action of the conditions of life—Colours adapted for protection—Colours of moths—Display—Perceptive powers of the Lepidoptera—Variability— Causes of the difference in colour between the males and females—Mimicry, female butterflies more brilliantly coloured than the males—Bright colours of caterpillars—Summary and concluding remarks on the secondary sexual characters of insects—Birds and insects compared.

In this great Order the most interesting points for us are the differences in colour between the sexes of the same species, and between the distinct species of the same genus. Nearly the whole of the following chapter will be devoted to this subject; but I will first make a few remarks on one or two other points. Several males may often be seen pursuing and crowding round the same female. Their courtship appears to be a prolonged affair, for I have frequently watched one or more males pirouetting round a female until I was tired, without seeing the end of the courtship. Mr. A.G. Butler also informs me that he has several times watched a male courting a female for a full quarter of an hour; but she pertinaciously refused him, and at last settled on the ground and closed her wings, so as to escape from his addresses.

Although butterflies are weak and fragile creatures, they are pugnacious, and an emperor butterfly (1. Apatura Iris: ‘The Entomologist’s Weekly Intelligence,’ 1859, p. 139. For the Bornean Butterflies, see C. Collingwood, ‘Rambles of a Naturalist,’ 1868, p. 183.) has been captured with the tips of its wings broken from a conflict with another male. Mr. Collingwood, in speaking of the frequent battles between the butterflies of Borneo, says, “They whirl round each other with the greatest rapidity, and appear to be incited by the greatest ferocity.”

The Ageronia feronia makes a noise like that produced by a toothed wheel passing under a spring catch, and which can be heard at the distance of several yards: I noticed this sound at Rio de Janeiro, only when two of these butterflies were chasing each other in an irregular course, so that it is probably made during the courtship of the sexes. (2. See my ‘Journal of Researches,’ 1845, p. 33. Mr. Doubleday has detected (‘Proc. Ent. Soc.’ March 3, 1845, p. 123) a peculiar membranous sac at the base of the front wings, which is probably connected with the production of the sound. For the case of Thecophora, see ‘Zoological Record,’ 1869, p. 401. For Mr. Buchanan White’s observations, the Scottish Naturalist, July 1872, p. 214.)

Some moths also produce sounds; for instance, the males Theocophora fovea. On two occasions Mr. F. Buchanan White (3. ‘The Scottish Naturalist,’ July 1872, p. 213.) heard a sharp quick noise made by the male of Hylophila prasinana, and which he believes to be produced, as in Cicada, by an elastic membrane, furnished with a muscle. He quotes, also, Guenee, that Setina produces a sound like the ticking of a watch, apparently by the aid of “two large tympaniform vesicles, situated in the pectoral region”; and these “are much more developed in the male than in the female.” Hence the sound-producing organs in the Lepidoptera appear to stand in some relation with the sexual functions. I have not alluded to the well-known noise made by the Death’s Head Sphinx, for it is generally heard soon after the moth has emerged from its cocoon.

Giard has always observed that the musky odour, which is emitted by two species of Sphinx moths, is peculiar to the males (4. ‘Zoological Record,’ 1869, p. 347.); and in the higher classes we shall meet with many instances of the males alone being odoriferous.

Every one must have admired the extreme beauty of many butterflies and of some moths; and it may be asked, are their colours and diversified patterns the result of the direct action of the physical conditions to which these insects have been exposed, without any benefit being thus derived? Or have successive variations been accumulated and determined as a protection, or for some unknown purpose, or that one sex may be attractive to the other? And, again, what is the meaning of the colours being widely different in the males and females of certain species, and alike in the two sexes of other species of the same genus? Before attempting to answer these questions a body of facts must be given.

With our beautiful English butterflies, the admiral, peacock, and painted lady (Vanessae), as well as many others, the sexes are alike. This is also the case with the magnificent Heliconidae, and most of the Danaidae in the tropics. But in certain other tropical groups, and in some of our English butterflies, as the purple emperor, orange-tip, etc. (Apatura Iris and Anthocharis cardamines), the sexes differ either greatly or slightly in colour. No language suffices to describe the splendour of the males of some tropical species. Even within the same genus we often find species presenting extraordinary differences between the sexes, whilst others have their sexes closely alike. Thus in the South American genus Epicalia, Mr. Bates, to whom I am indebted for most of the following facts, and for looking over this whole discussion, informs me that he knows twelve species, the two sexes of which haunt the same stations (and this is not always the case with butterflies), and which, therefore, cannot have been differently affected by external conditions. (5. See also Mr. Bates’s paper in ‘Proc. Ent. Soc. of Philadelphia,’ 1865, p. 206. Also Mr. Wallace on the same subject, in regard to Diadema, in ‘Transactions, Entomological Society of London,’ 1869, p. 278.) In nine of these twelve species the males rank amongst the most brilliant of all butterflies, and differ so greatly from the comparatively plain females that they were formerly placed in distinct genera. The females of these nine species resemble each other in their general type of coloration; and they likewise resemble both sexes of the species in several allied genera found in various parts of the world. Hence we may infer that these nine species, and probably all the others of the genus, are descended from an ancestral form which was coloured in nearly the same manner. In the tenth species the female still retains the same general colouring, but the male resembles her, so that he is coloured in a much less gaudy and contrasted manner than the males of the previous species. In the eleventh and twelfth species, the females depart from the usual type, for they are gaily decorated almost like the males, but in a somewhat less degree. Hence in these two latter species the bright colours of the males seem to have been transferred to the females; whilst in the tenth species the male has either retained or recovered the plain colours of the female, as well as of the parent-form of the genus. The sexes in these three cases have thus been rendered nearly alike, though in an opposite manner. In the allied genus Eubagis, both sexes of some of the species are plain-coloured and nearly alike; whilst with the greater number the males are decorated with beautiful metallic tints in a diversified manner, and differ much from their females. The females throughout the genus retain the same general style of colouring, so that they resemble one another much more closely than they resemble their own males.

In the genus Papilio, all the species of the Aeneas group are remarkable for their conspicuous and strongly contrasted colours, and they illustrate the frequent tendency to gradation in the amount of difference between the sexes. In a few species, for instance in P. ascanius, the males and females are alike; in others the males are either a little brighter, or very much more superb than the females. The genus Junonia, allied to our Vanessae, offers a nearly parallel case, for although the sexes of most of the species resemble each other, and are destitute of rich colours, yet in certain species, as in J. oenone, the male is rather more bright-coloured than the female, and in a few (for instance J. andremiaja) the male is so different from the female that he might be mistaken for an entirely distinct species.

Another striking case was pointed out to me in the British Museum by Mr. A. Butler, namely, one of the tropical American Theclae, in which both sexes are nearly alike and wonderfully splendid; in another species the male is coloured in a similarly gorgeous manner, whilst the whole upper surface of the female is of a dull uniform brown. Our common little English blue butterflies of the genus Lycaena, illustrate the various differences in colour between the sexes, almost as well, though not in so striking a manner, as the above exotic genera. In Lycaena agestis both sexes have wings of a brown colour, bordered with small ocellated orange spots, and are thus alike. In L. oegon the wings of the males are of a fine blue, bordered with black, whilst those of the female are brown, with a similar border, closely resembling the wings of L. agestis. Lastly, in L. arion both sexes are of a blue colour and are very like, though in the female the edges of the wings are rather duskier, with the black spots plainer; and in a bright blue Indian species both sexes are still more alike.

I have given the foregoing details in order to shew, in the first place, that when the sexes of butterflies differ, the male as a general rule is the more beautiful, and departs more from the usual type of colouring of the group to which the species belongs. Hence in most groups the females of the several species resemble each other much more closely than do the males. In some cases, however, to which I shall hereafter allude, the females are coloured more splendidly than the males. In the second place, these details have been given to bring clearly before the mind that within the same genus, the two sexes frequently present every gradation from no difference in colour, to so great a difference that it was long before the two were placed by entomologists in the same genus. In the third place, we have seen that when the sexes nearly resemble each other, this appears due either to the male having transferred his colours to the female, or to the male having retained, or perhaps recovered, the primordial colours of the group. It also deserves notice that in those groups in which the sexes differ, the females usually somewhat resemble the males, so that when the males are beautiful to an extraordinary degree, the females almost invariably exhibit some degree of beauty. From the many cases of gradation in the amount of difference between the sexes, and from the prevalence of the same general type of coloration throughout the whole of the same group, we may conclude that the causes have generally been the same which have determined the brilliant colouring of the males alone of some species, and of both sexes of other species.

As so many gorgeous butterflies inhabit the tropics, it has often been supposed that they owe their colours to the great heat and moisture of these zones; but Mr. Bates (6. ‘The Naturalist on the Amazons,’ vol. i. 1863, p. 19.) has shown by the comparison of various closely-allied groups of insects from the temperate and tropical regions, that this view cannot be maintained; and the evidence becomes conclusive when brilliantly- coloured males and plain-coloured females of the same species inhabit the same district, feed on the same food, and follow exactly the same habits of life. Even when the sexes resemble each other, we can hardly believe that their brilliant and beautifully-arranged colours are the purposeless result of the nature of the tissues and of the action of the surrounding conditions.

With animals of all kinds, whenever colour has been modified for some special purpose, this has been, as far as we can judge, either for direct or indirect protection, or as an attraction between the sexes. With many species of butterflies the upper surfaces of the wings are obscure; and this in all probability leads to their escaping observation and danger. But butterflies would be particularly liable to be attacked by their enemies when at rest; and most kinds whilst resting raise their wings vertically over their backs, so that the lower surface alone is exposed to view. Hence it is this side which is often coloured so as to imitate the objects on which these insects commonly rest. Dr. Rossler, I believe, first noticed the similarity of the closed wings of certain Vanessae and other butterflies to the bark of trees. Many analogous and striking facts could be given. The most interesting one is that recorded by Mr. Wallace (7. See the interesting article in the ‘Westminster Review,’ July 1867, p. 10. A woodcut of the Kallima is given by Mr. Wallace in ‘Hardwicke’s Science Gossip,’ September 1867, p. 196.) of a common Indian and Sumatran butterfly (Kallima) which disappears like magic when it settles on a bush; for it hides its head and antennae between its closed wings, which, in form, colour and veining, cannot be distinguished from a withered leaf with its footstalk. In some other cases the lower surfaces of the wings are brilliantly coloured, and yet are protective; thus in Thecla rubi the wings when closed are of an emerald green, and resemble the young leaves of the bramble, on which in spring this butterfly may often be seen seated. It is also remarkable that in very many species in which the sexes differ greatly in colour on their upper surface, the lower surface is closely similar or identical in both sexes, and serves as a protection. (8. Mr. G. Fraser, in ‘Nature,’ April 1871, p. 489.)

Although the obscure tints both of the upper and under sides of many butterflies no doubt serve to conceal them, yet we cannot extend this view to the brilliant and conspicuous colours on the upper surface of such species as our admiral and peacock Vanessae, our white cabbage-butterflies (Pieris), or the great swallow-tail Papilio which haunts the open fens—for these butterflies are thus rendered visible to every living creature. In these species both sexes are alike; but in the common brimstone butterfly (Gonepteryx rhamni), the male is of an intense yellow, whilst the female is much paler; and in the orange-tip (Anthocharis cardamines) the males alone have their wings tipped with bright orange. Both the males and females in these cases are conspicuous, and it is not credible that their difference in colour should stand in any relation to ordinary protection. Prof. Weismann remarks (9. ‘Einfluss der Isolirung auf die Artbildung,’ 1872, p. 58.), that the female of one of the Lycaenae expands her brown wings when she settles on the ground, and is then almost invisible; the male, on the other hand, as if aware of the danger incurred from the bright blue of the upper surface of his wings, rests with them closed; and this shows that the blue colour cannot be in any way protective. Nevertheless, it is probable that conspicuous colours are indirectly beneficial to many species, as a warning that they are unpalatable. For in certain other cases, beauty has been gained through the imitation of other beautiful species, which inhabit the same district and enjoy an immunity from attack by being in some way offensive to their enemies; but then we have to account for the beauty of the imitated species.

As Mr. Walsh has remarked to me, the females of our orange-tip butterfly, above referred to, and of an American species (Anth. genutia) probably shew us the primordial colours of the parent-species of the genus; for both sexes of four or five widely-distributed species are coloured in nearly the same manner. As in several previous cases, we may here infer that it is the males of Anth. cardamines and genutia which have departed from the usual type of the genus. In the Anth. sara from California, the orange- tips to the wings have been partially developed in the female; but they are paler than in the male, and slightly different in some other respects. In an allied Indian form, the Iphias glaucippe, the orange-tips are fully developed in both sexes. In this Iphias, as pointed out to me by Mr. A. Butler, the under surface of the wings marvellously resembles a pale- coloured leaf; and in our English orange-tip, the under surface resembles the flower-head of the wild parsley, on which the butterfly often rests at night. (10. See the interesting observations by T.W. Wood, ‘The Student,’ Sept. 1868, p. 81.) The same reason which compels us to believe that the lower surfaces have here been coloured for the sake of protection, leads us to deny that the wings have been tipped with bright orange for the same purpose, especially when this character is confined to the males.

Most Moths rest motionless during the whole or greater part of the day with their wings depressed; and the whole upper surface is often shaded and coloured in an admirable manner, as Mr. Wallace has remarked, for escaping detection. The front-wings of the Bombycidae and Noctuidae (11. Mr. Wallace in ‘Hardwicke’s Science Gossip,’ September 1867, p. 193.), when at rest, generally overlap and conceal the hind-wings; so that the latter might be brightly coloured without much risk; and they are in fact often thus coloured. During flight, moths would often be able to escape from their enemies; nevertheless, as the hind-wings are then fully exposed to view, their bright colours must generally have been acquired at some little risk. But the following fact shews how cautious we ought to be in drawing conclusions on this head. The common Yellow Under-wings (Triphaena) often fly about during the day or early evening, and are then conspicuous from the colour of their hind-wings. It would naturally be thought that this would be a source of danger; but Mr. J. Jenner Weir believes that it actually serves them as a means of escape, for birds strike at these brightly coloured and fragile surfaces, instead of at the body. For instance, Mr. Weir turned into his aviary a vigorous specimen of Triphaena pronuba, which was instantly pursued by a robin; but the bird’s attention being caught by the coloured wings, the moth was not captured until after about fifty attempts, and small portions of the wings were repeatedly broken off. He tried the same experiment, in the open air, with a swallow and T. fimbria; but the large size of this moth probably interfered with its capture. (12. See also, on this subject, Mr. Weir’s paper in ‘Transactions, Entomological Society,’ 1869, p. 23.) We are thus reminded of a statement made by Mr. Wallace (13. ‘Westminster Review,’ July 1867, p. 16.), namely, that in the Brazilian forests and Malayan islands, many common and highly-decorated butterflies are weak flyers, though furnished with a broad expanse of wing; and they “are often captured with pierced and broken wings, as if they had been seized by birds, from which they had escaped: if the wings had been much smaller in proportion to the body, it seems probable that the insect would more frequently have been struck or pierced in a vital part, and thus the increased expanse of the wings may have been indirectly beneficial.”

显示器

The bright colours of many butterflies and of some moths are specially arranged for display, so that they may be readily seen. During the night colours are not visible, and there can be no doubt that the nocturnal moths, taken as a body, are much less gaily decorated than butterflies, all of which are diurnal in their habits. But the moths of certain families, such as the Zygaenidae, several Sphingidae, Uraniidae, some Arctiidae and Saturniidae, fly about during the day or early evening, and many of these are extremely beautiful, being far brighter coloured than the strictly nocturnal kinds. A few exceptional cases, however, of bright-coloured nocturnal species have been recorded. (14. For instance, Lithosia; but Prof. Westwood (‘Modern Class. of Insects,’ vol. ii. p. 390) seems surprised at this case. On the relative colours of diurnal and nocturnal Lepidoptera, see ibid. pp. 333 and 392; also Harris, ‘Treatise on the Insects of New England,’ 1842, p. 315.)

There is evidence of another kind in regard to display. Butterflies, as before remarked, elevate their wings when at rest, but whilst basking in the sunshine often alternately raise and depress them, thus exposing both surfaces to full view; and although the lower surface is often coloured in an obscure manner as a protection, yet in many species it is as highly decorated as the upper surface, and sometimes in a very different manner. In some tropical species the lower surface is even more brilliantly coloured than the upper. (15. Such differences between the upper and lower surfaces of the wings of several species of Papilio may be seen in the beautiful plates to Mr. Wallace’s ‘Memoir on the Papilionidae of the Malayan Region,’ in ‘Transactions of the Linnean Society,’ vol. xxv. part i. 1865.) In the English fritillaries (Argynnis) the lower surface alone is ornamented with shining silver. Nevertheless, as a general rule, the upper surface, which is probably more fully exposed, is coloured more brightly and diversely than the lower. Hence the lower surface generally affords to entomologists the more useful character for detecting the affinities of the various species. Fritz Müller informs me that three species of Castnia are found near his house in S. Brazil: of two of them the hind-wings are obscure, and are always covered by the front-wings when these butterflies are at rest; but the third species has black hind-wings, beautifully spotted with red and white, and these are fully expanded and displayed whenever the butterfly rests. Other such cases could be added.

If we now turn to the enormous group of moths, which, as I hear from Mr. Stainton, do not habitually expose the under surface of their wings to full view, we find this side very rarely coloured with a brightness greater than, or even equal to, that of the upper side. Some exceptions to the rule, either real or apparent, must be noticed, as the case of Hypopyra. (16. See Mr. Wormald on this moth: ‘Proceedings of the Entomological Society,’ March 2, 1868.) Mr. Trimen informs me that in Guenee’s great work, three moths are figured, in which the under surface is much the more brilliant. For instance, in the Australian Gastrophora the upper surface of the fore-wing is pale greyish-ochreous, while the lower surface is magnificently ornamented by an ocellus of cobalt-blue, placed in the midst of a black mark, surrounded by orange-yellow, and this by bluish-white. But the habits of these three moths are unknown; so that no explanation can be given of their unusual style of colouring. Mr. Trimen also informs me that the lower surface of the wings in certain other Geometrae (17. See also an account of the S. American genus Erateina (one of the Geometrae) in ‘Transactions, Ent. Soc.’ new series, vol. v. pl. xv. and xvi.) and quadrifid Noctuae are either more variegated or more brightly-coloured than the upper surface; but some of these species have the habit of “holding their wings quite erect over their backs, retaining them in this position for a considerable time,” and thus exposing the under surface to view. Other species, when settled on the ground or herbage, now and then suddenly and slightly lift up their wings. Hence the lower surface of the wings being brighter than the upper surface in certain moths is not so anomalous as it at first appears. The Saturniidae include some of the most beautiful of all moths, their wings being decorated, as in our British Emperor moth, with fine ocelli; and Mr. T.W. Wood (18. ‘Proc Ent. Soc. of London,’ July 6, 1868, p. xxvii.) observes that they resemble butterflies in some of their movements; “for instance, in the gentle waving up and down of the wings as if for display, which is more characteristic of diurnal than of nocturnal Lepidoptera.”

It is a singular fact that no British moths which are brilliantly coloured, and, as far as I can discover, hardly any foreign species, differ much in colour according to sex; though this is the case with many brilliant butterflies. The male, however, of one American moth, the Saturnia Io, is described as having its fore-wings deep yellow, curiously marked with purplish-red spots; whilst the wings of the female are purple-brown, marked with grey lines. (19. Harris, ‘Treatise,’ etc., edited by Flint, 1862, p. 395.) The British moths which differ sexually in colour are all brown, or of various dull yellow tints, or nearly white. In several species the males are much darker than the females (20. For instance, I observe in my son’s cabinet that the males are darker than the females in the Lasiocampa quercus, Odonestis potatoria, Hypogymna dispar, Dasychira pudibunda, and Cycnia mendica. In this latter species the difference in colour between the two sexes is strongly marked; and Mr. Wallace informs me that we here have, as he believes, an instance of protective mimicry confined to one sex, as will hereafter be more fully explained. The white female of the Cycnia resembles the very common Spilosoma menthrasti, both sexes of which are white; and Mr. Stainton observed that this latter moth was rejected with utter disgust by a whole brood of young turkeys, which were fond of eating other moths; so that if the Cycnia was commonly mistaken by British birds for the Spilosoma, it would escape being devoured, and its white deceptive colour would thus be highly beneficial.), and these belong to groups which generally fly about during the afternoon. On the other hand, in many genera, as Mr. Stainton informs me, the males have the hind-wings whiter than those of the female—of which fact Agrotis exclamationis offers a good instance. In the Ghost Moth (Hepialus humuli) the difference is more strongly marked; the males being white, and the females yellow with darker markings. (21. It is remarkable, that in the Shetland Islands the male of this moth, instead of differing widely from the female, frequently resembles her closely in colour (see Mr. MacLachlan, ‘Transactions, Entomological Society,’ vol. ii. 1866, p. 459). Mr. G. Fraser suggests (‘Nature,’ April 1871, p. 489) that at the season of the year when the ghost-moth appears in these northern islands, the whiteness of the males would not be needed to render them visible to the females in the twilight night.) It is probable that in these cases the males are thus rendered more conspicuous, and more easily seen by the females whilst flying about in the dusk.

From the several foregoing facts it is impossible to admit that the brilliant colours of butterflies, and of some few moths, have commonly been acquired for the sake of protection. We have seen that their colours and elegant patterns are arranged and exhibited as if for display. Hence I am led to believe that the females prefer or are most excited by the more brilliant males; for on any other supposition the males would, as far as we can see, be ornamented to no purpose. We know that ants and certain Lamellicorn beetles are capable of feeling an attachment for each other, and that ants recognise their fellows after an interval of several months. Hence there is no abstract improbability in the Lepidoptera, which probably stand nearly or quite as high in the scale as these insects, having sufficient mental capacity to admire bright colours. They certainly discover flowers by colour. The Humming-bird Sphinx may often be seen to swoop down from a distance on a bunch of flowers in the midst of green foliage; and I have been assured by two persons abroad, that these moths repeatedly visit flowers painted on the walls of a room, and vainly endeavour to insert their proboscis into them. Fritz Müller informs me that several kinds of butterflies in S. Brazil shew an unmistakable preference for certain colours over others: he observed that they very often visited the brilliant red flowers of five or six genera of plants, but never the white or yellow flowering species of the same and other genera, growing in the same garden; and I have received other accounts to the same effect. As I hear from Mr. Doubleday, the common white butterfly often flies down to a bit of paper on the ground, no doubt mistaking it for one of its own species. Mr. Collingwood (22. ‘Rambles of a Naturalist in the Chinese Seas,’ 1868, p. 182.) in speaking of the difficulty in collecting certain butterflies in the Malay Archipelago, states that “a dead specimen pinned upon a conspicuous twig will often arrest an insect of the same species in its headlong flight, and bring it down within easy reach of the net, especially if it be of the opposite sex.”

The courtship of butterflies is, as before remarked, a prolonged affair. The males sometimes fight together in rivalry; and many may be seen pursuing or crowding round the same female. Unless, then, the females prefer one male to another, the pairing must be left to mere chance, and this does not appear probable. If, on the other band, the females habitually, or even occasionally, prefer the more beautiful males, the colours of the latter will have been rendered brighter by degrees, and will have been transmitted to both sexes or to one sex, according to the law of inheritance which has prevailed. The process of sexual selection will have been much facilitated, if the conclusion can be trusted, arrived at from various kinds of evidence in the supplement to the ninth chapter; namely, that the males of many Lepidoptera, at least in the imago state, greatly exceed the females in number.

Some facts, however, are opposed to the belief that female butterflies prefer the more beautiful males; thus, as I have been assured by several collectors, fresh females may frequently be seen paired with battered, faded, or dingy males; but this is a circumstance which could hardly fail often to follow from the males emerging from their cocoons earlier than the females. With moths of the family of the Bombycidae, the sexes pair immediately after assuming the imago state; for they cannot feed, owing to the rudimentary condition of their mouths. The females, as several entomologists have remarked to me, lie in an almost torpid state, and appear not to evince the least choice in regard to their partners. This is the case with the common silk-moth (B. mori), as I have been told by some continental and English breeders. Dr. Wallace, who has had great experience in breeding Bombyx cynthia, is convinced that the females evince no choice or preference. He has kept above 300 of these moths together, and has often found the most vigorous females mated with stunted males. The reverse appears to occur seldom; for, as he believes, the more vigorous males pass over the weakly females, and are attracted by those endowed with most vitality. Nevertheless, the Bombycidae, though obscurely-coloured, are often beautiful to our eyes from their elegant and mottled shades.

I have as yet only referred to the species in which the males are brighter coloured than the females, and I have attributed their beauty to the females for many generations having chosen and paired with the more attractive males. But converse cases occur, though rarely, in which the females are more brilliant than the males; and here, as I believe, the males have selected the more beautiful females, and have thus slowly added to their beauty. We do not know why in various classes of animals the males of some few species have selected the more beautiful females instead of having gladly accepted any female, as seems to be the general rule in the animal kingdom: but if, contrary to what generally occurs with the Lepidoptera, the females were much more numerous than the males, the latter would be likely to pick out the more beautiful females. Mr. Butler shewed me several species of Callidryas in the British Museum, in some of which the females equalled, and in others greatly surpassed the males in beauty; for the females alone have the borders of their wings suffused with crimson and orange, and spotted with black. The plainer males of these species closely resemble each other, shewing that here the females have been modified; whereas in those cases, where the males are the more ornate, it is these which have been modified, the females remaining closely alike.

In England we have some analogous cases, though not so marked. The females alone of two species of Thecla have a bright-purple or orange patch on their fore-wings. In Hipparchia the sexes do not differ much; but it is the female of H. janira which has a conspicuous light-brown patch on her wings; and the females of some of the other species are brighter coloured than their males. Again, the females of Colias edusa and hyale have “orange or yellow spots on the black marginal border, represented in the males only by thin streaks”; and in Pieris it is the females which “are ornamented with black spots on the fore-wings, and these are only partially present in the males.” Now the males of many butterflies are known to support the females during their marriage flight; but in the species just named it is the females which support the males; so that the part which the two sexes play is reversed, as is their relative beauty. Throughout the animal kingdom the males commonly take the more active share in wooing, and their beauty seems to have been increased by the females having accepted the more attractive individuals; but with these butterflies, the females take the more active part in the final marriage ceremony, so that we may suppose that they likewise do so in the wooing; and in this case we can understand how it is that they have been rendered the more beautiful. Mr. Meldola, from whom the foregoing statements have been taken, says in conclusion: “Though I am not convinced of the action of sexual selection in producing the colours of insects, it cannot be denied that these facts are strikingly corroborative of Mr. Darwin’s views.” (23. ‘Nature,’ April 27, 1871, p. 508. Mr. Meldola quotes Donzel, in ‘Soc. Ent. de France,’ 1837, p. 77, on the flight of butterflies whilst pairing. See also Mr. G. Fraser, in ‘Nature,’ April 20, 1871, p. 489, on the sexual differences of several British butterflies.)

As sexual selection primarily depends on variability, a few words must be added on this subject. In respect to colour there is no difficulty, for any number of highly variable Lepidoptera could be named. One good instance will suffice. Mr. Bates shewed me a whole series of specimens of Papilio sesostris and P. childrenae; in the latter the males varied much in the extent of the beautifully enamelled green patch on the fore-wings, and in the size of the white mark, and of the splendid crimson stripe on the hind-wings; so that there was a great contrast amongst the males between the most and the least gaudy. The male of Papilio sesostris is much less beautiful than of P. childrenae; and it likewise varies a little in the size of the green patch on the fore-wings, and in the occasional appearance of the small crimson stripe on the hind-wings, borrowed, as it would seem, from its own female; for the females of this and of many other species in the Aeneas group possess this crimson stripe. Hence between the brightest specimens of P. sesostris and the dullest of P. childrenae, there was but a small interval; and it was evident that as far as mere variability is concerned, there would be no difficulty in permanently increasing the beauty of either species by means of selection. The variability is here almost confined to the male sex; but Mr. Wallace and Mr. Bates have shewn (24. Wallace on the Papilionidae of the Malayan Region, in ‘Transact. Linn. Soc.’ vol. xxv. 1865, pp. 8, 36. A striking case of a rare variety, strictly intermediate between two other well-marked female varieties, is given by Mr. Wallace. See also Mr. Bates, in ‘Proc. Entomolog. Soc.’ Nov. 19, 1866, p. xl.) that the females of some species are extremely variable, the males being nearly constant. In a future chapter I shall have occasion to shew that the beautiful eye-like spots, or ocelli, found on the wings of many Lepidoptera, are eminently variable. I may here add that these ocelli offer a difficulty on the theory of sexual selection; for though appearing to us so ornamental, they are never present in one sex and absent in the other, nor do they ever differ much in the two sexes. (25. Mr. Bates was so kind as to lay this subject before the Entomological Society, and I have received answers to this effect from several entomologists.) This fact is at present inexplicable; but if it should hereafter be found that the formation of an ocellus is due to some change in the tissues of the wings, for instance, occurring at a very early period of development, we might expect, from what we know of the laws of inheritance, that it would be transmitted to both sexes, though arising and perfected in one sex alone.

On the whole, although many serious objections may be urged, it seems probable that most of the brilliantly-coloured species of Lepidoptera owe their colours to sexual selection, excepting in certain cases, presently to be mentioned, in which conspicuous colours have been gained through mimicry as a protection. From the ardour of the male throughout the animal kingdom, he is generally willing to accept any female; and it is the female which usually exerts a choice. Hence, if sexual selection has been efficient with the Lepidoptera, the male, when the sexes differ, ought to be the more brilliantly coloured, and this undoubtedly is the case. When both sexes are brilliantly coloured and resemble each other, the characters acquired by the males appear to have been transmitted to both. We are led to this conclusion by cases, even within the same genus, of gradation from an extraordinary amount of difference to identity in colour between the two sexes.

But it may be asked whether the difference in colour between the sexes may not be accounted for by other means besides sexual selection. Thus the males and females of the same species of butterfly are in several cases known (26. H.W. Bates, ‘The Naturalist on the Amazons,’ vol. ii. 1863, p. 228. A.R. Wallace, in ‘Transactions, Linnean Society,’ vol. xxv. 1865, p. 10.) to inhabit different stations, the former commonly basking in the sunshine, the latter haunting gloomy forests. It is therefore possible that different conditions of life may have acted directly on the two sexes; but this is not probable (27. On this whole subject see ‘The Variation of Animals and Plants under Domestication,’ 1868, vol. ii. chap. xxiii.) as in the adult state they are exposed to different conditions during a very short period; and the larvae of both are exposed to the same conditions. Mr. Wallace believes that the difference between the sexes is due not so much to the males having been modified, as to the females having in all or almost all cases acquired dull colours for the sake of protection. It seems to me, on the contrary, far more probable that it is the males which have been chiefly modified through sexual selection, the females having been comparatively little changed. We can thus understand how it is that the females of allied species generally resemble one another so much more closely than do the males. They thus shew us approximately the primordial colouring of the parent-species of the group to which they belong. They have, however, almost always been somewhat modified by the transfer to them of some of the successive variations, through the accumulation of which the males were rendered beautiful. But I do not wish to deny that the females alone of some species may have been specially modified for protection. In most cases the males and females of distinct species will have been exposed during their prolonged larval state to different conditions, and may have been thus affected; though with the males any slight change of colour thus caused will generally have been masked by the brilliant tints gained through sexual selection. When we treat of Birds, I shall have to discuss the whole question, as to how far the differences in colour between the sexes are due to the males having been modified through sexual selection for ornamental purposes, or to the females having been modified through natural selection for the sake of protection, so that I will here say but little on the subject.

In all the cases in which the more common form of equal inheritance by both sexes has prevailed, the selection of bright-coloured males would tend to make the females bright-coloured; and the selection of dull-coloured females would tend to make the males dull. If both processes were carried on simultaneously, they would tend to counteract each other; and the final result would depend on whether a greater number of females from being well protected by obscure colours, or a greater number of males by being brightly-coloured and thus finding partners, succeeded in leaving more numerous offspring.

In order to account for the frequent transmission of characters to one sex alone, Mr. Wallace expresses his belief that the more common form of equal inheritance by both sexes can be changed through natural selection into inheritance by one sex alone, but in favour of this view I can discover no evidence. We know from what occurs under domestication that new characters often appear, which from the first are transmitted to one sex alone; and by the selection of such variations there would not be the slightest difficulty in giving bright colours to the males alone, and at the same time or subsequently, dull colours to the females alone. In this manner the females of some butterflies and moths have, it is probable, been rendered inconspicuous for the sake of protection, and widely different from their males.

I am, however, unwilling without distinct evidence to admit that two complex processes of selection, each requiring the transference of new characters to one sex alone, have been carried on with a multitude of species,—that the males have been rendered more brilliant by beating their rivals, and the females more dull-coloured by having escaped from their enemies. The male, for instance, of the common brimstone butterfly (Gonepteryx), is of a far more intense yellow than the female, though she is equally conspicuous; and it does not seem probable that she specially acquired her pale tints as a protection, though it is probable that the male acquired his bright colours as a sexual attraction. The female of Anthocharis cardamines does not possess the beautiful orange wing-tips of the male; consequently she closely resembles the white butterflies (Pieris) so common in our gardens; but we have no evidence that this resemblance is beneficial to her. As, on the other hand, she resembles both sexes of several other species of the genus inhabiting various quarters of the world, it is probable that she has simply retained to a large extent her primordial colours.

Finally, as we have seen, various considerations lead to the conclusion that with the greater number of brilliantly-coloured Lepidoptera it is the male which has been chiefly modified through sexual selection; the amount of difference between the sexes mostly depending on the form of inheritance which has prevailed. Inheritance is governed by so many unknown laws or conditions, that it seems to us to act in a capricious manner (28. The ‘Variation of Animals and Plants under Domestication,’ vol. ii. chap. xii. p. 17.); and we can thus, to a certain extent, understand how it is that with closely allied species the sexes either differ to an astonishing degree, or are identical in colour. As all the successive steps in the process of variation are necessarily transmitted through the female, a greater or less number of such steps might readily become developed in her; and thus we can understand the frequent gradations from an extreme difference to none at all between the sexes of allied species. These cases of gradation, it may be added, are much too common to favour the supposition that we here see females actually undergoing the process of transition and losing their brightness for the sake of protection; for we have every reason to conclude that at any one time the greater number of species are in a fixed condition.

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This principle was first made clear in an admirable paper by Mr. Bates (29. ‘Transact. Linn. Soc.’ vol. xxiii. 1862, p. 495.), who thus threw a flood of light on many obscure problems. It had previously been observed that certain butterflies in S. America belonging to quite distinct families, resembled the Heliconidae so closely in every stripe and shade of colour, that they could not be distinguished save by an experienced entomologist. As the Heliconidae are coloured in their usual manner, whilst the others depart from the usual colouring of the groups to which they belong, it is clear that the latter are the imitators, and the Heliconidae the imitated. Mr. Bates further observed that the imitating species are comparatively rare, whilst the imitated abound, and that the two sets live mingled together. From the fact of the Heliconidae being conspicuous and beautiful insects, yet so numerous in individuals and species, he concluded that they must be protected from the attacks of enemies by some secretion or odour; and this conclusion has now been amply confirmed (30. ‘Proc. Entomological Soc.’ Dec. 3, 1866, p. xlv.), especially by Mr. Belt. Hence Mr. Bates inferred that the butterflies which imitate the protected species have acquired their present marvellously deceptive appearance through variation and natural selection, in order to be mistaken for the protected kinds, and thus to escape being devoured. No explanation is here attempted of the brilliant colours of the imitated, but only of the imitating butterflies. We must account for the colours of the former in the same general manner, as in the cases previously discussed in this chapter. Since the publication of Mr. Bates’ paper, similar and equally striking facts have been observed by Mr. Wallace in the Malayan region, by Mr. Trimen in South Africa, and by Mr. Riley in the United States. (31. Wallace, ‘Transact. Linn. Soc.’ vol. xxv. 1865 p. i.; also, ‘Transact. Ent. Soc.’ vol. iv. (3rd series), 1867, p. 301. Trimen, ‘Linn. Transact.’ vol. xxvi. 1869, p. 497. Riley, ‘Third Annual Report on the Noxious Insects of Missouri,’ 1871, pp. 163-168. This latter essay is valuable, as Mr. Riley here discusses all the objections which have been raised against Mr. Bates’s theory.)

As some writers have felt much difficulty in understanding how the first steps in the process of mimicry could have been effected through natural selection, it may be well to remark that the process probably commenced long ago between forms not widely dissimilar in colour. In this case even a slight variation would be beneficial, if it rendered the one species more like the other; and afterwards the imitated species might be modified to an extreme degree through sexual selection or other means, and if the changes were gradual, the imitators might easily be led along the same track, until they differed to an equally extreme degree from their original condition; and they would thus ultimately assume an appearance or colouring wholly unlike that of the other members of the group to which they belonged. It should also be remembered that many species of Lepidoptera are liable to considerable and abrupt variations in colour. A few instances have been given in this chapter; and many more may be found in the papers of Mr. Bates and Mr. Wallace.

With several species the sexes are alike, and imitate the two sexes of another species. But Mr. Trimen gives, in the paper already referred to, three cases in which the sexes of the imitated form differ from each other in colour, and the sexes of the imitating form differ in a like manner. Several cases have also been recorded where the females alone imitate brilliantly-coloured and protected species, the males retaining “the normal aspect of their immediate congeners.” It is here obvious that the successive variations by which the female has been modified have been transmitted to her alone. It is, however, probable that some of the many successive variations would have been transmitted to, and developed in, the males had not such males been eliminated by being thus rendered less attractive to the females; so that only those variations were preserved which were from the first strictly limited in their transmission to the female sex. We have a partial illustration of these remarks in a statement by Mr. Belt (32. ‘The Naturalist in Nicaragua,’ 1874, p. 385.); that the males of some of the Leptalides, which imitate protected species, still retain in a concealed manner some of their original characters. Thus in the males “the upper half of the lower wing is of a pure white, whilst all the rest of the wings is barred and spotted with black, red and yellow, like the species they mimic. The females have not this white patch, and the males usually conceal it by covering it with the upper wing, so that I cannot imagine its being of any other use to them than as an attraction in courtship, when they exhibit it to the females, and thus gratify their deep-seated preference for the normal colour of the Order to which the Leptalides belong.”

Bright Colours of Caterpillars

Whilst reflecting on the beauty of many butterflies, it occurred to me that some caterpillars were splendidly coloured; and as sexual selection could not possibly have here acted, it appeared rash to attribute the beauty of the mature insect to this agency, unless the bright colours of their larvae could be somehow explained. In the first place, it may be observed that the colours of caterpillars do not stand in any close correlation with those of the mature insect. Secondly, their bright colours do not serve in any ordinary manner as a protection. Mr. Bates informs me, as an instance of this, that the most conspicuous caterpillar which he ever beheld (that of a Sphinx) lived on the large green leaves of a tree on the open llanos of South America; it was about four inches in length, transversely banded with black and yellow, and with its head, legs, and tail of a bright red. Hence it caught the eye of any one who passed by, even at the distance of many yards, and no doubt that of every passing bird.

I then applied to Mr. Wallace, who has an innate genius for solving difficulties. After some consideration he replied: “Most caterpillars require protection, as may be inferred from some kinds being furnished with spines or irritating hairs, and from many being coloured green like the leaves on which they feed, or being curiously like the twigs of the trees on which they live.” Another instance of protection, furnished me by Mr. J. Mansel Weale, may be added, namely, that there is a caterpillar of a moth which lives on the mimosas in South Africa, and fabricates for itself a case quite indistinguishable from the surrounding thorns. From such considerations Mr. Wallace thought it probable that conspicuously coloured caterpillars were protected by having a nauseous taste; but as their skin is extremely tender, and as their intestines readily protrude from a wound, a slight peck from the beak of a bird would be as fatal to them as if they had been devoured. Hence, as Mr. Wallace remarks, “distastefulness alone would be insufficient to protect a caterpillar unless some outward sign indicated to its would-be destroyer that its prey was a disgusting morsel.” Under these circumstances it would be highly advantageous to a caterpillar to be instantaneously and certainly recognised as unpalatable by all birds and other animals. Thus the most gaudy colours would be serviceable, and might have been gained by variation and the survival of the most easily- recognised individuals.

This hypothesis appears at first sight very bold, but when it was brought before the Entomological Society (33. ‘Proceedings, Entomological Society,’ Dec. 3, 1866, p. xlv. and March 4, 1867, p. lxxx.) it was supported by various statements; and Mr. J. Jenner Weir, who keeps a large number of birds in an aviary, informs me that he has made many trials, and finds no exception to the rule, that all caterpillars of nocturnal and retiring habits with smooth skins, all of a green colour, and all which imitate twigs, are greedily devoured by his birds. The hairy and spinose kinds are invariably rejected, as were four conspicuously-coloured species. When the birds rejected a caterpillar, they plainly shewed, by shaking their heads, and cleansing their beaks, that they were disgusted by the taste. (34. See Mr. J. Jenner Weir’s paper on Insects and Insectivorous Birds, in ‘Transact. Ent. Soc.’ 1869, p. 21; also Mr. Butler’s paper, ibid. p. 27. Mr. Riley has given analogous facts in the ‘Third Annual Report on the Noxious Insects of Missouri,’ 1871, p. 148. Some opposed cases are, however, given by Dr. Wallace and M. H. d’Orville; see ‘Zoological Record,’ 1869, p. 349.) Three conspicuous kinds of caterpillars and moths were also given to some lizards and frogs, by Mr. A. Butler, and were rejected, though other kinds were eagerly eaten. Thus the probability of Mr. Wallace’s view is confirmed, namely, that certain caterpillars have been made conspicuous for their own good, so as to be easily recognised by their enemies, on nearly the same principle that poisons are sold in coloured bottles by druggists for the good of man. We cannot, however, at present thus explain the elegant diversity in the colours of many caterpillars; but any species which had at some former period acquired a dull, mottled, or striped appearance, either in imitation of surrounding objects, or from the direct action of climate, etc., almost certainly would not become uniform in colour, when its tints were rendered intense and bright; for in order to make a caterpillar merely conspicuous, there would be no selection in any definite direction.

Summary and Concluding Remarks on Insects

Looking back to the several Orders, we see that the sexes often differ in various characters, the meaning of which is not in the least understood. The sexes, also, often differ in their organs of sense and means of locomotion, so that the males may quickly discover and reach the females. They differ still oftener in the males possessing diversified contrivances for retaining the females when found. We are, however, here concerned only in a secondary degree with sexual differences of these kinds.

In almost all the Orders, the males of some species, even of weak and delicate kinds, are known to be highly pugnacious; and some few are furnished with special weapons for fighting with their rivals. But the law of battle does not prevail nearly so widely with insects as with the higher animals. Hence it probably arises, that it is in only a few cases that the males have been rendered larger and stronger than the females. On the contrary, they are usually smaller, so that they may be developed within a shorter time, to be ready in large numbers for the emergence of the females.

In two families of the Homoptera and in three of the Orthoptera, the males alone possess sound-producing organs in an efficient state. These are used incessantly during the breeding-season, not only for calling the females, but apparently for charming or exciting them in rivalry with other males. No one who admits the agency of selection of any kind, will, after reading the above discussion, dispute that these musical instruments have been acquired through sexual selection. In four other Orders the members of one sex, or more commonly of both sexes, are provided with organs for producing various sounds, which apparently serve merely as call-notes. When both sexes are thus provided, the individuals which were able to make the loudest or most continuous noise would gain partners before those which were less noisy, so that their organs have probably been gained through sexual selection. It is instructive to reflect on the wonderful diversity of the means for producing sound, possessed by the males alone, or by both sexes, in no less than six Orders. We thus learn how effectual sexual selection has been in leading to modifications which sometimes, as with the Homoptera, relate to important parts of the organisation.

From the reasons assigned in the last chapter, it is probable that the great horns possessed by the males of many Lamellicorn, and some other beetles, have been acquired as ornaments. From the small size of insects, we are apt to undervalue their appearance. If we could imagine a male Chalcosoma (Fig. 16), with its polished bronzed coat of mail, and its vast complex horns, magnified to the size of a horse, or even of a dog, it would be one of the most imposing animals in the world.

The colouring of insects is a complex and obscure subject. When the male differs slightly from the female, and neither are brilliantly-coloured, it is probable that the sexes have varied in a slightly different manner, and that the variations have been transmitted by each sex to the same without any benefit or evil thus accruing. When the male is brilliantly-coloured and differs conspicuously from the female, as with some dragon-flies and many butterflies, it is probable that he owes his colours to sexual selection; whilst the female has retained a primordial or very ancient type of colouring, slightly modified by the agencies before explained. But in some cases the female has apparently been made obscure by variations transmitted to her alone, as a means of direct protection; and it is almost certain that she has sometimes been made brilliant, so as to imitate other protected species inhabiting the same district. When the sexes resemble each other and both are obscurely coloured, there is no doubt that they have been in a multitude of cases so coloured for the sake of protection. So it is in some instances when both are brightly-coloured, for they thus imitate protected species, or resemble surrounding objects such as flowers; or they give notice to their enemies that they are unpalatable. In other cases in which the sexes resemble each other and are both brilliant, especially when the colours are arranged for display, we may conclude that they have been gained by the male sex as an attraction, and have been transferred to the female. We are more especially led to this conclusion whenever the same type of coloration prevails throughout a whole group, and we find that the males of some species differ widely in colour from the females, whilst others differ slightly or not at all with intermediate gradations connecting these extreme states.

In the same manner as bright colours have often been partially transferred from the males to the females, so it has been with the extraordinary horns of many Lamellicorn and some other beetles. So again, the sound-producing organs proper to the males of the Homoptera and Orthoptera have generally been transferred in a rudimentary, or even in a nearly perfect condition, to the females; yet not sufficiently perfect to be of any use. It is also an interesting fact, as bearing on sexual selection, that the stridulating organs of certain male Orthoptera are not fully developed until the last moult; and that the colours of certain male dragon-flies are not fully developed until some little time after their emergence from the pupal state, and when they are ready to breed.

Sexual selection implies that the more attractive individuals are preferred by the opposite sex; and as with insects, when the sexes differ, it is the male which, with some rare exceptions, is the more ornamented, and departs more from the type to which the species belongs;—and as it is the male which searches eagerly for the female, we must suppose that the females habitually or occasionally prefer the more beautiful males, and that these have thus acquired their beauty. That the females in most or all the Orders would have the power of rejecting any particular male, is probable from the many singular contrivances possessed by the males, such as great jaws, adhesive cushions, spines, elongated legs, etc., for seizing the female; for these contrivances show that there is some difficulty in the act, so that her concurrence would seem necessary. Judging from what we know of the perceptive powers and affections of various insects, there is no antecedent improbability in sexual selection having come largely into play; but we have as yet no direct evidence on this head, and some facts are opposed to the belief. Nevertheless, when we see many males pursuing the same female, we can hardly believe that the pairing is left to blind chance—that the female exerts no choice, and is not influenced by the gorgeous colours or other ornaments with which the male is decorated.

If we admit that the females of the Homoptera and Orthoptera appreciate the musical tones of their male partners, and that the various instruments have been perfected through sexual selection, there is little improbability in the females of other insects appreciating beauty in form or colour, and consequently in such characters having been thus gained by the males. But from the circumstance of colour being so variable, and from its having been so often modified for the sake of protection, it is difficult to decide in how large a proportion of cases sexual selection has played a part. This is more especially difficult in those Orders, such as Orthoptera, Hymenoptera, and Coleoptera, in which the two sexes rarely differ much in colour; for we are then left to mere analogy. With the Coleoptera, however, as before remarked, it is in the great Lamellicorn group, placed by some authors at the head of the Order, and in which we sometimes see a mutual attachment between the sexes, that we find the males of some species possessing weapons for sexual strife, others furnished with wonderful horns, many with stridulating organs, and others ornamented with splendid metallic tints. Hence it seems probable that all these characters have been gained through the same means, namely sexual selection. With butterflies we have the best evidence, as the males sometimes take pains to display their beautiful colours; and we cannot believe that they would act thus, unless the display was of use to them in their courtship.

When we treat of Birds, we shall see that they present in their secondary sexual characters the closest analogy with insects. Thus, many male birds are highly pugnacious, and some are furnished with special weapons for fighting with their rivals. They possess organs which are used during the breeding-season for producing vocal and instrumental music. They are frequently ornamented with combs, horns, wattles and plumes of the most diversified kinds, and are decorated with beautiful colours, all evidently for the sake of display. We shall find that, as with insects, both sexes in certain groups are equally beautiful, and are equally provided with ornaments which are usually confined to the male sex. In other groups both sexes are equally plain-coloured and unornamented. Lastly, in some few anomalous cases, the females are more beautiful than the males. We shall often find, in the same group of birds, every gradation from no difference between the sexes, to an extreme difference. We shall see that female birds, like female insects, often possess more or less plain traces or rudiments of characters which properly belong to the males and are of use only to them. The analogy, indeed, in all these respects between birds and insects is curiously close. Whatever explanation applies to the one class probably applies to the other; and this explanation, as we shall hereafter attempt to shew in further detail, is sexual selection.

第十二章 •10,400字
鱼类、两栖动物和爬行动物的第二性征

FISHES: Courtship and battles of the males—Larger size of the females— Males, bright colours and ornamental appendages; other strange characters— Colours and appendages acquired by the males during the breeding-season alone—Fishes with both sexes brilliantly coloured—Protective colours—The less conspicuous colours of the female cannot be accounted for on the principle of protection—Male fishes building nests, and taking charge of the ova and young.

AMPHIBIANS: Differences in structure and colour between the sexes—Vocal organs.

REPTILES: Chelonians—Crocodiles—Snakes, colours in some cases protective—Lizards, battles of—Ornamental appendages—Strange differences in structure between the sexes—Colours—Sexual differences almost as great as with birds.

We have now arrived at the great sub-kingdom of the Vertebrata, and will commence with the lowest class, that of fishes. The males of Plagiostomous fishes (sharks, rays) and of Chimaeroid fishes are provided with claspers which serve to retain the female, like the various structures possessed by many of the lower animals. Besides the claspers, the males of many rays have clusters of strong sharp spines on their heads, and several rows along “the upper outer surface of their pectoral fins.” These are present in the males of some species, which have other parts of their bodies smooth. They are only temporarily developed during the breeding-season; and Dr. Gunther suspects that they are brought into action as prehensile organs by the doubling inwards and downwards of the two sides of the body. It is a remarkable fact that the females and not the males of some species, as of Raia clavata, have their backs studded with large hook-formed spines. (1. Yarrell’s ‘Hist. of British Fishes,’ vol. ii. 1836, pp 417, 425, 436. Dr. Gunther informs me that the spines in R. clavata are peculiar to the female.)

The males alone of the capelin (Mallotus villosus, one of Salmonidae), are provided with a ridge of closely-set, brush-like scales, by the aid of which two males, one on each side, hold the female, whilst she runs with great swiftness on the sandy beach, and there deposits her spawn. (2. The ‘American Naturalist,’ April 1871, p. 119.) The widely distinct Monacanthus scopas presents a somewhat analogous structure. The male, as Dr. Gunther informs me, has a cluster of stiff, straight spines, like those of a comb, on the sides of the tail; and these in a specimen six inches long were nearly one and a half inches in length; the female has in the same place a cluster of bristles, which may be compared with those of a tooth-brush. In another species, M. peronii, the male has a brush like that possessed by the female of the last species, whilst the sides of the tail in the female are smooth. In some other species of the same genus the tail can be perceived to be a little roughened in the male and perfectly smooth in the female; and lastly in others, both sexes have smooth sides.

The males of many fish fight for the possession of the females. Thus the male stickleback (Gasterosteus leiurus) has been described as “mad with delight,” when the female comes out of her hiding-place and surveys the nest which he has made for her. “He darts round her in every direction, then to his accumulated materials for the nest, then back again in an instant; and as she does not advance he endeavours to push her with his snout, and then tries to pull her by the tail and side-spine to the nest.” (3. See Mr. R. Warington’s interesting articles in ‘Annals and Magazine of Natural History,’ October 1852, and November 1855.) The males are said to be polygamists (4. Noel Humphreys, ‘River Gardens,’ 1857.); they are extraordinarily bold and pugnacious, whilst “the females are quite pacific.” Their battles are at times desperate; “for these puny combatants fasten tight on each other for several seconds, tumbling over and over again until their strength appears completely exhausted.” With the rough- tailed stickleback (G. trachurus) the males whilst fighting swim round and round each other, biting and endeavouring to pierce each other with their raised lateral spines. The same writer adds (5. Loudon’s ‘Magazine of Natural History,’ vol. iii. 1830, p. 331.), “the bite of these little furies is very severe. They also use their lateral spines with such fatal effect, that I have seen one during a battle absolutely rip his opponent quite open, so that he sank to the bottom and died.” When a fish is conquered, “his gallant bearing forsakes him; his gay colours fade away; and he hides his disgrace among his peaceable companions, but is for some time the constant object of his conqueror’s persecution.”

The male salmon is as pugnacious as the little stickleback; and so is the male trout, as I hear from Dr. Gunther. Mr. Shaw saw a violent contest between two male salmon which lasted the whole day; and Mr. R. Buist, Superintendent of Fisheries, informs me that he has often watched from the bridge at Perth the males driving away their rivals, whilst the females were spawning. The males “are constantly fighting and tearing each other on the spawning-beds, and many so injure each other as to cause the death of numbers, many being seen swimming near the banks of the river in a state of exhaustion, and apparently in a dying state.” (6. The ‘Field,’ June 29, 1867. For Mr. Shaw’s Statement, see ‘Edinburgh Review,’ 1843. Another experienced observer (Scrope’s ‘Days of Salmon Fishing,’ p. 60) remarks that like the stag, the male would, if he could, keep all other males away.) Mr. Buist informs me, that in June 1868, the keeper of the Stormontfield breeding-ponds visited the northern Tyne and found about 300 dead salmon, all of which with one exception were males; and he was convinced that they had lost their lives by fighting.

[Fig. 27. Head of male common salmon (Salmo salar) during the breeding-
季节。
[This drawing, as well as all the others in the present chapter, have been
executed by the well-known artist, Mr. G. Ford, from specimens in the
British Museum, under the kind superintendence of Dr. Gunther.]

Fig. 28. Head of female salmon.]

The most curious point about the male salmon is that during the breeding- season, besides a slight change in colour, “the lower jaw elongates, and a cartilaginous projection turns upwards from the point, which, when the jaws are closed, occupies a deep cavity between the intermaxillary bones of the upper jaw.” (7. Yarrell, ‘History of British Fishes,’ vol. ii. 1836, p. 10.) (Figs. 27 and 28.) In our salmon this change of structure lasts only during the breeding-season; but in the Salmo lycaodon of N.W. America the change, as Mr. J.K. Lord (8. ‘The Naturalist in Vancouver’s Island,’ vol. i. 1866, p. 54.) believes, is permanent, and best marked in the older males which have previously ascended the rivers. In these old males the jaw becomes developed into an immense hook-like projection, and the teeth grow into regular fangs, often more than half an inch in length. With the European salmon, according to Mr. Lloyd (9. ‘Scandinavian Adventures,’ vol. i. 1854, pp. 100, 104.), the temporary hook-like structure serves to strengthen and protect the jaws, when one male charges another with wonderful violence; but the greatly developed teeth of the male American salmon may be compared with the tusks of many male mammals, and they indicate an offensive rather than a protective purpose.

The salmon is not the only fish in which the teeth differ in the two sexes; as this is the case with many rays. In the thornback (Raia clavata) the adult male has sharp, pointed teeth, directed backwards, whilst those of the female are broad and flat, and form a pavement; so that these teeth differ in the two sexes of the same species more than is usual in distinct genera of the same family. The teeth of the male become sharp only when he is adult: whilst young they are broad and flat like those of the female. As so frequently occurs with secondary sexual characters, both sexes of some species of rays (for instance R. batis), when adult, possess sharp pointed teeth; and here a character, proper to and primarily gained by the male, appears to have been transmitted to the offspring of both sexes. The teeth are likewise pointed in both sexes of R. maculata, but only when quite adult; the males acquiring them at an earlier age than the females. We shall hereafter meet with analogous cases in certain birds, in which the male acquires the plumage common to both sexes when adult, at a somewhat earlier age than does the female. With other species of rays the males even when old never possess sharp teeth, and consequently the adults of both sexes are provided with broad, flat teeth like those of the young, and like those of the mature females of the above-mentioned species. (10. See Yarrell’s account of the rays in his ‘History of British Fishes,’ vol. ii. 1836, p. 416, with an excellent figure, and pp. 422, 432.) As the rays are bold, strong and voracious fish, we may suspect that the males require their sharp teeth for fighting with their rivals; but as they possess many parts modified and adapted for the prehension of the female, it is possible that their teeth may be used for this purpose.

In regard to size, M. Carbonnier (11. As quoted in ‘The Farmer,’ 1868, p. 369.) maintains that the female of almost all fishes is larger than the male; and Dr. Gunther does not know of a single instance in which the male is actually larger than the female. With some Cyprinodonts the male is not even half as large. As in many kinds of fishes the males habitually fight together, it is surprising that they have not generally become larger and stronger than the females through the effects of sexual selection. The males suffer from their small size, for according to M. Carbonnier, they are liable to be devoured by the females of their own species when carnivorous, and no doubt by other species. Increased size must be in some manner of more importance to the females, than strength and size are to the males for fighting with other males; and this perhaps is to allow of the production of a vast number of ova.

[Fig. 29. Callionymus lyra.
Upper figure, male;
lower figure, female.
N.B. The lower figure is more reduced than the upper.]

In many species the male alone is ornamented with bright colours; or these are much brighter in the male than the female. The male, also, is sometimes provided with appendages which appear to be of no more use to him for the ordinary purposes of life, than are the tail feathers to the peacock. I am indebted for most of the following facts to the kindness of Dr. Gunther. There is reason to suspect that many tropical fishes differ sexually in colour and structure; and there are some striking cases with our British fishes. The male Callionymus lyra has been called the gemmeous dragonet “from its brilliant gem-like colours.” When fresh caught from the sea the body is yellow of various shades, striped and spotted with vivid blue on the head; the dorsal fins are pale brown with dark longitudinal bands; the ventral, caudal, and anal fins being bluish-black. The female, or sordid dragonet, was considered by Linnaeus, and by many subsequent naturalists, as a distinct species; it is of a dingy reddish-brown, with the dorsal fin brown and the other fins white. The sexes differ also in the proportional size of the head and mouth, and in the position of the eyes (12. I have drawn up this description from Yarrell’s ‘British Fishes,’ vol. i. 1836, pp. 261 and 266.); but the most striking difference is the extraordinary elongation in the male (Fig. 29) of the dorsal fin. Mr. W. Saville Kent remarks that this “singular appendage appears from my observations of the species in confinement, to be subservient to the same end as the wattles, crests, and other abnormal adjuncts of the male in gallinaceous birds, for the purpose of fascinating their mates.” (13. ‘Nature,’ July 1873, p. 264.) The young males resemble the adult females in structure and colour. Throughout the genus Callionymus (14. ‘Catalogue of Acanth. Fishes in the British Museum,’ by Dr. Gunther, 1861, pp. 138- 151.), the male is generally much more brightly spotted than the female, and in several species, not only the dorsal, but the anal fin is much elongated in the males.

The male of the Cottus scorpius, or sea-scorpion, is slenderer and smaller than the female. There is also a great difference in colour between them. It is difficult, as Mr. Lloyd (15. ‘Game Birds of Sweden,’ etc., 1867, p. 466.) remarks, “for any one, who has not seen this fish during the spawning-season, when its hues are brightest, to conceive the admixture of brilliant colours with which it, in other respects so ill-favoured, is at that time adorned.” Both sexes of the Labrus mixtus, although very different in colour, are beautiful; the male being orange with bright blue stripes, and the female bright red with some black spots on the back.

[Fig. 30. Xiphophorus Hellerii. Upper figure, male; lower figure, female.]

In the very distinct family of the Cyprinodontidae—inhabitants of the fresh waters of foreign lands—the sexes sometimes differ much in various characters. In the male of the Mollienesia petenensis (16. With respect to this and the following species I am indebted to Dr. Gunther for information: see also his paper on the ‘Fishes of Central America,’ in ‘Transact. Zoological Soc.’ vol. vi. 1868, p. 485.), the dorsal fin is greatly developed and is marked with a row of large, round, ocellated, bright-coloured spots; whilst the same fin in the female is smaller, of a different shape, and marked only with irregularly curved brown spots. In the male the basal margin of the anal fin is also a little produced and dark coloured. In the male of an allied form, the Xiphophorus Hellerii (Fig. 30), the inferior margin of the caudal fin is developed into a long filament, which, as I hear from Dr. Gunther, is striped with bright colours. This filament does not contain any muscles, and apparently cannot be of any direct use to the fish. As in the case of the Callionymus, the males whilst young resemble the adult females in colour and structure. Sexual differences such as these may be strictly compared with those which are so frequent with gallinaceous birds. (17. Dr. Gunther makes this remark; ‘Catalogue of Fishes in the British Museum,’ vol. iii. 1861, p. 141.)

[Fig.31. Plecostomus barbatus. Upper figure, head of male; lower figure, female.]

In a siluroid fish, inhabiting the fresh waters of South America, the Plecostomus barbatus (18. See Dr. Gunther on this genus, in ‘Proceedings of the Zoological Society,’ 1868, p. 232.) (Fig. 31), the male has its mouth and inter-operculum fringed with a beard of stiff hairs, of which the female shows hardly a trace. These hairs are of the nature of scales. In another species of the same genus, soft flexible tentacles project from the front part of the head of the male, which are absent in the female. These tentacles are prolongations of the true skin, and therefore are not homologous with the stiff hairs of the former species; but it can hardly be doubted that both serve the same purpose. What this purpose may be, it is difficult to conjecture; ornament does not here seem probable, but we can hardly suppose that stiff hairs and flexible filaments can be useful in any ordinary way to the males alone. In that strange monster, the Chimaera monstrosa, the male has a hook-shaped bone on the top of the head, directed forwards, with its end rounded and covered with sharp spines; in the female “this crown is altogether absent,” but what its use may be to the male is utterly unknown. (19. F. Buckland, in ‘Land and Water,’ July 1868, p. 377, with a figure. Many other cases could be added of structures peculiar to the male, of which the uses are not known.)

The structures as yet referred to are permanent in the male after he has arrived at maturity; but with some Blennies, and in another allied genus (20. Dr. Gunther, ‘Catalogue of Fishes,’ vol. iii. pp. 221 and 240.), a crest is developed on the head of the male only during the breeding-season, and the body at the same time becomes more brightly-coloured. There can be little doubt that this crest serves as a temporary sexual ornament, for the female does not exhibit a trace of it. In other species of the same genus both sexes possess a crest, and in at least one species neither sex is thus provided. In many of the Chromidae, for instance in Geophagus and especially in Cichla, the males, as I hear from Professor Agassiz (21. See also ‘A Journey in Brazil,’ by Prof. and Mrs. Agassiz, 1868, p. 220.), have a conspicuous protuberance on the forehead, which is wholly wanting in the females and in the young males. Professor Agassiz adds, “I have often observed these fishes at the time of spawning when the protuberance is largest, and at other seasons when it is totally wanting, and the two sexes shew no difference whatever in the outline of the profile of the head. I never could ascertain that it subserves any special function, and the Indians on the Amazon know nothing about its use.” These protuberances resemble, in their periodical appearance, the fleshy carbuncles on the heads of certain birds; but whether they serve as ornaments must remain at present doubtful.

I hear from Professor Agassiz and Dr. Gunther, that the males of those fishes, which differ permanently in colour from the females, often become more brilliant during the breeding-season. This is likewise the case with a multitude of fishes, the sexes of which are identical in colour at all other seasons of the year. The tench, roach, and perch may be given as instances. The male salmon at this season is “marked on the cheeks with orange-coloured stripes, which give it the appearance of a Labrus, and the body partakes of a golden orange tinge. The females are dark in colour, and are commonly called black-fish.” (22. Yarrell, ‘History of British Fishes,’ vol. ii. 1836, pp. 10, 12, 35.) An analogous and even greater change takes place with the Salmo eriox or bull trout; the males of the char (S. umbla) are likewise at this season rather brighter in colour than the females. (23. W. Thompson, in ‘Annals and Magazine of Natural History,’ vol. vi. 1841, p. 440.) The colours of the pike (Esox reticulatus) of the United States, especially of the male, become, during the breeding-season, exceedingly intense, brilliant, and iridescent. (24. ‘The American Agriculturalist,’ 1868, p. 100.) Another striking instance out of many is afforded by the male stickleback (Gasterosteus leiurus), which is described by Mr. Warington (25. ‘Annals and Mag. of Nat. Hist.’ Oct. 1852.), as being then “beautiful beyond description.” The back and eyes of the female are simply brown, and the belly white. The eyes of the male, on the other hand, are “of the most splendid green, having a metallic lustre like the green feathers of some humming-birds. The throat and belly are of a bright crimson, the back of an ashy-green, and the whole fish appears as though it were somewhat translucent and glowed with an internal incandescence.” After the breeding season these colours all change, the throat and belly become of a paler red, the back more green, and the glowing tints subside.

With respect to the courtship of fishes, other cases have been observed since the first edition of this book appeared, besides that already given of the stickleback. Mr. W.S. Kent says that the male of the Labrus mixtus, which, as we have seen, differs in colour from the female, makes “a deep hollow in the sand of the tank, and then endeavours in the most persuasive manner to induce a female of the same species to share it with him, swimming backwards and forwards between her and the completed nest, and plainly exhibiting the greatest anxiety for her to follow.” The males of Cantharus lineatus become, during the breeding-season, of deep leaden- black; they then retire from the shoal, and excavate a hollow as a nest. “Each male now mounts vigilant guard over his respective hollow, and vigorously attacks and drives away any other fish of the same sex. Towards his companions of the opposite sex his conduct is far different; many of the latter are now distended with spawn, and these he endeavours by all the means in his power to lure singly to his prepared hollow, and there to deposit the myriad ova with which they are laden, which he then protects and guards with the greatest care.” (26. ‘Nature,’ May 1873, p. 25.)

A more striking case of courtship, as well as of display, by the males of a Chinese Macropus has been given by M. Carbonnier, who carefully observed these fishes under confinement. (27. ‘Bulletin de la Societé d’Acclimat.’ Paris, July 1869, and Jan. 1870.) The males are most beautifully coloured, more so than the females. During the breeding-season they contend for the possession of the females; and, in the act of courtship, expand their fins, which are spotted and ornamented with brightly coloured rays, in the same manner, according to M. Carbonnier, as the peacock. They then also bound about the females with much vivacity, and appear by “l’étalage de leurs vives couleurs chercher a attirer l’attention des femelles, lesquelles ne paraissaient indifférentes a ce manège, elles nageaient avec une molle lenteur vers les males et semblaient se complaire dans leur voisinage.” After the male has won his bride, he makes a little disc of froth by blowing air and mucus out of his mouth. He then collects the fertilised ova, dropped by the female, in his mouth; and this caused M. Carbonnier much alarm, as he thought that they were going to be devoured. But the male soon deposits them in the disc of froth, afterwards guarding them, repairing the froth, and taking care of the young when hatched. I mention these particulars because, as we shall presently see, there are fishes, the males of which hatch their eggs in their mouths; and those who do not believe in the principle of gradual evolution might ask how could such a habit have originated; but the difficulty is much diminished when we know that there are fishes which thus collect and carry the eggs; for if delayed by any cause in depositing them, the habit of hatching them in their mouths might have been acquired.

To return to our more immediate subject. The case stands thus: female fishes, as far as I can learn, never willingly spawn except in the presence of the males; and the males never fertilise the ova except in the presence of the females. The males fight for the possession of the females. In many species, the males whilst young resemble the females in colour; but when adult become much more brilliant, and retain their colours throughout life. In other species the males become brighter than the females and otherwise more highly ornamented, only during the season of love. The males sedulously court the females, and in one case, as we have seen, take pains in displaying their beauty before them. Can it be believed that they would thus act to no purpose during their courtship? And this would be the case, unless the females exert some choice and select those males which please or excite them most. If the female exerts such choice, all the above facts on the ornamentation of the males become at once intelligible by the aid of sexual selection.

We have next to inquire whether this view of the bright colours of certain male fishes having been acquired through sexual selection can, through the law of the equal transmission of characters to both sexes, be extended to those groups in which the males and females are brilliant in the same, or nearly the same degree and manner. In such a genus as Labrus, which includes some of the most splendid fishes in the world—for instance, the Peacock Labrus (L. pavo), described (28. Bory Saint Vincent, in ‘Dict. Class. d’Hist. Nat.’ tom. ix. 1826, p. 151.), with pardonable exaggeration, as formed of polished scales of gold, encrusting lapis-lazuli, rubies, sapphires, emeralds, and amethysts—we may, with much probability, accept this belief; for we have seen that the sexes in at least one species of the genus differ greatly in colour. With some fishes, as with many of the lowest animals, splendid colours may be the direct result of the nature of their tissues and of the surrounding conditions, without the aid of selection of any kind. The gold-fish (Cyprinus auratus), judging from the analogy of the golden variety of the common carp, is perhaps a case in point, as it may owe its splendid colours to a single abrupt variation, due to the conditions to which this fish has been subjected under confinement. It is, however, more probable that these colours have been intensified through artificial selection, as this species has been carefully bred in China from a remote period. (29. Owing to some remarks on this subject, made in my work ‘On the Variation of Animals under Domestication,’ Mr. W.F. Mayers (‘Chinese Notes and Queries,’ Aug. 1868, p. 123) has searched the ancient Chinese encyclopedias. He finds that gold-fish were first reared in confinement during the Sung Dynasty, which commenced A.D. 960. In the year 1129 these fishes abounded. In another place it is said that since the year 1548 there has been “produced at Hangchow a variety called the fire-fish, from its intensely red colour. It is universally admired, and there is not a household where it is not cultivated, IN RIVALRY AS TO ITS COLOUR, and as a source of profit.”) Under natural conditions it does not seem probable that beings so highly organised as fishes, and which live under such complex relations, should become brilliantly coloured without suffering some evil or receiving some benefit from so great a change, and consequently without the intervention of natural selection.

What, then, are we to conclude in regard to the many fishes, both sexes of which are splendidly coloured? Mr. Wallace (30. ‘Westminster Review,’ July 1867, p. 7.) believes that the species which frequent reefs, where corals and other brightly-coloured organisms abound, are brightly coloured in order to escape detection by their enemies; but according to my recollection they were thus rendered highly conspicuous. In the fresh- waters of the tropics there are no brilliantly-coloured corals or other organisms for the fishes to resemble; yet many species in the Amazons are beautifully coloured, and many of the carnivorous Cyprinidae in India are ornamented with “bright longitudinal lines of various tints.” (31. ‘Indian Cyprinidae,’ by Mr. M’Clelland, ‘Asiatic Researches,’ vol. xix. part ii. 1839, p. 230.) Mr. M’Clelland, in describing these fishes, goes so far as to suppose that “the peculiar brilliancy of their colours” serves as “a better mark for king-fishers, terns, and other birds which are destined to keep the number of these fishes in check”; but at the present day few naturalists will admit that any animal has been made conspicuous as an aid to its own destruction. It is possible that certain fishes may have been rendered conspicuous in order to warn birds and beasts of prey that they were unpalatable, as explained when treating of caterpillars; but it is not, I believe, known that any fish, at least any fresh-water fish, is rejected from being distasteful to fish-devouring animals. On the whole, the most probable view in regard to the fishes, of which both sexes are brilliantly coloured, is that their colours were acquired by the males as a sexual ornament, and were transferred equally, or nearly so, to the other sex.

We have now to consider whether, when the male differs in a marked manner from the female in colour or in other ornaments, he alone has been modified, the variations being inherited by his male offspring alone; or whether the female has been specially modified and rendered inconspicuous for the sake of protection, such modifications being inherited only by the females. It is impossible to doubt that colour has been gained by many fishes as a protection: no one can examine the speckled upper surface of a flounder, and overlook its resemblance to the sandy bed of the sea on which it lives. Certain fishes, moreover, can through the action of the nervous system change their colours in adaptation to surrounding objects, and that within a short time. (32. G. Pouchet, ‘L’Institut.’ Nov. 1, 1871, p. 134.) One of the most striking instances ever recorded of an animal being protected by its colour (as far as it can be judged of in preserved specimens), as well as by its form, is that given by Dr. Gunther (33. ‘Proc. Zoolog. Soc.’ 1865, p. 327, pl. xiv. and xv.) of a pipe-fish, which, with its reddish streaming filaments, is hardly distinguishable from the sea-weed to which it clings with its prehensile tail. But the question now under consideration is whether the females alone have been modified for this object. We can see that one sex will not be modified through natural selection for the sake of protection more than the other, supposing both to vary, unless one sex is exposed for a longer period to danger, or has less power of escaping from such danger than the other; and it does not appear that with fishes the sexes differ in these respects. As far as there is any difference, the males, from being generally smaller and from wandering more about, are exposed to greater danger than the females; and yet, when the sexes differ, the males are almost always the more conspicuously coloured. The ova are fertilised immediately after being deposited; and when this process lasts for several days, as in the case of the salmon (34. Yarrell, ‘British Fishes,’ vol. ii. p. 11.), the female, during the whole time, is attended by the male. After the ova are fertilised they are, in most cases, left unprotected by both parents, so that the males and females, as far as oviposition is concerned, are equally exposed to danger, and both are equally important for the production of fertile ova; consequently the more or less brightly-coloured individuals of either sex would be equally liable to be destroyed or preserved, and both would have an equal influence on the colours of their offspring.

Certain fishes, belonging to several families, make nests, and some of them take care of their young when hatched. Both sexes of the bright coloured Crenilabrus massa and melops work together in building their nests with sea-weed, shells, etc. (35. According to the observations of M. Gerbe; see Gunther’s ‘Record of Zoolog. Literature,’ 1865, p. 194.) But the males of certain fishes do all the work, and afterwards take exclusive charge of the young. This is the case with the dull-coloured gobies (36. Cuvier, ‘Regne Animal,’ vol. ii. 1829, p. 242.), in which the sexes are not known to differ in colour, and likewise with the sticklebacks (Gasterosteus), in which the males become brilliantly coloured during the spawning season. The male of the smooth-tailed stickleback (G. leiurus) performs the duties of a nurse with exemplary care and vigilance during a long time, and is continually employed in gently leading back the young to the nest, when they stray too far. He courageously drives away all enemies including the females of his own species. It would indeed be no small relief to the male, if the female, after depositing her eggs, were immediately devoured by some enemy, for he is forced incessantly to drive her from the nest. (37. See Mr. Warington’s most interesting description of the habits of the Gasterosteus leiurus in ‘Annals and Magazine of Nat. History,’ November 1855.)

The males of certain other fishes inhabiting South America and Ceylon, belonging to two distinct Orders, have the extraordinary habit of hatching within their mouths, or branchial cavities, the eggs laid by the females. (38. Prof. Wyman, in ‘Proc. Boston Soc. of Nat. Hist.’ Sept. 15, 1857. Also Prof. Turner, in ‘Journal of Anatomy and Physiology,’ Nov. 1, 1866, p. 78. Dr. Gunther has likewise described other cases.) I am informed by Professor Agassiz that the males of the Amazonian species which follow this habit, “not only are generally brighter than the females, but the difference is greater at the spawning-season than at any other time.” The species of Geophagus act in the same manner; and in this genus, a conspicuous protuberance becomes developed on the forehead of the males during the breeding-season. With the various species of Chromids, as Professor Agassiz likewise informs me, sexual differences in colour may be observed, “whether they lay their eggs in the water among aquatic plants, or deposit them in holes, leaving them to come out without further care, or build shallow nests in the river mud, over which they sit, as our Pomotis does. It ought also to be observed that these sitters are among the brightest species in their respective families; for instance, Hygrogonus is bright green, with large black ocelli, encircled with the most brilliant red.” Whether with all the species of Chromids it is the male alone which sits on the eggs is not known. It is, however, manifest that the fact of the eggs being protected or unprotected by the parents, has had little or no influence on the differences in colour between the sexes. It is further manifest, in all the cases in which the males take exclusive charge of the nests and young, that the destruction of the brighter-coloured males would be far more influential on the character of the race, than the destruction of the brighter-coloured females; for the death of the male during the period of incubation or nursing would entail the death of the young, so that they could not inherit his peculiarities; yet, in many of these very cases the males are more conspicuously coloured than the females.

In most of the Lophobranchii (Pipe-fish, Hippocampi, etc.) the males have either marsupial sacks or hemispherical depressions on the abdomen, in which the ova laid by the female are hatched. The males also shew great attachment to their young. (39. Yarrell, ‘History of British Fishes,’ vol. ii. 1836, pp. 329, 338.) The sexes do not commonly differ much in colour; but Dr. Gunther believes that the male Hippocampi are rather brighter than the females. The genus Solenostoma, however, offers a curious exceptional case (40. Dr. Gunther, since publishing an account of this species in ‘The Fishes of Zanzibar,’ by Col. Playfair, 1866, p. 137, has re-examined the specimens, and has given me the above information.), for the female is much more vividly-coloured and spotted than the male, and she alone has a marsupial sack and hatches the eggs; so that the female of Solenostoma differs from all the other Lophobranchii in this latter respect, and from almost all other fishes, in being more brightly-coloured than the male. It is improbable that this remarkable double inversion of character in the female should be an accidental coincidence. As the males of several fishes, which take exclusive charge of the eggs and young, are more brightly coloured than the females, and as here the female Solenostoma takes the same charge and is brighter than the male, it might be argued that the conspicuous colours of that sex which is the more important of the two for the welfare of the offspring, must be in some manner protective. But from the large number of fishes, of which the males are either permanently or periodically brighter than the females, but whose life is not at all more important for the welfare of the species than that of the female, this view can hardly be maintained. When we treat of birds we shall meet with analogous cases, where there has been a complete inversion of the usual attributes of the two sexes, and we shall then give what appears to be the probable explanation, namely, that the males have selected the more attractive females, instead of the latter having selected, in accordance with the usual rule throughout the animal kingdom, the more attractive males.

On the whole we may conclude, that with most fishes, in which the sexes differ in colour or in other ornamental characters, the males originally varied, with their variations transmitted to the same sex, and accumulated through sexual selection by attracting or exciting the females. In many cases, however, such characters have been transferred, either partially or completely, to the females. In other cases, again, both sexes have been coloured alike for the sake of protection; but in no instance does it appear that the female alone has had her colours or other characters specially modified for this latter purpose.

The last point which need be noticed is that fishes are known to make various noises, some of which are described as being musical. Dr. Dufosse, who has especially attended to this subject, says that the sounds are voluntarily produced in several ways by different fishes: by the friction of the pharyngeal bones—by the vibration of certain muscles attached to the swim bladder, which serves as a resounding board—and by the vibration of the intrinsic muscles of the swim bladder. By this latter means the Trigla produces pure and long-drawn sounds which range over nearly an octave. But the most interesting case for us is that of two species of Ophidium, in which the males alone are provided with a sound-producing apparatus, consisting of small movable bones, with proper muscles, in connection with the swim bladder. (41. ‘Comptes-Rendus,’ tom. xlvi. 1858, p. 353; tom. xlvii. 1858, p. 916; tom. liv. 1862, p. 393. The noise made by the Umbrinas (Sciaena aquila), is said by some authors to be more like that of a flute or organ, than drumming: Dr. Zouteveen, in the Dutch translation of this work (vol. ii. p. 36), gives some further particulars on the sounds made by fishes.) The drumming of the Umbrinas in the European seas is said to be audible from a depth of twenty fathoms; and the fishermen of Rochelle assert “that the males alone make the noise during the spawning-time; and that it is possible by imitating it, to take them without bait.” (42. The Rev. C. Kingsley, in ‘Nature,’ May 1870, p. 40.) From this statement, and more especially from the case of Ophidium, it is almost certain that in this, the lowest class of the Vertebrata, as with so many insects and spiders, sound-producing instruments have, at least in some cases, been developed through sexual selection, as a means for bringing the sexes together.

两栖动物

Urodela

[Fig. 32. Triton cristatus (half natural size, from Bell’s ‘British
Reptiles’).
Upper figure, male during the breeding season;
lower figure, female.]

I will begin with the tailed amphibians. The sexes of salamanders or newts often differ much both in colour and structure. In some species prehensile claws are developed on the fore-legs of the males during the breeding- season: and at this season in the male Triton palmipes the hind-feet are provided with a swimming-web, which is almost completely absorbed during the winter; so that their feet then resemble those of the female. (43. Bell, ‘History of British Reptiles,’ 2nd ed., 1849, pp. 156-159.) This structure no doubt aids the male in his eager search and pursuit of the female. Whilst courting her he rapidly vibrates the end of his tail. With our common newts (Triton punctatus and cristatus) a deep, much indented crest is developed along the back and tail of the male during the breeding- season, which disappears during the winter. Mr. St. George Mivart informs me that it is not furnished with muscles, and therefore cannot be used for locomotion. As during the season of courtship it becomes edged with bright colours, there can hardly be a doubt that it is a masculine ornament. In many species the body presents strongly contrasted, though lurid tints, and these become more vivid during the breeding-season. The male, for instance, of our common little newt (Triton punctatus) is “brownish-grey above, passing into yellow beneath, which in the spring becomes a rich bright orange, marked everywhere with round dark spots.” The edge of the crest also is then tipped with bright red or violet. The female is usually of a yellowish-brown colour with scattered brown dots, and the lower surface is often quite plain. (44. Bell, ‘History of British Reptiles,’ 2nd ed., 1849, pp. 146, 151.) The young are obscurely tinted. The ova are fertilised during the act of deposition, and are not subsequently tended by either parent. We may therefore conclude that the males have acquired their strongly-marked colours and ornamental appendages through sexual selection; these being transmitted either to the male offspring alone, or to both sexes.

Anura or Batrachia

With many frogs and toads the colours evidently serve as a protection, such as the bright green tints of tree frogs and the obscure mottled shades of many terrestrial species. The most conspicuously-coloured toad which I ever saw, the Phryniscus nigricans (45. ‘Zoology of the Voyage of the “Beagle,”‘ 1843. Bell, ibid. p. 49.), had the whole upper surface of the body as black as ink, with the soles of the feet and parts of the abdomen spotted with the brightest vermilion. It crawled about the bare sandy or open grassy plains of La Plata under a scorching sun, and could not fail to catch the eye of every passing creature. These colours are probably beneficial by making this animal known to all birds of prey as a nauseous mouthful.

In Nicaragua there is a little frog “dressed in a bright livery of red and blue” which does not conceal itself like most other species, but hops about during the daytime, and Mr. Belt says (46. ‘The Naturalist in Nicaragua,’ 1874, p. 321.) that as soon as he saw its happy sense of security, he felt sure that it was uneatable. After several trials he succeeded in tempting a young duck to snatch up a young one, but it was instantly rejected; and the duck “went about jerking its head, as if trying to throw off some unpleasant taste.”

With respect to sexual differences of colour, Dr. Gunther does not know of any striking instance either with frogs or toads; yet he can often distinguish the male from the female by the tints of the former being a little more intense. Nor does he know of any striking difference in external structure between the sexes, excepting the prominences which become developed during the breeding-season on the front legs of the male, by which he is enabled to hold the female. (47. The male alone of the Bufo sikimmensis (Dr. Anderson, ‘Proc. Zoolog. Soc.’ 1871, p. 204) has two plate-like callosities on the thorax and certain rugosities on the fingers, which perhaps subserve the same end as the above-mentioned prominences.) It is surprising that these animals have not acquired more strongly-marked sexual characters; for though cold-blooded their passions are strong. Dr. Gunther informs me that he has several times found an unfortunate female toad dead and smothered from having been so closely embraced by three or four males. Frogs have been observed by Professor Hoffman in Giessen fighting all day long during the breeding-season, and with so much violence that one had its body ripped open.

Frogs and toads offer one interesting sexual difference, namely, in the musical powers possessed by the males; but to speak of music, when applied to the discordant and overwhelming sounds emitted by male bull-frogs and some other species, seems, according to our taste, a singularly inappropriate expression. Nevertheless, certain frogs sing in a decidedly pleasing manner. Near Rio Janeiro I used often to sit in the evening to listen to a number of little Hylae, perched on blades of grass close to the water, which sent forth sweet chirping notes in harmony. The various sounds are emitted chiefly by the males during the breeding-season, as in the case of the croaking of our common frog. (48. Bell, ‘History British Reptiles,’ 1849, p. 93.) In accordance with this fact the vocal organs of the males are more highly-developed than those of the females. In some genera the males alone are provided with sacs which open into the larynx. (49. J. Bishop, in ‘Todd’s Cyclopaedia of Anatomy and Physiology,’ vol. iv. p. 1503.) For instance, in the edible frog (Rana esculenta) “the sacs are peculiar to the males, and become, when filled with air in the act of croaking, large globular bladders, standing out one on each side of the head, near the corners of the mouth.” The croak of the male is thus rendered exceedingly powerful; whilst that of the female is only a slight groaning noise. (50. Bell, ibid. pp. 112-114.) In the several genera of the family the vocal organs differ considerably in structure, and their development in all cases may be attributed to sexual selection.

爬行动物

龟属

Tortoises and turtles do not offer well-marked sexual differences. In some species, the tail of the male is longer than that of the female. In some, the plastron or lower surface of the shell of the male is slightly concave in relation to the back of the female. The male of the mud-turtle of the United States (Chrysemys picta) has claws on its front feet twice as long as those of the female; and these are used when the sexes unite. (51. Mr. C.J. Maynard, ‘The American Naturalist,’ Dec. 1869, p. 555.) With the huge tortoise of the Galapagos Islands (Testudo nigra) the males are said to grow to a larger size than the females: during the pairing-season, and at no other time, the male utters a hoarse bellowing noise, which can be heard at the distance of more than a hundred yards; the female, on the other hand, never uses her voice. (52. See my ‘Journal of Researches during the Voyage of the “Beagle,”‘ 1845, p. 384.)

With the Testudo elegans of India, it is said “that the combats of the males may be heard at some distance, from the noise they produce in butting against each other.” (53. Dr. Gunther, ‘Reptiles of British India,’ 1864, p. 7.)

鳄鱼属

The sexes apparently do not differ in colour; nor do I know that the males fight together, though this is probable, for some kinds make a prodigious display before the females. Bartram (54. ‘Travels through Carolina,’ etc., 1791, p. 128.) describes the male alligator as striving to win the female by splashing and roaring in the midst of a lagoon, “swollen to an extent ready to burst, with its head and tail lifted up, he springs or twirls round on the surface of the water, like an Indian chief rehearsing his feats of war.” During the season of love, a musky odour is emitted by the submaxillary glands of the crocodile, and pervades their haunts. (55. Owen, ‘Anatomy of Vertebrates,’ vol. i. 1866, p. 615.)

蛇目

Dr. Gunther informs me that the males are always smaller than the females, and generally have longer and slenderer tails; but he knows of no other difference in external structure. In regard to colour, be can almost always distinguish the male from the female, by his more strongly- pronounced tints; thus the black zigzag band on the back of the male English viper is more distinctly defined than in the female. The difference is much plainer in the rattle-snakes of N. America, the male of which, as the keeper in the Zoological Gardens shewed me, can at once be distinguished from the female by having more lurid yellow about its whole body. In S. Africa the Bucephalus capensis presents an analogous difference, for the female “is never so fully variegated with yellow on the sides as the male.” (56. Sir Andrew Smith, ‘Zoology of S. Africa: Reptilia,’ 1849, pl. x.) The male of the Indian Dipsas cynodon, on the other hand, is blackish-brown, with the belly partly black, whilst the female is reddish or yellowish-olive, with the belly either uniform yellowish or marbled with black. In the Tragops dispar of the same country the male is bright green, and the female bronze-coloured. (57. Dr. A. Gunther, ‘Reptiles of British India,’ Ray Soc., 1864, pp. 304, 308.) No doubt the colours of some snakes are protective, as shewn by the green tints of tree-snakes, and the various mottled shades of the species which live in sandy places; but it is doubtful whether the colours of many kinds, for instance of the common English snake and viper, serve to conceal them; and this is still more doubtful with the many foreign species which are coloured with extreme elegance. The colours of certain species are very different in the adult and young states. (58. Dr. Stoliczka, ‘Journal of Asiatic Society of Bengal,’ vol. xxxix, 1870, pp. 205, 211.)

During the breeding-season the anal scent-glands of snakes are in active function (59. Owen, ‘Anatomy of Vertebrates,’ vol. i. 1866, p. 615.); and so it is with the same glands in lizards, and as we have seen with the submaxillary glands of crocodiles. As the males of most animals search for the females, these odoriferous glands probably serve to excite or charm the female, rather than to guide her to the spot where the male may be found. Male snakes, though appearing so sluggish, are amorous; for many have been observed crowding round the same female, and even round her dead body. They are not known to fight together from rivalry. Their intellectual powers are higher than might have been anticipated. In the Zoological Gardens they soon learn not to strike at the iron bar with which their cages are cleaned; and Dr. Keen of Philadelphia informs me that some snakes which he kept learned after four or five times to avoid a noose, with which they were at first easily caught. An excellent observer in Ceylon, Mr. E. Layard, saw (60. ‘Rambles in Ceylon,’ in ‘Annals and Magazine of Natural History,’ 2nd series, vol. ix. 1852, p. 333.) a cobra thrust its head through a narrow hole and swallow a toad. “With this encumbrance he could not withdraw himself; finding this, he reluctantly disgorged the precious morsel, which began to move off; this was too much for snake philosophy to bear, and the toad was again seized, and again was the snake, after violent efforts to escape, compelled to part with its prey. This time, however, a lesson had been learnt, and the toad was seized by one leg, withdrawn, and then swallowed in triumph.”

The keeper in the Zoological Gardens is positive that certain snakes, for instance Crotalus and Python, distinguish him from all other persons. Cobras kept together in the same cage apparently feel some attachment towards each other. (61. Dr. Gunther, ‘Reptiles of British India,’ 1864, p. 340.)

It does not, however, follow because snakes have some reasoning power, strong passions and mutual affection, that they should likewise be endowed with sufficient taste to admire brilliant colours in their partners, so as to lead to the adornment of the species through sexual selection. Nevertheless, it is difficult to account in any other manner for the extreme beauty of certain species; for instance, of the coral-snakes of S. America, which are of a rich red with black and yellow transverse bands. I well remember how much surprise I felt at the beauty of the first coral- snake which I saw gliding across a path in Brazil. Snakes coloured in this peculiar manner, as Mr. Wallace states on the authority of Dr. Gunther (62. ‘Westminster Review,’ July 1st, 1867, p. 32.), are found nowhere else in the world except in S. America, and here no less than four genera occur. One of these, Elaps, is venomous; a second and widely-distinct genus is doubtfully venomous, and the two others are quite harmless. The species belonging to these distinct genera inhabit the same districts, and are so like each other that no one “but a naturalist would distinguish the harmless from the poisonous kinds.” Hence, as Mr. Wallace believes, the innocuous kinds have probably acquired their colours as a protection, on the principle of imitation; for they would naturally be thought dangerous by their enemies. The cause, however, of the bright colours of the venomous Elaps remains to be explained, and this may perhaps be sexual selection.

Snakes produce other sounds besides hissing. The deadly Echis carinata has on its sides some oblique rows of scales of a peculiar structure with serrated edges; and when this snake is excited these scales are rubbed against each other, which produces “a curious prolonged, almost hissing sound.” (63. Dr. Anderson, ‘Proc. Zoolog. Soc.’ 1871, p. 196.) With respect to the rattling of the rattle-snake, we have at last some definite information: for Professor Aughey states (64. The ‘American Naturalist,’ 1873, p. 85.), that on two occasions, being himself unseen, he watched from a little distance a rattle-snake coiled up with head erect, which continued to rattle at short intervals for half an hour: and at last he saw another snake approach, and when they met they paired. Hence he is satisfied that one of the uses of the rattle is to bring the sexes together. Unfortunately he did not ascertain whether it was the male or the female which remained stationary and called for the other. But it by no means follows from the above fact that the rattle may not be of use to these snakes in other ways, as a warning to animals which would otherwise attack them. Nor can I quite disbelieve the several accounts which have appeared of their thus paralysing their prey with fear. Some other snakes also make a distinct noise by rapidly vibrating their tails against the surrounding stalks of plants; and I have myself heard this in the case of a Trigonocephalus in S. America.

紫荆属

The males of some, probably of many kinds of lizards, fight together from rivalry. Thus the arboreal Anolis cristatellus of S. America is extremely pugnacious: “During the spring and early part of the summer, two adult males rarely meet without a contest. On first seeing one another, they nod their heads up and down three or four times, and at the same time expanding the frill or pouch beneath the throat; their eyes glisten with rage, and after waving their tails from side to side for a few seconds, as if to gather energy, they dart at each other furiously, rolling over and over, and holding firmly with their teeth. The conflict generally ends in one of the combatants losing his tail, which is often devoured by the victor.” The male of this species is considerably larger than the female (65. Mr. N.L. Austen kept these animals alive for a considerable time; see ‘Land and Water,’ July 1867, p. 9.); and this, as far as Dr. Gunther has been able to ascertain, is the general rule with lizards of all kinds. The male alone of the Cyrtodactylus rubidus of the Andaman Islands possesses pre-anal pores; and these pores, judging from analogy, probably serve to emit an odour. (66. Stoliczka, ‘Journal of the Asiatic Society of Bengal,’ vol. xxxiv. 1870, p. 166.)

[Fig.33. Sitana minor.
Male with the gular pouch expanded (from Gunther’s ‘Reptiles of India’)’]

The sexes often differ greatly in various external characters. The male of the above-mentioned Anolis is furnished with a crest which runs along the back and tail, and can be erected at pleasure; but of this crest the female does not exhibit a trace. In the Indian Cophotis ceylanica, the female has a dorsal crest, though much less developed than in the male; and so it is, as Dr. Gunther informs me, with the females of many Iguanas, Chameleons, and other lizards. In some species, however, the crest is equally developed in both sexes, as in the Iguana tuberculata. In the genus Sitana, the males alone are furnished with a large throat pouch (Fig. 33), which can be folded up like a fan, and is coloured blue, black, and red; but these splendid colours are exhibited only during the pairing-season. The female does not possess even a rudiment of this appendage. In the Anolis cristatellus, according to Mr. Austen, the throat pouch, which is bright red marbled with yellow, is present in the female, though in a rudimental condition. Again, in certain other lizards, both sexes are equally well provided with throat pouches. Here we see with species belonging to the same group, as in so many previous cases, the same character either confined to the males, or more largely developed in them than in the females, or again equally developed in both sexes. The little lizards of the genus Draco, which glide through the air on their rib- supported parachutes, and which in the beauty of their colours baffle description, are furnished with skinny appendages to the throat “like the wattles of gallinaceous birds.” These become erected when the animal is excited. They occur in both sexes, but are best developed when the male arrives at maturity, at which age the middle appendage is sometimes twice as long as the head. Most of the species likewise have a low crest running along the neck; and this is much more developed in the full-grown males than in the females or young males. (67. All the foregoing statements and quotations, in regard to Cophotis, Sitana and Draco, as well as the following facts in regard to Ceratophora and Chamaeleon, are from Dr. Gunther himself, or from his magnificent work on the ‘Reptiles of British India,’ Ray Soc., 1864, pp. 122, 130, 135.)

A Chinese species is said to live in pairs during the spring; “and if one is caught, the other falls from the tree to the ground, and allows itself to be captured with impunity”—I presume from despair. (68. Mr. Swinhoe, ‘Proc. Zoolog. Soc.’ 1870, p. 240.)

[Fig. 34. Ceratophora Stoddartii. Upper figure; lower figure, female.]

There are other and much more remarkable differences between the sexes of certain lizards. The male of Ceratophora aspera bears on the extremity of his snout an appendage half as long as the head. It is cylindrical, covered with scales, flexible, and apparently capable of erection: in the female it is quite rudimental. In a second species of the same genus a terminal scale forms a minute horn on the summit of the flexible appendage; and in a third species (C. Stoddartii, fig. 34) the whole appendage is converted into a horn, which is usually of a white colour, but assumes a purplish tint when the animal is excited. In the adult male of this latter species the horn is half an inch in length, but it is of quite minute size in the female and in the young. These appendages, as Dr. Gunther has remarked to me, may be compared with the combs of gallinaceous birds, and apparently serve as ornaments.

[Fig. 35. Chamaeleo bifurcus. Upper figure, male; lower figure, female.

Fig. 36. Chamaeleo Owenii. Upper figure, male; lower figure, female.]

In the genus Chamaeleon we come to the acme of difference between the sexes. The upper part of the skull of the male C. bifurcus (Fig. 35), an inhabitant of Madagascar, is produced into two great, solid, bony projections, covered with scales like the rest of the head; and of this wonderful modification of structure the female exhibits only a rudiment. Again, in Chamaeleo Owenii (Fig. 36), from the West Coast of Africa, the male bears on his snout and forehead three curious horns, of which the female has not a trace. These horns consist of an excrescence of bone covered with a smooth sheath, forming part of the general integuments of the body, so that they are identical in structure with those of a bull, goat, or other sheath-horned ruminant. Although the three horns differ so much in appearance from the two great prolongations of the skull in C. bifurcus, we can hardly doubt that they serve the same general purpose in the economy of these two animals. The first conjecture, which will occur to every one, is that they are used by the males for fighting together; and as these animals are very quarrelsome (69. Dr. Buchholz, ‘Monatsbericht K. Preuss. Akad.’ Jan. 1874, p. 78.), this is probably a correct view. Mr. T.W. Wood also informs me that he once watched two individuals of C. pumilus fighting violently on the branch of a tree; they flung their heads about and tried to bite each other; they then rested for a time and afterwards continued their battle.

With many lizards the sexes differ slightly in colour, the tints and stripes of the males being brighter and more distinctly defined than in the females. This, for instance, is the case with the above Cophotis and with the Acanthodactylus capensis of S. Africa. In a Cordylus of the latter country, the male is either much redder or greener than the female. In the Indian Calotes nigrilabris there is a still greater difference; the lips also of the male are black, whilst those of the female are green. In our common little viviparous lizard (Zootoca vivipara) “the under side of the body and base of the tail in the male are bright orange, spotted with black; in the female these parts are pale-greyish-green without spots.” (70. Bell, ‘History of British Reptiles,’ 2nd ed., 1849, p. 40.) We have seen that the males alone of Sitana possess a throat-pouch; and this is splendidly tinted with blue, black, and red. In the Proctotretus tenuis of Chile the male alone is marked with spots of blue, green, and coppery-red. (71. For Proctotretus, see ‘Zoology of the Voyage of the “Beagle”; Reptiles,’ by Mr. Bell, p. 8. For the Lizards of S. Africa, see ‘Zoology of S. Africa: Reptiles,’ by Sir Andrew Smith, pl. 25 and 39. For the Indian Calotes, see ‘Reptiles of British India,’ by Dr. Gunther, p. 143.) In many cases the males retain the same colours throughout the year, but in others they become much brighter during the breeding-season; I may give as an additional instance the Calotes maria, which at this season has a bright red head, the rest of the body being green. (72. Gunther in ‘Proceedings, Zoological Society,’ 1870, p. 778, with a coloured figure.)

Both sexes of many species are beautifully coloured exactly alike; and there is no reason to suppose that such colours are protective. No doubt with the bright green kinds which live in the midst of vegetation, this colour serves to conceal them; and in N. Patagonia I saw a lizard (Proctotretus multimaculatus) which, when frightened, flattened its body, closed its eyes, and then from its mottled tints was hardly distinguishable from the surrounding sand. But the bright colours with which so many lizards are ornamented, as well as their various curious appendages, were probably acquired by the males as an attraction, and then transmitted either to their male offspring alone, or to both sexes. Sexual selection, indeed, seems to have played almost as important a part with reptiles as with birds; and the less conspicuous colours of the females in comparison with the males cannot be accounted for, as Mr. Wallace believes to be the case with birds, by the greater exposure of the females to danger during incubation.

第十三章 •16,400字
鸟类的第二性征

Sexual differences—Law of battle—Special weapons—Vocal organs— Instrumental music—Love-antics and dances—Decorations, permanent and seasonal—Double and single annual moults—Display of ornaments by the males.

Secondary sexual characters are more diversified and conspicuous in birds, though not perhaps entailing more important changes of structure, than in any other class of animals. I shall, therefore, treat the subject at considerable length. Male birds sometimes, though rarely, possess special weapons for fighting with each other. They charm the female by vocal or instrumental music of the most varied kinds. They are ornamented by all sorts of combs, wattles, protuberances, horns, air-distended sacks, top- knots, naked shafts, plumes and lengthened feathers gracefully springing from all parts of the body. The beak and naked skin about the head, and the feathers, are often gorgeously coloured. The males sometimes pay their court by dancing, or by fantastic antics performed either on the ground or in the air. In one instance, at least, the male emits a musky odour, which we may suppose serves to charm or excite the female; for that excellent observer, Mr. Ramsay (1. ‘Ibis,’ vol. iii. (new series), 1867, p. 414.), says of the Australian musk-duck (Biziura lobata) that “the smell which the male emits during the summer months is confined to that sex, and in some individuals is retained throughout the year; I have never, even in the breeding-season, shot a female which had any smell of musk.” So powerful is this odour during the pairing-season, that it can be detected long before the bird can be seen. (2. Gould, ‘Handbook of the Birds of Australia,’ 1865, vol. ii. p. 383.) On the whole, birds appear to be the most aesthetic of all animals, excepting of course man, and they have nearly the same taste for the beautiful as we have. This is shewn by our enjoyment of the singing of birds, and by our women, both civilised and savage, decking their heads with borrowed plumes, and using gems which are hardly more brilliantly coloured than the naked skin and wattles of certain birds. In man, however, when cultivated, the sense of beauty is manifestly a far more complex feeling, and is associated with various intellectual ideas.

Before treating of the sexual characters with which we are here more particularly concerned, I may just allude to certain differences between the sexes which apparently depend on differences in their habits of life; for such cases, though common in the lower, are rare in the higher classes. Two humming-birds belonging to the genus Eustephanus, which inhabit the island of Juan Fernandez, were long thought to be specifically distinct, but are now known, as Mr. Gould informs me, to be the male and female of the same species, and they differ slightly in the form of the beak. In another genus of humming-birds (Grypus), the beak of the male is serrated along the margin and hooked at the extremity, thus differing much from that of the female. In the Neomorpha of New Zealand, there is, as we have seen, a still wider difference in the form of the beak in relation to the manner of feeding of the two sexes. Something of the same kind has been observed with the goldfinch (Carduelis elegans), for I am assured by Mr. J. Jenner Weir that the bird-catchers can distinguish the males by their slightly longer beaks. The flocks of males are often found feeding on the seeds of the teazle (Dipsacus), which they can reach with their elongated beaks, whilst the females more commonly feed on the seeds of the betony or Scrophularia. With a slight difference of this kind as a foundation, we can see how the beaks of the two sexes might be made to differ greatly through natural selection. In some of the above cases, however, it is possible that the beaks of the males may have been first modified in relation to their contests with other males; and that this afterwards led to slightly changed habits of life.

Law of Battle

Almost all male birds are extremely pugnacious, using their beaks, wings, and legs for fighting together. We see this every spring with our robins and sparrows. The smallest of all birds, namely the humming-bird, is one of the most quarrelsome. Mr. Gosse (3. Quoted by Mr. Gould, ‘Introduction to the Trochilidae,’ 1861, page 29.) describes a battle in which a pair seized hold of each other’s beaks, and whirled round and round, till they almost fell to the ground; and M. Montes de Oca, in speaking or another genus of humming-bird, says that two males rarely meet without a fierce aerial encounter: when kept in cages “their fighting has mostly ended in the splitting of the tongue of one of the two, which then surely dies from being unable to feed.” (4. Gould, ibid. p. 52.) With waders, the males of the common water-hen (Gallinula chloropus) “when pairing, fight violently for the females: they stand nearly upright in the water and strike with their feet.” Two were seen to be thus engaged for half an hour, until one got hold of the head of the other, which would have been killed had not the observer interfered; the female all the time looking on as a quiet spectator. (5. W. Thompson, ‘Natural History of Ireland: Birds,’ vol. ii. 1850, p. 327.) Mr. Blyth informs me that the males of an allied bird (Gallicrex cristatus) are a third larger than the females, and are so pugnacious during the breeding-season that they are kept by the natives of Eastern Bengal for the sake of fighting. Various other birds are kept in India for the same purpose, for instance, the bulbuls (Pycnonotus hoemorrhous) which “fight with great spirit.” (6. Jerdon, ‘Birds of India,’ 1863, vol. ii. p. 96.)

[Fig. 37. The Ruff or Machetes pugnax (from Brehm’s ‘Thierleben’).]

The polygamous ruff (Machetes pugnax, Fig. 37) is notorious for his extreme pugnacity; and in the spring, the males, which are considerably larger than the females, congregate day after day at a particular spot, where the females propose to lay their eggs. The fowlers discover these spots by the turf being trampled somewhat bare. Here they fight very much like game- cocks, seizing each other with their beaks and striking with their wings. The great ruff of feathers round the neck is then erected, and according to Col. Montagu “sweeps the ground as a shield to defend the more tender parts”; and this is the only instance known to me in the case of birds of any structure serving as a shield. The ruff of feathers, however, from its varied and rich colours probably serves in chief part as an ornament. Like most pugnacious birds, they seem always ready to fight, and when closely confined, often kill each other; but Montagu observed that their pugnacity becomes greater during the spring, when the long feathers on their necks are fully developed; and at this period the least movement by any one bird provokes a general battle. (7. Macgillivray, ‘History of British Birds,’ vol. iv. 1852, pp. 177-181.) Of the pugnacity of web-footed birds, two instances will suffice: in Guiana “bloody fights occur during the breeding-season between the males of the wild musk-duck (Cairina moschata); and where these fights have occurred the river is covered for some distance with feathers.” (8. Sir R. Schomburgk, in ‘Journal of Royal Geographic Society,’ vol. xiii. 1843, p. 31.) Birds which seem ill-adapted for fighting engage in fierce conflicts; thus the stronger males of the pelican drive away the weaker ones, snapping with their huge beaks and giving heavy blows with their wings. Male snipe fight together, “tugging and pushing each other with their bills in the most curious manner imaginable.” Some few birds are believed never to fight; this is the case, according to Audubon, with one of the woodpeckers of the United States (Picu sauratus), although “the hens are followed by even half a dozen of their gay suitors.” (9. ‘Ornithological Biography,’ vol. i. p. 191. For pelicans and snipes, see vol. iii. pp. 138, 477.)

The males of many birds are larger than the females, and this no doubt is the result of the advantage gained by the larger and stronger males over their rivals during many generations. The difference in size between the two sexes is carried to an extreme point in several Australian species; thus the male musk-duck (Biziura), and the male Cincloramphus cruralis (allied to our pipits) are by measurement actually twice as large as their respective females. (10. Gould, ‘Handbook of Birds of Australia,’ vol. i. p. 395; vol. ii. p. 383.) With many other birds the females are larger than the males; and, as formerly remarked, the explanation often given, namely, that the females have most of the work in feeding their young, will not suffice. In some few cases, as we shall hereafter see, the females apparently have acquired their greater size and strength for the sake of conquering other females and obtaining possession of the males.

The males of many gallinaceous birds, especially of the polygamous kinds, are furnished with special weapons for fighting with their rivals, namely spurs, which can be used with fearful effect. It has been recorded by a trustworthy writer (11. Mr. Hewitt, in the ‘Poultry Book’ by Tegetmeier, 1866, p. 137.) that in Derbyshire a kite struck at a game-hen accompanied by her chickens, when the cock rushed to the rescue, and drove his spur right through the eye and skull of the aggressor. The spur was with difficulty drawn from the skull, and as the kite, though dead, retained his grasp, the two birds were firmly locked together; but the cock when disentangled was very little injured. The invincible courage of the game- cock is notorious: a gentleman who long ago witnessed the brutal scene, told me that a bird had both its legs broken by some accident in the cockpit, and the owner laid a wager that if the legs could be spliced so that the bird could stand upright, he would continue fighting. This was effected on the spot, and the bird fought with undaunted courage until he received his death-stroke. In Ceylon a closely allied, wild species, the Gallus Stanleyi, is known to fight desperately “in defence of his seraglio,” so that one of the combatants is frequently found dead. (12. Layard, ‘Annals and Magazine of Natural History,’ vol. xiv. 1854, p. 63.) An Indian partridge (Ortygornis gularis), the male of which is furnished with strong and sharp spurs, is so quarrelsome “that the scars of former fights disfigure the breast of almost every bird you kill.” (13. Jerdon, ‘Birds of India,’ vol. iii. p. 574.)

The males of almost all gallinaceous birds, even those which are not furnished with spurs, engage during the breeding-season in fierce conflicts. The Capercailzie and Black-cock (Tetrao urogallus and T. tetrix), which are both polygamists, have regular appointed places, where during many weeks they congregate in numbers to fight together and to display their charms before the females. Dr. W. Kovalevsky informs me that in Russia he has seen the snow all bloody on the arenas where the capercailzie have fought; and the black-cocks “make the feathers fly in every direction,” when several “engage in a battle royal.” The elder Brehm gives a curious account of the Balz, as the love-dances and love-songs of the Black-cock are called in Germany. The bird utters almost continuously the strangest noises: “he holds his tail up and spreads it out like a fan, he lifts up his head and neck with all the feathers erect, and stretches his wings from the body. Then he takes a few jumps in different directions, sometimes in a circle, and presses the under part of his beak so hard against the ground that the chin feathers are rubbed off. During these movements he beats his wings and turns round and round. The more ardent he grows the more lively he becomes, until at last the bird appears like a frantic creature.” At such times the black-cocks are so absorbed that they become almost blind and deaf, but less so than the capercailzie: hence bird after bird may be shot on the same spot, or even caught by the hand. After performing these antics the males begin to fight: and the same black-cock, in order to prove his strength over several antagonists, will visit in the course of one morning several Balz-places, which remain the same during successive years. (14. Brehm, ‘Thierleben,’ 1867, B. iv. s. 351. Some of the foregoing statements are taken from L. Lloyd, ‘The Game Birds of Sweden,’ etc., 1867, p. 79.)

The peacock with his long train appears more like a dandy than a warrior, but he sometimes engages in fierce contests: the Rev. W. Darwin Fox informs me that at some little distance from Chester two peacocks became so excited whilst fighting, that they flew over the whole city, still engaged, until they alighted on the top of St. John’s tower.

The spur, in those gallinaceous birds which are thus provided, is generally single; but Polyplectron (Fig. 51) has two or more on each leg; and one of the Blood-pheasants (Ithaginis cruentus) has been seen with five spurs. The spurs are generally confined to the male, being represented by mere knobs or rudiments in the female; but the females of the Java peacock (Pavo muticus) and, as I am informed by Mr. Blyth, of the small fire-backed pheasant (Euplocamus erythrophthalmus) possess spurs. In Galloperdix it is usual for the males to have two spurs, and for the females to have only one on each leg. (15. Jerdon, ‘Birds of India’: on Ithaginis, vol. iii. p. 523; on Galloperdix, p. 541.) Hence spurs may be considered as a masculine structure, which has been occasionally more or less transferred to the females. Like most other secondary sexual characters, the spurs are highly variable, both in number and development, in the same species.

[Fig.38. Palamedea cornuta (from Brehm), shewing the double wing-spurs, and the filament on the head.]

Various birds have spurs on their wings. But the Egyptian goose (Chenalopex aegyptiacus) has only “bare obtuse knobs,” and these probably shew us the first steps by which true spurs have been developed in other species. In the spur-winged goose, Plectropterus gambensis, the males have much larger spurs than the females; and they use them, as I am informed by Mr. Bartlett, in fighting together, so that, in this case, the wing-spurs serve as sexual weapons; but according to Livingstone, they are chiefly used in the defence of the young. The Palamedea (Fig. 38) is armed with a pair of spurs on each wing; and these are such formidable weapons that a single blow has been known to drive a dog howling away. But it does not appear that the spurs in this case, or in that of some of the spur-winged rails, are larger in the male than in the female. (16. For the Egyptian goose, see Macgillivray, ‘British Birds,’ vol. iv. p. 639. For Plectropterus, Livingstone’s ‘Travels,’ p. 254. For Palamedea, Brehm’s ‘Thierleben,’ B. iv. s. 740. See also on this bird Azara, ‘Voyages dans l’Amerique merid.’ tom. iv. 1809, pp. 179, 253.) In certain plovers, however, the wing-spurs must be considered as a sexual character. Thus in the male of our common peewit (Vanellus cristatus) the tubercle on the shoulder of the wing becomes more prominent during the breeding-season, and the males fight together. In some species of Lobivanellus a similar tubercle becomes developed during the breeding-season “into a short horny spur.” In the Australian L. lobatus both sexes have spurs, but these are much larger in the males than in the females. In an allied bird, the Hoplopterus armatus, the spurs do not increase in size during the breeding- season; but these birds have been seen in Egypt to fight together, in the same manner as our peewits, by turning suddenly in the air and striking sideways at each other, sometimes with fatal results. Thus also they drive away other enemies. (17. See, on our peewit, Mr. R. Carr in ‘Land and Water,’ Aug. 8th, 1868, p. 46. In regard to Lobivanellus, see Jerdon’s ‘Birds of India,’ vol. iii. p. 647, and Gould’s ‘Handbook of Birds of Australia,’ vol. ii. p. 220. For the Hoplopterus, see Mr. Allen in the ‘Ibis,’ vol. v. 1863, p. 156.)

The season of love is that of battle; but the males of some birds, as of the game-fowl and ruff, and even the young males of the wild turkey and grouse (18. Audubon, ‘Ornithological Biography,’ vol. ii. p. 492; vol. i. pp. 4-13.), are ready to fight whenever they meet. The presence of the female is the teterrima belli causa. The Bengali baboos make the pretty little males of the amadavat (Estrelda amandava) fight together by placing three small cages in a row, with a female in the middle; after a little time the two males are turned loose, and immediately a desperate battle ensues. (19. Mr. Blyth, ‘Land and Water,’ 1867, p. 212.) When many males congregate at the same appointed spot and fight together, as in the case of grouse and various other birds, they are generally attended by the females (20. Richardson on Tetrao umbellus, ‘Fauna Bor. Amer.: Birds,’ 1831, p. 343. L. Lloyd, ‘Game Birds of Sweden,’ 1867, pp. 22, 79, on the capercailzie and black-cock. Brehm, however, asserts (‘Thierleben,’ B. iv. s. 352) that in Germany the grey-hens do not generally attend the Balzen of the black-cocks, but this is an exception to the common rule; possibly the hens may lie hidden in the surrounding bushes, as is known to be the case with the gray-hens in Scandinavia, and with other species in N. America.), which afterwards pair with the victorious combatants. But in some cases the pairing precedes instead of succeeding the combat: thus according to Audubon (21. ‘Ornithological Biography,’ vol. ii. p. 275.), several males of the Virginian goat-sucker (Caprimulgus virgianus) “court, in a highly entertaining manner the female, and no sooner has she made her choice, than her approved gives chase to all intruders, and drives them beyond his dominions.” Generally the males try to drive away or kill their rivals before they pair. It does not, however, appear that the females invariably prefer the victorious males. I have indeed been assured by Dr. W. Kovalevsky that the female capercailzie sometimes steals away with a young male who has not dared to enter the arena with the older cocks, in the same manner as occasionally happens with the does of the red-deer in Scotland. When two males contend in presence of a single female, the victor, no doubt, commonly gains his desire; but some of these battles are caused by wandering males trying to distract the peace of an already mated pair. (22. Brehm, ‘Thierleben,’ etc., B. iv. 1867, p. 990. Audubon, ‘Ornithological Biography,’ vol. ii. p. 492.)

Even with the most pugnacious species it is probable that the pairing does not depend exclusively on the mere strength and courage of the male; for such males are generally decorated with various ornaments, which often become more brilliant during the breeding-season, and which are sedulously displayed before the females. The males also endeavour to charm or excite their mates by love-notes, songs, and antics; and the courtship is, in many instances, a prolonged affair. Hence it is not probable that the females are indifferent to the charms of the opposite sex, or that they are invariably compelled to yield to the victorious males. It is more probable that the females are excited, either before or after the conflict, by certain males, and thus unconsciously prefer them. In the case of Tetrao umbellus, a good observer (23. ‘Land and Water,’ July 25, 1868, p. 14.) goes so far as to believe that the battles of the male “are all a sham, performed to show themselves to the greatest advantage before the admiring females who assemble around; for I have never been able to find a maimed hero, and seldom more than a broken feather.” I shall have to recur to this subject, but I may here add that with the Tetrao cupido of the United States, about a score of males assemble at a particular spot, and, strutting about, make the whole air resound with their extraordinary noises. At the first answer from a female the males begin to fight furiously, and the weaker give way; but then, according to Audubon, both the victors and vanquished search for the female, so that the females must either then exert a choice, or the battle must be renewed. So, again, with one of the field-starlings of the United States (Sturnella ludoviciana) the males engage in fierce conflicts, “but at the sight of a female they all fly after her as if mad.” (24. Audubon’s ‘Ornithological Biography;’ on Tetrao cupido, vol. ii. p. 492; on the Sturnus, vol. ii. p. 219.)

声乐和器乐

With birds the voice serves to express various emotions, such as distress, fear, anger, triumph, or mere happiness. It is apparently sometimes used to excite terror, as in the case of the hissing noise made by some nestling-birds. Audubon (25. ‘Ornithological Biography,’ vol. v. p. 601.), relates that a night-heron (Ardea nycticorax, Linn.), which he kept tame, used to hide itself when a cat approached, and then “suddenly start up uttering one of the most frightful cries, apparently enjoying the cat’s alarm and flight.” The common domestic cock clucks to the hen, and the hen to her chickens, when a dainty morsel is found. The hen, when she has laid an egg, “repeats the same note very often, and concludes with the sixth above, which she holds for a longer time” (26. The Hon. Daines Barrington, ‘Philosophical Transactions,’ 1773, p. 252.); and thus she expresses her joy. Some social birds apparently call to each other for aid; and as they flit from tree to tree, the flock is kept together by chirp answering chirp. During the nocturnal migrations of geese and other water-fowl, sonorous clangs from the van may be heard in the darkness overhead, answered by clangs in the rear. Certain cries serve as danger signals, which, as the sportsman knows to his cost, are understood by the same species and by others. The domestic cock crows, and the humming-bird chirps, in triumph over a defeated rival. The true song, however, of most birds and various strange cries are chiefly uttered during the breeding- season, and serve as a charm, or merely as a call-note, to the other sex.

Naturalists are much divided with respect to the object of the singing of birds. Few more careful observers ever lived than Montagu, and he maintained that the “males of song-birds and of many others do not in general search for the female, but, on the contrary, their business in the spring is to perch on some conspicuous spot, breathing out their full and amorous notes, which, by instinct, the female knows, and repairs to the spot to choose her mate.” (27. ‘Ornithological Dictionary,’ 1833, p. 475.) Mr. Jenner Weir informs me that this is certainly the case with the nightingale. Bechstein, who kept birds during his whole life, asserts, “that the female canary always chooses the best singer, and that in a state of nature the female finch selects that male out of a hundred whose notes please her most. (28. ‘Naturgeschichte der Stubenvögel,’ 1840, s. 4. Mr. Harrison Weir likewise writes to me:—”I am informed that the best singing males generally get a mate first, when they are bred in the same room.”) There can be no doubt that birds closely attend to each other’s song. Mr. Weir has told me of the case of a bullfinch which had been taught to pipe a German waltz, and who was so good a performer that he cost ten guineas; when this bird was first introduced into a room where other birds were kept and he began to sing, all the others, consisting of about twenty linnets and canaries, ranged themselves on the nearest side of their cages, and listened with the greatest interest to the new performer. Many naturalists believe that the singing of birds is almost exclusively “the effect of rivalry and emulation,” and not for the sake of charming their mates. This was the opinion of Daines Barrington and White of Selborne, who both especially attended to this subject. (29. ‘Philosophical Transactions,’ 1773, p. 263. White’s ‘Natural History of Selborne,’ 1825, vol. i. p. 246.) Barrington, however, admits that “superiority in song gives to birds an amazing ascendancy over others, as is well known to bird- catchers.”

It is certain that there is an intense degree of rivalry between the males in their singing. Bird-fanciers match their birds to see which will sing longest; and I was told by Mr. Yarrell that a first-rate bird will sometimes sing till he drops down almost dead, or according to Bechstein (30. ‘Naturgesch. der Stubenvögel,’ 1840, s. 252.), quite dead from rupturing a vessel in the lungs. Whatever the cause may be, male birds, as I hear from Mr. Weir, often die suddenly during the season of song. That the habit of singing is sometimes quite independent of love is clear, for a sterile, hybrid canary-bird has been described (31. Mr. Bold, ‘Zoologist,’ 1843-44, p. 659.) as singing whilst viewing itself in a mirror, and then dashing at its own image; it likewise attacked with fury a female canary, when put into the same cage. The jealousy excited by the act of singing is constantly taken advantage of by bird-catchers; a male, in good song, is hidden and protected, whilst a stuffed bird, surrounded by limed twigs, is exposed to view. In this manner, as Mr. Weir informs me, a man has in the course of a single day caught fifty, and in one instance, seventy, male chaffinches. The power and inclination to sing differ so greatly with birds that although the price of an ordinary male chaffinch is only sixpence, Mr. Weir saw one bird for which the bird-catcher asked three pounds; the test of a really good singer being that it will continue to sing whilst the cage is swung round the owner’s head.

That male birds should sing from emulation as well as for charming the female, is not at all incompatible; and it might have been expected that these two habits would have concurred, like those of display and pugnacity. Some authors, however, argue that the song of the male cannot serve to charm the female, because the females of some few species, such as of the canary, robin, lark, and bullfinch, especially when in a state of widowhood, as Bechstein remarks, pour forth fairly melodious strains. In some of these cases the habit of singing may be in part attributed to the females having been highly fed and confined (32. D. Barrington, ‘Philosophical Transactions,’ 1773, p. 262. Bechstein, ‘Stubenvögel,’ 1840, s. 4.), for this disturbs all the functions connected with the reproduction of the species. Many instances have already been given of the partial transference of secondary masculine characters to the female, so that it is not at all surprising that the females of some species should possess the power of song. It has also been argued, that the song of the male cannot serve as a charm, because the males of certain species, for instance of the robin, sing during the autumn. (33. This is likewise the case with the water-ouzel; see Mr. Hepburn in the ‘Zoologist,’ 1845-46, p. 1068.) But nothing is more common than for animals to take pleasure in practising whatever instinct they follow at other times for some real good. How often do we see birds which fly easily, gliding and sailing through the air obviously for pleasure? The cat plays with the captured mouse, and the cormorant with the captured fish. The weaver-bird (Ploceus), when confined in a cage, amuses itself by neatly weaving blades of grass between the wires of its cage. Birds which habitually fight during the breeding-season are generally ready to fight at all times; and the males of the capercailzie sometimes hold their Balzen or leks at the usual place of assemblage during the autumn. (34. L. Lloyd, ‘Game Birds of Sweden,’ 1867, p. 25.) Hence it is not at all surprising that male birds should continue singing for their own amusement after the season for courtship is over.

As shewn in a previous chapter, singing is to a certain extent an art, and is much improved by practice. Birds can be taught various tunes, and even the unmelodious sparrow has learnt to sing like a linnet. They acquire the song of their foster parents (35. Barrington, ibid. p. 264, Bechstein, ibid. s. 5.), and sometimes that of their neighbours. (36. Dureau de la Malle gives a curious instance (‘Annales des Sc. Nat.’ 3rd series, Zoolog., tom. x. p. 118) of some wild blackbirds in his garden in Paris, which naturally learnt a republican air from a caged bird.) All the common songsters belong to the Order of Insessores, and their vocal organs are much more complex than those of most other birds; yet it is a singular fact that some of the Insessores, such as ravens, crows, and magpies, possess the proper apparatus (37. Bishop, in ‘Todd’s Cyclopaedia of Anatomy and Physiology,’ vol. iv. p. 1496.), though they never sing, and do not naturally modulate their voices to any great extent. Hunter asserts (38. As stated by Barrington in ‘Philosophical Transactions,’ 1773, p. 262.) that with the true songsters the muscles of the larynx are stronger in the males than in the females; but with this slight exception there is no difference in the vocal organs of the two sexes, although the males of most species sing so much better and more continuously than the females.

It is remarkable that only small birds properly sing. The Australian genus Menura, however, must be excepted; for the Menura Alberti, which is about the size of a half-grown turkey, not only mocks other birds, but “its own whistle is exceedingly beautiful and varied.” The males congregate and form “corroborying places,” where they sing, raising and spreading their tails like peacocks, and drooping their wings. (39. Gould, ‘Handbook to the Birds of Australia,’ vol. i. 1865, pp. 308-310. See also Mr. T.W. Wood in the ‘Student,’ April 1870, p. 125.) It is also remarkable that birds which sing well are rarely decorated with brilliant colours or other ornaments. Of our British birds, excepting the bullfinch and goldfinch, the best songsters are plain-coloured. The kingfisher, bee-eater, roller, hoopoe, woodpeckers, etc., utter harsh cries; and the brilliant birds of the tropics are hardly ever songsters. (40. See remarks to this effect in Gould’s ‘Introduction to the Trochilidae,’ 1861, p. 22.) Hence bright colours and the power of song seem to replace each other. We can perceive that if the plumage did not vary in brightness, or if bright colours were dangerous to the species, other means would be employed to charm the females; and melody of voice offers one such means.

[Fig. 39. Tetrao cupido: male. (T.W. Wood.)]

In some birds the vocal organs differ greatly in the two sexes. In the Tetrao cupido (Fig. 39) the male has two bare, orange-coloured sacks, one on each side of the neck; and these are largely inflated when the male, during the breeding-season, makes his curious hollow sound, audible at a great distance. Audubon proved that the sound was intimately connected with this apparatus (which reminds us of the air-sacks on each side of the mouth of certain male frogs), for he found that the sound was much diminished when one of the sacks of a tame bird was pricked, and when both were pricked it was altogether stopped. The female has “a somewhat similar, though smaller naked space of skin on the neck; but this is not capable of inflation.” (41. ‘The Sportsman and Naturalist in Canada,’ by Major W. Ross King, 1866, pp. 144-146. Mr. T.W. Wood gives in the ‘Student’ (April 1870, p. 116) an excellent account of the attitude and habits of this bird during its courtship. He states that the ear-tufts or neck-plumes are erected, so that they meet over the crown of the head. See his drawing, Fig. 39.) The male of another kind of grouse (Tetrao urophasianus), whilst courting the female, has his “bare yellow oesophagus inflated to a prodigious size, fully half as large as the body”; and he then utters various grating, deep, hollow tones. With his neck-feathers erect, his wings lowered, and buzzing on the ground, and his long pointed tail spread out like a fan, he displays a variety of grotesque attitudes. The oesophagus of the female is not in any way remarkable. (42. Richardson, ‘Fauna Bor. Americana: Birds,’ 1831, p. 359. Audubon, ibid. vol. iv. p. 507.)

[Fig. 40. The Umbrella-bird or Cephalopterus ornatus, male (from Brehm).]

It seems now well made out that the great throat pouch of the European male bustard (Otis tarda), and of at least four other species, does not, as was formerly supposed, serve to hold water, but is connected with the utterance during the breeding-season of a peculiar sound resembling “oak.” (43. The following papers have been lately written on this subject: Prof. A. Newton, in the ‘Ibis,’ 1862, p. 107; Dr. Cullen, ibid. 1865, p. 145; Mr. Flower, in ‘Proc. Zool. Soc.’ 1865, p. 747; and Dr. Murie, in ‘Proc. Zool. Soc.’ 1868, p. 471. In this latter paper an excellent figure is given of the male Australian Bustard in full display with the sack distended. It is a singular fact that the sack is not developed in all the males of the same species.) A crow-like bird inhabiting South America (see Cephalopterus ornatus, Fig. 40) is called the umbrella-bird, from its immense top knot, formed of bare white quills surmounted by dark-blue plumes, which it can elevate into a great dome no less than five inches in diameter, covering the whole head. This bird has on its neck a long, thin, cylindrical fleshy appendage, which is thickly clothed with scale-like blue feathers. It probably serves in part as an ornament, but likewise as a resounding apparatus; for Mr. Bates found that it is connected “with an unusual development of the trachea and vocal organs.” It is dilated when the bird utters its singularly deep, loud and long sustained fluty note. The head- crest and neck-appendage are rudimentary in the female. (44. Bates, ‘The Naturalist on the Amazons,’ 1863, vol. ii. p. 284; Wallace, in ‘Proceedings, Zoological Society,’ 1850, p. 206. A new species, with a still larger neck-appendage (C. penduliger), has lately been discovered, see ‘Ibis,’ vol. i. p. 457.)

The vocal organs of various web-footed and wading birds are extraordinarily complex, and differ to a certain extent in the two sexes. In some cases the trachea is convoluted, like a French horn, and is deeply embedded in the sternum. In the wild swan (Cygnus ferus) it is more deeply embedded in the adult male than in the adult female or young male. In the male Merganser the enlarged portion of the trachea is furnished with an additional pair of muscles. (45. Bishop, in Todd’s ‘Cyclopaedia of Anatomy and Physiology,’ vol. iv. p. 1499.) In one of the ducks, however, namely Anas punctata, the bony enlargement is only a little more developed in the male than in the female. (46. Prof. Newton, ‘Proc. Zoolog. Soc.’ 1871, p. 651.) But the meaning of these differences in the trachea of the two sexes of the Anatidae is not understood; for the male is not always the more vociferous; thus with the common duck, the male hisses, whilst the female utters a loud quack. (47. The spoonbill (Platalea) has its trachea convoluted into a figure of eight, and yet this bird (Jerdon, ‘Birds of India,’ vol. iii. p. 763) is mute; but Mr. Blyth informs me that the convolutions are not constantly present, so that perhaps they are now tending towards abortion.) In both sexes of one of the cranes (Grus virgo) the trachea penetrates the sternum, but presents “certain sexual modifications.” In the male of the black stork there is also a well-marked sexual difference in the length and curvature of the bronchi. (48. ‘Elements of Comparative Anatomy,’ by R. Wagner, Eng. translat. 1845, p. 111. With respect to the swan, as given above, Yarrell’s ‘History of British Birds,’ 2nd edition, 1845, vol. iii. p. 193.) Highly important structures have, therefore, in these cases been modified according to sex.

It is often difficult to conjecture whether the many strange cries and notes uttered by male birds during the breeding-season serve as a charm or merely as a call to the female. The soft cooing of the turtle-dove and of many pigeons, it may be presumed, pleases the female. When the female of the wild turkey utters her call in the morning, the male answers by a note which differs from the gobbling noise made, when with erected feathers, rustling wings and distended wattles, he puffs and struts before her. (49. C.L. Bonaparte, quoted in the ‘Naturalist Library: Birds,’ vol. xiv. p. 126.) The spel of the black-cock certainly serves as a call to the female, for it has been known to bring four or five females from a distance to a male under confinement; but as the black-cock continues his spel for hours during successive days, and in the case of the capercailzie “with an agony of passion,” we are led to suppose that the females which are present are thus charmed. (50. L. Lloyd, ‘The Game Birds of Sweden,’ etc., 1867, pp. 22, 81.) The voice of the common rook is known to alter during the breeding-season, and is therefore in some way sexual. (51. Jenner, ‘Philosophical Transactions,’ 1824, p. 20.) But what shall we say about the harsh screams of, for instance, some kinds of macaws; have these birds as bad taste for musical sounds as they apparently have for colour, judging by the inharmonious contrast of their bright yellow and blue plumage? It is indeed possible that without any advantage being thus gained, the loud voices of many male birds may be the result of the inherited effects of the continued use of their vocal organs when excited by the strong passions of love, jealousy and rage; but to this point we shall recur when we treat of quadrupeds.

We have as yet spoken only of the voice, but the males of various birds practise, during their courtship, what may be called instrumental music. Peacocks and Birds of Paradise rattle their quills together. Turkey-cocks scrape their wings against the ground, and some kinds of grouse thus produce a buzzing sound. Another North American grouse, the Tetrao umbellus, when with his tail erect, his ruffs displayed, “he shows off his finery to the females, who lie hid in the neighbourhood,” drums by rapidly striking his wings together above his back, according to Mr. R. Haymond, and not, as Audubon thought, by striking them against his sides. The sound thus produced is compared by some to distant thunder, and by others to the quick roll of a drum. The female never drums, “but flies directly to the place where the male is thus engaged.” The male of the Kalij-pheasant, in the Himalayas, often makes a singular drumming noise with his wings, not unlike the sound produced by shaking a stiff piece of cloth.” On the west coast of Africa the little black-weavers (Ploceus?) congregate in a small party on the bushes round a small open space, and sing and glide through the air with quivering wings, “which make a rapid whirring sound like a child’s rattle.” One bird after another thus performs for hours together, but only during the courting-season. At this season, and at no other time, the males of certain night-jars (Caprimulgus) make a strange booming noise with their wings. The various species of woodpeckers strike a sonorous branch with their beaks, with so rapid a vibratory movement that “the head appears to be in two places at once.” The sound thus produced is audible at a considerable distance but cannot be described; and I feel sure that its source would never be conjectured by any one hearing it for the first time. As this jarring sound is made chiefly during the breeding-season, it has been considered as a love-song; but it is perhaps more strictly a love- call. The female, when driven from her nest, has been observed thus to call her mate, who answered in the same manner and soon appeared. Lastly, the male hoopoe (Upupa epops) combines vocal and instrumental music; for during the breeding-season this bird, as Mr. Swinhoe observed, first draws in air, and then taps the end of its beak perpendicularly down against a stone or the trunk of a tree, “when the breath being forced down the tubular bill produces the correct sound.” If the beak is not thus struck against some object, the sound is quite different. Air is at the same time swallowed, and the oesophagus thus becomes much swollen; and this probably acts as a resonator, not only with the hoopoe, but with pigeons and other birds. (52。 For the foregoing facts see, on Birds of Paradise, Brehm, ‘Thierleben,’ Band iii. s. 325. On Grouse, Richardson, ‘Fauna Bor. Americ.: Birds,’ pp. 343 and 359; Major W. Ross King, ‘The Sportsman in Canada,’ 1866, p. 156; Mr. Haymond, in Prof. Cox’s ‘Geol. Survey of Indiana,’ p. 227; Audubon, ‘American Ornitholog. Biograph.’ vol. i. p. 216. On the Kalij-pheasant, Jerdon, ‘Birds of India,’ vol. III。 p. 533. On the Weavers, Livingstone’s ‘Expedition to the Zambesi,’ 1865, p. 425. On Woodpeckers, Macgillivray, ‘Hist. of British Birds,’ vol. III。 1840页。 84,88,89,和95的。 On the Hoopoe, Mr. Swinhoe, in ‘Proc. 动物园。 Soc.’ June 23, 1863 and 1871, p. 348. On the Night-jar, Audubon, ibid. 飞行。 II。 p. 255, and ‘American Naturalist,’ 1873, p. 672.

[Fig. 41. Outer tail-feather of Scolopax gallinago (from ‘Proc. Zool.
Soc.’ 1858).

Fig. 42. Outer tail-feather of Scolopax frenata.

Fig. 43. Outer tail-feather of Scolopax javensis.]

In the foregoing cases sounds are made by the aid of structures already present and otherwise necessary; but in the following cases certain feathers have been specially modified for the express purpose of producing sounds. The drumming, bleating, neighing, or thundering noise (as expressed by different observers) made by the common snipe (Scolopax gallinago) must have surprised every one who has ever heard it. This bird, during the pairing-season, flies to “perhaps a thousand feet in height,” and after zig-zagging about for a time descends to the earth in a curved line, with outspread tail and quivering pinions, and surprising velocity. The sound is emitted only during this rapid descent. No one was able to explain the cause until M. Meves observed that on each side of the tail the outer feathers are peculiarly formed (Fig. 41), having a stiff sabre-shaped shaft with the oblique barbs of unusual length, the outer webs being strongly bound together. He found that by blowing on these feathers, or by fastening them to a long thin stick and waving them rapidly through the air, he could reproduce the drumming noise made by the living bird. Both sexes are furnished with these feathers, but they are generally larger in the male than in the female, and emit a deeper note. In some species, as in S. frenata (Fig. 42), four feathers, and in S. javensis (Fig. 43), no less than eight on each side of the tail are greatly modified. Different tones are emitted by the feathers of the different species when waved through the air; and the Scolopax Wilsonii of the United States makes a switching noise whilst descending rapidly to the earth. (53. See M. Meves’ interesting paper in ‘Proc. Zool. Soc.’ 1858, p. 199. For the habits of the snipe, Macgillivray, ‘History of British Birds,’ vol. iv. p. 371. For the American snipe, Capt. Blakiston, ‘Ibis,’ vol. v. 1863, p. 131.)

[Fig. 44. Primary wing-feather of a Humming-bird, the Selasphorus platycercus (from a sketch by Mr. Salvin). Upper figure, that of male; lower figure, corresponding feather of female.]

In the male of the Chamaepetes unicolor (a large gallinaceous bird of America), the first primary wing-feather is arched towards the tip and is much more attenuated than in the female. In an allied bird, the Penelope nigra, Mr. Salvin observed a male, which, whilst it flew downwards “with outstretched wings, gave forth a kind of crashing rushing noise,” like the falling of a tree. (54. Mr. Salvin, in ‘Proceedings, Zoological Society,’ 1867, p. 160. I am much indebted to this distinguished ornithologist for sketches of the feathers of the Chamaepetes, and for other information.) The male alone of one of the Indian bustards (Sypheotides auritus) has its primary wing-feathers greatly acuminated; and the male of an allied species is known to make a humming noise whilst courting the female. (55. Jerdon, ‘Birds of India,’ vol. iii. pp. 618, 621.) In a widely different group of birds, namely Humming-birds, the males alone of certain kinds have either the shafts of their primary wing-feathers broadly dilated, or the webs abruptly excised towards the extremity. The male, for instance, of Selasphorus platycercus, when adult, has the first primary wing-feather (Fig. 44), thus excised. Whilst flying from flower to flower he makes “a shrill, almost whistling noise” (56. Gould, ‘Introduction to the Trochilidae,’ 1861, p. 49. Salvin, ‘Proceedings, Zoological Society,’ 1867, p. 160.); but it did not appear to Mr. Salvin that the noise was intentionally made.

[Fig. 45. Secondary wing-feathers of Pipra deliciosa (from Mr. Sclater, in ‘Proc. Zool. Soc.’ 1860). The three upper feathers, a, b, c, from the male; the three lower corresponding feathers, d, e, f, from the female. a and d, fifth secondary wing-feather of male and female, upper surface. b and e, sixth secondary, upper surface. c and f, seventh secondary, lower surface.]

Lastly, in several species of a sub-genus of Pipra or Manakin, the males, as described by Mr. Sclater, have their SECONDARY wing-feathers modified in a still more remarkable manner. In the brilliantly-coloured P. deliciosa the first three secondaries are thick-stemmed and curved towards the body; in the fourth and fifth (Fig. 45, a) the change is greater; and in the sixth and seventh (b, c) the shaft “is thickened to an extraordinary degree, forming a solid horny lump.” The barbs also are greatly changed in shape, in comparison with the corresponding feathers (d, e, f) in the female. Even the bones of the wing, which support these singular feathers in the male, are said by Mr. Fraser to be much thickened. These little birds make an extraordinary noise, the first “sharp note being not unlike the crack of a whip.” (57. Sclater, in ‘Proceedings, Zoological Society,’ 1860, p. 90, and in ‘Ibis,’ vol. iv. 1862, p. 175. Also Salvin, in ‘Ibis,’ 1860, p. 37.)

The diversity of the sounds, both vocal and instrumental, made by the males of many birds during the breeding-season, and the diversity of the means for producing such sounds, are highly remarkable. We thus gain a high idea of their importance for sexual purposes, and are reminded of the conclusion arrived at as to insects. It is not difficult to imagine the steps by which the notes of a bird, primarily used as a mere call or for some other purpose, might have been improved into a melodious love song. In the case of the modified feathers, by which the drumming, whistling, or roaring noises are produced, we know that some birds during their courtship flutter, shake, or rattle their unmodified feathers together; and if the females were led to select the best performers, the males which possessed the strongest or thickest, or most attenuated feathers, situated on any part of the body, would be the most successful; and thus by slow degrees the feathers might be modified to almost any extent. The females, of course, would not notice each slight successive alteration in shape, but only the sounds thus produced. It is a curious fact that in the same class of animals, sounds so different as the drumming of the snipe’s tail, the tapping of the woodpecker’s beak, the harsh trumpet-like cry of certain water-fowl, the cooing of the turtle-dove, and the song of the nightingale, should all be pleasing to the females of the several species. But we must not judge of the tastes of distinct species by a uniform standard; nor must we judge by the standard of man’s taste. Even with man, we should remember what discordant noises, the beating of tom-toms and the shrill notes of reeds, please the ears of savages. Sir S. Baker remarks (58. ‘The Nile Tributaries of Abyssinia,’ 1867, p. 203.), that “as the stomach of the Arab prefers the raw meat and reeking liver taken hot from the animal, so does his ear prefer his equally coarse and discordant music to all other.”

Love Antics and Dances

The curious love gestures of some birds have already been incidentally noticed; so that little need here be added. In Northern America large numbers of a grouse, the Tetrao phasianellus, meet every morning during the breeding-season on a selected level spot, and here they run round and round in a circle of about fifteen or twenty feet in diameter, so that the ground is worn quite bare, like a fairy-ring. In these Partridge-dances, as they are called by the hunters, the birds assume the strangest attitudes, and run round, some to the left and some to the right. Audubon describes the males of a heron (Ardea herodias) as walking about on their long legs with great dignity before the females, bidding defiance to their rivals. With one of the disgusting carrion-vultures (Cathartes jota) the same naturalist states that “the gesticulations and parade of the males at the beginning of the love-season are extremely ludicrous.” Certain birds perform their love-antics on the wing, as we have seen with the black African weaver, instead of on the ground. During the spring our little white-throat (Sylvia cinerea) often rises a few feet or yards in the air above some bush, and “flutters with a fitful and fantastic motion, singing all the while, and then drops to its perch.” The great English bustard throws himself into indescribably odd attitudes whilst courting the female, as has been figured by Wolf. An allied Indian bustard (Otis bengalensis) at such times “rises perpendicularly into the air with a hurried flapping of his wings, raising his crest and puffing out the feathers of his neck and breast, and then drops to the ground;” he repeats this manoeuvre several times, at the same time humming in a peculiar tone. Such females as happen to be near “obey this saltatory summons,” and when they approach he trails his wings and spreads his tail like a turkey-cock. (59. For Tetrao phasianellus, see Richardson, ‘Fauna, Bor. America,’ p. 361, and for further particulars Capt. Blakiston, ‘Ibis,’ 1863, p. 125. For the Cathartes and Ardea, Audubon, ‘Ornithological Biography,’ vol. ii. p. 51, and vol. iii. p. 89. On the White-throat, Macgillivray, ‘History of British Birds,’ vol. ii. p. 354. On the Indian Bustard, Jerdon, ‘Birds of India,’ vol. iii. p. 618.)

[Fig. 46. Bower-bird, Chlamydera maculata, with bower (from Brehm).]

But the most curious case is afforded by three allied genera of Australian birds, the famous Bower-birds,—no doubt the co-descendants of some ancient species which first acquired the strange instinct of constructing bowers for performing their love-antics. The bowers (Fig. 46), which, as we shall hereafter see, are decorated with feathers, shells, bones, and leaves, are built on the ground for the sole purpose of courtship, for their nests are formed in trees. Both sexes assist in the erection of the bowers, but the male is the principal workman. So strong is this instinct that it is practised under confinement, and Mr. Strange has described (60. Gould, ‘Handbook to the Birds of Australia,’ vol. i. pp. 444, 449, 455. The bower of the Satin Bower-bird may be seen in the Zoological Society’s Gardens, Regent’s Park.) the habits of some Satin Bower-birds which he kept in an aviary in New South Wales. “At times the male will chase the female all over the aviary, then go to the bower, pick up a gay feather or a large leaf, utter a curious kind of note, set all his feathers erect, run round the bower and become so excited that his eyes appear ready to start from his head; he continues opening first one wing then the other, uttering a low, whistling note, and, like the domestic cock, seems to be picking up something from the ground, until at last the female goes gently towards him.” Captain Stokes has described the habits and “play-houses” of another species, the Great Bower-bird, which was seen “amusing itself by flying backwards and forwards, taking a shell alternately from each side, and carrying it through the archway in its mouth.” These curious structures, formed solely as halls of assemblage, where both sexes amuse themselves and pay their court, must cost the birds much labour. The bower, for instance, of the Fawn-breasted species, is nearly four feet in length, eighteen inches in height, and is raised on a thick platform of sticks.

装饰

I will first discuss the cases in which the males are ornamented either exclusively or in a much higher degree than the females, and in a succeeding chapter those in which both sexes are equally ornamented, and finally the rare cases in which the female is somewhat more brightly- coloured than the male. As with the artificial ornaments used by savage and civilised men, so with the natural ornaments of birds, the head is the chief seat of decoration. (61. See remarks to this effect, on the ‘Feeling of Beauty among Animals,’ by Mr. J. Shaw, in the ‘Athenaeum,’ Nov. 24th, 1866, p. 681.) The ornaments, as mentioned at the commencement of this chapter, are wonderfully diversified. The plumes on the front or back of the head consist of variously-shaped feathers, sometimes capable of erection or expansion, by which their beautiful colours are fully displayed. Elegant ear-tufts (Fig. 39) are occasionally present. The head is sometimes covered with velvety down, as with the pheasant; or is naked and vividly coloured. The throat, also, is sometimes ornamented with a beard, wattles, or caruncles. Such appendages are generally brightly- coloured, and no doubt serve as ornaments, though not always ornamental in our eyes; for whilst the male is in the act of courting the female, they often swell and assume vivid tints, as in the male turkey. At such times the fleshy appendages about the head of the male Tragopan pheasant (Ceriornis Temminckii) swell into a large lappet on the throat and into two horns, one on each side of the splendid top-knot; and these are then coloured of the most intense blue which I have ever beheld. (62. See Dr. Murie’s account with coloured figures in ‘Proceedings, Zoological Society,’ 1872, p. 730.) The African hornbill (Bucorax abyssinicus) inflates the scarlet bladder-like wattle on its neck, and with its wings drooping and tail expanded “makes quite a grand appearance.” (63. Mr. Monteiro, ‘Ibis,’ vol. iv. 1862, p. 339.) Even the iris of the eye is sometimes more brightly-coloured in the male than in the female; and this is frequently the case with the beak, for instance, in our common blackbird. In Buceros corrugatus, the whole beak and immense casque are coloured more conspicuously in the male than in the female; and “the oblique grooves upon the sides of the lower mandible are peculiar to the male sex.” (64. ‘Land and Water,’ 1868, p. 217.)

The head, again, often supports fleshy appendages, filaments, and solid protuberances. These, if not common to both sexes, are always confined to the males. The solid protuberances have been described in detail by Dr. W. Marshall (65. ‘Ueber die Schädelhöcker,’ etc., ‘Niederland. Archiv. fur Zoologie,’ B. I. Heft 2, 1872.), who shews that they are formed either of cancellated bone coated with skin, or of dermal and other tissues. With mammals true horns are always supported on the frontal bones, but with birds various bones have been modified for this purpose; and in species of the same group the protuberances may have cores of bone, or be quite destitute of them, with intermediate gradations connecting these two extremes. Hence, as Dr. Marshall justly remarks, variations of the most different kinds have served for the development through sexual selection of these ornamental appendages. Elongated feathers or plumes spring from almost every part of the body. The feathers on the throat and breast are sometimes developed into beautiful ruffs and collars. The tail-feathers are frequently increased in length; as we see in the tail-coverts of the peacock, and in the tail itself of the Argus pheasant. With the peacock even the bones of the tail have been modified to support the heavy tail- coverts. (66. Dr. W. Marshall, ‘Über den Vogelschwanz,’ ibid. B. I. Heft 2, 1872.) The body of the Argus is not larger than that of a fowl; yet the length from the end of the beak to the extremity of the tail is no less than five feet three inches (67. Jardine’s ‘Naturalist Library: Birds,’ vol. xiv. p. 166.), and that of the beautifully ocellated secondary wing- feathers nearly three feet. In a small African night-jar (Cosmetornis vexillarius) one of the primary wing-feathers, during the breeding-season, attains a length of twenty-six inches, whilst the bird itself is only ten inches in length. In another closely-allied genus of night-jars, the shafts of the elongated wing-feathers are naked, except at the extremity, where there is a disc. (68. Sclater, in the ‘Ibis,’ vol. vi. 1864, p. 114; Livingstone, ‘Expedition to the Zambesi,’ 1865, p. 66.) Again, in another genus of night-jars, the tail-feathers are even still more prodigiously developed. In general the feathers of the tail are more often elongated than those of the wings, as any great elongation of the latter impedes flight. We thus see that in closely-allied birds ornaments of the same kind have been gained by the males through the development of widely different feathers.

It is a curious fact that the feathers of species belonging to very distinct groups have been modified in almost exactly the same peculiar manner. Thus the wing-feathers in one of the above-mentioned night-jars are bare along the shaft, and terminate in a disc; or are, as they are sometimes called, spoon or racket-shaped. Feathers of this kind occur in the tail of a motmot (Eumomota superciliaris), of a king-fisher, finch, humming-bird, parrot, several Indian drongos (Dicrurus and Edolius, in one of which the disc stands vertically), and in the tail of certain birds of paradise. In these latter birds, similar feathers, beautifully ocellated, ornament the head, as is likewise the case with some gallinaceous birds. In an Indian bustard (Sypheotides auritus) the feathers forming the ear- tufts, which are about four inches in length, also terminate in discs. (69. Jerdon, ‘Birds of India,’ vol. iii. p. 620.) It is a most singular fact that the motmots, as Mr. Salvin has clearly shewn (70. ‘Proceedings, Zoological Society,’ 1873, p. 429.), give to their tail feathers the racket-shape by biting off the barbs, and, further, that this continued mutilation has produced a certain amount of inherited effect.

[Fig. 47. Paradisea Papuana (T.W. Wood).]

Again, the barbs of the feathers in various widely-distinct birds are filamentous or plumose, as with some herons, ibises, birds of paradise, and Gallinaceae. In other cases the barbs disappear, leaving the shafts bare from end to end; and these in the tail of the Paradisea apoda attain a length of thirty-four inches (71. Wallace, in ‘Annals and Magazine of Natural History,’ vol. xx. 1857, p. 416, and in his ‘Malay Archipelago,’ vol. ii. 1869, p. 390.): in P. Papuana (Fig. 47) they are much shorter and thin. Smaller feathers when thus denuded appear like bristles, as on the breast of the turkey-cock. As any fleeting fashion in dress comes to be admired by man, so with birds a change of almost any kind in the structure or colouring of the feathers in the male appears to have been admired by the female. The fact of the feathers in widely distinct groups having been modified in an analogous manner no doubt depends primarily on all the feathers having nearly the same structure and manner of development, and consequently tending to vary in the same manner. We often see a tendency to analogous variability in the plumage of our domestic breeds belonging to distinct species. Thus top-knots have appeared in several species. In an extinct variety of the turkey, the top-knot consisted of bare quills surmounted with plumes of down, so that they somewhat resembled the racket- shaped feathers above described. In certain breeds of the pigeon and fowl the feathers are plumose, with some tendency in the shafts to be naked. In the Sebastopol goose the scapular feathers are greatly elongated, curled, or even spirally twisted, with the margins plumose. (72. See my work on ‘The Variation of Animals and Plants under Domestication,’ vol. i. pp. 289, 293.)

In regard to colour, hardly anything need here be said, for every one knows how splendid are the tints of many birds, and how harmoniously they are combined. The colours are often metallic and iridescent. Circular spots are sometimes surrounded by one or more differently shaded zones, and are thus converted into ocelli. Nor need much be said on the wonderful difference between the sexes of many birds. The common peacock offers a striking instance. Female birds of paradise are obscurely coloured and destitute of all ornaments, whilst the males are probably the most highly decorated of all birds, and in so many different ways that they must be seen to be appreciated. The elongated and golden-orange plumes which spring from beneath the wings of the Paradisea apoda, when vertically erected and made to vibrate, are described as forming a sort of halo, in the centre of which the head “looks like a little emerald sun with its rays formed by the two plumes.” (73. Quoted from M. de Lafresnaye in ‘Annals and Mag. of Natural History,’ vol. xiii. 1854, p. 157: see also Mr. Wallace’s much fuller account in vol. xx. 1857, p. 412, and in his ‘Malay Archipelago.’) In another most beautiful species the head is bald, “and of a rich cobalt blue, crossed by several lines of black velvety feathers.” (74. Wallace, ‘The Malay Archipelago,’ vol. ii. 1869, p. 405.)

[Fig. 48. Lophornis ornatus, male and female (from Brehm).

Fig. 49. Spathura underwoodi, male and female (from Brehm).]

Male humming-birds (Figs. 48 and 49) almost vie with birds of paradise in their beauty, as every one will admit who has seen Mr. Gould’s splendid volumes, or his rich collection. It is very remarkable in how many different ways these birds are ornamented. Almost every part of their plumage has been taken advantage of, and modified; and the modifications have been carried, as Mr. Gould shewed me, to a wonderful extreme in some species belonging to nearly every sub-group. Such cases are curiously like those which we see in our fancy breeds, reared by man for the sake of ornament; certain individuals originally varied in one character, and other individuals of the same species in other characters; and these have been seized on by man and much augmented—as shewn by the tail of the fantail- pigeon, the hood of the jacobin, the beak and wattle of the carrier, and so forth. The sole difference between these cases is that in the one, the result is due to man’s selection, whilst in the other, as with humming- birds, birds of paradise, etc., it is due to the selection by the females of the more beautiful males.

I will mention only one other bird, remarkable from the extreme contrast in colour between the sexes, namely the famous bell-bird (Chasmorhynchus niveus) of S. America, the note of which can be distinguished at the distance of nearly three miles, and astonishes every one when first hearing it. The male is pure white, whilst the female is dusky-green; and white is a very rare colour in terrestrial species of moderate size and inoffensive habits. The male, also, as described by Waterton, has a spiral tube, nearly three inches in length, which rises from the base of the beak. It is jet-black, dotted over with minute downy feathers. This tube can be inflated with air, through a communication with the palate; and when not inflated hangs down on one side. The genus consists of four species, the males of which are very distinct, whilst the females, as described by Mr. Sclater in a very interesting paper, closely resemble each other, thus offering an excellent instance of the common rule that within the same group the males differ much more from each other than do the females. In a second species (C. nudicollis) the male is likewise snow-white, with the exception of a large space of naked skin on the throat and round the eyes, which during the breeding-season is of a fine green colour. In a third species (C. tricarunculatus) the head and neck alone of the male are white, the rest of the body being chestnut-brown, and the male of this species is provided with three filamentous projections half as long as the body—one rising from the base of the beak, and the two others from the corners of the mouth. (75. Mr. Sclater, ‘Intellectual Observer,’ Jan. 1867. Waterton’s ‘Wanderings,’ p. 118. See also Mr. Salvin’s interesting paper, with a plate, in the ‘Ibis,’ 1865, p. 90.)

The coloured plumage and certain other ornaments of the adult males are either retained for life, or are periodically renewed during the summer and breeding-season. At this same season the beak and naked skin about the head frequently change colour, as with some herons, ibises, gulls, one of the bell-birds just noticed, etc. In the white ibis, the cheeks, the inflatable skin of the throat, and the basal portion of the beak then become crimson. (76. ‘Land and Water,’ 1867, p. 394.) In one of the rails, Gallicrex cristatus, a large red caruncle is developed during this period on the head of the male. So it is with a thin horny crest on the beak of one of the pelicans, P. erythrorhynchus; for, after the breeding- season, these horny crests are shed, like horns from the heads of stags, and the shore of an island in a lake in Nevada was found covered with these curious exuviae. (77. Mr. D.G. Elliot, in ‘Proc. Zool. Soc.’ 1869, p. 589.)

Changes of colour in the plumage according to the season depend, firstly on a double annual moult, secondly on an actual change of colour in the feathers themselves, and thirdly on their dull-coloured margins being periodically shed, or on these three processes more or less combined. The shedding of the deciduary margins may be compared with the shedding of their down by very young birds; for the down in most cases arises from the summits of the first true feathers. (78. Nitzsch’s ‘Pterylography,’ edited by P.L. Sclater, Ray Society, 1867, p. 14.)

With respect to the birds which annually undergo a double moult, there are, firstly, some kinds, for instance snipes, swallow-plovers (Glareolae), and curlews, in which the two sexes resemble each other, and do not change colour at any season. I do not know whether the winter plumage is thicker and warmer than the summer plumage, but warmth seems the most probable end attained of a double moult, where there is no change of colour. Secondly, there are birds, for instance, certain species of Totanus and other Grallatores, the sexes of which resemble each other, but in which the summer and winter plumage differ slightly in colour. The difference, however, in these cases is so small that it can hardly be an advantage to them; and it may, perhaps, be attributed to the direct action of the different conditions to which the birds are exposed during the two seasons. Thirdly, there are many other birds the sexes of which are alike, but which are widely different in their summer and winter plumage. Fourthly, there are birds the sexes of which differ from each other in colour; but the females, though moulting twice, retain the same colours throughout the year, whilst the males undergo a change of colour, sometimes a great one, as with certain bustards. Fifthly and lastly, there are birds the sexes of which differ from each other in both their summer and winter plumage; but the male undergoes a greater amount of change at each recurrent season than the female—of which the ruff (Machetes pugnax) offers a good instance.

With respect to the cause or purpose of the differences in colour between the summer and winter plumage, this may in some instances, as with the ptarmigan (79. The brown mottled summer plumage of the ptarmigan is of as much importance to it, as a protection, as the white winter plumage; for in Scandinavia during the spring, when the snow has disappeared, this bird is known to suffer greatly from birds of prey, before it has acquired its summer dress: see Wilhelm von Wright, in Lloyd, ‘Game Birds of Sweden,’ 1867, p. 125.), serve during both seasons as a protection. When the difference between the two plumages is slight it may perhaps be attributed, as already remarked, to the direct action of the conditions of life. But with many birds there can hardly be a doubt that the summer plumage is ornamental, even when both sexes are alike. We may conclude that this is the case with many herons, egrets, etc., for they acquire their beautiful plumes only during the breeding-season. Moreover, such plumes, top-knots, etc., though possessed by both sexes, are occasionally a little more developed in the male than in the female; and they resemble the plumes and ornaments possessed by the males alone of other birds. It is also known that confinement, by affecting the reproductive system of male birds, frequently checks the development of their secondary sexual characters, but has no immediate influence on any other characters; and I am informed by Mr. Bartlett that eight or nine specimens of the Knot (Tringa canutus) retained their unadorned winter plumage in the Zoological Gardens throughout the year, from which fact we may infer that the summer plumage, though common to both sexes, partakes of the nature of the exclusively masculine plumage of many other birds. (80. In regard to the previous statements on moulting, see, on snipes, etc., Macgillivray, ‘Hist. Brit. Birds,’ vol. iv. p. 371; on Glareolae, curlews, and bustards, Jerdon, ‘Birds of India,’ vol. iii. pp. 615, 630, 683; on Totanus, ibid. p. 700; on the plumes of herons, ibid. p. 738, and Macgillivray, vol. iv. pp. 435 and 444, and Mr. Stafford Allen, in the ‘Ibis,’ vol. v. 1863, p. 33.)

From the foregoing facts, more especially from neither sex of certain birds changing colour during either annual moult, or changing so slightly that the change can hardly be of any service to them, and from the females of other species moulting twice yet retaining the same colours throughout the year, we may conclude that the habit of annually moulting twice has not been acquired in order that the male should assume an ornamental character during the breeding-season; but that the double moult, having been originally acquired for some distinct purpose, has subsequently been taken advantage of in certain cases for gaining a nuptial plumage.

It appears at first sight a surprising circumstance that some closely- allied species should regularly undergo a double annual moult, and others only a single one. The ptarmigan, for instance, moults twice or even thrice in the year, and the blackcock only once: some of the splendidly coloured honey-suckers (Nectariniae) of India and some sub-genera of obscurely coloured pipits (Anthus) have a double, whilst others have only a single annual moult. (81。 On the moulting of the ptarmigan, see Gould’s ‘Birds of Great Britain.’ On the honey-suckers, Jerdon, ‘Birds of India,’ vol. i. 第 359,365,369。 On the moulting of Anthus, see Blyth, in ‘Ibis,’ 1867, p. 32.) But the gradations in the manner of moulting, which are known to occur with various birds, shew us how species, or whole groups, might have originally acquired their double annual moult, or having once gained the habit, have again lost it. With certain bustards and plovers the vernal moult is far from complete, some feathers being renewed, and some changed in colour. There is also reason to believe that with certain bustards and rail-like birds, which properly undergo a double moult, some of the older males retain their nuptial plumage throughout the year. A few highly modified feathers may merely be added during the spring to the plumage, as occurs with the disc-formed tail-feathers of certain drongos (Bhringa) in India, and with the elongated feathers on the back, neck, and crest of certain herons. By such steps as these, the vernal moult might be rendered more and more complete, until a perfect double moult was acquired. Some of the birds of paradise retain their nuptial feathers throughout the year, and thus have only a single moult; others cast them directly after the breeding-season, and thus have a double moult; and others again cast them at this season during the first year, but not afterwards; so that these latter species are intermediate in their manner of moulting. There is also a great difference with many birds in the length of time during which the two annual plumages are retained; so that the one might come to be retained for the whole year, and the other completely lost. Thus in the spring Machetes pugnax retains his ruff for barely two months. In Natal the male widow-bird (Chera progne) acquires his fine plumage and long tail-feathers in December or January, and loses them in March; so that they are retained only for about three months. Most species, which undergo a double moult, keep their ornamental feathers for about six months. The male, however, of the wild Gallus bankiva retains his neck-hackles for nine or ten months; and when these are cast off, the underlying black feathers on the neck are fully exposed to view. But with the domesticated descendant of this species, the neck-hackles of the male are immediately replaced by new ones; so that we here see, as to part of the plumage, a double moult changed under domestication into a single moult. (82。 For the foregoing statements in regard to partial moults, and on old males retaining their nuptial plumage, see Jerdon, on bustards and plovers, in ‘Birds of India,’ vol. III。 第 617,637,709,711。 Also Blyth in ‘Land and Water,’ 1867, p. 84. On the moulting of Paradisea, see an interesting article by Dr. W. Marshall, ‘Archives Neerlandaises,’ tom. vi. 1871. On the Vidua, ‘Ibis,’ vol. III。 1861。 133. On the Drongo- shrikes, Jerdon, ibid. 飞行。 i. p. 435. On the vernal moult of the Herodias bubulcus, Mr. SS Allen, in ‘Ibis,’ 1863, p. 33. On Gallus bankiva, Blyth, in ‘Annals and Mag. of Natural History,’ vol. i. 1848。 455; see, also, on this subject, my ‘Variation of Animals under Domestication,’ vol. i. p.

The common drake (Anas boschas), after the breeding-season, is well known to lose his male plumage for a period of three months, during which time he assumes that of the female. The male pin-tail duck (Anas acuta) loses his plumage for the shorter period of six weeks or two months; and Montagu remarks that “this double moult within so short a time is a most extraordinary circumstance, that seems to bid defiance to all human reasoning.” But the believer in the gradual modification of species will be far from feeling surprise at finding gradations of all kinds. If the male pin-tail were to acquire his new plumage within a still shorter period, the new male feathers would almost necessarily be mingled with the old, and both with some proper to the female; and this apparently is the case with the male of a not distantly-allied bird, namely the Merganser serrator, for the males are said to “undergo a change of plumage, which assimilates them in some measure to the female.” By a little further acceleration in the process, the double moult would be completely lost. (83. See Macgillivray, ‘Hist. British Birds’ (vol. v. pp. 34, 70, and 223), on the moulting of the Anatidae, with quotations from Waterton and Montagu. Also Yarrell, ‘History of British Birds,’ vol. iii. p. 243.)

Some male birds, as before stated, become more brightly coloured in the spring, not by a vernal moult, but either by an actual change of colour in the feathers, or by their obscurely-coloured deciduary margins being shed. Changes of colour thus caused may last for a longer or shorter time. In the Pelecanus onocrotalus a beautiful rosy tint, with lemon-coloured marks on the breast, overspreads the whole plumage in the spring; but these tints, as Mr. Sclater states, “do not last long, disappearing generally in about six weeks or two months after they have been attained.” Certain finches shed the margins of their feathers in the spring, and then become brighter coloured, while other finches undergo no such change. Thus the Fringilla tristis of the United States (as well as many other American species) exhibits its bright colours only when the winter is past, whilst our goldfinch, which exactly represents this bird in habits, and our siskin, which represents it still more closely in structure, undergo no such annual change. But a difference of this kind in the plumage of allied species is not surprising, for with the common linnet, which belongs to the same family, the crimson forehead and breast are displayed only during the summer in England, whilst in Madeira these colours are retained throughout the year. (84. On the pelican, see Sclater, in ‘Proc. Zool. Soc.’ 1868, p. 265. On the American finches, see Audubon, ‘Ornithological Biography,’ vol. i. pp. 174, 221, and Jerdon, ‘Birds of India,’ vol. ii. p. 383. On the Fringilla cannabina of Madeira, Mr. E. Vernon Harcourt, ‘Ibis,’ vol. v. 1863, p. 230.)

Display by Male Birds of Their Plumage

Ornaments of all kinds, whether permanently or temporarily gained, are sedulously displayed by the males, and apparently serve to excite, attract, or fascinate the females. But the males will sometimes display their ornaments, when not in the presence of the females, as occasionally occurs with grouse at their balz-places, and as may be noticed with the peacock; this latter bird, however, evidently wishes for a spectator of some kind, and, as I have often seen, will shew off his finery before poultry, or even pigs. (85. See also ‘Ornamental Poultry,’ by Rev. E.S. Dixon, 1848, p. 8.) All naturalists who have closely attended to the habits of birds, whether in a state of nature or under confinement, are unanimously of opinion that the males take delight in displaying their beauty. Audubon frequently speaks of the male as endeavouring in various ways to charm the female. Mr. Gould, after describing some peculiarities in a male humming- bird, says he has no doubt that it has the power of displaying them to the greatest advantage before the female. Dr. Jerdon (86. ‘Birds of India,’ introduct., vol. i. p. xxiv.; on the peacock, vol. iii. p. 507. See Gould’s ‘Introduction to Trochilidae,’ 1861, pp. 15 and 111.) insists that the beautiful plumage of the male serves “to fascinate and attract the female.” Mr. Bartlett, at the Zoological Gardens, expressed himself to me in the strongest terms to the same effect.

[Fig. 50. Rupicola crocea, male (T.W. Wood).]

It must be a grand sight in the forests of India “to come suddenly on twenty or thirty pea-fowl, the males displaying their gorgeous trains, and strutting about in all the pomp of pride before the gratified females.” The wild turkey-cock erects his glittering plumage, expands his finely- zoned tail and barred wing-feathers, and altogether, with his crimson and blue wattles, makes a superb, though, to our eyes, grotesque appearance. Similar facts have already been given with respect to grouse of various kinds. Turning to another Order: The male Rupicola crocea (Fig. 50) is one of the most beautiful birds in the world, being of a splendid orange, with some of the feathers curiously truncated and plumose. The female is brownish-green, shaded with red, and has a much smaller crest. Sir R. Schomburgk has described their courtship; he found one of their meeting- places where ten males and two females were present. The space was from four to five feet in diameter, and appeared to have been cleared of every blade of grass and smoothed as if by human hands. A male “was capering, to the apparent delight of several others. Now spreading its wings, throwing up its head, or opening its tail like a fan; now strutting about with a hopping gait until tired, when it gabbled some kind of note, and was relieved by another. Thus three of them successively took the field, and then, with self-approbation, withdrew to rest.” The Indians, in order to obtain their skins, wait at one of the meeting-places till the birds are eagerly engaged in dancing, and then are able to kill with their poisoned arrows four or five males, one after the other. (87. ‘Journal of R. Geograph. Soc.’ vol. x. 1840, p. 236.) With birds of paradise a dozen or more full-plumaged males congregate in a tree to hold a dancing-party, as it is called by the natives: and here they fly about, raise their wings, elevate their exquisite plumes, and make them vibrate, and the whole tree seems, as Mr. Wallace remarks, to be filled with waving plumes. When thus engaged, they become so absorbed that a skilful archer may shoot nearly the whole party. These birds, when kept in confinement in the Malay Archipelago, are said to take much care in keeping their feathers clean; often spreading them out, examining them, and removing every speck of dirt. One observer, who kept several pairs alive, did not doubt that the display of the male was intended to please the female. (88. ‘Annals and Mag. of Nat. Hist.’ vol. xiii. 1854, p. 157; also Wallace, ibid. vol. xx. 1857, p. 412, and ‘The Malay Archipelago,’ vol. ii. 1869, p. 252. Also Dr. Bennett, as quoted by Brehm, ‘Thierleben,’ B. iii. s. 326.)

[Fig. 51. Polyplectron chinquis, male (T.W. Wood).]

The Gold and Amherst pheasants during their courtship not only expand and raise their splendid frills, but twist them, as I have myself seen, obliquely towards the female on whichever side she may be standing, obviously in order that a large surface may be displayed before her. (89. Mr. T.W. Wood has given (‘The Student,’ April 1870, p. 115) a full account of this manner of display, by the Gold pheasant and by the Japanese pheasant, Ph. versicolor; and he calls it the lateral or one-sided display.) They likewise turn their beautiful tails and tail-coverts a little towards the same side. Mr. Bartlett has observed a male Polyplectron (Fig. 51) in the act of courtship, and has shewn me a specimen stuffed in the attitude then assumed. The tail and wing-feathers of this bird are ornamented with beautiful ocelli, like those on the peacock’s train. Now when the peacock displays himself, he expands and erects his tail transversely to his body, for he stands in front of the female, and has to shew off, at the same time, his rich blue throat and breast. But the breast of the Polyplectron is obscurely coloured, and the ocelli are not confined to the tail-feathers. Consequently the Polyplectron does not stand in front of the female; but he erects and expands his tail-feathers a little obliquely, lowering the expanded wing on the same side, and raising that on the opposite side. In this attitude the ocelli over the whole body are exposed at the same time before the eyes of the admiring female in one grand bespangled expanse. To whichever side she may turn, the expanded wings and the obliquely-held tail are turned towards her. The male Tragopan pheasant acts in nearly the same manner, for he raises the feathers of the body, though not the wing itself, on the side which is opposite to the female, and which would otherwise be concealed, so that nearly all the beautifully spotted feathers are exhibited at the same time.

[Fig. 52. Side view of male Argus pheasant, whilst displaying before the female. Observed and sketched from nature by T.W. Wood.]

The Argus pheasant affords a much more remarkable case. The immensely developed secondary wing-feathers are confined to the male; and each is ornamented with a row of from twenty to twenty-three ocelli, above an inch in diameter. These feathers are also elegantly marked with oblique stripes and rows of spots of a dark colour, like those on the skin of a tiger and leopard combined. These beautiful ornaments are hidden until the male shows himself off before the female. He then erects his tail, and expands his wing-feathers into a great, almost upright, circular fan or shield, which is carried in front of the body. The neck and head are held on one side, so that they are concealed by the fan; but the bird in order to see the female, before whom he is displaying himself, sometimes pushes his head between two of the long wing-feathers (as Mr. Bartlett has seen), and then presents a grotesque appearance. This must be a frequent habit with the bird in a state of nature, for Mr. Bartlett and his son on examining some perfect skins sent from the East, found a place between two of the feathers which was much frayed, as if the head had here frequently been pushed through. Mr. Wood thinks that the male can also peep at the female on one side, beyond the margin of the fan.

The ocelli on the wing-feathers are wonderful objects; for they are so shaded that, as the Duke of Argyll remarks (90. ‘The Reign of Law,’ 1867, p. 203.), they stand out like balls lying loosely within sockets. When I looked at the specimen in the British Museum, which is mounted with the wings expanded and trailing downwards, I was however greatly disappointed, for the ocelli appeared flat, or even concave. But Mr. Gould soon made the case clear to me, for he held the feathers erect, in the position in which they would naturally be displayed, and now, from the light shining on them from above, each ocellus at once resembled the ornament called a ball and socket. These feathers have been shown to several artists, and all have expressed their admiration at the perfect shading. It may well be asked, could such artistically shaded ornaments have been formed by means of sexual selection? But it will be convenient to defer giving an answer to this question until we treat in the next chapter of the principle of gradation.

The foregoing remarks relate to the secondary wing-feathers, but the primary wing-feathers, which in most gallinaceous birds are uniformly coloured, are in the Argus pheasant equally wonderful. They are of a soft brown tint with numerous dark spots, each of which consists of two or three black dots with a surrounding dark zone. But the chief ornament is a space parallel to the dark-blue shaft, which in outline forms a perfect second feather lying within the true feather. This inner part is coloured of a lighter chestnut, and is thickly dotted with minute white points. I have shewn this feather to several persons, and many have admired it even more than the ball and socket feathers, and have declared that it was more like a work of art than of nature. Now these feathers are quite hidden on all ordinary occasions, but are fully displayed, together with the long secondary feathers, when they are all expanded together so as to form the great fan or shield.

The case of the male Argus pheasant is eminently interesting, because it affords good evidence that the most refined beauty may serve as a sexual charm, and for no other purpose. We must conclude that this is the case, as the secondary and primary wing-feathers are not at all displayed, and the ball and socket ornaments are not exhibited in full perfection until the male assumes the attitude of courtship. The Argus pheasant does not possess brilliant colours, so that his success in love appears to depend on the great size of his plumes, and on the elaboration of the most elegant patterns. Many will declare that it is utterly incredible that a female bird should be able to appreciate fine shading and exquisite patterns. It is undoubtedly a marvellous fact that she should possess this almost human degree of taste. He who thinks that he can safely gauge the discrimination and taste of the lower animals may deny that the female Argus pheasant can appreciate such refined beauty; but he will then be compelled to admit that the extraordinary attitudes assumed by the male during the act of courtship, by which the wonderful beauty of his plumage is fully displayed, are purposeless; and this is a conclusion which I for one will never admit.

Although so many pheasants and allied gallinaceous birds carefully display their plumage before the females, it is remarkable, as Mr. Bartlett informs me, that this is not the case with the dull-coloured Eared and Cheer pheasants (Crossoptilon auritum and Phasianus wallichii); so that these birds seem conscious that they have little beauty to display. Mr. Bartlett has never seen the males of either of these species fighting together, though he has not had such good opportunities for observing the Cheer as the Eared pheasant. Mr. Jenner Weir, also, finds that all male birds with rich or strongly-characterised plumage are more quarrelsome than the dull- coloured species belonging to the same groups. The goldfinch, for instance, is far more pugnacious than the linnet, and the blackbird than the thrush. Those birds which undergo a seasonal change of plumage likewise become much more pugnacious at the period when they are most gaily ornamented. No doubt the males of some obscurely-coloured birds fight desperately together, but it appears that when sexual selection has been highly influential, and has given bright colours to the males of any species, it has also very often given a strong tendency to pugnacity. We shall meet with nearly analogous cases when we treat of mammals. On the other hand, with birds the power of song and brilliant colours have rarely been both acquired by the males of the same species; but in this case the advantage gained would have been the same, namely success in charming the female. Nevertheless it must be owned that the males of several brilliantly coloured birds have had their feathers specially modified for the sake of producing instrumental music, though the beauty of this cannot be compared, at least according to our taste, with that of the vocal music of many songsters.

We will now turn to male birds which are not ornamented in any high degree, but which nevertheless display during their courtship whatever attractions they may possess. These cases are in some respects more curious than the foregoing, and have been but little noticed. I owe the following facts to Mr. Weir, who has long kept confined birds of many kinds, including all the British Fringillidae and Emberizidae. The facts have been selected from a large body of valuable notes kindly sent me by him. The bullfinch makes his advances in front of the female, and then puffs out his breast, so that many more of the crimson feathers are seen at once than otherwise would be the case. At the same time he twists and bows his black tail from side to side in a ludicrous manner. The male chaffinch also stands in front of the female, thus shewing his red breast and “blue bell,” as the fanciers call his head; the wings at the same time being slightly expanded, with the pure white bands on the shoulders thus rendered conspicuous. The common linnet distends his rosy breast, slightly expands his brown wings and tail, so as to make the best of them by exhibiting their white edgings. We must, however, be cautious in concluding that the wings are spread out solely for display, as some birds do so whose wings are not beautiful. This is the case with the domestic cock, but it is always the wing on the side opposite to the female which is expanded, and at the same time scraped on the ground. The male goldfinch behaves differently from all other finches: his wings are beautiful, the shoulders being black, with the dark-tipped wing-feathers spotted with white and edged with golden yellow. When he courts the female, he sways his body from side to side, and quickly turns his slightly expanded wings first to one side, then to the other, with a golden flashing effect. Mr. Weir informs me that no other British finch turns thus from side to side during his courtship, not even the closely- allied male siskin, for he would not thus add to his beauty.

Most of the British Buntings are plain coloured birds; but in the spring the feathers on the head of the male reed-bunting (Emberiza schoeniculus) acquire a fine black colour by the abrasion of the dusky tips; and these are erected during the act of courtship. Mr. Weir has kept two species of Amadina from Australia: the A. castanotis is a very small and chastely coloured finch, with a dark tail, white rump, and jet-black upper tail- coverts, each of the latter being marked with three large conspicuous oval spots of white. (91. For the description of these birds, see Gould’s ‘Handbook to the Birds of Australia,’ vol. i. 1865, p. 417.) This species, when courting the female, slightly spreads out and vibrates these parti- coloured tail-coverts in a very peculiar manner. The male Amadina Lathami behaves very differently, exhibiting before the female his brilliantly spotted breast, scarlet rump, and scarlet upper tail-coverts. I may here add from Dr. Jerdon that the Indian bulbul (Pycnonotus hoemorrhous) has its under tail-coverts of a crimson colour, and these, it might be thought, could never be well exhibited; but the bird “when excited often spreads them out laterally, so that they can be seen even from above.” (92. ‘Birds of India,’ vol. ii. p. 96.) The crimson under tail-coverts of some other birds, as with one of the woodpeckers, Picus major, can be seen without any such display. The common pigeon has iridescent feathers on the breast, and every one must have seen how the male inflates his breast whilst courting the female, thus shewing them off to the best advantage. One of the beautiful bronze-winged pigeons of Australia (Ocyphaps lophotes) behaves, as described to me by Mr. Weir, very differently: the male, whilst standing before the female, lowers his head almost to the ground, spreads out and raises his tail, and half expands his wings. He then alternately and slowly raises and depresses his body, so that the iridescent metallic feathers are all seen at once, and glitter in the sun.

Sufficient facts have now been given to shew with what care male birds display their various charms, and this they do with the utmost skill. Whilst preening their feathers, they have frequent opportunities for admiring themselves, and of studying how best to exhibit their beauty. But as all the males of the same species display themselves in exactly the same manner, it appears that actions, at first perhaps intentional, have become instinctive. If so, we ought not to accuse birds of conscious vanity; yet when we see a peacock strutting about, with expanded and quivering tail- feathers, he seems the very emblem of pride and vanity.

The various ornaments possessed by the males are certainly of the highest importance to them, for in some cases they have been acquired at the expense of greatly impeded powers of flight or of running. The African night-jar (Cosmetornis), which during the pairing-season has one of its primary wing-feathers developed into a streamer of very great length, is thereby much retarded in its flight, although at other times remarkable for its swiftness. The “unwieldy size” of the secondary wing-feathers of the male Argus pheasant is said “almost entirely to deprive the bird of flight.” The fine plumes of male birds of paradise trouble them during a high wind. The extremely long tail-feathers of the male widow-birds (Vidua) of Southern Africa render “their flight heavy;” but as soon as these are cast off they fly as well as the females. As birds always breed when food is abundant, the males probably do not suffer much inconvenience in searching for food from their impeded powers of movement; but there can hardly be a doubt that they must be much more liable to be struck down by birds of prey. Nor can we doubt that the long train of the peacock and the long tail and wing-feathers of the Argus pheasant must render them an easier prey to any prowling tiger-cat than would otherwise be the case. Even the bright colours of many male birds cannot fail to make them conspicuous to their enemies of all kinds. Hence, as Mr. Gould has remarked, it probably is that such birds are generally of a shy disposition, as if conscious that their beauty was a source of danger, and are much more difficult to discover or approach, than the sombre coloured and comparatively tame females or than the young and as yet unadorned males. (93. On the Cosmetornis, see Livingstone’s ‘Expedition to the Zambesi,’ 1865, p. 66. On the Argus pheasant, Jardine’s ‘Nat. Hist. Lib.: Birds,’ vol. xiv. p. 167. On Birds of Paradise, Lesson, quoted by Brehm, ‘Thierleben,’ B. iii. s. 325. On the widow-bird, Barrow’s ‘Travels in Africa,’ vol. i. p. 243, and ‘Ibis,’ vol. iii. 1861 p. 133. Mr. Gould, on the shyness of male birds, ‘Handbook to Birds of Australia,’ vol. i. 1865, pp. 210, 457.)

It is a more curious fact that the males of some birds which are provided with special weapons for battle, and which in a state of nature are so pugnacious that they often kill each other, suffer from possessing certain ornaments. Cock-fighters trim the hackles and cut off the combs and gills of their cocks; and the birds are then said to be dubbed. An undubbed bird, as Mr. Tegetmeier insists, “is at a fearful disadvantage; the comb and gills offer an easy hold to his adversary’s beak, and as a cock always strikes where he holds, when once he has seized his foe, he has him entirely in his power. Even supposing that the bird is not killed, the loss of blood suffered by an undubbed cock is much greater than that sustained by one that has been trimmed.” (94. Tegetmeier, ‘The Poultry Book,’ 1866, p. 139.) Young turkey-cocks in fighting always seize hold of each other’s wattles; and I presume that the old birds fight in the same manner. It may perhaps be objected that the comb and wattles are not ornamental, and cannot be of service to the birds in this way; but even to our eyes, the beauty of the glossy black Spanish cock is much enhanced by his white face and crimson comb; and no one who has ever seen the splendid blue wattles of the male Tragopan pheasant distended in courtship can for a moment doubt that beauty is the object gained. From the foregoing facts we clearly see that the plumes and other ornaments of the males must be of the highest importance to them; and we further see that beauty is even sometimes more important than success in battle.

第十四章 •17,100字
鸟类——续

Choice exerted by the female—Length of courtship—Unpaired birds—Mental qualities and taste for the beautiful—Preference or antipathy shewn by the female for particular males—Variability of birds—Variations sometimes abrupt—Laws of variation—Formation of ocelli—Gradations of character— Case of Peacock, Argus pheasant, and Urosticte.

When the sexes differ in beauty or in the power of singing, or in producing what I have called instrumental music, it is almost invariably the male who surpasses the female. These qualities, as we have just seen, are evidently of high importance to the male. When they are gained for only a part of the year it is always before the breeding-season. It is the male alone who elaborately displays his varied attractions, and often performs strange antics on the ground or in the air, in the presence of the female. Each male drives away, or if he can, kills his rivals. Hence we may conclude that it is the object of the male to induce the female to pair with him, and for this purpose he tries to excite or charm her in various ways; and this is the opinion of all those who have carefully studied the habits of living birds. But there remains a question which has an all important bearing on sexual selection, namely, does every male of the same species excite and attract the female equally? Or does she exert a choice, and prefer certain males? This latter question can be answered in the affirmative by much direct and indirect evidence. It is far more difficult to decide what qualities determine the choice of the females; but here again we have some direct and indirect evidence that it is to a large extent the external attractions of the male; though no doubt his vigour, courage, and other mental qualities come into play. We will begin with the indirect evidence.

Length of Courtship

The lengthened period during which both sexes of certain birds meet day after day at an appointed place probably depends partly on the courtship being a prolonged affair, and partly on reiteration in the act of pairing. Thus in Germany and Scandinavia the balzen or leks of the black-cocks last from the middle of March, all through April into May. As many as forty or fifty, or even more birds congregate at the leks; and the same place is often frequented during successive years. The lek of the capercailzie lasts from the end of March to the middle or even end of May. In North America “the partridge dances” of the Tetrao phasianellus “last for a month or more.” Other kinds of grouse, both in North America and Eastern Siberia (1. Nordman describes (‘Bull. Soc. Imp. des Nat. Moscou,’ 1861, tom. xxxiv. p. 264) the balzen of Tetrao urogalloides in Amur Land. He estimated the number of birds assembled at above a hundred, not counting the females, which lie hid in the surrounding bushes. The noises uttered differ from those of T. urogallus.), follow nearly the same habits. The fowlers discover the hillocks where the ruffs congregate by the grass being trampled bare, and this shews that the same spot is long frequented. The Indians of Guiana are well acquainted with the cleared arenas, where they expect to find the beautiful cocks of the Rock; and the natives of New Guinea know the trees where from ten to twenty male birds of paradise in full plumage congregate. In this latter case it is not expressly stated that the females meet on the same trees, but the hunters, if not specially asked, would probably not mention their presence, as their skins are valueless. Small parties of an African weaver (Ploceus) congregate, during the breeding-season, and perform for hours their graceful evolutions. Large numbers of the Solitary snipe (Scolopax major) assemble during dusk in a morass; and the same place is frequented for the same purpose during successive years; here they may be seen running about “like so many large rats,” puffing out their feathers, flapping their wings, and uttering the strangest cries. (2. With respect to the assemblages of the above named grouse, see Brehm, ‘Thierleben,’ B. iv. s. 350; also L. Lloyd, ‘Game Birds of Sweden,’ 1867, pp. 19, 78. Richardson, ‘Fauna Bor. Americana: Birds,’ p. 362. References in regard to the assemblages of other birds have already been given. On Paradisea, see Wallace, in ‘Annals and Mag. of Nat. Hist.’ vol. xx. 1857, p. 412. On the snipe, Lloyd, ibid. p. 221.)

Some of the above birds,—the black-cock, capercailzie, pheasant-grouse, ruff, solitary snipe, and perhaps others,—are, as is believed, polygamists. With such birds it might have been thought that the stronger males would simply have driven away the weaker, and then at once have taken possession of as many females as possible; but if it be indispensable for the male to excite or please the female, we can understand the length of the courtship and the congregation of so many individuals of both sexes at the same spot. Certain strictly monogamous species likewise hold nuptial assemblages; this seems to be the case in Scandinavia with one of the ptarmigans, and their leks last from the middle of March to the middle of May. In Australia the lyre-bird (Menura superba) forms “small round hillocks,” and the M. Alberti scratches for itself shallow holes, or, as they are called by the natives, “corroborying places,” where it is believed both sexes assemble. The meetings of the M. superba are sometimes very large; and an account has lately been published (3. Quoted by Mr. T.W. Wood, in the ‘Student,’ April 1870, p. 125.) by a traveller, who heard in a valley beneath him, thickly covered with scrub, “a din which completely astonished” him; on crawling onwards he beheld, to his amazement, about one hundred and fifty of the magnificent lyre-cocks, “ranged in order of battle, and fighting with indescribable fury.” The bowers of the Bower- birds are the resort of both sexes during the breeding-season; and “here the males meet and contend with each other for the favours of the female, and here the latter assemble and coquet with the males.” With two of the genera, the same bower is resorted to during many years. (4. Gould, ‘Handbook to the Birds of Australia,’ vol. i. pp. 300, 308, 448, 451. On the ptarmigan, above alluded to, see Lloyd, ibid. p. 129.)

The common magpie (Corvus pica, Linn.), as I have been informed by the Rev. W. Darwin Fox, used to assemble from all parts of Delamere Forest, in order to celebrate the “great magpie marriage.” Some years ago these birds abounded in extraordinary numbers, so that a gamekeeper killed in one morning nineteen males, and another killed by a single shot seven birds at roost together. They then had the habit of assembling very early in the spring at particular spots, where they could be seen in flocks, chattering, sometimes fighting, bustling and flying about the trees. The whole affair was evidently considered by the birds as one of the highest importance. Shortly after the meeting they all separated, and were then observed by Mr. Fox and others to be paired for the season. In any district in which a species does not exist in large numbers, great assemblages cannot, of course, be held, and the same species may have different habits in different countries. For instance, I have heard of only one instance, from Mr. Wedderburn, of a regular assemblage of black game in Scotland, yet these assemblages are so well known in Germany and Scandinavia that they have received special names.

Unpaired Birds

From the facts now given, we may conclude that the courtship of birds belonging to widely different groups, is often a prolonged, delicate, and troublesome affair. There is even reason to suspect, improbable as this will at first appear, that some males and females of the same species, inhabiting the same district, do not always please each other, and consequently do not pair. Many accounts have been published of either the male or female of a pair having been shot, and quickly replaced by another. This has been observed more frequently with the magpie than with any other bird, owing perhaps to its conspicuous appearance and nest. The illustrious Jenner states that in Wiltshire one of a pair was daily shot no less than seven times successively, “but all to no purpose, for the remaining magpie soon found another mate”; and the last pair reared their young. A new partner is generally found on the succeeding day; but Mr. Thompson gives the case of one being replaced on the evening of the same day. Even after the eggs are hatched, if one of the old birds is destroyed a mate will often be found; this occurred after an interval of two days, in a case recently observed by one of Sir J. Lubbock’s keepers. (5. On magpies, Jenner, in ‘Philosophical Transactions,’ 1824, p. 21. Macgillivray, ‘Hist. British Birds,’ vol. i. p. 570. Thompson, in ‘Annals and Magazine of Natural History,’ vol. viii. 1842, p. 494.) The first and most obvious conjecture is that male magpies must be much more numerous than females; and that in the above cases, as well as in many others which could be given, the males alone had been killed. This apparently holds good in some instances, for the gamekeepers in Delamere Forest assured Mr. Fox that the magpies and carrion-crows which they formerly killed in succession in large numbers near their nests, were all males; and they accounted for this fact by the males being easily killed whilst bringing food to the sitting females. Macgillivray, however, gives, on the authority of an excellent observer, an instance of three magpies successively killed on the same nest, which were all females; and another case of six magpies successively killed whilst sitting on the same eggs, which renders it probable that most of them were females; though, as I hear from Mr. Fox, the male will sit on the eggs when the female is killed.

Sir J. Lubbock’s gamekeeper has repeatedly shot, but how often he could not say, one of a pair of jays (Garrulus glandarius), and has never failed shortly afterwards to find the survivor re-matched. Mr. Fox, Mr. F. Bond, and others have shot one of a pair of carrion-crows (Corvus corone), but the nest was soon again tenanted by a pair. These birds are rather common; but the peregrine-falcon (Falco peregrinus) is rare, yet Mr. Thompson states that in Ireland “if either an old male or female be killed in the breeding-season (not an uncommon circumstance), another mate is found within a very few days, so that the eyries, notwithstanding such casualties, are sure to turn out their complement of young.” Mr. Jenner Weir has known the same thing with the peregrine-falcons at Beachy Head. The same observer informs me that three kestrels (Falco tinnunculus), all males, were killed one after the other whilst attending the same nest; two of these were in mature plumage, but the third was in the plumage of the previous year. Even with the rare golden eagle (Aquila chrysaetos), Mr. Birkbeck was assured by a trustworthy gamekeeper in Scotland, that if one is killed, another is soon found. So with the white owl (Strix flammea), “the survivor readily found a mate, and the mischief went on.”

White of Selborne, who gives the case of the owl, adds that he knew a man, who from believing that partridges when paired were disturbed by the males fighting, used to shoot them; and though he had widowed the same female several times, she always soon found a fresh partner. This same naturalist ordered the sparrows, which deprived the house-martins of their nests, to be shot; but the one which was left, “be it cock or hen, presently procured a mate, and so for several times following.” I could add analogous cases relating to the chaffinch, nightingale, and redstart. With respect to the latter bird (Phoenicura ruticilla), a writer expresses much surprise how the sitting female could so soon have given effectual notice that she was a widow, for the species was not common in the neighbourhood. Mr. Jenner Weir has mentioned to me a nearly similar case; at Blackheath he never sees or hears the note of the wild bullfinch, yet when one of his caged males has died, a wild one in the course of a few days has generally come and perched near the widowed female, whose call-note is not loud. I will give only one other fact, on the authority of this same observer; one of a pair of starlings (Sturnus vulgaris) was shot in the morning; by noon a new mate was found; this was again shot, but before night the pair was complete; so that the disconsolate widow or widower was thrice consoled during the same day. Mr. Engleheart also informs me that he used during several years to shoot one of a pair of starlings which built in a hole in a house at Blackheath; but the loss was always immediately repaired. During one season he kept an account, and found that he had shot thirty-five birds from the same nest; these consisted of both males and females, but in what proportion he could not say: nevertheless, after all this destruction, a brood was reared. (6. On the peregrine falcon, see Thompson, ‘Nat. Hist. of Ireland: Birds,’ vol. i. 1849, p. 39. On owls, sparrows, and partridges, see White, ‘Nat. Hist. of Selborne,’ edit. of 1825, vol. i. p. 139. On the Phoenicura, see Loudon’s ‘Mag. of Nat. Hist.’ vol. vii. 1834, p. 245. Brehm (‘Thierleben,’ B. iv. s. 991) also alludes to cases of birds thrice mated during the same day.)

These facts well deserve attention. How is it that there are birds enough ready to replace immediately a lost mate of either sex? Magpies, jays, carrion-crows, partridges, and some other birds, are always seen during the spring in pairs, and never by themselves; and these offer at first sight the most perplexing cases. But birds of the same sex, although of course not truly paired, sometimes live in pairs or in small parties, as is known to be the case with pigeons and partridges. Birds also sometimes live in triplets, as has been observed with starlings, carrion-crows, parrots, and partridges. With partridges two females have been known to live with one male, and two males with one female. In all such cases it is probable that the union would be easily broken; and one of the three would readily pair with a widow or widower. The males of certain birds may occasionally be heard pouring forth their love-song long after the proper time, shewing that they have either lost or never gained a mate. Death from accident or disease of one of a pair would leave the other free and single; and there is reason to believe that female birds during the breeding-season are especially liable to premature death. Again, birds which have had their nests destroyed, or barren pairs, or retarded individuals, would easily be induced to desert their mates, and would probably be glad to take what share they could of the pleasures and duties of rearing offspring although not their own. (7。 See White (‘Nat. 历史。 of Selborne,’ 1825, vol. i. p. 140) on the existence, early in the season, of small coveys of male partridges, of which fact I have heard other instances. See Jenner, on the retarded state of the generative organs in certain birds, in ‘Phil. Transact.’ 1824. In regard to birds living in triplets, I owe to Mr. Jenner Weir the cases of the starlings and parrots, and to Mr. Fox, of partridges; on carrion-crows, see the ‘Field,’ 1868, p. 415. On various male birds singing after the proper period, see Rev. L. Jenyns, ‘Observations in Natural History,’ 1846, p. 87.) Such contingencies as these probably explain most of the foregoing cases. (8。 The following case has been given (‘The Times,’ Aug. 6, 1868) by the Rev. FO Morris, on the authority of the Hon. and Rev. OW 森林人。 “The gamekeeper here found a hawk’s nest this year, with five young ones on it. He took four and killed them, but left one with its wings clipped as a decoy to destroy the old ones by. They were both shot next day, in the act of feeding the young one, and the keeper thought it was done with. The next day he came again and found two other charitable hawks, who had come with an adopted feeling to succour the orphan. These two he killed, and then left the nest. On returning afterwards he found two more charitable individuals on the same errand of mercy. One of these he killed; the other he also shot, but could not find. No more came on the like fruitless errand.”) Nevertheless, it is a strange fact that within the same district, during the height of the breeding-season, there should be so many males and females always ready to repair the loss of a mated bird. Why do not such spare birds immediately pair together? Have we not some reason to suspect, and the suspicion has occurred to Mr. Jenner Weir, that as the courtship of birds appears to be in many cases prolonged and tedious, so it occasionally happens that certain males and females do not succeed, during the proper season, in exciting each other’s love, and consequently do not pair?

Mental Qualities of Birds, And Their Taste for the Beautiful

Before we further discuss the question whether the females select the more attractive males or accept the first whom they may encounter, it will be advisable briefly to consider the mental powers of birds. Their reason is generally, and perhaps justly, ranked as low; yet some facts could be given leading to an opposite conclusion. (9. I am indebted to Prof. Newton for the following passage from Mr. Adam’s ‘Travels of a Naturalist,’ 1870, p. 278. Speaking of Japanese nut-hatches in confinement, he says: “Instead of the more yielding fruit of the yew, which is the usual food of the nut- hatch of Japan, at one time I substituted hard hazel-nuts. As the bird was unable to crack them, he placed them one by one in his water-glass, evidently with the notion that they would in time become softer—an interesting proof of intelligence on the part of these birds.”) Low powers of reasoning, however, are compatible, as we see with mankind, with strong affections, acute perception, and a taste for the beautiful; and it is with these latter qualities that we are here concerned. It has often been said that parrots become so deeply attached to each other that when one dies the other pines for a long time; but Mr. Jenner Weir thinks that with most birds the strength of their affection has been much exaggerated. Nevertheless when one of a pair in a state of nature has been shot, the survivor has been heard for days afterwards uttering a plaintive call; and Mr. St. John gives various facts proving the attachment of mated birds. (10. ‘A Tour in Sutherlandshire,’ vol. i. 1849, p. 185. Dr. Buller says (‘Birds of New Zealand,’ 1872, p. 56) that a male King Lory was killed; and the female “fretted and moped, refused her food, and died of a broken heart.”) Mr. Bennett relates (11. ‘Wanderings in New South Wales,’ vol. ii. 1834, p. 62.) that in China after a drake of the beautiful mandarin Teal had been stolen, the duck remained disconsolate, though sedulously courted by another mandarin drake, who displayed before her all his charms. After an interval of three weeks the stolen drake was recovered, and instantly the pair recognised each other with extreme joy. On the other hand, starlings, as we have seen, may be consoled thrice in the same day for the loss of their mates. Pigeons have such excellent local memories, that they have been known to return to their former homes after an interval of nine months, yet, as I hear from Mr. Harrison Weir, if a pair which naturally would remain mated for life be separated for a few weeks during the winter, and afterwards matched with other birds, the two when brought together again, rarely, if ever, recognise each other.

Birds sometimes exhibit benevolent feelings; they will feed the deserted young ones even of distinct species, but this perhaps ought to be considered as a mistaken instinct. They will feed, as shewn in an earlier part of this work, adult birds of their own species which have become blind. Mr. Buxton gives a curious account of a parrot which took care of a frost-bitten and crippled bird of a distinct species, cleansed her feathers, and defended her from the attacks of the other parrots which roamed freely about his garden. It is a still more curious fact that these birds apparently evince some sympathy for the pleasures of their fellows. When a pair of cockatoos made a nest in an acacia tree, “it was ridiculous to see the extravagant interest taken in the matter by the others of the same species.” These parrots, also, evinced unbounded curiosity, and clearly had “the idea of property and possession.” (12. ‘Acclimatization of Parrots,’ by C. Buxton, M.P., ‘Annals and Mag. of Nat. Hist.’ Nov. 1868, p. 381.) They have good memories, for in the Zoological Gardens they have plainly recognised their former masters after an interval of some months.

Birds possess acute powers of observation. Every mated bird, of course, recognises its fellow. Audubon states that a certain number of mocking- thrushes (Mimus polyglottus) remain all the year round in Louisiana, whilst others migrate to the Eastern States; these latter, on their return, are instantly recognised, and always attacked, by their southern brethren. Birds under confinement distinguish different persons, as is proved by the strong and permanent antipathy or affection which they shew, without any apparent cause, towards certain individuals. I have heard of numerous instances with jays, partridges, canaries, and especially bullfinches. Mr. Hussey has described in how extraordinary a manner a tamed partridge recognised everybody: and its likes and dislikes were very strong. This bird seemed “fond of gay colours, and no new gown or cap could be put on without catching his attention.” (13. The ‘Zoologist,’ 1847-48, p. 1602.) Mr. Hewitt has described the habits of some ducks (recently descended from wild birds), which, at the approach of a strange dog or cat, would rush headlong into the water, and exhaust themselves in their attempts to escape; but they knew Mr. Hewitt’s own dogs and cats so well that they would lie down and bask in the sun close to them. They always moved away from a strange man, and so they would from the lady who attended them if she made any great change in her dress. Audubon relates that he reared and tamed a wild turkey which always ran away from any strange dog; this bird escaped into the woods, and some days afterwards Audubon saw, as he thought, a wild turkey, and made his dog chase it; but, to his astonishment, the bird did not run away, and the dog, when he came up, did not attack the bird, for they mutually recognised each other as old friends. (14. Hewitt on wild ducks, ‘Journal of Horticulture,’ Jan. 13, 1863, p. 39. Audubon on the wild turkey, ‘Ornithological Biography,’ vol. i. p. 14. On the mocking-thrush, ibid. vol. i. p. 110.)

Mr. Jenner Weir is convinced that birds pay particular attention to the colours of other birds, sometimes out of jealousy, and sometimes as a sign of kinship. Thus he turned a reed-bunting (Emberiza schoeniculus), which had acquired its black head-dress, into his aviary, and the new-comer was not noticed by any bird, except by a bullfinch, which is likewise black- headed. This bullfinch was a very quiet bird, and had never before quarrelled with any of its comrades, including another reed-bunting, which had not as yet become black-headed: but the reed-bunting with a black head was so unmercifully treated that it had to be removed. Spiza cyanea, during the breeding-season, is of a bright blue colour; and though generally peaceable, it attacked S. ciris, which has only the head blue, and completely scalped the unfortunate bird. Mr. Weir was also obliged to turn out a robin, as it fiercely attacked all the birds in his aviary with any red in their plumage, but no other kinds; it actually killed a red- breasted crossbill, and nearly killed a goldfinch. On the other hand, he has observed that some birds, when first introduced, fly towards the species which resemble them most in colour, and settle by their sides.

As male birds display their fine plumage and other ornaments with so much care before the females, it is obviously probable that these appreciate the beauty of their suitors. It is, however, difficult to obtain direct evidence of their capacity to appreciate beauty. When birds gaze at themselves in a looking-glass (of which many instances have been recorded) we cannot feel sure that it is not from jealousy of a supposed rival, though this is not the conclusion of some observers. In other cases it is difficult to distinguish between mere curiosity and admiration. It is perhaps the former feeling which, as stated by Lord Lilford (15. The ‘Ibis,’ vol. ii. 1860, p. 344.), attracts the ruff towards any bright object, so that, in the Ionian Islands, “it will dart down to a bright- coloured handkerchief, regardless of repeated shots.” The common lark is drawn down from the sky, and is caught in large numbers, by a small mirror made to move and glitter in the sun. Is it admiration or curiosity which leads the magpie, raven, and some other birds to steal and secrete bright objects, such as silver articles or jewels?

Mr. Gould states that certain humming-birds decorate the outsides of their nests “with the utmost taste; they instinctively fasten thereon beautiful pieces of flat lichen, the larger pieces in the middle, and the smaller on the part attached to the branch. Now and then a pretty feather is intertwined or fastened to the outer sides, the stem being always so placed that the feather stands out beyond the surface.” The best evidence, however, of a taste for the beautiful is afforded by the three genera of Australian bower-birds already mentioned. Their bowers (Fig. 46), where the sexes congregate and play strange antics, are variously constructed, but what most concerns us is, that they are decorated by the several species in a different manner. The Satin bower-bird collects gaily- coloured articles, such as the blue tail-feathers of parrakeets, bleached bones and shells, which it sticks between the twigs or arranges at the entrance. Mr. Gould found in one bower a neatly-worked stone tomahawk and a slip of blue cotton, evidently procured from a native encampment. These objects are continually re-arranged, and carried about by the birds whilst at play. The bower of the Spotted bower-bird “is beautifully lined with tall grasses, so disposed that the heads nearly meet, and the decorations are very profuse.” Round stones are used to keep the grass-stems in their proper places, and to make divergent paths leading to the bower. The stones and shells are often brought from a great distance. The Regent bird, as described by Mr. Ramsay, ornaments its short bower with bleached land-shells belonging to five or six species, and with “berries of various colours, blue, red, and black, which give it when fresh a very pretty appearance. Besides these there were several newly-picked leaves and young shoots of a pinkish colour, the whole showing a decided taste for the beautiful.” Well may Mr. Gould say that “these highly decorated halls of assembly must be regarded as the most wonderful instances of bird- architecture yet discovered;” and the taste, as we see, of the several species certainly differs. (16. On the ornamented nests of humming-birds, Gould, ‘Introduction to the Trochilidae,’ 1861, p. 19. On the bower-birds, Gould, ‘Handbook to the Birds of Australia,’ 1865, vol. i. pp. 444-461. Ramsay, in the ‘Ibis,’ 1867, p. 456.)

Preference for Particular Males by the Females

Having made these preliminary remarks on the discrimination and taste of birds, I will give all the facts known to me which bear on the preference shewn by the female for particular males. It is certain that distinct species of birds occasionally pair in a state of nature and produce hybrids. Many instances could be given: thus Macgillivray relates how a male blackbird and female thrush “fell in love with each other,” and produced offspring. (17. ‘History of Brit. Birds,’ vol. ii. p. 92.) Several years ago eighteen cases had been recorded of the occurrence in Great Britain of hybrids between the black grouse and pheasant (18. ‘Zoologist,’ 1853-1854, p. 3946.); but most of these cases may perhaps be accounted for by solitary birds not finding one of their own species to pair with. With other birds, as Mr. Jenner Weir has reason to believe, hybrids are sometimes the result of the casual intercourse of birds building in close proximity. But these remarks do not apply to the many recorded instances of tamed or domestic birds, belonging to distinct species, which have become absolutely fascinated with each other, although living with their own species. Thus Waterton (19. Waterton, ‘Essays on Nat. Hist.’ 2nd series, pp. 42 and 117. For the following statements see on the wigeon, ‘Loudon’s Mag. of Nat. Hist.’ vol. ix. p. 616; L. Lloyd, ‘Scandinavian Adventures,’ vol. i. 1854, p. 452. Dixon, ‘Ornamental and Domestic Poultry,’ p. 137; Hewitt, in ‘Journal of Horticulture,’ Jan. 13, 1863, p. 40; Bechstein, ‘Stubenvögel,’ 1840, s. 230. Mr. J. Jenner Weir has lately given me an analogous case with ducks of two species.) states that out of a flock of twenty-three Canada geese, a female paired with a solitary Bernicle gander, although so different in appearance and size; and they produced hybrid offspring. A male wigeon (Mareca penelope), living with females of the same species, has been known to pair with a pintail duck, Querquedula acuta. Lloyd describes the remarkable attachment between a shield-drake (Tadorna vulpanser) and a common duck. Many additional instances could be given; and the Rev. E.S. Dixon remarks that “those who have kept many different species of geese together well know what unaccountable attachments they are frequently forming, and that they are quite as likely to pair and rear young with individuals of a race (species) apparently the most alien to themselves as with their own stock.”

The Rev. W.D. Fox informs me that he possessed at the same time a pair of Chinese geese (Anser cygnoides), and a common gander with three geese. The two lots kept quite separate, until the Chinese gander seduced one of the common geese to live with him. Moreover, of the young birds hatched from the eggs of the common geese, only four were pure, the other eighteen proving hybrids; so that the Chinese gander seems to have had prepotent charms over the common gander. I will give only one other case; Mr. Hewitt states that a wild duck, reared in captivity, “after breeding a couple of seasons with her own mallard, at once shook him off on my placing a male Pintail on the water. It was evidently a case of love at first sight, for she swam about the new-comer caressingly, though he appeared evidently alarmed and averse to her overtures of affection. From that hour she forgot her old partner. Winter passed by, and the next spring the pintail seemed to have become a convert to her blandishments, for they nested and produced seven or eight young ones.”

What the charm may have been in these several cases, beyond mere novelty, we cannot even conjecture. Colour, however, sometimes comes into play; for in order to raise hybrids from the siskin (Fringilla spinus) and the canary, it is much the best plan, according to Bechstein, to place birds of the same tint together. Mr. Jenner Weir turned a female canary into his aviary, where there were male linnets, goldfinches, siskins, greenfinches, chaffinches, and other birds, in order to see which she would choose; but there never was any doubt, and the greenfinch carried the day. They paired and produced hybrid offspring.

The fact of the female preferring to pair with one male rather than with another of the same species is not so likely to excite attention, as when this occurs, as we have just seen, between distinct species. The former cases can best be observed with domesticated or confined birds; but these are often pampered by high feeding, and sometimes have their instincts vitiated to an extreme degree. Of this latter fact I could give sufficient proofs with pigeons, and especially with fowls, but they cannot be here related. Vitiated instincts may also account for some of the hybrid unions above mentioned; but in many of these cases the birds were allowed to range freely over large ponds, and there is no reason to suppose that they were unnaturally stimulated by high feeding.

With respect to birds in a state of nature, the first and most obvious supposition which will occur to every one is that the female at the proper season accepts the first male whom she may encounter; but she has at least the opportunity for exerting a choice, as she is almost invariably pursued by many males. Audubon—and we must remember that he spent a long life in prowling about the forests of the United States and observing the birds— does not doubt that the female deliberately chooses her mate; thus, speaking of a woodpecker, he says the hen is followed by half-a-dozen gay suitors, who continue performing strange antics, “until a marked preference is shewn for one.” The female of the red-winged starling (Agelaeus phoeniceus) is likewise pursued by several males, “until, becoming fatigued, she alights, receives their addresses, and soon makes a choice.” He describes also how several male night-jars repeatedly plunge through the air with astonishing rapidity, suddenly turning, and thus making a singular noise; “but no sooner has the female made her choice than the other males are driven away.” With one of the vultures (Cathartes aura) of the United States, parties of eight, ten, or more males and females assemble on fallen logs, “exhibiting the strongest desire to please mutually,” and after many caresses, each male leads off his partner on the wing. Audubon likewise carefully observed the wild flocks of Canada geese (Anser canadensis), and gives a graphic description of their love-antics; he says that the birds which had been previously mated “renewed their courtship as early as the month of January, while the others would be contending or coquetting for hours every day, until all seemed satisfied with the choice they had made, after which, although they remained together, any person could easily perceive that they were careful to keep in pairs. I have observed also that the older the birds the shorter were the preliminaries of their courtship. The bachelors and old maids whether in regret, or not caring to be disturbed by the bustle, quietly moved aside and lay down at some distance from the rest.” (20. Audubon, ‘Ornithological Biography,’ vol. i. pp. 191, 349; vol. ii. pp. 42, 275; vol. iii. p. 2.) Many similar statements with respect to other birds could be cited from this same observer.

Turning now to domesticated and confined birds, I will commence by giving what little I have learnt respecting the courtship of fowls. I have received long letters on this subject from Messrs. Hewitt and Tegetmeier, and almost an essay from the late Mr. Brent. It will be admitted by every one that these gentlemen, so well known from their published works, are careful and experienced observers. They do not believe that the females prefer certain males on account of the beauty of their plumage; but some allowance must be made for the artificial state under which these birds have long been kept. Mr. Tegetmeier is convinced that a gamecock, though disfigured by being dubbed and with his hackles trimmed, would be accepted as readily as a male retaining all his natural ornaments. Mr. Brent, however, admits that the beauty of the male probably aids in exciting the female; and her acquiescence is necessary. Mr. Hewitt is convinced that the union is by no means left to mere chance, for the female almost invariably prefers the most vigorous, defiant, and mettlesome male; hence it is almost useless, as he remarks, “to attempt true breeding if a game- cock in good health and condition runs the locality, for almost every hen on leaving the roosting-place will resort to the game-cock, even though that bird may not actually drive away the male of her own variety.” Under ordinary circumstances the males and females of the fowl seem to come to a mutual understanding by means of certain gestures, described to me by Mr. Brent. But hens will often avoid the officious attentions of young males. Old hens, and hens of a pugnacious disposition, as the same writer informs me, dislike strange males, and will not yield until well beaten into compliance. Ferguson, however, describes how a quarrelsome hen was subdued by the gentle courtship of a Shanghai cock. (21. ‘Rare and Prize Poultry,’ 1854, p. 27.)

There is reason to believe that pigeons of both sexes prefer pairing with birds of the same breed; and dovecot-pigeons dislike all the highly improved breeds. (22. ‘Variation of Animals and Plants under Domestication,’ vol. ii. p. 103.) Mr. Harrison Weir has lately heard from a trustworthy observer, who keeps blue pigeons, that these drive away all other coloured varieties, such as white, red, and yellow; and from another observer, that a female dun carrier could not, after repeated trials, be matched with a black male, but immediately paired with a dun. Again, Mr. Tegetmeier had a female blue turbit that obstinately refused to pair with two males of the same breed, which were successively shut up with her for weeks; but on being let out she would have immediately accepted the first blue dragon that offered. As she was a valuable bird, she was then shut up for many weeks with a silver (i.e., very pale blue) male, and at last mated with him. Nevertheless, as a general rule, colour appears to have little influence on the pairing of pigeons. Mr. Tegetmeier, at my request, stained some of his birds with magenta, but they were not much noticed by the others.

Female pigeons occasionally feel a strong antipathy towards certain males, without any assignable cause. Thus MM. Boitard and Corbie, whose experience extended over forty-five years, state: “Quand une femelle éprouve de l’antipathie pour un mâle avec lequel on veut l’accoupler, malgré tous les feux de l’amour, malgré l’alpiste et le chenevis dont on la nourrit pour augmenter son ardeur, malgré un emprisonnement de six mois et même d’un an, elle refuse constamment ses caresses; les avances empressées, les agaceries, les tournoiemens, les tendres roucoulemens, rien ne peut lui plaire ni l’émouvoir; gonflée, boudeuse, blottie dans un coin de sa prison, elle n’en sort que pour boire et manger, ou pour repousser avec une espèce de rage des caresses devenues trop pressantes.” (23. Boitard and Corbie, ‘Les Pigeons,’ etc., 1824, p. 12. Prosper Lucas (‘Traité de l’Héréd. Nat.’ tom. ii. 1850, p. 296) has himself observed nearly similar facts with pigeons.) On the other hand, Mr. Harrison Weir has himself observed, and has heard from several breeders, that a female pigeon will occasionally take a strong fancy for a particular male, and will desert her own mate for him. Some females, according to another experienced observer, Riedel (24. Die Taubenzucht, 1824, s. 86.), are of a profligate disposition, and prefer almost any stranger to their own mate. Some amorous males, called by our English fanciers “gay birds,” are so successful in their gallantries, that, as Mr. H. Weir informs me, they must be shut up on account of the mischief which they cause.

Wild turkeys in the United States, according to Audubon, “sometimes pay their addresses to the domesticated females, and are generally received by them with great pleasure.” So that these females apparently prefer the wild to their own males. (25. ‘Ornithological Biography,’ vol. i. p. 13. See to the same effect, Dr. Bryant, in Allen’s ‘Mammals and Birds of Florida,’ p. 344.)

Here is a more curious case. Sir R. Heron during many years kept an account of the habits of the peafowl, which he bred in large numbers. He states that “the hens have frequently great preference to a particular peafowl. They were all so fond of an old pied cock, that one year, when he was confined, though still in view, they were constantly assembled close to the trellice-walls of his prison, and would not suffer a japanned peacock to touch them. On his being let out in the autumn, the oldest of the hens instantly courted him and was successful in her courtship. The next year he was shut up in a stable, and then the hens all courted his rival.” (26. ‘Proceedings, Zoological Society,’ 1835, p. 54. The japanned peacock is considered by Mr. Sclater as a distinct species, and has been named Pavo nigripennis; but the evidence seems to me to show that it is only a variety.) This rival was a japanned or black-winged peacock, to our eyes a more beautiful bird than the common kind.

Lichtenstein, who was a good observer and had excellent opportunities of observation at the Cape of Good Hope, assured Rudolphi that the female widow-bird (Chera progne) disowns the male when robbed of the long tail- feathers with which he is ornamented during the breeding-season. I presume that this observation must have been made on birds under confinement. (27. Rudolphi, ‘Beiträge zur Anthropologie,’ 1812, s. 184.) Here is an analogous case; Dr. Jaeger (28. ‘Die Darwin’sche Theorie, und ihre Stellung zu Moral und Religion,’ 1869, s. 59.), director of the Zoological Gardens of Vienna, states that a male silver-pheasant, who had been triumphant over all other males and was the accepted lover of the females, had his ornamental plumage spoiled. He was then immediately superseded by a rival, who got the upper hand and afterwards led the flock.

It is a remarkable fact, as shewing how important colour is in the courtship of birds, that Mr. Boardman, a well-known collector and observer of birds for many years in the Northern United States, has never in his large experience seen an albino paired with another bird; yet he has had opportunities of observing many albinos belonging to several species. (29. This statement is given by Mr. A. Leith Adams, in his ‘Field and Forest Rambles,’ 1873, p. 76, and accords with his own experience.) It can hardly be maintained that albinos in a state of nature are incapable of breeding, as they can be raised with the greatest facility under confinement. It appears, therefore, that we must attribute the fact that they do not pair to their rejection by their normally coloured comrades.

Female birds not only exert a choice, but in some few cases they court the male, or even fight together for his possession. Sir R. Heron states that with peafowl, the first advances are always made by the female; something of the same kind takes place, according to Audubon, with the older females of the wild turkey. With the capercailzie, the females flit round the male whilst he is parading at one of the places of assemblage, and solicit his attention. (30. In regard to peafowl, see Sir R. Heron, ‘Proc. Zoolog. Soc.’ 1835, p. 54, and the Rev. E.S. Dixon, ‘Ornamental Poultry,’ 1848, p. 8. For the turkey, Audubon, ibid. p. 4. For the capercailzie, Lloyd, ‘Game Birds of Sweden,’ 1867, p. 23.) We have seen that a tame wild-duck seduced an unwilling pintail drake after a long courtship. Mr. Bartlett believes that the Lophophorus, like many other gallinaceous birds, is naturally polygamous, but two females cannot be placed in the same cage with a male, as they fight so much together. The following instance of rivalry is more surprising as it relates to bullfinches, which usually pair for life. Mr. Jenner Weir introduced a dull-coloured and ugly female into his aviary, and she immediately attacked another mated female so unmercifully that the latter had to be separated. The new female did all the courtship, and was at last successful, for she paired with the male; but after a time she met with a just retribution, for, ceasing to be pugnacious, she was replaced by the old female, and the male then deserted his new and returned to his old love.

In all ordinary cases the male is so eager that he will accept any female, and does not, as far as we can judge, prefer one to the other; but, as we shall hereafter see, exceptions to this rule apparently occur in some few groups. With domesticated birds, I have heard of only one case of males shewing any preference for certain females, namely, that of the domestic cock, who, according to the high authority of Mr. Hewitt, prefers the younger to the older hens. On the other hand, in effecting hybrid unions between the male pheasant and common hens, Mr. Hewitt is convinced that the pheasant invariably prefers the older birds. He does not appear to be in the least influenced by their colour; but “is most capricious in his attachments” (31. Mr. Hewitt, quoted in Tegetmeier’s ‘Poultry Book,’ 1866, p. 165.): from some inexplicable cause he shews the most determined aversion to certain hens, which no care on the part of the breeder can overcome. Mr. Hewitt informs me that some hens are quite unattractive even to the males of their own species, so that they may be kept with several cocks during a whole season, and not one egg out of forty or fifty will prove fertile. On the other hand, with the long-tailed duck (Harelda glacialis), “it has been remarked,” says M. Ekstrom, “that certain females are much more courted than the rest. Frequently, indeed, one sees an individual surrounded by six or eight amorous males.” Whether this statement is credible, I know not; but the native sportsmen shoot these females in order to stuff them as decoys. (32. Quoted in Lloyd’s ‘Game Birds of Sweden,’ p. 345.)

With respect to female birds feeling a preference for particular males, we must bear in mind that we can judge of choice being exerted only by analogy. If an inhabitant of another planet were to behold a number of young rustics at a fair courting a pretty girl, and quarrelling about her like birds at one of their places of assemblage, he would, by the eagerness of the wooers to please her and to display their finery, infer that she had the power of choice. Now with birds the evidence stands thus: they have acute powers of observation, and they seem to have some taste for the beautiful both in colour and sound. It is certain that the females occasionally exhibit, from unknown causes, the strongest antipathies and preferences for particular males. When the sexes differ in colour or in other ornaments the males with rare exceptions are the more decorated, either permanently or temporarily during the breeding-season. They sedulously display their various ornaments, exert their voices, and perform strange antics in the presence of the females. Even well-armed males, who, it might be thought, would altogether depend for success on the law of battle, are in most cases highly ornamented; and their ornaments have been acquired at the expense of some loss of power. In other cases ornaments have been acquired, at the cost of increased risk from birds and beasts of prey. With various species many individuals of both sexes congregate at the same spot, and their courtship is a prolonged affair. There is even reason to suspect that the males and females within the same district do not always succeed in pleasing each other and pairing.

What then are we to conclude from these facts and considerations? Does the male parade his charms with so much pomp and rivalry for no purpose? Are we not justified in believing that the female exerts a choice, and that she receives the addresses of the male who pleases her most? It is not probable that she consciously deliberates; but she is most excited or attracted by the most beautiful, or melodious, or gallant males. Nor need it be supposed that the female studies each stripe or spot of colour; that the peahen, for instance, admires each detail in the gorgeous train of the peacock—she is probably struck only by the general effect. Nevertheless, after hearing how carefully the male Argus pheasant displays his elegant primary wing-feathers, and erects his ocellated plumes in the right position for their full effect; or again, how the male goldfinch alternately displays his gold-bespangled wings, we ought not to feel too sure that the female does not attend to each detail of beauty. We can judge, as already remarked, of choice being exerted, only from analogy; and the mental powers of birds do not differ fundamentally from ours. From these various considerations we may conclude that the pairing of birds is not left to chance; but that those males, which are best able by their various charms to please or excite the female, are under ordinary circumstances accepted. If this be admitted, there is not much difficulty in understanding how male birds have gradually acquired their ornamental characters. All animals present individual differences, and as man can modify his domesticated birds by selecting the individuals which appear to him the most beautiful, so the habitual or even occasional preference by the female of the more attractive males would almost certainly lead to their modification; and such modifications might in the course of time be augmented to almost any extent, compatible with the existence of the species.

Variability of Birds, And Especially of Their Secondary Sexual Characters

Variability and inheritance are the foundations for the work of selection. That domesticated birds have varied greatly, their variations being inherited, is certain. That birds in a state of nature have been modified into distinct races is now universally admitted. (33。 据博士 Blasius (‘Ibis,’ vol. II。 1860。 297), there are 425 indubitable species of birds which breed in Europe, besides sixty forms, which are frequently regarded as distinct species. Of the latter, Blasius thinks that only ten are really doubtful, and that the other fifty ought to be united with their nearest allies; but this shews that there must be a considerable amount of variation with some of our European birds. It is also an unsettled point with naturalists, whether several North American birds ought to be ranked as specifically distinct from the corresponding European species. So again many North American forms which until lately were named as distinct species, are now considered to be local races.) Variations may be divided into two classes; those which appear to our ignorance to arise spontaneously, and those which are directly related to the surrounding conditions, so that all or nearly all the individuals of the same species are similarly modified. Cases of the latter kind have recently been observed with care by Mr. JA Allen (34. ‘Mammals and Birds of East Florida,’ also an ‘Ornithological Reconnaissance of Kansas,’ etc. Notwithstanding the influence of climate on the colours of birds, it is difficult to account for the dull or dark tints of almost all the species inhabiting certain countries, for instance, the Galapagos Islands under the equator, the wide temperate plains of Patagonia, and, as it appears, Egypt (see Mr. Hartshorne in the ‘American Naturalist,’ 1873, p. 747)。 These countries are open, and afford little shelter to birds; but it seems doubtful whether the absence of brightly coloured species can be explained on the principle of protection, for on the Pampas, which are equally open, though covered by green grass, and where the birds would be equally exposed to danger, many brilliant and conspicuously coloured species are common. I have sometimes speculated whether the prevailing dull tints of the scenery in the above named countries may not have affected the appreciation of bright colours by the birds inhabiting them.), who shews that in the United States many species of birds gradually become more strongly coloured in proceeding southward, and more lightly coloured in proceeding westward to the arid plains of the interior. Both sexes seem generally to be affected in a like manner, but sometimes one sex more than the other.

Individual differences between the members of the same species are admitted by every one to occur under a state of nature. Sudden and strongly marked variations are rare; it is also doubtful whether if beneficial they would often be preserved through selection and transmitted to succeeding generations. (35。 ‘Origin of Species’ fifth edit. 1869,第104页。 I had always perceived, that rare and strongly-marked deviations of structure, deserving to be called monstrosities, could seldom be preserved through natural selection, and that the preservation of even highly-beneficial variations would depend to a certain extent on chance. I had also fully appreciated the importance of mere individual differences, and this led me to insist so strongly on the importance of that unconscious form of selection by man, which follows from the preservation of the most valued individuals of each breed, without any intention on his part to modify the characters of the breed. But until I read an able article in the ‘North British Review’ (March 1867, p. 289, et seq.), which has been of more use to me than any other Review, I did not see how great the chances were against the preservation of variations, whether slight or strongly pronounced, occurring only in single individuals.) Nevertheless, it may be worth while to give the few cases which I have been able to collect, relating chiefly to colour,—simple albinism and melanism being excluded. 先生。 Gould is well known to admit the existence of few varieties, for he esteems very slight differences as specific; yet he states (36. ‘Introduction to the Trochlidae,’ p. 102.) that near Bogota certain humming-birds belonging to the genus Cynanthus are divided into two or three races or varieties, which differ from each other in the colouring of the tail—”some having the whole of the feathers blue, while others have the eight central ones tipped with beautiful green.” It does not appear that intermediate gradations have been observed in this or the following cases. In the males alone of one of the Australian parrakeets “the thighs in some are scarlet, in others grass-green.” In another parrakeet of the same country “some individuals have the band across the wing-coverts bright-yellow, while in others the same part is tinged with red.” (37. Gould, ‘Handbook to Birds of Australia,’ vol. II。 第 32 and 68.) In the United States some few of the males of the scarlet tanager (Tanagra rubra) have “a beautiful transverse band of glowing red on the smaller wing- coverts” (38. Audubon, ‘Ornithological Biography,’ 1838, vol. IV。 p. 389.); but this variation seems to be somewhat rare, so that its preservation through sexual selection would follow only under usually favourable circumstances. In Bengal the Honey buzzard (Pernis cristata) has either a small rudimental crest on its head, or none at all: so slight a difference, however, would not have been worth notice, had not this same species possessed in Southern India a well-marked occipital crest formed of several graduated feathers.” (39. Jerdon, ‘Birds of India,’ vol. i. p. 108; and Mr. Blyth, in ‘Land and Water,’ 1868, p.

The following case is in some respects more interesting. A pied variety of the raven, with the head, breast, abdomen, and parts of the wings and tail- feathers white, is confined to the Feroe Islands. It is not very rare there, for Graba saw during his visit from eight to ten living specimens. Although the characters of this variety are not quite constant, yet it has been named by several distinguished ornithologists as a distinct species. The fact of the pied birds being pursued and persecuted with much clamour by the other ravens of the island was the chief cause which led Brunnich to conclude that they were specifically distinct; but this is now known to be an error. (40. Graba, ‘Tagebuch Reise nach Faro,’ 1830, ss. 51-54. Macgillivray, ‘History of British Birds,’ vol. iii. p. 745, ‘Ibis,’ vol. v. 1863, p. 469.) This case seems analogous to that lately given of albino birds not pairing from being rejected by their comrades.

In various parts of the northern seas a remarkable variety of the common Guillemot (Uria troile) is found; and in Feroe, one out of every five birds, according to Graba’s estimation, presents this variation. It is characterised (41. Graba, ibid. s. 54. Macgillivray, ibid. vol. v. p. 327.) by a pure white ring round the eye, with a curved narrow white line, an inch and a half in length, extending back from the ring. This conspicuous character has caused the bird to be ranked by several ornithologists as a distinct species under the name of U. lacrymans, but it is now known to be merely a variety. It often pairs with the common kind, yet intermediate gradations have never been seen; nor is this surprising, for variations which appear suddenly, are often, as I have elsewhere shewn (42. ‘Variation of Animals and Plants under Domestication,’ vol. ii. p. 92.), transmitted either unaltered or not at all. We thus see that two distinct forms of the same species may co-exist in the same district, and we cannot doubt that if the one had possessed any advantage over the other, it would soon have been multiplied to the exclusion of the latter. If, for instance, the male pied ravens, instead of being persecuted by their comrades, had been highly attractive (like the above pied peacock) to the black female ravens their numbers would have rapidly increased. And this would have been a case of sexual selection.

With respect to the slight individual differences which are common, in a greater or less degree, to all the members of the same species, we have every reason to believe that they are by far the most important for the work of selection. Secondary sexual characters are eminently liable to vary, both with animals in a state of nature and under domestication. (43. On these points see also ‘Variation of Animals and Plants under Domestication,’ vol. i. p. 253; vol ii. pp. 73, 75.) There is also reason to believe, as we have seen in our eighth chapter, that variations are more apt to occur in the male than in the female sex. All these contingencies are highly favourable for sexual selection. Whether characters thus acquired are transmitted to one sex or to both sexes, depends, as we shall see in the following chapter, on the form of inheritance which prevails.

It is sometimes difficult to form an opinion whether certain slight differences between the sexes of birds are simply the result of variability with sexually-limited inheritance, without the aid of sexual selection, or whether they have been augmented through this latter process. I do not here refer to the many instances where the male displays splendid colours or other ornaments, of which the female partakes to a slight degree; for these are almost certainly due to characters primarily acquired by the male having been more or less transferred to the female. But what are we to conclude with respect to certain birds in which, for instance, the eyes differ slightly in colour in the two sexes? (44. See, for instance, on the irides of a Podica and Gallicrex in ‘Ibis,’ vol. ii. 1860, p. 206; and vol. v. 1863, p. 426.) In some cases the eyes differ conspicuously; thus with the storks of the genus Xenorhynchus, those of the male are blackish- hazel, whilst those of the females are gamboge-yellow; with many hornbills (Buceros), as I hear from Mr. Blyth (45. See also Jerdon, ‘Birds of India,’ vol. i. pp. 243-245.), the males have intense crimson eyes, and those of the females are white. In the Buceros bicornis, the hind margin of the casque and a stripe on the crest of the beak are black in the male, but not so in the female. Are we to suppose that these black marks and the crimson colour of the eyes have been preserved or augmented through sexual selection in the males? This is very doubtful; for Mr. Bartlett shewed me in the Zoological Gardens that the inside of the mouth of this Buceros is black in the male and flesh-coloured in the female; and their external appearance or beauty would not be thus affected. I observed in Chile (46. ‘Zoology of the Voyage of H.M.S. “Beagle,”‘ 1841, p. 6.) that the iris in the condor, when about a year old, is dark-brown, but changes at maturity into yellowish-brown in the male, and into bright red in the female. The male has also a small, longitudinal, leaden-coloured, fleshy crest or comb. The comb of many gallinaceous birds is highly ornamental, and assumes vivid colours during the act of courtship; but what are we to think of the dull- coloured comb of the condor, which does not appear to us in the least ornamental? The same question may be asked in regard to various other characters, such as the knob on the base of the beak of the Chinese goose (Anser cygnoides), which is much larger in the male than in the female. No certain answer can be given to these questions; but we ought to be cautious in assuming that knobs and various fleshy appendages cannot be attractive to the female, when we remember that with savage races of man various hideous deformities—deep scars on the face with the flesh raised into protuberances, the septum of the nose pierced by sticks or bones, holes in the ears and lips stretched widely open—are all admired as ornamental.

Whether or not unimportant differences between the sexes, such as those just specified, have been preserved through sexual selection, these differences, as well as all others, must primarily depend on the laws of variation. On the principle of correlated development, the plumage often varies on different parts of the body, or over the whole body, in the same manner. We see this well illustrated in certain breeds of the fowl. In all the breeds the feathers on the neck and loins of the males are elongated, and are called hackles; now when both sexes acquire a top-knot, which is a new character in the genus, the feathers on the head of the male become hackle-shaped, evidently on the principle of correlation; whilst those on the head of the female are of the ordinary shape. The colour also of the hackles forming the top-knot of the male, is often correlated with that of the hackles on the neck and loins, as may be seen by comparing these feathers in the golden and silver-spangled Polish, the Houdans, and Creve-coeur breeds. In some natural species we may observe exactly the same correlation in the colours of these same feathers, as in the males of the splendid Gold and Amherst pheasants.

The structure of each individual feather generally causes any change in its colouring to be symmetrical; we see this in the various laced, spangled, and pencilled breeds of the fowl; and on the principle of correlation the feathers over the whole body are often coloured in the same manner. We are thus enabled without much trouble to rear breeds with their plumage marked almost as symmetrically as in natural species. In laced and spangled fowls the coloured margins of the feathers are abruptly defined; but in a mongrel raised by me from a black Spanish cock glossed with green, and a white game-hen, all the feathers were greenish-black, excepting towards their extremities, which were yellowish-white; but between the white extremities and the black bases, there was on each feather a symmetrical, curved zone of dark-brown. In some instances the shaft of the feather determines the distribution of the tints; thus with the body-feathers of a mongrel from the same black Spanish cock and a silver-spangled Polish hen, the shaft, together with a narrow space on each side, was greenish-black, and this was surrounded by a regular zone of dark-brown, edged with brownish-white. In these cases we have feathers symmetrically shaded, like those which give so much elegance to the plumage of many natural species. I have also noticed a variety of the common pigeon with the wing-bars symmetrically zoned with three bright shades, instead of being simply black on a slaty-blue ground, as in the parent-species.

In many groups of birds the plumage is differently coloured in the several species, yet certain spots, marks, or stripes are retained by all. Analogous cases occur with the breeds of the pigeon, which usually retain the two wing-bars, though they may be coloured red, yellow, white, black, or blue, the rest of the plumage being of some wholly different tint. Here is a more curious case, in which certain marks are retained, though coloured in a manner almost exactly the opposite of what is natural; the aboriginal pigeon has a blue tail, with the terminal halves of the outer webs of the two outer tail feathers white; now there is a sub-variety having a white instead of a blue tail, with precisely that part black which is white in the parent-species. (47. Bechstein, ‘Naturgeschichte Deutschlands,’ B. iv. 1795, s. 31, on a sub-variety of the Monck pigeon.)

Formation and Variability of the Ocelli or Eye-Like Spots on the Plumage of Birds

[Fig. 53. Cyllo leda, Linn., from a drawing by Mr. Trimen, shewing the
extreme range of variation in the ocelli.
A. Specimen, from Mauritius, upper surface of fore-wing.
A1. Specimen, from Natal, ditto.
B. Specimen, from Java, upper surface of hind-wing.
B1. Specimen, from Mauritius, ditto.]

As no ornaments are more beautiful than the ocelli on the feathers of various birds, on the hairy coats of some mammals, on the scales of reptiles and fishes, on the skin of amphibians, on the wings of many Lepidoptera and other insects, they deserve to be especially noticed. An ocellus consists of a spot within a ring of another colour, like the pupil within the iris, but the central spot is often surrounded by additional concentric zones. The ocelli on the tail-coverts of the peacock offer a familiar example, as well as those on the wings of the peacock-butterfly (Vanessa). Mr. Trimen has given me a description of a S. African moth (Gynanisa isis), allied to our Emperor moth, in which a magnificent ocellus occupies nearly the whole surface of each hinder wing; it consists of a black centre, including a semi-transparent crescent-shaped mark, surrounded by successive, ochre-yellow, black, ochre-yellow, pink, white, pink, brown, and whitish zones. Although we do not know the steps by which these wonderfully beautiful and complex ornaments have been developed, the process has probably been a simple one, at least with insects; for, as Mr. Trimen writes to me, “no characters of mere marking or coloration are so unstable in the Lepidoptera as the ocelli, both in number and size.” Mr. Wallace, who first called my attention to this subject, shewed me a series of specimens of our common meadow-brown butterfly (Hipparchia janira) exhibiting numerous gradations from a simple minute black spot to an elegantly-shaded ocellus. In a S. African butterfly (Cyllo leda, Linn.), belonging to the same family, the ocelli are even still more variable. In some specimens (A, Fig. 53) large spaces on the upper surface of the wings are coloured black, and include irregular white marks; and from this state a complete gradation can be traced into a tolerably perfect ocellus (A1), and this results from the contraction of the irregular blotches of colour. In another series of specimens a gradation can be followed from excessively minute white dots, surrounded by a scarcely visible black line (B), into perfectly symmetrical and large ocelli (B1). (48. This woodcut has been engraved from a beautiful drawing, most kindly made for me by Mr. Trimen; see also his description of the wonderful amount of variation in the coloration and shape of the wings of this butterfly, in his ‘Rhopalocera Africae Australis,’ p. 186.) In cases like these, the development of a perfect ocellus does not require a long course of variation and selection.

With birds and many other animals, it seems to follow from the comparison of allied species that circular spots are often generated by the breaking up and contraction of stripes. In the Tragopan pheasant faint white lines in the female represent the beautiful white spots in the male (49. Jerdon, ‘Birds of India,’ vol. iii. p. 517.); and something of the same kind may be observed in the two sexes of the Argus pheasant. However this may be, appearances strongly favour the belief that on the one hand, a dark spot is often formed by the colouring matter being drawn towards a central point from a surrounding zone, which latter is thus rendered lighter; and, on the other hand, that a white spot is often formed by the colour being driven away from a central point, so that it accumulates in a surrounding darker zone. In either case an ocellus is the result. The colouring matter seems to be a nearly constant quantity, but is redistributed, either centripetally or centrifugally. The feathers of the common guinea-fowl offer a good instance of white spots surrounded by darker zones; and wherever the white spots are large and stand near each other, the surrounding dark zones become confluent. In the same wing-feather of the Argus pheasant dark spots may be seen surrounded by a pale zone, and white spots by a dark zone. Thus the formation of an ocellus in its most elementary state appears to be a simple affair. By what further steps the more complex ocelli, which are surrounded by many successive zones of colour, have been generated, I will not pretend to say. But the zoned feathers of the mongrels from differently coloured fowls, and the extraordinary variability of the ocelli on many Lepidoptera, lead us to conclude that their formation is not a complex process, but depends on some slight and graduated change in the nature of the adjoining tissues.

Gradation of Secondary Sexual Characters

[Fig. 54. Feather of Peacock, about two-thirds of natural size, drawn by Mr. Ford. The transparent zone is represented by the outermost white zone, confined to the upper end of the disc.]

Cases of gradation are important, as shewing us that highly complex ornaments may be acquired by small successive steps. In order to discover the actual steps by which the male of any existing bird has acquired his magnificent colours or other ornaments, we ought to behold the long line of his extinct progenitors; but this is obviously impossible. We may, however, generally gain a clue by comparing all the species of the same group, if it be a large one; for some of them will probably retain, at least partially, traces of their former characters. Instead of entering on tedious details respecting various groups, in which striking instances of gradation could be given, it seems the best plan to take one or two strongly marked cases, for instance that of the peacock, in order to see if light can be thrown on the steps by which this bird has become so splendidly decorated. The peacock is chiefly remarkable from the extraordinary length of his tail-coverts; the tail itself not being much elongated. The barbs along nearly the whole length of these feathers stand separate or are decomposed; but this is the case with the feathers of many species, and with some varieties of the domestic fowl and pigeon. The barbs coalesce towards the extremity of the shaft forming the oval disc or ocellus, which is certainly one of the most beautiful objects in the world. It consists of an iridescent, intensely blue, indented centre, surrounded by a rich green zone, this by a broad coppery-brown zone, and this by five other narrow zones of slightly different iridescent shades. A trifling character in the disc deserves notice; the barbs, for a space along one of the concentric zones are more or less destitute of their barbules, so that a part of the disc is surrounded by an almost transparent zone, which gives it a highly finished aspect. But I have elsewhere described (50. ‘Variation of Animals and Plants under Domestication,’ vol. i. p. 254.) an exactly analogous variation in the hackles of a sub-variety of the game- cock, in which the tips, having a metallic lustre, “are separated from the lower part of the feather by a symmetrically shaped transparent zone, composed of the naked portions of the barbs.” The lower margin or base of the dark-blue centre of the ocellus is deeply indented on the line of the shaft. The surrounding zones likewise shew traces, as may be seen in the drawing (Fig. 54), of indentations, or rather breaks. These indentations are common to the Indian and Javan peacocks (Pavo cristatus and P. muticus); and they seem to deserve particular attention, as probably connected with the development of the ocellus; but for a long time I could not conjecture their meaning.

If we admit the principle of gradual evolution, there must formerly have existed many species which presented every successive step between the wonderfully elongated tail-coverts of the peacock and the short tail- coverts of all ordinary birds; and again between the magnificent ocelli of the former, and the simpler ocelli or mere coloured spots on other birds; and so with all the other characters of the peacock. Let us look to the allied Gallinaceae for any still-existing gradations. The species and sub- species of Polyplectron inhabit countries adjacent to the native land of the peacock; and they so far resemble this bird that they are sometimes called peacock-pheasants. I am also informed by Mr. Bartlett that they resemble the peacock in their voice and in some of their habits. During the spring the males, as previously described, strut about before the comparatively plain-coloured females, expanding and erecting their tail and wing-feathers, which are ornamented with numerous ocelli. I request the reader to turn back to the drawing (Fig. 51) of a Polyplectron; In P. napoleonis the ocelli are confined to the tail, and the back is of a rich metallic blue; in which respects this species approaches the Java peacock. P. hardwickii possesses a peculiar top-knot, which is also somewhat like that of the Java peacock. In all the species the ocelli on the wings and tail are either circular or oval, and consist of a beautiful, iridescent, greenish-blue or greenish-purple disc, with a black border. This border in P. chinquis shades into brown, edged with cream colour, so that the ocellus is here surrounded with variously shaded, though not bright, concentric zones. The unusual length of the tail-coverts is another remarkable character in Polyplectron; for in some of the species they are half, and in others two-thirds as long as the true tail-feathers. The tail-coverts are ocellated as in the peacock. Thus the several species of Polyplectron manifestly make a graduated approach to the peacock in the length of their tail-coverts, in the zoning of the ocelli, and in some other characters.

[Fig. 55. Part of a tail-covert of Polyplectron chinquis, with the two ocelli of natural size.

Fig. 56. Part of a tail-covert of Polyplectron malaccense, with the two ocelli, partially confluent, of natural size.]

Notwithstanding this approach, the first species of Polyplectron which I examined almost made me give up the search; for I found not only that the true tail-feathers, which in the peacock are quite plain, were ornamented with ocelli, but that the ocelli on all the feathers differed fundamentally from those of the peacock, in there being two on the same feather (Fig. 55), one on each side of the shaft. Hence I concluded that the early progenitors of the peacock could not have resembled a Polyplectron. But on continuing my search, I observed that in some of the species the two ocelli stood very near each other; that in the tail-feathers of P. hardwickii they touched each other; and, finally, that on the tail-coverts of this same species as well as of P. malaccense (Fig. 56) they were actually confluent. As the central part alone is confluent, an indentation is left at both the upper and lower ends; and the surrounding coloured zones are likewise indented. A single ocellus is thus formed on each tail-covert, though still plainly betraying its double origin. These confluent ocelli differ from the single ocelli of the peacock in having an indentation at both ends, instead of only at the lower or basal end. The explanation, however, of this difference is not difficult; in some species of Polyplectron the two oval ocelli on the same feather stand parallel to each other; in other species (as in P. chinquis) they converge towards one end; now the partial confluence of two convergent ocelli would manifestly leave a much deeper indentation at the divergent than at the convergent end. It is also manifest that if the convergence were strongly pronounced and the confluence complete, the indentation at the convergent end would tend to disappear.

The tail-feathers in both species of the peacock are entirely destitute of ocelli, and this apparently is related to their being covered up and concealed by the long tail-coverts. In this respect they differ remarkably from the tail-feathers of Polyplectron, which in most of the species are ornamented with larger ocelli than those on the tail-coverts. Hence I was led carefully to examine the tail-feathers of the several species, in order to discover whether their ocelli shewed any tendency to disappear; and to my great satisfaction, this appeared to be so. The central tail-feathers of P. napoleonis have the two ocelli on each side of the shaft perfectly developed; but the inner ocellus becomes less and less conspicuous on the more exterior tail-feathers, until a mere shadow or rudiment is left on the inner side of the outermost feather. Again, in P. malaccense, the ocelli on the tail-coverts are, as we have seen, confluent; and these feathers are of unusual length, being two-thirds of the length of the tail-feathers, so that in both these respects they approach the tail-coverts of the peacock. Now in P. malaccense, the two central tail-feathers alone are ornamented, each with two brightly-coloured ocelli, the inner ocellus having completely disappeared from all the other tail-feathers. Consequently the tail- coverts and tail-feathers of this species of Polyplectron make a near approach in structure and ornamentation to the corresponding feathers of the peacock.

As far, then, as gradation throws light on the steps by which the magnificent train of the peacock has been acquired, hardly anything more is needed. If we picture to ourselves a progenitor of the peacock in an almost exactly intermediate condition between the existing peacock, with his enormously elongated tail-coverts, ornamented with single ocelli, and an ordinary gallinaceous bird with short tail-coverts, merely spotted with some colour, we shall see a bird allied to Polyplectron—that is, with tail-coverts, capable of erection and expansion, ornamented with two partially confluent ocelli, and long enough almost to conceal the tail- feathers, the latter having already partially lost their ocelli. The indentation of the central disc and of the surrounding zones of the ocellus, in both species of peacock, speaks plainly in favour of this view, and is otherwise inexplicable. The males of Polyplectron are no doubt beautiful birds, but their beauty, when viewed from a little distance, cannot be compared with that of the peacock. Many female progenitors of the peacock must, during a long line of descent, have appreciated this superiority; for they have unconsciously, by the continued preference for the most beautiful males, rendered the peacock the most splendid of living birds.

Argus Pheasant

Another excellent case for investigation is offered by the ocelli on the wing-feathers of the Argus pheasant, which are shaded in so wonderful a manner as to resemble balls lying loose within sockets, and consequently differ from ordinary ocelli. No one, I presume, will attribute the shading, which has excited the admiration of many experienced artists, to chance—to the fortuitous concourse of atoms of colouring matter. That these ornaments should have been formed through the selection of many successive variations, not one of which was originally intended to produce the ball-and-socket effect, seems as incredible as that one of Raphael’s Madonnas should have been formed by the selection of chance daubs of paint made by a long succession of young artists, not one of whom intended at first to draw the human figure. In order to discover how the ocelli have been developed, we cannot look to a long line of progenitors, nor to many closely-allied forms, for such do not now exist. But fortunately the several feathers on the wing suffice to give us a clue to the problem, and they prove to demonstration that a gradation is at least possible from a mere spot to a finished ball-and-socket ocellus.

[Fig. 57. Part of secondary wing-feather of Argus pheasant, shewing two perfect ocelli, a and b. A, B, C, D, etc., are dark stripes running obliquely down, each to an ocellus. [Much of the web on both sides, especially to the left of the shaft, has been cut off.]

Fig.59. Portion of one of the secondary wing-feathers near to the body, shewing the so-called elliptic ornaments. The right-hand figure is given merely as a diagram for the sake of the letters of reference. A, B, C, D, etc. Rows of spots running down to and forming the elliptic ornaments. b. Lowest spot or mark in row B. c. The next succeeding spot or mark in the same row. d. Apparently a broken prolongation of the spot c. in the same row B.]

The wing-feathers, bearing the ocelli, are covered with dark stripes (Fig. 57) or with rows of dark spots (Fig. 59), each stripe or row of spots running obliquely down the outer side of the shaft to one of the ocelli. The spots are generally elongated in a line transverse to the row in which they stand. They often become confluent either in the line of the row—and then they form a longitudinal stripe—or transversely, that is, with the spots in the adjoining rows, and then they form transverse stripes. A spot sometimes breaks up into smaller spots, which still stand in their proper places.

It will be convenient first to describe a perfect ball-and-socket ocellus. This consists of an intensely black circular ring, surrounding a space shaded so as exactly to resemble a ball. The figure here given has been admirably drawn by Mr. Ford and well engraved, but a woodcut cannot exhibit the exquisite shading of the original. The ring is almost always slightly broken or interrupted (Fig. 57) at a point in the upper half, a little to the right of and above the white shade on the enclosed ball; it is also sometimes broken towards the base on the right hand. These little breaks have an important meaning. The ring is always much thickened, with the edges ill-defined towards the left-hand upper corner, the feather being held erect, in the position in which it is here drawn. Beneath this thickened part there is on the surface of the ball an oblique almost pure- white mark, which shades off downwards into a pale-leaden hue, and this into yellowish and brown tints, which insensibly become darker and darker towards the lower part of the ball. It is this shading which gives so admirably the effect of light shining on a convex surface. If one of the balls be examined, it will be seen that the lower part is of a brown tint and is indistinctly separated by a curved oblique line from the upper part, which is yellower and more leaden; this curved oblique line runs at right angles to the longer axis of the white patch of light, and indeed of all the shading; but this difference in colour, which cannot of course be shewn in the woodcut, does not in the least interfere with the perfect shading of the ball. It should be particularly observed that each ocellus stands in obvious connection either with a dark stripe, or with a longitudinal row of dark spots, for both occur indifferently on the same feather. Thus in Fig. 57 stripe A runs to ocellus a; B runs to ocellus b; stripe C is broken in the upper part, and runs down to the next succeeding ocellus, not represented in the woodcut; D to the next lower one, and so with the stripes E and F. Lastly, the several ocelli are separated from each other by a pale surface bearing irregular black marks.

[Fig. 58. Basal part of the secondary wing feather, nearest to the body.]

I will next describe the other extreme of the series, namely, the first trace of an ocellus. The short secondary wing-feather (Fig. 58), nearest to the body, is marked like the other feathers, with oblique, longitudinal, rather irregular, rows of very dark spots. The basal spot, or that nearest the shaft, in the five lower rows (excluding the lowest one) is a little larger than the other spots of the same row, and a little more elongated in a transverse direction. It differs also from the other spots by being bordered on its upper side with some dull fulvous shading. But this spot is not in any way more remarkable than those on the plumage of many birds, and might easily be overlooked. The next higher spot does not differ at all from the upper ones in the same row. The larger basal spots occupy exactly the same relative position on these feathers as do the perfect ocelli on the longer wing-feathers.

By looking to the next two or three succeeding wing-feathers, an absolutely insensible gradation can be traced from one of the last-described basal spots, together with the next higher one in the same row, to a curious ornament, which cannot be called an ocellus, and which I will name, from the want of a better term, an “elliptic ornament.” These are shewn in the accompanying figure (Fig. 59). We here see several oblique rows, A, B, C, D, etc. (see the lettered diagram on the right hand), of dark spots of the usual character. Each row of spots runs down to and is connected with one of the elliptic ornaments, in exactly the same manner as each stripe in Fig. 57 runs down to and is connected with one of the ball-and-socket ocelli. Looking to any one row, for instance, B, in Fig. 59, the lowest mark (b) is thicker and considerably longer than the upper spots, and has its left extremity pointed and curved upwards. This black mark is abruptly bordered on its upper side by a rather broad space of richly shaded tints, beginning with a narrow brown zone, which passes into orange, and this into a pale leaden tint, with the end towards the shaft much paler. These shaded tints together fill up the whole inner space of the elliptic ornament. The mark (b) corresponds in every respect with the basal shaded spot of the simple feather described in the last paragraph (Fig. 58), but is more highly developed and more brightly coloured. Above and to the right of this spot (b, Fig. 59), with its bright shading, there is a long narrow, black mark (c), belonging to the same row, and which is arched a little downwards so as to face (b). This mark is sometimes broken into two portions. It is also narrowly edged on the lower side with a fulvous tint. To the left of and above c, in the same oblique direction, but always more or less distinct from it, there is another black mark (d). This mark is generally sub-triangular and irregular in shape, but in the one lettered in the diagram it is unusually narrow, elongated, and regular. It apparently consists of a lateral and broken prolongation of the mark (c), together with its confluence with a broken and prolonged part of the next spot above; but I do not feel sure of this. These three marks, b, c, and d, with the intervening bright shades, form together the so-called elliptic ornament. These ornaments placed parallel to the shaft, manifestly correspond in position with the ball-and-socket ocelli. Their extremely elegant appearance cannot be appreciated in the drawing, as the orange and leaden tints, contrasting so well with the black marks, cannot be shewn.

[Fig. 60. An ocellus in an intermediate condition between the elliptic ornament and the perfect ball-and-socket ocellus.]

Between one of the elliptic ornaments and a perfect ball-and-socket ocellus, the gradation is so perfect that it is scarcely possible to decide when the latter term ought to be used. The passage from the one into the other is effected by the elongation and greater curvature in opposite directions of the lower black mark (b, Fig. 59), and more especially of the upper one (c), together with the contraction of the elongated sub- triangular or narrow mark (d), so that at last these three marks become confluent, forming an irregular elliptic ring. This ring is gradually rendered more and more circular and regular, increasing at the same time in diameter. I have here given a drawing (Fig. 60) of the natural size of an ocellus not as yet quite perfect. The lower part of the black ring is much more curved than is the lower mark in the elliptic ornament (b, Fig. 59). The upper part of the ring consists of two or three separate portions; and there is only a trace of the thickening of the portion which forms the black mark above the white shade. This white shade itself is not as yet much concentrated; and beneath it the surface is brighter coloured than in a perfect ball-and-socket ocellus. Even in the most perfect ocelli traces of the junction of three or four elongated black marks, by which the ring has been formed, may often be detected. The irregular sub-triangular or narrow mark (d, Fig. 59), manifestly forms, by its contraction and equalisation, the thickened portion of the ring above the white shade on a perfect ball-and-socket ocellus. The lower part of the ring is invariably a little thicker than the other parts (Fig. 57), and this follows from the lower black mark of the elliptic ornament (b, Fig. 59) having originally been thicker than the upper mark (c). Every step can be followed in the process of confluence and modification; and the black ring which surrounds the ball of the ocellus is unquestionably formed by the union and modification of the three black marks, b, c, d, of the elliptic ornament. The irregular zigzag black marks between the successive ocelli (Fig. 57) are plainly due to the breaking up of the somewhat more regular but similar marks between the elliptic ornaments.

The successive steps in the shading of the ball-and-socket ocelli can be followed out with equal clearness. The brown, orange, and pale-leadened narrow zones, which border the lower black mark of the elliptic ornament, can be seen gradually to become more and more softened and shaded into each other, with the upper lighter part towards the left-hand corner rendered still lighter, so as to become almost white, and at the same time more contracted. But even in the most perfect ball-and-socket ocelli a slight difference in the tints, though not in the shading, between the upper and lower parts of the ball can be perceived, as before noticed; and the line of separation is oblique, in the same direction as the bright coloured shades of the elliptic ornaments. Thus almost every minute detail in the shape and colouring of the ball-and-socket ocelli can be shewn to follow from gradual changes in the elliptic ornaments; and the development of the latter can be traced by equally small steps from the union of two almost simple spots, the lower one (Fig. 58) having some dull fulvous shading on its upper side.

[Fig. 61. Portion near summit of one of the secondary wing-feathers, bearing perfect ball-and-socket ocelli. a. Ornamented upper part. b. Uppermost, imperfect ball-and-socket ocellus. (The shading above the white mark on the summit of the ocellus is here a little too dark.) c. Perfect ocellus.]

The extremities of the longer secondary feathers which bear the perfect ball-and-socket ocelli, are peculiarly ornamented (Fig. 61). The oblique longitudinal stripes suddenly cease upwards and become confused; and above this limit the whole upper end of the feather (a) is covered with white dots, surrounded by little black rings, standing on a dark ground. The oblique stripe belonging to the uppermost ocellus (b) is barely represented by a very short irregular black mark with the usual, curved, transverse base. As this stripe is thus abruptly cut off, we can perhaps understand from what has gone before, how it is that the upper thickened part of the ring is here absent; for, as before stated, this thickened part apparently stands in some relation with a broken prolongation from the next higher spot. From the absence of the upper and thickened part of the ring, the uppermost ocellus, though perfect in all other respects, appears as if its top had been obliquely sliced off. It would, I think, perplex any one, who believes that the plumage of the Argus pheasant was created as we now see it, to account for the imperfect condition of the uppermost ocellus. I should add that on the secondary wing-feather farthest from the body all the ocelli are smaller and less perfect than on the other feathers, and have the upper part of the ring deficient, as in the case just mentioned. The imperfection here seems to be connected with the fact that the spots on this feather shew less tendency than usual to become confluent into stripes; they are, on the contrary, often broken up into smaller spots, so that two or three rows run down to the same ocellus.

There still remains another very curious point, first observed by Mr. T.W. Wood (51. The ‘Field,’ May 28, 1870.), which deserves attention. In a photograph, given me by Mr. Ward, of a specimen mounted as in the act of display, it may be seen that on the feathers which are held perpendicularly, the white marks on the ocelli, representing light reflected from a convex surface, are at the upper or further end, that is, are directed upwards; and the bird whilst displaying himself on the ground would naturally be illuminated from above. But here comes the curious point; the outer feathers are held almost horizontally, and their ocelli ought likewise to appear as if illuminated from above, and consequently the white marks ought to be placed on the upper sides of the ocelli; and, wonderful as is the fact, they are thus placed! Hence the ocelli on the several feathers, though occupying very different positions with respect to the light, all appear as if illuminated from above, just as an artist would have shaded them. Nevertheless they are not illuminated from strictly the same point as they ought to be; for the white marks on the ocelli of the feathers which are held almost horizontally, are placed rather too much towards the further end; that is, they are not sufficiently lateral. We have, however, no right to expect absolute perfection in a part rendered ornamental through sexual selection, any more than we have in a part modified through natural selection for real use; for instance, in that wondrous organ the human eye. And we know what Helmholtz, the highest authority in Europe on the subject, has said about the human eye; that if an optician had sold him an instrument so carelessly made, he would have thought himself fully justified in returning it. (52. ‘Popular Lectures on Scientific Subjects,’ Eng. trans. 1873, pp. 219, 227, 269, 390.)

We have now seen that a perfect series can be followed, from simple spots to the wonderful ball-and-socket ornaments. Mr. Gould, who kindly gave me some of these feathers, fully agrees with me in the completeness of the gradation. It is obvious that the stages in development exhibited by the feathers on the same bird do not at all necessarily shew us the steps passed through by the extinct progenitors of the species; but they probably give us the clue to the actual steps, and they at least prove to demonstration that a gradation is possible. Bearing in mind how carefully the male Argus pheasant displays his plumes before the female, as well as the many facts rendering it probable that female birds prefer the more attractive males, no one who admits the agency of sexual selection in any case will deny that a simple dark spot with some fulvous shading might be converted, through the approximation and modification of two adjoining spots, together with some slight increase of colour, into one of the so- called elliptic ornaments. These latter ornaments have been shewn to many persons, and all have admitted that they are beautiful, some thinking them even more so than the ball-and-socket ocelli. As the secondary plumes became lengthened through sexual selection, and as the elliptic ornaments increased in diameter, their colours apparently became less bright; and then the ornamentation of the plumes had to be gained by an improvement in the pattern and shading; and this process was carried on until the wonderful ball-and-socket ocelli were finally developed. Thus we can understand—and in no other way as it seems to me—the present condition and origin of the ornaments on the wing-feathers of the Argus pheasant.

From the light afforded by the principle of gradation—from what we know of the laws of variation—from the changes which have taken place in many of our domesticated birds—and, lastly, from the character (as we shall hereafter see more clearly) of the immature plumage of young birds—we can sometimes indicate, with a certain amount of confidence, the probable steps by which the males have acquired their brilliant plumage and various ornaments; yet in many cases we are involved in complete darkness. Mr. Gould several years ago pointed out to me a humming-bird, the Urosticte benjamini, remarkable for the curious differences between the sexes. The male, besides a splendid gorget, has greenish-black tail-feathers, with the four CENTRAL ones tipped with white; in the female, as with most of the allied species, the three OUTER tail-feathers on each side are tipped with white, so that the male has the four central, whilst the female has the six exterior feathers ornamented with white tips. What makes the case more curious is that, although the colouring of the tail differs remarkably in both sexes of many kinds of humming-birds, Mr. Gould does not know a single species, besides the Urosticte, in which the male has the four central feathers tipped with white.

The Duke of Argyll, in commenting on this case (53. ‘The Reign of Law,’ 1867, p. 247.), passes over sexual selection, and asks, “What explanation does the law of natural selection give of such specific varieties as these?” He answers “none whatever”; and I quite agree with him. But can this be so confidently said of sexual selection? Seeing in how many ways the tail-feathers of humming-birds differ, why should not the four central feathers have varied in this one species alone, so as to have acquired white tips? The variations may have been gradual, or somewhat abrupt as in the case recently given of the humming-birds near Bogota, in which certain individuals alone have the “central tail-feathers tipped with beautiful green.” In the female of the Urosticte I noticed extremely minute or rudimental white tips to the two outer of the four central black tail- feathers; so that here we have an indication of change of some kind in the plumage of this species. If we grant the possibility of the central tail- feathers of the male varying in whiteness, there is nothing strange in such variations having been sexually selected. The white tips, together with the small white ear-tufts, certainly add, as the Duke of Argyll admits, to the beauty of the male; and whiteness is apparently appreciated by other birds, as may be inferred from such cases as the snow-white male of the Bell-bird. The statement made by Sir R. Heron should not be forgotten, namely, that his peahens, when debarred from access to the pied peacock, would not unite with any other male, and during that season produced no offspring. Nor is it strange that variations in the tail-feathers of the Urosticte should have been specially selected for the sake of ornament, for the next succeeding genus in the family takes its name of Metallura from the splendour of these feathers. We have, moreover, good evidence that humming-birds take especial pains in displaying their tail-feathers; Mr. Belt (54. ‘The Naturalist in Nicaragua,’ 1874, p. 112.), after describing the beauty of the Florisuga mellivora, says, “I have seen the female sitting on a branch, and two males displaying their charms in front of her. One would shoot up like a rocket, then suddenly expanding the snow-white tail, like an inverted parachute, slowly descend in front of her, turning round gradually to shew off back and front…The expanded white tail covered more space than all the rest of the bird, and was evidently the grand feature in the performance. Whilst one male was descending, the other would shoot up and come slowly down expanded. The entertainment would end in a fight between the two performers; but whether the most beautiful or the most pugnacious was the accepted suitor, I know not.” Mr. Gould, after describing the peculiar plumage of the Urosticte, adds, “that ornament and variety is the sole object, I have myself but little doubt.” (55. ‘Introduction to the Trochilidae,’ 1861, p.

第十五章 •9,000字
鸟类-续

Discussion as to why the males alone of some species, and both sexes of others, are brightly coloured—On sexually-limited inheritance, as applied to various structures and to brightly-coloured plumage—Nidification in relation to colour—Loss of nuptial plumage during the winter.

We have in this chapter to consider why the females of many birds have not acquired the same ornaments as the male; and why, on the other hand, both sexes of many other birds are equally, or almost equally, ornamented? In the following chapter we shall consider the few cases in which the female is more conspicuously coloured than the male.

In my ‘Origin of Species’ (1. Fourth edition, 1866, p. 241.) I briefly suggested that the long tail of the peacock would be inconvenient and the conspicuous black colour of the male capercailzie dangerous, to the female during the period of incubation: and consequently that the transmission of these characters from the male to the female offspring had been checked through natural selection. I still think that this may have occurred in some few instances: but after mature reflection on all the facts which I have been able to collect, I am now inclined to believe that when the sexes differ, the successive variations have generally been from the first limited in their transmission to the same sex in which they first arose. Since my remarks appeared, the subject of sexual coloration has been discussed in some very interesting papers by Mr. Wallace (2. ‘Westminster Review,’ July 1867. ‘Journal of Travel,’ vol. i. 1868, p. 73.), who believes that in almost all cases the successive variations tended at first to be transmitted equally to both sexes; but that the female was saved, through natural selection, from acquiring the conspicuous colours of the male, owing to the danger which she would thus have incurred during incubation.

This view necessitates a tedious discussion on a difficult point, namely, whether the transmission of a character, which is at first inherited by both sexes can be subsequently limited in its transmission to one sex alone by means of natural selection. We must bear in mind, as shewn in the preliminary chapter on sexual selection, that characters which are limited in their development to one sex are always latent in the other. An imaginary illustration will best aid us in seeing the difficulty of the case; we may suppose that a fancier wished to make a breed of pigeons, in which the males alone should be coloured of a pale blue, whilst the females retained their former slaty tint. As with pigeons characters of all kinds are usually transmitted to both sexes equally, the fancier would have to try to convert this latter form of inheritance into sexually-limited transmission. All that he could do would be to persevere in selecting every male pigeon which was in the least degree of a paler blue; and the natural result of this process, if steadily carried on for a long time, and if the pale variations were strongly inherited or often recurred, would be to make his whole stock of a lighter blue. But our fancier would be compelled to match, generation after generation, his pale blue males with slaty females, for he wishes to keep the latter of this colour. The result would generally be the production either of a mongrel piebald lot, or more probably the speedy and complete loss of the pale-blue tint; for the primordial slaty colour would be transmitted with prepotent force. Supposing, however, that some pale-blue males and slaty females were produced during each successive generation, and were always crossed together, then the slaty females would have, if I may use the expression, much blue blood in their veins, for their fathers, grandfathers, etc., will all have been blue birds. Under these circumstances it is conceivable (though I know of no distinct facts rendering it probable) that the slaty females might acquire so strong a latent tendency to pale-blueness, that they would not destroy this colour in their male offspring, their female offspring still inheriting the slaty tint. If so, the desired end of making a breed with the two sexes permanently different in colour might be gained.

The extreme importance, or rather necessity in the above case of the desired character, namely, pale-blueness, being present though in a latent state in the female, so that the male offspring should not be deteriorated, will be best appreciated as follows: the male of Soemmerring’s pheasant has a tail thirty-seven inches in length, whilst that of the female is only eight inches; the tail of the male common pheasant is about twenty inches, and that of the female twelve inches long. Now if the female Soemmerring pheasant with her SHORT tail were crossed with the male common pheasant, there can be no doubt that the male hybrid offspring would have a much LONGER tail than that of the pure offspring of the common pheasant. On the other hand, if the female common pheasant, with a tail much longer than that of the female Soemmerring pheasant, were crossed with the male of the latter, the male hybrid offspring would have a much SHORTER tail than that of the pure offspring of Soemmerring’s pheasant. (3. Temminck says that the tail of the female Phasianus Soemmerringii is only six inches long, ‘Planches coloriees,’ vol. v. 1838, pp. 487 and 488: the measurements above given were made for me by Mr. Sclater. For the common pheasant, see Macgillivray, ‘History of British Birds,’ vol. i. pp. 118-121.)

Our fancier, in order to make his new breed with the males of a pale-blue tint, and the females unchanged, would have to continue selecting the males during many generations; and each stage of paleness would have to be fixed in the males, and rendered latent in the females. The task would be an extremely difficult one, and has never been tried, but might possibly be successfully carried out. The chief obstacle would be the early and complete loss of the pale-blue tint, from the necessity of reiterated crosses with the slaty female, the latter not having at first any LATENT tendency to produce pale-blue offspring.

On the other hand, if one or two males were to vary ever so slightly in paleness, and the variations were from the first limited in their transmission to the male sex, the task of making a new breed of the desired kind would be easy, for such males would simply have to be selected and matched with ordinary females. An analogous case has actually occurred, for there are breeds of the pigeon in Belgium (4. Dr. Chapuis, ‘Le Pigeon Voyageur Belge,’ 1865, p. 87.) in which the males alone are marked with black striae. So again Mr. Tegetmeier has recently shewn (5. The ‘Field,’ Sept. 1872.) that dragons not rarely produce silver-coloured birds, which are almost always hens; and he himself has bred ten such females. It is on the other hand a very unusual event when a silver male is produced; so that nothing would be easier, if desired, than to make a breed of dragons with blue males and silver females. This tendency is indeed so strong that when Mr. Tegetmeier at last got a silver male and matched him with one of the silver females, he expected to get a breed with both sexes thus coloured; he was however disappointed, for the young male reverted to the blue colour of his grandfather, the young female alone being silver. No doubt with patience this tendency to reversion in the males, reared from an occasional silver male matched with a silver hen, might be eliminated, and then both sexes would be coloured alike; and this very process has been followed with success by Mr. Esquilant in the case of silver turbits.

With fowls, variations of colour, limited in their transmission to the male sex, habitually occur. When this form of inheritance prevails, it might well happen that some of the successive variations would be transferred to the female, who would then slightly resemble the male, as actually occurs in some breeds. Or again, the greater number, but not all, of the successive steps might be transferred to both sexes, and the female would then closely resemble the male. There can hardly be a doubt that this is the cause of the male pouter pigeon having a somewhat larger crop, and of the male carrier pigeon having somewhat larger wattles, than their respective females; for fanciers have not selected one sex more than the other, and have had no wish that these characters should be more strongly displayed in the male than in the female, yet this is the case with both breeds.

The same process would have to be followed, and the same difficulties encountered, if it were desired to make a breed with the females alone of some new colour.

Lastly, our fancier might wish to make a breed with the two sexes differing from each other, and both from the parent species. Here the difficulty would be extreme, unless the successive variations were from the first sexually limited on both sides, and then there would be no difficulty. We see this with the fowl; thus the two sexes of the pencilled Hamburghs differ greatly from each other, and from the two sexes of the aboriginal Gallus bankiva; and both are now kept constant to their standard of excellence by continued selection, which would be impossible unless the distinctive characters of both were limited in their transmission.

The Spanish fowl offers a more curious case; the male has an immense comb, but some of the successive variations, by the accumulation of which it was acquired, appear to have been transferred to the female; for she has a comb many times larger than that of the females of the parent species. But the comb of the female differs in one respect from that of the male, for it is apt to lop over; and within a recent period it has been ordered by the fancy that this should always be the case, and success has quickly followed the order. Now the lopping of the comb must be sexually limited in its transmission, otherwise it would prevent the comb of the male from being perfectly upright, which would be abhorrent to every fancier. On the other hand, the uprightness of the comb in the male must likewise be a sexually- limited character, otherwise it would prevent the comb of the female from lopping over.

From the foregoing illustrations, we see that even with almost unlimited time at command, it would be an extremely difficult and complex, perhaps an impossible process, to change one form of transmission into the other through selection. Therefore, without distinct evidence in each case, I am unwilling to admit that this has been effected in natural species. On the other hand, by means of successive variations, which were from the first

sexually limited in their transmission, there would not be the least difficulty in rendering a male bird widely different in colour or in any other character from the female; the latter being left unaltered, or slightly altered, or specially modified for the sake of protection.

As bright colours are of service to the males in their rivalry with other males, such colours would be selected whether or not they were transmitted exclusively to the same sex. Consequently the females might be expected often to partake of the brightness of the males to a greater or less degree; and this occurs with a host of species. If all the successive variations were transmitted equally to both sexes, the females would be indistinguishable from the males; and this likewise occurs with many birds. If, however, dull colours were of high importance for the safety of the female during incubation, as with many ground birds, the females which varied in brightness, or which received through inheritance from the males any marked accession of brightness, would sooner or later be destroyed. But the tendency in the males to continue for an indefinite period transmitting to their female offspring their own brightness, would have to be eliminated by a change in the form of inheritance; and this, as shewn by our previous illustration, would be extremely difficult. The more probable result of the long-continued destruction of the more brightly-coloured females, supposing the equal form of transmission to prevail, would be the lessening or annihilation of the bright colours of the males, owing to their continual crossing with the duller females. It would be tedious to follow out all the other possible results; but I may remind the reader that if sexually-limited variations in brightness occurred in the females, even if they were not in the least injurious to them and consequently were not eliminated, yet they would not be favoured or selected, for the male usually accepts any female, and does not select the more attractive individuals; consequently these variations would be liable to be lost, and would have little influence on the character of the race; and this will aid in accounting for the females being commonly duller-coloured than the males.

In the eighth chapter instances were given, to which many might here be added, of variations occurring at various ages, and inherited at the corresponding age. It was also shewn that variations which occur late in life are commonly transmitted to the same sex in which they first appear; whilst variations occurring early in life are apt to be transmitted to both sexes; not that all the cases of sexually-limited transmission can thus be accounted for. It was further shewn that if a male bird varied by becoming brighter whilst young, such variations would be of no service until the age for reproduction had arrived, and there was competition between rival males. But in the case of birds living on the ground and commonly in need of the protection of dull colours, bright tints would be far more dangerous to the young and inexperienced than to the adult males. Consequently the males which varied in brightness whilst young would suffer much destruction and be eliminated through natural selection; on the other hand, the males which varied in this manner when nearly mature, notwithstanding that they were exposed to some additional danger, might survive, and from being favoured through sexual selection, would procreate their kind. As a relation often exists between the period of variation and the form of transmission, if the bright-coloured young males were destroyed and the mature ones were successful in their courtship, the males alone would acquire brilliant colours and would transmit them exclusively to their male offspring. But I by no means wish to maintain that the influence of age on the form of transmission, is the sole cause of the great difference in brilliancy between the sexes of many birds.

When the sexes of birds differ in colour, it is interesting to determine whether the males alone have been modified by sexual selection, the females having been left unchanged, or only partially and indirectly thus changed; or whether the females have been specially modified through natural selection for the sake of protection. I will therefore discuss this question at some length, even more fully than its intrinsic importance deserves; for various curious collateral points may thus be conveniently considered.

Before we enter on the subject of colour, more especially in reference to Mr. Wallace’s conclusions, it may be useful to discuss some other sexual differences under a similar point of view. A breed of fowls formerly existed in Germany (6. Bechstein, ‘Naturgeschichte Deutschlands,’ 1793, B. iii. 339.) in which the hens were furnished with spurs; they were good layers, but they so greatly disturbed their nests with their spurs that they could not be allowed to sit on their own eggs. Hence at one time it appeared to me probable that with the females of the wild Gallinaceae the development of spurs had been checked through natural selection, from the injury thus caused to their nests. This seemed all the more probable, as wing-spurs, which would not be injurious during incubation, are often as well-developed in the female as in the male; though in not a few cases they are rather larger in the male. When the male is furnished with leg-spurs the female almost always exhibits rudiments of them,—the rudiment sometimes consisting of a mere scale, as in Gallus. Hence it might be argued that the females had aboriginally been furnished with well-developed spurs, but that these had subsequently been lost through disuse or natural selection. But if this view be admitted, it would have to be extended to innumerable other cases; and it implies that the female progenitors of the existing spur-bearing species were once encumbered with an injurious appendage.

In some few genera and species, as in Galloperdix, Acomus, and the Javan peacock (Pavo muticus), the females, as well as the males, possess well- developed leg-spurs. Are we to infer from this fact that they construct a different sort of nest from that made by their nearest allies, and not liable to be injured by their spurs; so that the spurs have not been removed? Or are we to suppose that the females of these several species especially require spurs for their defence? It is a more probable conclusion that both the presence and absence of spurs in the females result from different laws of inheritance having prevailed, independently of natural selection. With the many females in which spurs appear as rudiments, we may conclude that some few of the successive variations, through which they were developed in the males, occurred very early in life, and were consequently transferred to the females. In the other and much rarer cases, in which the females possess fully developed spurs, we may conclude that all the successive variations were transferred to them; and that they gradually acquired and inherited the habit of not disturbing their nests.

The vocal organs and the feathers variously modified for producing sound, as well as the proper instincts for using them, often differ in the two sexes, but are sometimes the same in both. Can such differences be accounted for by the males having acquired these organs and instincts, whilst the females have been saved from inheriting them, on account of the danger to which they would have been exposed by attracting the attention of birds or beasts of prey? This does not seem to me probable, when we think of the multitude of birds which with impunity gladden the country with their voices during the spring. (7. Daines Barrington, however, thought it probable (‘Philosophical Transactions,’ 1773, p. 164) that few female birds sing, because the talent would have been dangerous to them during incubation. He adds, that a similar view may possibly account for the inferiority of the female to the male in plumage.) It is a safer conclusion that, as vocal and instrumental organs are of special service only to the males during their courtship, these organs were developed through sexual selection and their constant use in that sex alone—the successive variations and the effects of use having been from the first more or less limited in transmission to the male offspring.

Many analogous cases could be adduced; those for instance of the plumes on the head being generally longer in the male than in the female, sometimes of equal length in both sexes, and occasionally absent in the female,— these several cases occurring in the same group of birds. It would be difficult to account for such a difference between the sexes by the female having been benefited by possessing a slightly shorter crest than the male, and its consequent diminution or complete suppression through natural selection. But I will take a more favourable case, namely the length of the tail. The long train of the peacock would have been not only inconvenient but dangerous to the peahen during the period of incubation and whilst accompanying her young. Hence there is not the least a priori improbability in the development of her tail having been checked through natural selection. But the females of various pheasants, which apparently are exposed on their open nests to as much danger as the peahen, have tails of considerable length. The females as well as the males of the Menura superba have long tails, and they build a domed nest, which is a great anomaly in so large a bird. Naturalists have wondered how the female Menura could manage her tail during incubation; but it is now known (8. Mr. Ramsay, in ‘Proc. Zoolog. Soc.’ 1868, p. 50.) that she “enters the nest head first, and then turns round with her tail sometimes over her back, but more often bent round by her side. Thus in time the tail becomes quite askew, and is a tolerable guide to the length of time the bird has been sitting.” Both sexes of an Australian kingfisher (Tanysiptera sylvia) have the middle tail-feathers greatly lengthened, and the female makes her nest in a hole; and as I am informed by Mr. R.B. Sharpe these feathers become much crumpled during incubation.

In these two latter cases the great length of the tail-feathers must be in some degree inconvenient to the female; and as in both species the tail- feathers of the female are somewhat shorter than those of the male, it might be argued that their full development had been prevented through natural selection. But if the development of the tail of the peahen had been checked only when it became inconveniently or dangerously great, she would have retained a much longer tail than she actually possesses; for her tail is not nearly so long, relatively to the size of her body, as that of many female pheasants, nor longer than that of the female turkey. It must also be borne in mind that, in accordance with this view, as soon as the tail of the peahen became dangerously long, and its development was consequently checked, she would have continually reacted on her male progeny, and thus have prevented the peacock from acquiring his present magnificent train. We may therefore infer that the length of the tail in the peacock and its shortness in the peahen are the result of the requisite variations in the male having been from the first transmitted to the male offspring alone.

We are led to a nearly similar conclusion with respect to the length of the tail in the various species of pheasants. In the Eared pheasant (Crossoptilon auritum) the tail is of equal length in both sexes, namely sixteen or seventeen inches; in the common pheasant it is about twenty inches long in the male and twelve in the female; in Soemmerring’s pheasant, thirty-seven inches in the male and only eight in the female; and lastly in Reeve’s pheasant it is sometimes actually seventy-two inches long in the male and sixteen in the female. Thus in the several species, the tail of the female differs much in length, irrespectively of that of the male; and this can be accounted for, as it seems to me, with much more probability, by the laws of inheritance,—that is by the successive variations having been from the first more or less closely limited in their transmission to the male sex than by the agency of natural selection, resulting from the length of tail being more or less injurious to the females of these several allied species.

We may now consider Mr. Wallace’s arguments in regard to the sexual coloration of birds. He believes that the bright tints originally acquired through sexual selection by the males would in all, or almost all cases, have been transmitted to the females, unless the transference had been checked through natural selection. I may here remind the reader that various facts opposed to this view have already been given under reptiles, amphibians, fishes and lepidoptera. Mr. Wallace rests his belief chiefly, but not exclusively, as we shall see in the next chapter, on the following statement (9. ‘Journal of Travel,’ edited by A. Murray, vol. i. 1868, p. 78.), that when both sexes are coloured in a very conspicuous manner, the nest is of such a nature as to conceal the sitting bird; but when there is a marked contrast of colour between the sexes, the male being gay and the female dull-coloured, the nest is open and exposes the sitting bird to view. This coincidence, as far as it goes, certainly seems to favour the belief that the females which sit on open nests have been specially modified for the sake of protection; but we shall presently see that there is another and more probable explanation, namely, that conspicuous females have acquired the instinct of building domed nests oftener than dull- coloured birds. Mr. Wallace admits that there are, as might have been expected, some exceptions to his two rules, but it is a question whether the exceptions are not so numerous as seriously to invalidate them.

There is in the first place much truth in the Duke of Argyll’s remark (10. ‘Journal of Travel,’ edited by A. Murray, vol. i. 1868, p. 281.) that a large domed nest is more conspicuous to an enemy, especially to all tree- haunting carnivorous animals, than a smaller open nest. Nor must we forget that with many birds which build open nests, the male sits on the eggs and aids the female in feeding the young: this is the case, for instance, with Pyranga aestiva (11. Audubon, ‘Ornithological Biography,’ vol. i. p. 233.), one of the most splendid birds in the United States, the male being vermilion, and the female light brownish-green. Now if brilliant colours had been extremely dangerous to birds whilst sitting on their open nests, the males in these cases would have suffered greatly. It might, however, be of such paramount importance to the male to be brilliantly coloured, in order to beat his rivals, that this may have more than compensated some additional danger.

Mr. Wallace admits that with the King-crows (Dicrurus), Orioles, and Pittidae, the females are conspicuously coloured, yet build open nests; but he urges that the birds of the first group are highly pugnacious and could defend themselves; that those of the second group take extreme care in concealing their open nests, but this does not invariably hold good (12. Jerdon, ‘Birds of India,’ vol. ii. p. 108. Gould’s ‘Handbook of the Birds of Australia,’ vol. i. p. 463.); and that with the birds of the third group the females are brightly coloured chiefly on the under surface. Besides these cases, pigeons which are sometimes brightly, and almost always conspicuously coloured, and which are notoriously liable to the attacks of birds of prey, offer a serious exception to the rule, for they almost always build open and exposed nests. In another large family, that of the humming-birds, all the species build open nests, yet with some of the most gorgeous species the sexes are alike; and in the majority, the females, though less brilliant than the males, are brightly coloured. Nor can it be maintained that all female humming-birds, which are brightly coloured, escape detection by their tints being green, for some display on their upper surfaces red, blue, and other colours. (13. For instance, the female Eupetomena macroura has the head and tail dark blue with reddish loins; the female Lampornis porphyrurus is blackish-green on the upper surface, with the lores and sides of the throat crimson; the female Eulampis jugularis has the top of the head and back green, but the loins and the tail are crimson. Many other instances of highly conspicuous females could be given. See Mr. Gould’s magnificent work on this family.)

In regard to birds which build in holes or construct domed nests, other advantages, as Mr. Wallace remarks, besides concealment are gained, such as shelter from the rain, greater warmth, and in hot countries protection from the sun (14. Mr. Salvin noticed in Guatemala (‘Ibis,’ 1864, p. 375) that humming-birds were much more unwilling to leave their nests during very hot weather, when the sun was shining brightly, as if their eggs would be thus injured, than during cool, cloudy, or rainy weather.); so that it is no valid objection to his view that many birds having both sexes obscurely coloured build concealed nests. (15. I may specify, as instances of dull- coloured birds building concealed nests, the species belonging to eight Australian genera described in Gould’s ‘Handbook of the Birds of Australia,’ vol. i. pp. 340, 362, 365, 383, 387, 389, 391, 414.) The female Horn-bill (Buceros), for instance, of India and Africa is protected during incubation with extraordinary care, for she plasters up with her own excrement the orifice of the hole in which she sits on her eggs, leaving only a small orifice through which the male feeds her; she is thus kept a close prisoner during the whole period of incubation (16. Mr. C. Horne, ‘Proc. Zoolog. Soc.’ 1869. p. 243.); yet female horn-bills are not more conspicuously coloured than many other birds of equal size which build open nests. It is a more serious objection to Mr. Wallace’s view, as is admitted by him, that in some few groups the males are brilliantly coloured and the females obscure, and yet the latter hatch their eggs in domed nests. This is the case with the Grallinae of Australia, the Superb Warblers (Maluridae) of the same country, the Sun-birds (Nectariniae), and with several of the Australian Honey-suckers or Meliphagidae. (17. On the nidification and colours of these latter species, see Gould’s ‘Handbook to the Birds of Australia,’ vol. i. pp. 504, 527.)

If we look to the birds of England we shall see that there is no close and general relation between the colours of the female and the nature of the nest which is constructed. About forty of our British birds (excluding those of large size which could defend themselves) build in holes in banks, rocks, or trees, or construct domed nests. If we take the colours of the female goldfinch, bullfinch, or blackbird, as a standard of the degree of conspicuousness, which is not highly dangerous to the sitting female, then out of the above forty birds the females of only twelve can be considered as conspicuous to a dangerous degree, the remaining twenty-eight being inconspicuous. (18. I have consulted, on this subject, Macgillivray’s ‘British Birds,’ and though doubts may be entertained in some cases in regard to the degree of concealment of the nest, and to the degree of conspicuousness of the female, yet the following birds, which all lay their eggs in holes or in domed nests, can hardly be considered, by the above standard, as conspicuous: Passer, 2 species; Sturnus, of which the female is considerably less brilliant than the male; Cinclus; Motallica boarula (?); Erithacus (?); Fruticola, 2 sp.; Saxicola; Ruticilla, 2 sp.; Sylvia, 3 sp.; Parus, 3 sp.; Mecistura; Anorthura; Certhia; Sitta; Yunx; Muscicapa, 2 sp.; Hirundo, 3 sp.; and Cypselus. The females of the following 12 birds may be considered as conspicuous according to the same standard, viz., Pastor, Motacilla alba, Parus major and P. caeruleus, Upupa, Picus, 4 sp., Coracias, Alcedo, and Merops.) Nor is there any close relation within the same genus between a well-pronounced difference in colour between the sexes, and the nature of the nest constructed. Thus the male house sparrow (Passer domesticus) differs much from the female, the male tree-sparrow (P. montanus) hardly at all, and yet both build well-concealed nests. The two sexes of the common fly-catcher (Muscicapa grisola) can hardly be distinguished, whilst the sexes of the pied fly-catcher (M. luctuosa) differ considerably, and both species build in holes or conceal their nests. The female blackbird (Turdus merula) differs much, the female ring- ouzel (T. torquatus) differs less, and the female common thrush (T. musicus) hardly at all from their respective males; yet all build open nests. On the other hand, the not very distantly-allied water-ouzel (Cinclus aquaticus) builds a domed nest, and the sexes differ about as much as in the ring-ouzel. The black and red grouse (Tetrao tetrix and T. scoticus) build open nests in equally well-concealed spots, but in the one species the sexes differ greatly, and in the other very little.

Notwithstanding the foregoing objections, I cannot doubt, after reading Mr. Wallace’s excellent essay, that looking to the birds of the world, a large majority of the species in which the females are conspicuously coloured (and in this case the males with rare exceptions are equally conspicuous), build concealed nests for the sake of protection. Mr. Wallace enumerates (19. ‘Journal of Travel,’ edited by A. Murray, vol. i. p. 78.) a long series of groups in which this rule holds good; but it will suffice here to give, as instances, the more familiar groups of kingfishers, toucans, trogons, puff-birds (Capitonidae), plantain-eaters (Musophagae, woodpeckers, and parrots. Mr. Wallace believes that in these groups, as the males gradually acquired through sexual selection their brilliant colours, these were transferred to the females and were not eliminated by natural selection, owing to the protection which they already enjoyed from their manner of nidification. According to this view, their present manner of nesting was acquired before their present colours. But it seems to me much more probable that in most cases, as the females were gradually rendered more and more brilliant from partaking of the colours of the male, they were gradually led to change their instincts (supposing that they originally built open nests), and to seek protection by building domed or concealed nests. No one who studies, for instance, Audubon’s account of the differences in the nests of the same species in the Northern and Southern United States (20. See many statements in the ‘Ornithological Biography.’ See also some curious observations on the nests of Italian birds by Eugenio Bettoni, in the ‘Atti della Società Italiana,’ vol. xi. 1869, p. 487.), will feel any great difficulty in admitting that birds, either by a change (in the strict sense of the word) of their habits, or through the natural selection of so-called spontaneous variations of instinct, might readily be led to modify their manner of nesting.

This way of viewing the relation, as far as it holds good, between the bright colours of female birds and their manner of nesting, receives some support from certain cases occurring in the Sahara Desert. Here, as in most other deserts, various birds, and many other animals, have had their colours adapted in a wonderful manner to the tints of the surrounding surface. Nevertheless there are, as I am informed by the Rev. Mr. Tristram, some curious exceptions to the rule; thus the male of the Monticola cyanea is conspicuous from his bright blue colour, and the female almost equally conspicuous from her mottled brown and white plumage; both sexes of two species of Dromolaea are of a lustrous black; so that these three species are far from receiving protection from their colours, yet they are able to survive, for they have acquired the habit of taking refuge from danger in holes or crevices in the rocks.

With respect to the above groups in which the females are conspicuously coloured and build concealed nests, it is not necessary to suppose that each separate species had its nidifying instinct specially modified; but only that the early progenitors of each group were gradually led to build domed or concealed nests, and afterwards transmitted this instinct, together with their bright colours, to their modified descendants. As far as it can be trusted, the conclusion is interesting, that sexual selection together with equal or nearly equal inheritance by both sexes, have indirectly determined the manner of nidification of whole groups of birds.

According to Mr. Wallace, even in the groups in which the females, from being protected in domed nests during incubation, have not had their bright colours eliminated through natural selection, the males often differ in a slight, and occasionally in a considerable degree from the females. This is a significant fact, for such differences in colour must be accounted for by some of the variations in the males having been from the first limited in transmission to the same sex; as it can hardly be maintained that these differences, especially when very slight, serve as a protection to the female. Thus all the species in the splendid group of the Trogons build in holes; and Mr. Gould gives figures (21. See his Monograph of the Trogonidae, 1st edition.) of both sexes of twenty-five species, in all of which, with one partial exception, the sexes differ sometimes slightly, sometimes conspicuously, in colour,—the males being always finer than the females, though the latter are likewise beautiful. All the species of kingfishers build in holes, and with most of the species the sexes are equally brilliant, and thus far Mr. Wallace’s rule holds good; but in some of the Australian species the colours of the females are rather less vivid than those of the male; and in one splendidly-coloured species, the sexes differ so much that they were at first thought to be specifically distinct. (22. Namely, Cyanalcyon, Gould’s ‘Handbook to the Birds of Australia,’ vol. i. p. 133; see, also, pp. 130, 136.) Mr. R.B. Sharpe, who has especially studied this group, has shewn me some American species (Ceryle) in which the breast of the male is belted with black. Again, in Carcineutes, the difference between the sexes is conspicuous: in the male the upper surface is dull-blue banded with black, the lower surface being partly fawn-coloured, and there is much red about the head; in the female the upper surface is reddish-brown banded with black, and the lower surface white with black markings. It is an interesting fact, as shewing how the same peculiar style of sexual colouring often characterises allied forms, that in three species of Dacelo the male differs from the female only in the tail being dull-blue banded with black, whilst that of the female is brown with blackish bars; so that here the tail differs in colour in the two sexes in exactly the same manner as the whole upper surface in the two sexes of Carcineutes.

With parrots, which likewise build in holes, we find analogous cases: in most of the species, both sexes are brilliantly coloured and indistinguishable, but in not a few species the males are coloured rather more vividly than the females, or even very differently from them. Thus, besides other strongly-marked differences, the whole under surface of the male King Lory (Aprosmictus scapulatus) is scarlet, whilst the throat and chest of the female is green tinged with red: in the Euphema splendida there is a similar difference, the face and wing coverts moreover of the female being of a paler blue than in the male. (23. Every gradation of difference between the sexes may be followed in the parrots of Australia. See Gould’s ‘Handbook,’ etc., vol. ii. pp. 14-102.) In the family of the tits (Parinae), which build concealed nests, the female of our common blue tomtit (Parus caeruleus), is “much less brightly coloured” than the male: and in the magnificent Sultan yellow tit of India the difference is greater. (24. Macgillivray’s ‘British Birds,’ vol. ii. p. 433. Jerdon, ‘Birds of India,’ vol. ii. p. 282.)

Again, in the great group of the woodpeckers (25. All the following facts are taken from M. Malherbe’s magnificent ‘Monographie des Picidees,’ 1861.), the sexes are generally nearly alike, but in the Megapicus validus all those parts of the head, neck, and breast, which are crimson in the male are pale brown in the female. As in several woodpeckers the head of the male is bright crimson, whilst that of the female is plain, it occurred to me that this colour might possibly make the female dangerously conspicuous, whenever she put her head out of the hole containing her nest, and consequently that this colour, in accordance with Mr. Wallace’s belief, had been eliminated. This view is strengthened by what Malherbe states with respect to Indopicus carlotta; namely, that the young females, like the young males, have some crimson about their heads, but that this colour disappears in the adult female, whilst it is intensified in the adult male. Nevertheless the following considerations render this view extremely doubtful: the male takes a fair share in incubation (26. Audubon’s ‘Ornithological Biography,’ vol. ii. p. 75; see also the ‘Ibis,’ vol. i. p. 268.), and would be thus almost equally exposed to danger; both sexes of many species have their heads of an equally bright crimson; in other species the difference between the sexes in the amount of scarlet is so slight that it can hardly make any appreciable difference in the danger incurred; and lastly, the colouring of the head in the two sexes often differs slightly in other ways.

The cases, as yet given, of slight and graduated differences in colour between the males and females in the groups, in which as a general rule the sexes resemble each other, all relate to species which build domed or concealed nests. But similar gradations may likewise be observed in groups in which the sexes as a general rule resemble each other, but which build open nests.

As I have before instanced the Australian parrots, so I may here instance, without giving any details, the Australian pigeons. (27. Gould’s ‘Handbook to the Birds of Australia,’ vol. ii. pp. 109-149.) It deserves especial notice that in all these cases the slight differences in plumage between the sexes are of the same general nature as the occasionally greater differences. A good illustration of this fact has already been afforded by those kingfishers in which either the tail alone or the whole upper surface of the plumage differs in the same manner in the two sexes. Similar cases may be observed with parrots and pigeons. The differences in colour between the sexes of the same species are, also, of the same general nature as the differences in colour between the distinct species of the same group. For when in a group in which the sexes are usually alike, the male differs considerably from the female, he is not coloured in a quite new style. Hence we may infer that within the same group the special colours of both sexes when they are alike, and the colours of the male, when he differs slightly or even considerably from the female, have been in most cases determined by the same general cause; this being sexual selection.

It is not probable, as has already been remarked, that differences in colour between the sexes, when very slight, can be of service to the female as a protection. Assuming, however, that they are of service, they might be thought to be cases of transition; but we have no reason to believe that many species at any one time are undergoing change. Therefore we can hardly admit that the numerous females which differ very slightly in colour from their males are now all commencing to become obscure for the sake of protection. Even if we consider somewhat more marked sexual differences, is it probable, for instance, that the head of the female chaffinch,—the crimson on the breast of the female bullfinch,—the green of the female greenfinch,—the crest of the female golden-crested wren, have all been rendered less bright by the slow process of selection for the sake of protection? I cannot think so; and still less with the slight differences between the sexes of those birds which build concealed nests. On the other hand, the differences in colour between the sexes, whether great or small, may to a large extent be explained on the principle of the successive variations, acquired by the males through sexual selection, having been from the first more or less limited in their transmission to the females. That the degree of limitation should differ in different species of the same group will not surprise any one who has studied the laws of inheritance, for they are so complex that they appear to us in our ignorance to be capricious in their action. (28. See remarks to this effect in ‘Variation of Animals and Plants under Domestication,’ vol. ii. chap. xii.)

As far as I can discover there are few large groups of birds in which all the species have both sexes alike and brilliantly coloured, but I hear from Mr. Sclater, that this appears to be the case with the Musophagae or plantain-eaters. Nor do I believe that any large group exists in which the sexes of all the species are widely dissimilar in colour: Mr. Wallace informs me that the chatterers of S. America (Cotingidae) offer one of the best instances; but with some of the species, in which the male has a splendid red breast, the female exhibits some red on her breast; and the females of other species shew traces of the green and other colours of the males. Nevertheless we have a near approach to close sexual similarity or dissimilarity throughout several groups: and this, from what has just been said of the fluctuating nature of inheritance, is a somewhat surprising circumstance. But that the same laws should largely prevail with allied animals is not surprising. The domestic fowl has produced a great number of breeds and sub-breeds, and in these the sexes generally differ in plumage; so that it has been noticed as an unusual circumstance when in certain sub-breeds they resemble each other. On the other hand, the domestic pigeon has likewise produced a vast number of distinct breeds and sub-breeds, and in these, with rare exceptions, the two sexes are identically alike.

Therefore if other species of Gallus and Columba were domesticated and varied, it would not be rash to predict that similar rules of sexual similarity and dissimilarity, depending on the form of transmission, would hold good in both cases. In like manner the same form of transmission has generally prevailed under nature throughout the same groups, although marked exceptions to this rule occur. Thus within the same family or even genus, the sexes may be identically alike, or very different in colour. Instances have already been given in the same genus, as with sparrows, fly- catchers, thrushes and grouse. In the family of pheasants the sexes of almost all the species are wonderfully dissimilar, but are quite alike in the eared pheasant or Crossoptilon auritum. In two species of Chloephaga, a genus of geese, the male cannot be distinguished from the females, except by size; whilst in two others, the sexes are so unlike that they might easily be mistaken for distinct species. (29. The ‘Ibis,’ vol. vi. 1864, p. 122.)

The laws of inheritance can alone account for the following cases, in which the female acquires, late in life, certain characters proper to the male, and ultimately comes to resemble him more or less completely. Here protection can hardly have come into play. 先生。 Blyth informs me that the females of Oriolus melanocephalus and of some allied species, when sufficiently mature to breed, differ considerably in plumage from the adult males; but after the second or third moults they differ only in their beaks having a slight greenish tinge. In the dwarf bitterns (Ardetta), according to the same authority, “the male acquires his final livery at the first moult, the female not before the third or fourth moult; in the meanwhile she presents an intermediate garb, which is ultimately exchanged for the same livery as that of the male.” So again the female Falco peregrinus acquires her blue plumage more slowly than the male. 先生。 Swinhoe states that with one of the Drongo shrikes (Dicrurus macrocercus) the male, whilst almost a nestling, moults his soft brown plumage and becomes of a uniform glossy greenish-black; but the female retains for a long time the white striae and spots on the axillary feathers; and does not completely assume the uniform black colour of the male for three years. The same excellent observer remarks that in the spring of the second year the female spoon- bill (Platalea) of China resembles the male of the first year, and that apparently it is not until the third spring that she acquires the same adult plumage as that possessed by the male at a much earlier age. The female Bombycilla carolinensis differs very little from the male, but the appendages, which like beads of red sealing-wax ornament the wing-feathers (30. When the male courts the female, these ornaments are vibrated, and “are shewn off to great advantage,” on the outstretched wings: A. Leith Adams, ‘Field and Forest Rambles,’ 1873, p. 153.), are not developed in her so early in life as in the male. In the male of an Indian parrakeet (Palaeornis javanicus) the upper mandible is coral-red from his earliest youth, but in the female, as Mr. Blyth has observed with caged and wild birds, it is at first black and does not become red until the bird is at least a year old, at which age the sexes resemble each other in all respects. Both sexes of the wild turkey are ultimately furnished with a tuft of bristles on the breast, but in two-year-old birds the tuft is about four inches long in the male and hardly apparent in the female; when, however, the latter has reached her fourth year, it is from four to five inches in length. (31。 On Ardetta, Translation of Cuvier’s ‘Regne Animal,’ by Mr. Blyth, footnote, p. 159. On the Peregrine Falcon, Mr. Blyth, in Charlesworth’s ‘Mag. of Nat. Hist.’ vol. i. 1837。 304. On Dicrurus, ‘Ibis,’ 1863, p. 44. On the Platalea, ‘Ibis,’ vol. vi. 1864。 366. On the Bombycilla, Audubon’s ‘Ornitholog. Biography,’ vol. i. p. 229. On the Palaeornis, see, also, Jerdon, ‘Birds of India,’ vol. i. p. 263. On the wild turkey, Audubon, ibid. 飞行。 i. p. 15; but I hear from Judge Caton that in Illinois the female very rarely acquires a tuft. Analogous cases with the females of Petrocossyphus are given by Mr. R. Sharpe, ‘Proceedings of the Zoological Society,’ 1872, p.

These cases must not be confounded with those where diseased or old females abnormally assume masculine characters, nor with those where fertile females, whilst young, acquire the characters of the male, through variation or some unknown cause. (32. Of these latter cases Mr. Blyth has recorded (Translation of Cuvier’s ‘Regne Animal,’ p. 158) various instances with Lanius, Ruticilla, Linaria, and Anas. Audubon has also recorded a similar case (‘Ornitholog. Biography,’ vol. v. p. 519) with Pyranga aestiva.) But all these cases have so much in common that they depend, according to the hypothesis of pangenesis, on gemmules derived from each part of the male being present, though latent, in the female; their development following on some slight change in the elective affinities of her constituent tissues.

A few words must be added on changes of plumage in relation to the season of the year. From reasons formerly assigned there can be little doubt that the elegant plumes, long pendant feathers, crests, etc., of egrets, herons, and many other birds, which are developed and retained only during the summer, serve for ornamental and nuptial purposes, though common to both sexes. The female is thus rendered more conspicuous during the period of incubation than during the winter; but such birds as herons and egrets would be able to defend themselves. As, however, plumes would probably be inconvenient and certainly of no use during the winter, it is possible that the habit of moulting twice in the year may have been gradually acquired through natural selection for the sake of casting off inconvenient ornaments during the winter. But this view cannot be extended to the many waders, whose summer and winter plumages differ very little in colour. With defenceless species, in which both sexes, or the males alone, become extremely conspicuous during the breeding-season,—or when the males acquire at this season such long wing or tail-feathers as to impede their flight, as with Cosmetornis and Vidua,—it certainly at first appears highly probable that the second moult has been gained for the special purpose of throwing off these ornaments. We must, however, remember that many birds, such as some of the Birds of Paradise, the Argus pheasant and peacock, do not cast their plumes during the winter; and it can hardly be maintained that the constitution of these birds, at least of the Gallinaceae, renders a double moult impossible, for the ptarmigan moults thrice in the year. (33. See Gould’s ‘Birds of Great Britain.’) Hence it must be considered as doubtful whether the many species which moult their ornamental plumes or lose their bright colours during the winter, have acquired this habit on account of the inconvenience or danger which they would otherwise have suffered.

I conclude, therefore, that the habit of moulting twice in the year was in most or all cases first acquired for some distinct purpose, perhaps for gaining a warmer winter covering; and that variations in the plumage occurring during the summer were accumulated through sexual selection, and transmitted to the offspring at the same season of the year; that such variations were inherited either by both sexes or by the males alone, according to the form of inheritance which prevailed. This appears more probable than that the species in all cases originally tended to retain their ornamental plumage during the winter, but were saved from this through natural selection, resulting from the inconvenience or danger thus caused.

I have endeavoured in this chapter to shew that the arguments are not trustworthy in favour of the view that weapons, bright colours, and various ornaments, are now confined to the males owing to the conversion, by natural selection, of the equal transmission of characters to both sexes, into transmission to the male sex alone. It is also doubtful whether the colours of many female birds are due to the preservation, for the sake of protection, of variations which were from the first limited in their transmission to the female sex. But it will be convenient to defer any further discussion on this subject until I treat, in the following chapter, of the differences in plumage between the young and old.

第十六章 •17,500字
鸟——结束

The immature plumage in relation to the character of the plumage in both sexes when adult—Six classes of cases—Sexual differences between the males of closely-allied or representative species—The female assuming the characters of the male—Plumage of the young in relation to the summer and winter plumage of the adults—On the increase of beauty in the birds of the world—Protective colouring—Conspicuously coloured birds—Novelty appreciated—Summary of the four chapters on Birds.

We must now consider the transmission of characters, as limited by age, in reference to sexual selection. The truth and importance of the principle of inheritance at corresponding ages need not here be discussed, as enough has already been said on the subject. Before giving the several rather complex rules or classes of cases, under which the differences in plumage between the young and the old, as far as known to me, may be included, it will be well to make a few preliminary remarks.

With animals of all kinds when the adults differ in colour from the young, and the colours of the latter are not, as far as we can see, of any special service, they may generally be attributed, like various embryological structures, to the retention of a former character. But this view can be maintained with confidence, only when the young of several species resemble each other closely, and likewise resemble other adult species belonging to the same group; for the latter are the living proofs that such a state of things was formerly possible. Young lions and pumas are marked with feeble stripes or rows of spots, and as many allied species both young and old are similarly marked, no believer in evolution will doubt that the progenitor of the lion and puma was a striped animal, and that the young have retained vestiges of the stripes, like the kittens of black cats, which are not in the least striped when grown up. Many species of deer, which when mature are not spotted, are whilst young covered with white spots, as are likewise some few species in the adult state. So again the young in the whole family of pigs (Suidae), and in certain rather distantly allied animals, such as the tapir, are marked with dark longitudinal stripes; but here we have a character apparently derived from an extinct progenitor, and now preserved by the young alone. In all such cases the old have had their colours changed in the course of time, whilst the young have remained but little altered, and this has been effected through the principle of inheritance at corresponding ages.

This same principle applies to many birds belonging to various groups, in which the young closely resemble each other, and differ much from their respective adult parents. The young of almost all the Gallinaceae, and of some distantly allied birds such as ostriches, are covered with longitudinally striped down; but this character points back to a state of things so remote that it hardly concerns us. Young cross-bills (Loxia) have at first straight beaks like those of other finches, and in their immature striated plumage they resemble the mature red-pole and female siskin, as well as the young of the goldfinch, greenfinch, and some other allied species. The young of many kinds of buntings (Emberiza) resemble one another, and likewise the adult state of the common bunting, E. miliaria. In almost the whole large group of thrushes the young have their breasts spotted—a character which is retained throughout life by many species, but is quite lost by others, as by the Turdus migratorius. So again with many thrushes, the feathers on the back are mottled before they are moulted for the first time, and this character is retained for life by certain eastern species. The young of many species of shrikes (Lanius), of some woodpeckers, and of an Indian pigeon (Chalcophaps indicus), are transversely striped on the under surface; and certain allied species or whole genera are similarly marked when adult. In some closely-allied and resplendent Indian cuckoos (Chrysococcyx), the mature species differ considerably from one another in colour, but the young cannot be distinguished. The young of an Indian goose (Sarkidiornis melanonotus) closely resemble in plumage an allied genus, Dendrocygna, when mature. (1. In regard to thrushes, shrikes, and woodpeckers, see Mr. Blyth, in Charlesworth’s ‘Mag. of Nat. Hist.’ vol. i. 1837, p. 304; also footnote to his translation of Cuvier’s ‘Regne Animal,’ p. 159. I give the case of Loxia on Mr. Blyth’s information. On thrushes, see also Audubon, ‘Ornith. Biog.’ vol. ii. p. 195. On Chrysococcyx and Chalcophaps, Blyth, as quoted in Jerdon’s ‘Birds of India,’ vol. iii. p. 485. On Sarkidiornis, Blyth, in ‘Ibis,’ 1867, p. 175.) Similar facts will hereafter be given in regard to certain herons. Young black-grouse (Tetrao tetrix) resemble the young as well as the old of certain other species, for instance the red-grouse or T. scoticus. Finally, as Mr. Blyth, who has attended closely to this subject, has well remarked, the natural affinities of many species are best exhibited in their immature plumage; and as the true affinities of all organic beings depend on their descent from a common progenitor, this remark strongly confirms the belief that the immature plumage approximately shews us the former or ancestral condition of the species.

Although many young birds, belonging to various families, thus give us a glimpse of the plumage of their remote progenitors, yet there are many other birds, both dull-coloured and bright-coloured, in which the young closely resemble their parents. In such cases the young of the different species cannot resemble each other more closely than do the parents; nor can they strikingly resemble allied forms when adult. They give us but little insight into the plumage of their progenitors, excepting in so far that, when the young and the old are coloured in the same general manner throughout a whole group of species, it is probable that their progenitors were similarly coloured.

We may now consider the classes of cases, under which the differences and resemblances between the plumage of the young and the old, in both sexes or in one sex alone, may be grouped. Rules of this kind were first enounced by Cuvier; but with the progress of knowledge they require some modification and amplification. This I have attempted to do, as far as the extreme complexity of the subject permits, from information derived from various sources; but a full essay on this subject by some competent ornithologist is much needed. In order to ascertain to what extent each rule prevails, I have tabulated the facts given in four great works, namely, by Macgillivray on the birds of Britain, Audubon on those of North America, Jerdon on those of India, and Gould on those of Australia. I may here premise, first, that the several cases or rules graduate into each other; and secondly, that when the young are said to resemble their parents, it is not meant that they are identically alike, for their colours are almost always less vivid, and the feathers are softer and often of a different shape.

Rules or Classes of Cases

I. When the adult male is more beautiful or conspicuous than the adult female, the young of both sexes in their first plumage closely resemble the adult female, as with the common fowl and peacock; or, as occasionally occurs, they resemble her much more closely than they do the adult male.

II. When the adult female is more conspicuous than the adult male, as sometimes though rarely occurs, the young of both sexes in their first plumage resemble the adult male.

III. When the adult male resembles the adult female, the young of both sexes have a peculiar first plumage of their own, as with the robin.

IV. When the adult male resembles the adult female, the young of both sexes in their first plumage resemble the adults, as with the kingfisher, many parrots, crows, hedge-warblers.

V. When the adults of both sexes have a distinct winter and summer plumage, whether or not the male differs from the female, the young resemble the adults of both sexes in their winter dress, or much more rarely in their summer dress, or they resemble the females alone. Or the young may have an intermediate character; or again they may differ greatly from the adults in both their seasonal plumages.

VI. In some few cases the young in their first plumage differ from each other according to sex; the young males resembling more or less closely the adult males, and the young females more or less closely the adult females.

I类

In this class, the young of both sexes more or less closely resemble the adult female, whilst the adult male differs from the adult female, often in the most conspicuous manner. Innumerable instances in all Orders could be given; it will suffice to call to mind the common pheasant, duck, and house-sparrow. The cases under this class graduate into others. Thus the two sexes when adult may differ so slightly, and the young so slightly from the adults, that it is doubtful whether such cases ought to come under the present, or under the third or fourth classes. So again the young of the two sexes, instead of being quite alike, may differ in a slight degree from each other, as in our sixth class. These transitional cases, however, are few, or at least are not strongly pronounced, in comparison with those which come strictly under the present class.

The force of the present law is well shewn in those groups, in which, as a general rule, the two sexes and the young are all alike; for when in these groups the male does differ from the female, as with certain parrots, kingfishers, pigeons, etc., the young of both sexes resemble the adult female. (2. See, for instance, Mr. Gould’s account (‘Handbook to the Birds of Australia,’ vol. i. p. 133) of Cyanalcyon (one of the Kingfishers), in which, however, the young male, though resembling the adult female, is less brilliantly coloured. In some species of Dacelo the males have blue tails, and the females brown ones; and Mr. R.B. Sharpe informs me that the tail of the young male of D. gaudichaudi is at first brown. Mr. Gould has described (ibid. vol. ii. pp. 14, 20, 37) the sexes and the young of certain black Cockatoos and of the King Lory, with which the same rule prevails. Also Jerdon (‘Birds of India,’ vol. i. p. 260) on the Palaeornis rosa, in which the young are more like the female than the male. See Audubon (‘Ornithological Biography,’ vol. ii. p. 475) on the two sexes and the young of Columba passerina.) We see the same fact exhibited still more clearly in certain anomalous cases; thus the male of Heliothrix auriculata (one of the humming-birds) differs conspicuously from the female in having a splendid gorget and fine ear-tufts, but the female is remarkable from having a much longer tail than that of the male; now the young of both sexes resemble (with the exception of the breast being spotted with bronze) the adult female in all other respects, including the length of her tail, so that the tail of the male actually becomes shorter as he reaches maturity, which is a most unusual circumstance. (3. I owe this information to Mr. Gould, who shewed me the specimens; see also his ‘Introduction to the Trochilidae,’ 1861, p. 120.) Again, the plumage of the male goosander (Mergus merganser) is more conspicuously coloured than that of the female, with the scapular and secondary wing-feathers much longer; but differently from what occurs, as far as I know, in any other bird, the crest of the adult male, though broader than that of the female, is considerably shorter, being only a little above an inch in length; the crest of the female being two and a half inches long. Now the young of both sexes entirely resemble the adult female, so that their crests are actually of greater length, though narrower, than in the adult male. (4. Macgillivray, ‘Hist. Brit. Birds,’ vol. v. pp. 207-214.)

When the young and the females closely resemble each other and both differ from the males, the most obvious conclusion is that the males alone have been modified. Even in the anomalous cases of the Heliothrix and Mergus, it is probable that originally both adult sexes were furnished—the one species with a much elongated tail, and the other with a much elongated crest—these characters having since been partially lost by the adult males from some unexplained cause, and transmitted in their diminished state to their male offspring alone, when arrived at the corresponding age of maturity. The belief that in the present class the male alone has been modified, as far as the differences between the male and the female together with her young are concerned, is strongly supported by some remarkable facts recorded by Mr. Blyth (5. See his admirable paper in the ‘Journal of the Asiatic Soc. of Bengal,’ vol. xix. 1850, p. 223; see also Jerdon, ‘Birds of India,’ vol. i. introduction, p. xxix. In regard to Tanysiptera, Prof. Schlegel told Mr. Blyth that he could distinguish several distinct races, solely by comparing the adult males.), with respect to closely-allied species which represent each other in distinct countries. For with several of these representative species the adult males have undergone a certain amount of change and can be distinguished; the females and the young from the distinct countries being indistinguishable, and therefore absolutely unchanged. This is the case with certain Indian chats (Thamnobia), with certain honey-suckers (Nectarinia), shrikes (Tephrodornis), certain kingfishers (Tanysiptera), Kalij pheasants (Gallophasis), and tree-partridges (Arboricola).

In some analogous cases, namely with birds having a different summer and winter plumage, but with the two sexes nearly alike, certain closely-allied species can easily be distinguished in their summer or nuptial plumage, yet are indistinguishable in their winter as well as in their immature plumage. This is the case with some of the closely-allied Indian wagtails or Motacillae. Mr. Swinhoe (6. See also Mr. Swinhoe, in ‘Ibis,’ July 1863, p. 131; and a previous paper, with an extract from a note by Mr. Blyth, in ‘Ibis,’ January, 1861, p. 25.) informs me that three species of Ardeola, a genus of herons, which represent one another on separate continents, are “most strikingly different” when ornamented with their summer plumes, but are hardly, if at all, distinguishable during the winter. The young also of these three species in their immature plumage closely resemble the adults in their winter dress. This case is all the more interesting, because with two other species of Ardeola both sexes retain, during the winter and summer, nearly the same plumage as that possessed by the three first species during the winter and in their immature state; and this plumage, which is common to several distinct species at different ages and seasons, probably shews us how the progenitors of the genus were coloured. In all these cases, the nuptial plumage which we may assume was originally acquired by the adult males during the breeding-season, and transmitted to the adults of both sexes at the corresponding season, has been modified, whilst the winter and immature plumages have been left unchanged.

The question naturally arises, how is it that in these latter cases the winter plumage of both sexes, and in the former cases the plumage of the adult females, as well as the immature plumage of the young, have not been at all affected? The species which represent each other in distinct countries will almost always have been exposed to somewhat different conditions, but we can hardly attribute to this action the modification of the plumage in the males alone, seeing that the females and the young, though similarly exposed, have not been affected. Hardly any fact shews us more clearly how subordinate in importance is the direct action of the conditions of life, in comparison with the accumulation through selection of indefinite variations, than the surprising difference between the sexes of many birds; for both will have consumed the same food, and have been exposed to the same climate. Nevertheless we are not precluded from believing that in the course of time new conditions may produce some direct effect either on both sexes, or from their constitutional differences chiefly on one sex. We see only that this is subordinate in importance to the accumulated results of selection. Judging, however, from a wide-spread analogy, when a species migrates into a new country (and this must precede the formation of representative species), the changed conditions to which they will almost always have been exposed will cause them to undergo a certain amount of fluctuating variability. In this case sexual selection, which depends on an element liable to change—the taste or admiration of the female—will have had new shades of colour or other differences to act on and accumulate; and as sexual selection is always at work, it would (from what we know of the results on domestic animals of man’s unintentional selection), be surprising if animals inhabiting separate districts, which can never cross and thus blend their newly-acquired characters, were not, after a sufficient lapse of time, differently modified. These remarks likewise apply to the nuptial or summer plumage, whether confined to the males, or common to both sexes.

Although the females of the above closely-allied or representative species, together with their young, differ hardly at all from one another, so that the males alone can be distinguished, yet the females of most species within the same genus obviously differ from each other. The differences, however, are rarely as great as between the males. We see this clearly in the whole family of the Gallinaceae: the females, for instance, of the common and Japan pheasant, and especially of the gold and Amherst pheasant —of the silver pheasant and the wild fowl—resemble one another very closely in colour, whilst the males differ to an extraordinary degree. So it is with the females of most of the Cotingidae, Fringillidae, and many other families. There can indeed be no doubt that, as a general rule, the females have been less modified than the males. Some few birds, however, offer a singular and inexplicable exception; thus the females of Paradisea apoda and P. papuana differ from each other more than do their respective males (7. Wallace, ‘The Malay Archipelago,’ vol. ii. 1869, p. 394.); the female of the latter species having the under surface pure white, whilst the female P. apoda is deep brown beneath. So, again, as I hear from Professor Newton, the males of two species of Oxynotus (shrikes), which represent each other in the islands of Mauritius and Bourbon (8. These species are described with coloured figures, by M. F. Pollen, in ‘Ibis,’ 1866, p. 275.), differ but little in colour, whilst the females differ much. In the Bourbon species the female appears to have partially retained an immature condition of plumage, for at first sight she “might be taken for the young of the Mauritian species.” These differences may be compared with those inexplicable ones, which occur independently of man’s selection in certain sub-breeds of the game-fowl, in which the females are very different, whilst the males can hardly be distinguished. (9. ‘Variation of Animals,’ etc., vol. i. p. 251.)

As I account so largely by sexual selection for the differences between the males of allied species, how can the differences between the females be accounted for in all ordinary cases? We need not here consider the species which belong to distinct genera; for with these, adaptation to different habits of life, and other agencies, will have come into play. In regard to the differences between the females within the same genus, it appears to me almost certain, after looking through various large groups, that the chief agent has been the greater or less transference to the female of the characters acquired by the males through sexual selection. In the several British finches, the two sexes differ either very slightly or considerably; and if we compare the females of the greenfinch, chaffinch, goldfinch, bullfinch, crossbill, sparrow, etc., we shall see that they differ from one another chiefly in the points in which they partially resemble their respective males; and the colours of the males may safely be attributed to sexual selection. With many gallinaceous species the sexes differ to an extreme degree, as with the peacock, pheasant, and fowl, whilst with other species there has been a partial or even complete transference of character from the male to the female. The females of the several species of Polyplectron exhibit in a dim condition, and chiefly on the tail, the splendid ocelli of their males. The female partridge differs from the male only in the red mark on her breast being smaller; and the female wild turkey only in her colours being much duller. In the guinea-fowl the two sexes are indistinguishable. There is no improbability in the plain, though peculiarly spotted plumage of this latter bird having been acquired through sexual selection by the males, and then transmitted to both sexes; for it is not essentially different from the much more beautifully spotted plumage, characteristic of the males alone of the Tragopan pheasants.

It should be observed that, in some instances, the transference of characters from the male to the female has been effected apparently at a remote period, the male having subsequently undergone great changes, without transferring to the female any of his later-gained characters. For instance, the female and the young of the black-grouse (Tetrao tetrix) resemble pretty closely both sexes and the young of the red-grouse (T. scoticus); and we may consequently infer that the black-grouse is descended from some ancient species, of which both sexes were coloured in nearly the same manner as the red-grouse. As both sexes of this latter species are more distinctly barred during the breeding-season than at any other time, and as the male differs slightly from the female in his more strongly- pronounced red and brown tints (10. Macgillivray, ‘History of British Birds,’ vol. i. pp. 172-174.), we may conclude that his plumage has been influenced by sexual selection, at least to a certain extent. If so, we may further infer that nearly similar plumage of the female black-grouse was similarly produced at some former period. But since this period the male black-grouse has acquired his fine black plumage, with his forked and outwardly-curled tail-feathers; but of these characters there has hardly been any transference to the female, excepting that she shews in her tail a trace of the curved fork.

We may therefore conclude that the females of distinct though allied species have often had their plumage rendered more or less different by the transference in various degrees of characters acquired by the males through sexual selection, both during former and recent times. But it deserves especial attention that brilliant colours have been transferred much more rarely than other tints. For instance, the male of the red-throated blue- breast (Cyanecula suecica) has a rich blue breast, including a sub- triangular red mark; now marks of nearly the same shape have been transferred to the female, but the central space is fulvous instead of red, and is surrounded by mottled instead of blue feathers. The Gallinaceae offer many analogous cases; for none of the species, such as partridges, quails, guinea-fowls, etc., in which the colours of the plumage have been largely transferred from the male to the female, are brilliantly coloured. This is well exemplified with the pheasants, in which the male is generally so much more brilliant than the female; but with the Eared and Cheer pheasants (Crossoptilon auritum and Phasianus wallichii) the sexes closely resemble each other and their colours are dull. We may go so far as to believe that if any part of the plumage in the males of these two pheasants had been brilliantly coloured, it would not have been transferred to the females. These facts strongly support Mr. Wallace’s view that with birds which are exposed to much danger during incubation, the transference of bright colours from the male to the female has been checked through natural selection. We must not, however, forget that another explanation, before given, is possible; namely, that the males which varied and became bright, whilst they were young and inexperienced, would have been exposed to much danger, and would generally have been destroyed; the older and more cautious males, on the other hand, if they varied in a like manner, would not only have been able to survive, but would have been favoured in their rivalry with other males. Now variations occurring late in life tend to be transmitted exclusively to the same sex, so that in this case extremely bright tints would not have been transmitted to the females. On the other hand, ornaments of a less conspicuous kind, such as those possessed by the Eared and Cheer pheasants, would not have been dangerous, and if they appeared during early youth, would generally have been transmitted to both sexes.

In addition to the effects of the partial transference of characters from the males to the females, some of the differences between the females of closely allied species may be attributed to the direct or definite action of the conditions of life. (11. See, on this subject, chap. xxiii. in the ‘Variation of Animals and Plants under Domestication.’) With the males, any such action would generally have been masked by the brilliant colours gained through sexual selection; but not so with the females. Each of the endless diversities in plumage which we see in our domesticated birds is, of course, the result of some definite cause; and under natural and more uniform conditions, some one tint, assuming that it was in no way injurious, would almost certainly sooner or later prevail. The free intercrossing of the many individuals belonging to the same species would ultimately tend to make any change of colour, thus induced, uniform in character.

No one doubts that both sexes of many birds have had their colours adapted for the sake of protection; and it is possible that the females alone of some species may have been modified for this end. Although it would be a difficult, perhaps an impossible process, as shewn in the last chapter, to convert one form of transmission into another through selection, there would not be the least difficulty in adapting the colours of the female, independently of those of the male, to surrounding objects, through the accumulation of variations which were from the first limited in their transmission to the female sex. If the variations were not thus limited, the bright tints of the male would be deteriorated or destroyed. Whether the females alone of many species have been thus specially modified, is at present very doubtful. I wish I could follow Mr. Wallace to the full extent; for the admission would remove some difficulties. Any variations which were of no service to the female as a protection would be at once obliterated, instead of being lost simply by not being selected, or from free intercrossing, or from being eliminated when transferred to the male and in any way injurious to him. Thus the plumage of the female would be kept constant in character. It would also be a relief if we could admit that the obscure tints of both sexes of many birds had been acquired and preserved for the sake of protection,—for example, of the hedge-warbler or kitty-wren (Accentor modularis and Troglodytes vulgaris), with respect to which we have no sufficient evidence of the action of sexual selection. We ought, however, to be cautious in concluding that colours which appear to us dull, are not attractive to the females of certain species; we should bear in mind such cases as that of the common house-sparrow, in which the male differs much from the female, but does not exhibit any bright tints. No one probably will dispute that many gallinaceous birds which live on the open ground, have acquired their present colours, at least in part, for the sake of protection. We know how well they are thus concealed; we know that ptarmigans, whilst changing from their winter to their summer plumage, both of which are protective, suffer greatly from birds of prey. But can we believe that the very slight differences in tints and markings between, for instance, the female black-grouse and red-grouse serve as a protection? Are partridges, as they are now coloured, better protected than if they had resembled quails? Do the slight differences between the females of the common pheasant, the Japan and gold pheasants, serve as a protection, or might not their plumages have been interchanged with impunity? From what Mr. Wallace has observed of the habits of certain gallinaceous birds in the East, he thinks that such slight differences are beneficial. For myself, I will only say that I am not convinced.

Formerly when I was inclined to lay much stress on protection as accounting for the duller colours of female birds, it occurred to me that possibly both sexes and the young might aboriginally have been equally bright coloured; but that subsequently, the females from the danger incurred during incubation, and the young from being inexperienced, had been rendered dull as a protection. But this view is not supported by any evidence, and is not probable; for we thus in imagination expose during past times the females and the young to danger, from which it has subsequently been necessary to shield their modified descendants. We have, also, to reduce, through a gradual process of selection, the females and the young to almost exactly the same tints and markings, and to transmit them to the corresponding sex and period of life. On the supposition that the females and the young have partaken during each stage of the process of modification of a tendency to be as brightly coloured as the males, it is also a somewhat strange fact that the females have never been rendered dull-coloured without the young participating in the same change; for there are no instances, as far as I can discover, of species with the females dull and the young bright coloured. A partial exception, however, is offered by the young of certain woodpeckers, for they have “the whole upper part of the head tinged with red,” which afterwards either decreases into a mere circular red line in the adults of both sexes, or quite disappears in the adult females. (12. Audubon, ‘Ornith. Biography,’ vol. i. p. 193. Macgillivray, ‘History of British Birds,’ vol. iii. p. 85. See also the case before given of Indopicus carlotta.)

Finally, with respect to our present class of cases, the most probable view appears to be that successive variations in brightness or in other ornamental characters, occurring in the males at a rather late period of life have alone been preserved; and that most or all of these variations, owing to the late period of life at which they appeared, have been from the first transmitted only to the adult male offspring. Any variations in brightness occurring in the females or in the young, would have been of no service to them, and would not have been selected; and moreover, if dangerous, would have been eliminated. Thus the females and the young will either have been left unmodified, or (as is much more common) will have been partially modified by receiving through transference from the males some of his successive variations. Both sexes have perhaps been directly acted on by the conditions of life to which they have long been exposed: but the females from not being otherwise much modified, will best exhibit any such effects. These changes and all others will have been kept uniform by the free intercrossing of many individuals. In some cases, especially with ground birds, the females and the young may possibly have been modified, independently of the males, for the sake of protection, so as to have acquired the same dull-coloured plumage.

II类

When the Adult Female Is More Conspicuous Than the Adult Male, The Young of Both Sexes in Their First Plumage Resemble the Adult Male

This class is exactly the reverse of the last, for the females are here brighter coloured or more conspicuous than the males; and the young, as far as they are known, resemble the adult males instead of the adult females. But the difference between the sexes is never nearly so great as with many birds in the first class, and the cases are comparatively rare. Mr. Wallace, who first called attention to the singular relation which exists between the less bright colours of the males and their performing the duties of incubation, lays great stress on this point (13. ‘Westminster Review,’ July 1867, and A. Murray, ‘Journal of Travel,’ 1868, p. 83.), as a crucial test that obscure colours have been acquired for the sake of protection during the period of nesting. A different view seems to me more probable. As the cases are curious and not numerous, I will briefly give all that I have been able to find.

In one section of the genus Turnix, quail-like birds, the female is invariably larger than the male (being nearly twice as large in one of the Australian species), and this is an unusual circumstance with the Gallinaceae. In most of the species the female is more distinctly coloured and brighter than the male (14. For the Australian species, see Gould’s ‘Handbook,’ etc., vol. ii. pp. 178, 180, 186, and 188. In the British Museum specimens of the Australian Plain-wanderer (Pedionomus torquatus) may be seen, shewing similar sexual differences.), but in some few species the sexes are alike. In Turnix taigoor of India the male “wants the black on the throat and neck, and the whole tone of the plumage is lighter and less pronounced than that of the female.” The female appears to be noisier, and is certainly much more pugnacious than the male; so that the females and not the males are often kept by the natives for fighting, like game-cocks. As male birds are exposed by the English bird-catchers for a decoy near a trap, in order to catch other males by exciting their rivalry, so the females of this Turnix are employed in India. When thus exposed the females soon begin their “loud purring call, which can be heard a long way off, and any females within ear-shot run rapidly to the spot, and commence fighting with the caged bird.” In this way from twelve to twenty birds, all breeding females, may be caught in the course of a single day. The natives assert that the females after laying their eggs associate in flocks, and leave the males to sit on them. There is no reason to doubt the truth of this assertion, which is supported by some observations made in China by Mr. Swinhoe. (15. Jerdon, ‘Birds of India,’ vol. iii. p. 596. Mr. Swinhoe, in ‘Ibis,’ 1865, p. 542; 1866, pp. 131, 405.) Mr. Blyth believes, that the young of both sexes resemble the adult male.

[Fig. 62. Rhynchaea capensis (from Brehm).]

The females of the three species of Painted Snipes (Rhynchaea, Fig. 62) “are not only larger but much more richly coloured than the males.” (16. Jerdon, ‘Birds of India,’ vol. iii. p. 677.) With all other birds in which the trachea differs in structure in the two sexes it is more developed and complex in the male than in the female; but in the Rhynchaea australis it is simple in the male, whilst in the female it makes four distinct convolutions before entering the lungs. (17. Gould’s ‘Handbook to the Birds of Australia,’ vol. ii. p. 275.) The female therefore of this species has acquired an eminently masculine character. Mr. Blyth ascertained, by examining many specimens, that the trachea is not convoluted in either sex of R. bengalensis, which species resembles R. australis so closely, that it can hardly be distinguished except by its shorter toes. This fact is another striking instance of the law that secondary sexual characters are often widely different in closely-allied forms, though it is a very rare circumstance when such differences relate to the female sex. The young of both sexes of R. bengalensis in their first plumage are said to resemble the mature male. (18. ‘The Indian Field,’ Sept. 1858, p. 3.) There is also reason to believe that the male undertakes the duty of incubation, for Mr. Swinhoe (19. ‘Ibis,’ 1866, p. 298.) found the females before the close of the summer associated in flocks, as occurs with the females of the Turnix.

The females of Phalaropus fulicarius and P. hyperboreus are larger, and in their summer plumage “more gaily attired than the males.” But the difference in colour between the sexes is far from conspicuous. According to Professor Steenstrup, the male alone of P. fulicarius undertakes the duty of incubation; this is likewise shewn by the state of his breast- feathers during the breeding-season. The female of the dotterel plover (Eudromias morinellus) is larger than the male, and has the red and black tints on the lower surface, the white crescent on the breast, and the stripes over the eyes, more strongly pronounced. The male also takes at least a share in hatching the eggs; but the female likewise attends to the young. (20. For these several statements, see Mr. Gould’s ‘Birds of Great Britain.’ Prof. Newton informs me that he has long been convinced, from his own observations and from those of others, that the males of the above- named species take either the whole or a large share of the duties of incubation, and that they “shew much greater devotion towards their young, when in danger, than do the females.” So it is, as he informs me, with Limosa lapponica and some few other Waders, in which the females are larger and have more strongly contrasted colours than the males.) I have not been able to discover whether with these species the young resemble the adult males more closely than the adult females; for the comparison is somewhat difficult to make on account of the double moult.

Turning now to the ostrich Order: the male of the common cassowary (Casuarius galeatus) would be thought by any one to be the female, from his smaller size and from the appendages and naked skin about his head being much less brightly coloured; and I am informed by Mr. Bartlett that in the Zoological Gardens, it is certainly the male alone who sits on the eggs and takes care of the young. (21. The natives of Ceram (Wallace, ‘Malay Archipelago,’ vol. ii. p. 150) assert that the male and female sit alternately on the eggs; but this assertion, as Mr. Bartlett thinks, may be accounted for by the female visiting the nest to lay her eggs.) The female is said by Mr. T.W. Wood (22. The ‘Student,’ April 1870, p. 124.) to exhibit during the breeding-season a most pugnacious disposition; and her wattles then become enlarged and more brilliantly coloured. So again the female of one of the emus (Dromoeus irroratus) is considerably larger than the male, and she possesses a slight top-knot, but is otherwise indistinguishable in plumage. She appears, however, “to have greater power, when angry or otherwise excited, of erecting, like a turkey-cock, the feathers of her neck and breast. She is usually the more courageous and pugilistic. She makes a deep hollow guttural boom especially at night, sounding like a small gong. The male has a slenderer frame and is more docile, with no voice beyond a suppressed hiss when angry, or a croak.” He not only performs the whole duty of incubation, but has to defend the young from their mother; “for as soon as she catches sight of her progeny she becomes violently agitated, and notwithstanding the resistance of the father appears to use her utmost endeavours to destroy them. For months afterwards it is unsafe to put the parents together, violent quarrels being the inevitable result, in which the female generally comes off conqueror.” (23. See the excellent account of the habits of this bird under confinement, by Mr. A.W. Bennett, in ‘Land and Water,’ May 1868, p. 233.) So that with this emu we have a complete reversal not only of the parental and incubating instincts, but of the usual moral qualities of the two sexes; the females being savage, quarrelsome, and noisy, the males gentle and good. The case is very different with the African ostrich, for the male is somewhat larger than the female and has finer plumes with more strongly contrasted colours; nevertheless he undertakes the whole duty of incubation. (24. Mr. Sclater, on the incubation of the Struthiones, ‘Proc. Zool. Soc.’ June 9, 1863. So it is with the Rhea darwinii: Captain Musters says (‘At Home with the Patagonians,’ 1871, p. 128), that the male is larger, stronger and swifter than the female, and of slightly darker colours; yet he takes sole charge of the eggs and of the young, just as does the male of the common species of Rhea.)

I will specify the few other cases known to me, in which the female is more conspicuously coloured than the male, although nothing is known about the manner of incubation. With the carrion-hawk of the Falkland Islands (Milvago leucurus) I was much surprised to find by dissection that the individuals, which had all their tints strongly pronounced, with the cere and legs orange-coloured, were the adult females; whilst those with duller plumage and grey legs were the males or the young. In an Australian tree- creeper (Climacteris erythrops) the female differs from the male in “being adorned with beautiful, radiated, rufous markings on the throat, the male having this part quite plain.” Lastly, in an Australian night-jar “the female always exceeds the male in size and in the brilliance of her tints; the males, on the other hand, have two white spots on the primaries more conspicuous than in the female.” (25. For the Milvago, see ‘Zoology of the Voyage of the “Beagle,” Birds,’ 1841, p. 16. For the Climacteris and night-jar (Eurostopodus), see Gould’s ‘Handbook to the Birds of Australia,’ vol. i. pp. 602 and 97. The New Zealand shieldrake (Tadorna variegata) offers a quite anomalous case; the head of the female is pure white, and her back is redder than that of the male; the head of the male is of a rich dark bronzed colour, and his back is clothed with finely pencilled slate- coloured feathers, so that altogether he may be considered as the more beautiful of the two. He is larger and more pugnacious than the female, and does not sit on the eggs. So that in all these respects this species comes under our first class of cases; but Mr. Sclater (‘Proceedings of the Zoological Society,’ 1866, p. 150) was much surprised to observe that the young of both sexes, when about three months old, resembled in their dark heads and necks the adult males, instead of the adult females; so that it would appear in this case that the females have been modified, whilst the males and the young have retained a former state of plumage.)

We thus see that the cases in which female birds are more conspicuously coloured than the males, with the young in their immature plumage resembling the adult males instead of the adult females, as in the previous class, are not numerous, though they are distributed in various Orders. The amount of difference, also, between the sexes is incomparably less than that which frequently occurs in the last class; so that the cause of the difference, whatever it may have been, has here acted on the females either less energetically or less persistently than on the males in the last class. Mr. Wallace believes that the males have had their colours rendered less conspicuous for the sake of protection during the period of incubation; but the difference between the sexes in hardly any of the foregoing cases appears sufficiently great for this view to be safely accepted. In some of the cases, the brighter tints of the female are almost confined to the lower surface, and the males, if thus coloured, would not have been exposed to danger whilst sitting on the eggs. It should also be borne in mind that the males are not only in a slight degree less conspicuously coloured than the females, but are smaller and weaker. They have, moreover, not only acquired the maternal instinct of incubation, but are less pugnacious and vociferous than the females, and in one instance have simpler vocal organs. Thus an almost complete transposition of the instincts, habits, disposition, colour, size, and of some points of structure, has been effected between the two sexes.

Now if we might assume that the males in the present class have lost some of that ardour which is usual to their sex, so that they no longer search eagerly for the females; or, if we might assume that the females have become much more numerous than the males—and in the case of one Indian Turnix the females are said to be “much more commonly met with than the males” (26. Jerdon, ‘Birds of India,’ vol. iii. p. 598.)—then it is not improbable that the females would have been led to court the males, instead of being courted by them. This indeed is the case to a certain extent with some birds, as we have seen with the peahen, wild turkey, and certain kinds of grouse. Taking as our guide the habits of most male birds, the greater size and strength as well as the extraordinary pugnacity of the females of the Turnix and emu, must mean that they endeavour to drive away rival females, in order to gain possession of the male; and on this view all the facts become clear; for the males would probably be most charmed or excited by the females which were the most attractive to them by their bright colours, other ornaments, or vocal powers. Sexual selection would then do its work, steadily adding to the attractions of the females; the males and the young being left not at all, or but little modified.

III级

When the Adult Male Resembles the Adult Female, The Young of Both Sexes Have a Peculiar First Plumage of Their Own

In this class the sexes when adult resemble each other, and differ from the young. This occurs with many birds of many kinds. The male robin can hardly be distinguished from the female, but the young are widely different, with their mottled dusky-olive and brown plumage. The male and female of the splendid scarlet ibis are alike, whilst the young are brown; and the scarlet colour, though common to both sexes, is apparently a sexual character, for it is not well developed in either sex under confinement; and a loss of colour often occurs with brilliant males when they are confined. With many species of herons the young differ greatly from the adults; and the summer plumage of the latter, though common to both sexes, clearly has a nuptial character. Young swans are slate-coloured, whilst the mature birds are pure white; but it would be superfluous to give additional instances. These differences between the young and the old apparently depend, as in the last two classes, on the young having retained a former or ancient state of plumage, whilst the old of both sexes have acquired a new one. When the adults are bright coloured, we may conclude from the remarks just made in relation to the scarlet ibis and to many herons, and from the analogy of the species in the first class, that such colours have been acquired through sexual selection by the nearly mature males; but that, differently from what occurs in the first two classes, the transmission, though limited to the same age, has not been limited to the same sex. Consequently, the sexes when mature resemble each other and differ from the young.

第四类

When the Adult Male Resembles the Adult Female, The Young of Both Sexes in Their First Plumage Resemble the Adults

In this class the young and the adults of both sexes, whether brilliantly or obscurely coloured, resemble each other. Such cases are, I think, more common than those in the last class. We have in England instances in the kingfisher, some woodpeckers, the jay, magpie, crow, and many small dull- coloured birds, such as the hedge-warbler or kitty-wren. But the similarity in plumage between the young and the old is never complete, and graduates away into dissimilarity. Thus the young of some members of the kingfisher family are not only less vividly coloured than the adults, but many of the feathers on the lower surface are edged with brown (27. Jerdon, ‘Birds of India,’ vol. i. pp. 222, 228. Gould’s ‘Handbook to the Birds of Australia,’ vol. i. pp. 124, 130.),—a vestige probably of a former state of the plumage. Frequently in the same group of birds, even within the same genus, for instance in an Australian genus of parrakeets (Platycercus), the young of some species closely resemble, whilst the young of other species differ considerably, from their parents of both sexes, which are alike. (28. Gould, ibid. vol. ii. pp. 37, 46, 56.) Both sexes and the young of the common jay are closely similar; but in the Canada jay (Perisoreus canadensis) the young differ so much from their parents that they were formerly described as distinct species. (29. Audubon, ‘Ornith. Biography,’ vol. ii. p. 55.)

I may remark before proceeding that, under the present and next two classes of cases, the facts are so complex and the conclusions so doubtful, that any one who feels no especial interest in the subject had better pass them over.

The brilliant or conspicuous colours which characterise many birds in the present class, can rarely or never be of service to them as a protection; so that they have probably been gained by the males through sexual selection, and then transferred to the females and the young. It is, however, possible that the males may have selected the more attractive females; and if these transmitted their characters to their offspring of both sexes, the same results would follow as from the selection of the more attractive males by the females. But there is evidence that this contingency has rarely, if ever, occurred in any of those groups of birds in which the sexes are generally alike; for, if even a few of the successive variations had failed to be transmitted to both sexes, the females would have slightly exceeded the males in beauty. Exactly the reverse occurs under nature; for, in almost every large group in which the sexes generally resemble each other, the males of some few species are in a slight degree more brightly coloured than the females. It is again possible that the females may have selected the more beautiful males, these males having reciprocally selected the more beautiful females; but it is doubtful whether this double process of selection would be likely to occur, owing to the greater eagerness of one sex than the other, and whether it would be more efficient than selection on one side alone. It is, therefore, the most probable view that sexual selection has acted, in the present class, as far as ornamental characters are concerned, in accordance with the general rule throughout the animal kingdom, that is, on the males; and that these have transmitted their gradually-acquired colours, either equally or almost equally, to their offspring of both sexes.

Another point is more doubtful, namely, whether the successive variations first appeared in the males after they had become nearly mature, or whilst quite young. In either case sexual selection must have acted on the male when he had to compete with rivals for the possession of the female; and in both cases the characters thus acquired have been transmitted to both sexes and all ages. But these characters if acquired by the males when adult, may have been transmitted at first to the adults alone, and at some subsequent period transferred to the young. For it is known that, when the law of inheritance at corresponding ages fails, the offspring often inherit characters at an earlier age than that at which they first appeared in their parents. (30. ‘Variation of Animals and Plants under Domestication,’ vol. ii. p. 79.) Cases apparently of this kind have been observed with birds in a state of nature. For instance Mr. Blyth has seen specimens of Lanius rufus and of Colymbus glacialis which had assumed whilst young, in a quite anomalous manner, the adult plumage of their parents. (31. ‘Charlesworth’s Magazine of Natural History,’ vol. i. 1837, pp. 305, 306.) Again, the young of the common swan (Cygnus olor) do not cast off their dark feathers and become white until eighteen months or two years old; but Dr. F. Forel has described the case of three vigorous young birds, out of a brood of four, which were born pure white. These young birds were not albinos, as shewn by the colour of their beaks and legs, which nearly resembled the same parts in the adults. (32. ‘Bulletin de la Soc. Vaudoise des Sc. Nat.’ vol. x. 1869, p. 132. The young of the Polish swan, Cygnus immutabilis of Yarrell, are always white; but this species, as Mr. Sclater informs me, is believed to be nothing more than a variety of the domestic swan (Cygnus olor).)

It may be worth while to illustrate the above three modes by which, in the present class, the two sexes and the young may have come to resemble each other, by the curious case of the genus Passer. (33. I am indebted to Mr. Blyth for information in regard to this genus. The sparrow of Palestine belongs to the sub-genus Petronia.) In the house-sparrow (P. domesticus) the male differs much from the female and from the young. The young and the females are alike, and resemble to a large extent both sexes and the young of the sparrow of Palestine (P. brachydactylus), as well as of some allied species. We may therefore assume that the female and young of the house-sparrow approximately shew us the plumage of the progenitor of the genus. Now with the tree-sparrow (P. montanus) both sexes and the young closely resemble the male of the house-sparrow; so that they have all been modified in the same manner, and all depart from the typical colouring of their early progenitor. This may have been effected by a male ancestor of the tree-sparrow having varied, firstly, when nearly mature; or, secondly, whilst quite young, and by having in either case transmitted his modified plumage to the females and the young; or, thirdly, he may have varied when adult and transmitted his plumage to both adult sexes, and, owing to the failure of the law of inheritance at corresponding ages, at some subsequent period to his young.

It is impossible to decide which of these three modes has generally prevailed throughout the present class of cases. That the males varied whilst young, and transmitted their variations to their offspring of both sexes, is the most probable. I may here add that I have, with little success, endeavoured, by consulting various works, to decide how far the period of variation in birds has generally determined the transmission of characters to one sex or to both. The two rules, often referred to (namely, that variations occurring late in life are transmitted to one and the same sex, whilst those which occur early in life are transmitted to both sexes), apparently hold good in the first (34. For instance, the males of Tanagra aestiva and Fringilla cyanea require three years, the male of Fringilla ciris four years, to complete their beautiful plumage. (See Audubon, ‘Ornith. Biography,’ vol. i. pp. 233, 280, 378). The Harlequin duck takes three years (ibid. vol. iii. p. 614). The male of the Gold pheasant, as I hear from Mr. Jenner Weir, can be distinguished from the female when about three months old, but he does not acquire his full splendour until the end of the September in the following year.), second, and fourth classes of cases; but they fail in the third, often in the fifth (35. Thus the Ibis tantalus and Grus americanus take four years, the Flamingo several years, and the Ardea ludovicana two years, before they acquire their perfect plumage. See Audubon, ibid. vol. i. p. 221; vol. iii. pp. 133, 139, 211.), and in the sixth small class. They apply, however, as far as I can judge, to a considerable majority of the species; and we must not forget the striking generalisation by Dr. W. Marshall with respect to the protuberances on the heads of birds. Whether or not the two rules generally hold good, we may conclude from the facts given in the eighth chapter, that the period of variation is one important element in determining the form of transmission.

With birds it is difficult to decide by what standard we ought to judge of the earliness or lateness of the period of variation, whether by the age in reference to the duration of life, or to the power of reproduction, or to the number of moults through which the species passes. The moulting of birds, even within the same family, sometimes differs much without any assignable cause. Some birds moult so early, that nearly all the body feathers are cast off before the first wing-feathers are fully grown; and we cannot believe that this was the primordial state of things. When the period of moulting has been accelerated, the age at which the colours of the adult plumage are first developed will falsely appear to us to be earlier than it really is. This may be illustrated by the practice followed by some bird-fanciers, who pull out a few feathers from the breast of nestling bullfinches, and from the head or neck of young gold-pheasants, in order to ascertain their sex; for in the males, these feathers are immediately replaced by coloured ones. (36. Mr. Blyth, in Charlesworth’s ‘Magazine of Natural History,’ vol. i. 1837, p. 300. Mr. Bartlett has informed me in regard to gold pheasants.) The actual duration of life is known in but few birds, so that we can hardly judge by this standard. And, with reference to the period at which the power of reproduction is gained, it is a remarkable fact that various birds occasionally breed whilst retaining their immature plumage. (37. I have noticed the following cases in Audubon’s ‘Ornith. Biography.’ The redstart of America (Muscapica ruticilla, vol. i. p. 203). The Ibis tantalus takes four years to come to full maturity, but sometimes breeds in the second year (vol. iii. p. 133). The Grus americanus takes the same time, but breeds before acquiring its full plumage (vol. iii. p. 211). The adults of Ardea caerulea are blue, and the young white; and white, mottled, and mature blue birds may all be seen breeding together (vol. iv. p. 58): but Mr. Blyth informs me that certain herons apparently are dimorphic, for white and coloured individuals of the same age may be observed. The Harlequin duck (Anas histrionica, Linn.) takes three years to acquire its full plumage, though many birds breed in the second year (vol. iii. p. 614). The White-headed Eagle (Falco leucocephalus, vol. iii. p. 210) is likewise known to breed in its immature state. Some species of Oriolus (according to Mr. Blyth and Mr. Swinhoe, in ‘Ibis,’ July 1863, p. 68) likewise breed before they attain their full plumage.)

The fact of birds breeding in their immature plumage seems opposed to the belief that sexual selection has played as important a part, as I believe it has, in giving ornamental colours, plumes, etc., to the males, and, by means of equal transmission, to the females of many species. The objection would be a valid one, if the younger and less ornamented males were as successful in winning females and propagating their kind, as the older and more beautiful males. But we have no reason to suppose that this is the case. Audubon speaks of the breeding of the immature males of Ibis tantalus as a rare event, as does Mr. Swinhoe, in regard to the immature males of Oriolus. (38. See footnote 37 above.) If the young of any species in their immature plumage were more successful in winning partners than the adults, the adult plumage would probably soon be lost, as the males would prevail, which retained their immature dress for the longest period, and thus the character of the species would ultimately be modified. (39. Other animals, belonging to quite distinct classes, are either habitually or occasionally capable of breeding before they have fully acquired their adult characters. This is the case with the young males of the salmon. Several amphibians have been known to breed whilst retaining their larval structure. Fritz Müller has shewn (‘Facts and arguments for Darwin,’ Eng. trans. 1869, p. 79) that the males of several amphipod crustaceans become sexually mature whilst young; and I infer that this is a case of premature breeding, because they have not as yet acquired their fully-developed claspers. All such facts are highly interesting, as bearing on one means by which species may undergo great modifications of character.) If, on the other hand, the young never succeeded in obtaining a female, the habit of early reproduction would perhaps be sooner or later eliminated, from being superfluous and entailing waste of power.

The plumage of certain birds goes on increasing in beauty during many years after they are fully mature; this is the case with the train of the peacock, with some of the birds of paradise, and with the crest and plumes of certain herons, for instance, the Ardea ludovicana. (40. Jerdon, ‘Birds of India,’ vol. iii. p. 507, on the peacock. Dr. Marshall thinks that the older and more brilliant males of birds of paradise, have an advantage over the younger males; see ‘Archives Neerlandaises,’ tom. vi. 1871.—On Ardea, Audubon, ibid. vol. iii. p. 139.) But it is doubtful whether the continued development of such feathers is the result of the selection of successive beneficial variations (though this is the most probable view with birds of paradise) or merely of continuous growth. Most fishes continue increasing in size, as long as they are in good health and have plenty of food; and a somewhat similar law may prevail with the plumes of birds.

第五类

When the Adults of Both Sexes Have a Distinct Winter and Summer Plumage, Whether or Not the Male Differs from the Female, The Young Resemble the Adults of Both Sexes in Their Winter Dress, Or Much More Rarely in Their Summer Dress, Or They Resemble the Females Alone. Or the Young May Have an Intermediate Character; Or, Again, They May Differ Greatly from the Adults in Both Their Seasonal Plumages

The cases in this class are singularly complex; nor is this surprising, as they depend on inheritance, limited in a greater or less degree in three different ways, namely, by sex, age, and the season of the year. In some cases the individuals of the same species pass through at least five distinct states of plumage. With the species, in which the male differs from the female during the summer season alone, or, which is rarer, during both seasons (41. For illustrative cases, see vol. iv. of Macgillivray’s ‘History of British Birds;’ on Tringa, etc., pp. 229, 271; on the Machetes, p. 172; on the Charadrius hiaticula, p. 118; on the Charadrius pluvialis, p. 94.), the young generally resemble the females,—as with the so-called goldfinch of North America, and apparently with the splendid Maluri of Australia. (42. For the goldfinch of N. America, Fringilla tristis, Linn., see Audubon, ‘Ornithological Biography,’ vol. i. p. 172. For the Maluri, Gould’s ‘Handbook of the Birds of Australia,’ vol. i. p. 318.) With those species, the sexes of which are alike during both the summer and winter, the young may resemble the adults, firstly, in their winter dress; secondly, and this is of much rarer occurrence, in their summer dress; thirdly, they may be intermediate between these two states; and, fourthly, they may differ greatly from the adults at all seasons. We have an instance of the first of these four cases in one of the egrets of India (Buphus coromandus), in which the young and the adults of both sexes are white during the winter, the adults becoming golden-buff during the summer.

With the gaper (Anastomus oscitans) of India we have a similar case, but the colours are reversed: for the young and the adults of both sexes are grey and black during the winter, the adults becoming white during the summer. (43. I am indebted to Mr. Blyth for information as to the Buphus; see also Jerdon, ‘Birds of India,’ vol. iii. p. 749. On the Anastomus, see Blyth, in ‘Ibis,’ 1867, p. 173.) As an instance of the second case, the young of the razor-bill (Alca torda, Linn.), in an early state of plumage, are coloured like the adults during the summer; and the young of the white- crowned sparrow of North America (Fringilla leucophrys), as soon as fledged, have elegant white stripes on their heads, which are lost by the young and the old during the winter. (44. On the Alca, see Macgillivray, ‘Hist. Brit. Birds,’ vol. v. p. 347. On the Fringilla leucophrys, Audubon, ibid. vol. ii. p. 89. I shall have hereafter to refer to the young of certain herons and egrets being white.) With respect to the third case, namely, that of the young having an intermediate character between the summer and winter adult plumages, Yarrell (45. ‘History of British Birds,’ vol. i. 1839, p. 159.) insists that this occurs with many waders. Lastly, in regard to the young differing greatly from both sexes in their adult summer and winter plumages, this occurs with some herons and egrets of North America and India,—the young alone being white.

I will make only a few remarks on these complicated cases. When the young resemble the females in their summer dress, or the adults of both sexes in their winter dress, the cases differ from those given under Classes I. and III. only in the characters originally acquired by the males during the breeding-season, having been limited in their transmission to the corresponding season. When the adults have a distinct summer and winter plumage, and the young differ from both, the case is more difficult to understand. We may admit as probable that the young have retained an ancient state of plumage; we can account by sexual selection for the summer or nuptial plumage of the adults, but how are we to account for their distinct winter plumage? If we could admit that this plumage serves in all cases as a protection, its acquirement would be a simple affair; but there seems no good reason for this admission. It may be suggested that the widely different conditions of life during the winter and summer have acted in a direct manner on the plumage; this may have had some effect, but I have not much confidence in so great a difference as we sometimes see between the two plumages, having been thus caused. A more probable explanation is, that an ancient style of plumage, partially modified through the transference of some characters from the summer plumage, has been retained by the adults during the winter. Finally, all the cases in our present class apparently depend on characters acquired by the adult males, having been variously limited in their transmission according to age, season, and sex; but it would not be worth while to attempt to follow out these complex relations.

第VI级

The Young in Their First Plumage Differ from Each Other According to Sex; The Young Males Resembling More or Less Closely the Adult Males, And the Young Females More or Less Closely the Adult Females

The cases in the present class, though occurring in various groups, are not numerous; yet it seems the most natural thing that the young should at first somewhat resemble the adults of the same sex, and gradually become more and more like them. The adult male blackcap (Sylvia atricapilla) has a black head, that of the female being reddish-brown; and I am informed by Mr. Blyth, that the young of both sexes can be distinguished by this character even as nestlings. In the family of thrushes an unusual number of similar cases have been noticed; thus, the male blackbird (Turdus merula) can be distinguished in the nest from the female. The two sexes of the mocking bird (Turdus polyglottus, Linn.) differ very little from each other, yet the males can easily be distinguished at a very early age from the females by showing more pure white. (46. Audubon, ‘Ornith. Biography,’ vol. i. p. 113.) The males of a forest-thrush and of a rock- thrush (Orocetes erythrogastra and Petrocincla cyanea) have much of their plumage of a fine blue, whilst the females are brown; and the nestling males of both species have their main wing and tail-feathers edged with blue whilst those of the female are edged with brown. (47. Mr. C.A. Wright, in ‘Ibis,’ vol. vi. 1864, p. 65. Jerdon, ‘Birds of India,’ vol. i. p. 515. See also on the blackbird, Blyth in Charlesworth’s ‘Magazine of Natural History,’ vol. i. 1837, p. 113.) In the young blackbird the wing- feathers assume their mature character and become black after the others; on the other hand, in the two species just named the wing-feathers become blue before the others. The most probable view with reference to the cases in the present class is that the males, differently from what occurs in Class I., have transmitted their colours to their male offspring at an earlier age than that at which they were first acquired; for, if the males had varied whilst quite young, their characters would probably have been transmitted to both sexes. (48. The following additional cases may be mentioned; the young males of Tanagra rubra can be distinguished from the young females (Audubon, ‘Ornith. Biography,’ vol. iv. p. 392), and so it is within the nestlings of a blue nuthatch, Dendrophila frontalis of India (Jerdon, ‘Birds of India,’ vol. i. p. 389). Mr. Blyth also informs me that the sexes of the stonechat, Saxicola rubicola, are distinguishable at a very early age. Mr. Salvin gives (‘Proc. Zoolog. Soc.’ 1870, p. 206) the case of a humming-bird, like the following one of Eustephanus.)

In Aithurus polytmus, a humming-bird, the male is splendidly coloured black and green, and two of the tail-feathers are immensely lengthened; the female has an ordinary tail and inconspicuous colours; now the young males, instead of resembling the adult female, in accordance with the common rule, begin from the first to assume the colours proper to their sex, and their tail-feathers soon become elongated. I owe this information to Mr. Gould, who has given me the following more striking and as yet unpublished case. Two humming-birds belonging to the genus Eustephanus, both beautifully coloured, inhabit the small island of Juan Fernandez, and have always been ranked as specifically distinct. But it has lately been ascertained that the one which is of a rich chestnut-brown colour with a golden-red head, is the male, whilst the other which is elegantly variegated with green and white with a metallic green head is the female. Now the young from the first somewhat resemble the adults of the corresponding sex, the resemblance gradually becoming more and more complete.

In considering this last case, if as before we take the plumage of the young as our guide, it would appear that both sexes have been rendered beautiful independently; and not that one sex has partially transferred its beauty to the other. The male apparently has acquired his bright colours through sexual selection in the same manner as, for instance, the peacock or pheasant in our first class of cases; and the female in the same manner as the female Rhynchaea or Turnix in our second class of cases. But there is much difficulty in understanding how this could have been effected at the same time with the two sexes of the same species. Mr. Salvin states, as we have seen in the eighth chapter, that with certain humming-birds the males greatly exceed the females in number, whilst with other species inhabiting the same country the females greatly exceed the males. If, then, we might assume that during some former lengthened period the males of the Juan Fernandez species had greatly exceeded the females in number, but that during another lengthened period the females had far exceeded the males, we could understand how the males at one time, and the females at another, might have been rendered beautiful by the selection of the brighter coloured individuals of either sex; both sexes transmitting their characters to their young at a rather earlier age than usual. Whether this is the true explanation I will not pretend to say; but the case is too remarkable to be passed over without notice.

We have now seen in all six classes, that an intimate relation exists between the plumage of the young and the adults, either of one sex or both. These relations are fairly well explained on the principle that one sex— this being in the great majority of cases the male—first acquired through variation and sexual selection bright colours or other ornaments, and transmitted them in various ways, in accordance with the recognised laws of inheritance. Why variations have occurred at different periods of life, even sometimes with species of the same group, we do not know, but with respect to the form of transmission, one important determining cause seems to be the age at which the variations first appear.

From the principle of inheritance at corresponding ages, and from any variations in colour which occurred in the males at an early age not being then selected—on the contrary being often eliminated as dangerous—whilst similar variations occurring at or near the period of reproduction have been preserved, it follows that the plumage of the young will often have been left unmodified, or but little modified. We thus get some insight into the colouring of the progenitors of our existing species. In a vast number of species in five out of our six classes of cases, the adults of one sex or of both are bright coloured, at least during the breeding- season, whilst the young are invariably less brightly coloured than the adults, or are quite dull coloured; for no instance is known, as far as I can discover, of the young of dull-coloured species displaying bright colours, or of the young of bright-coloured species being more brilliant than their parents. In the fourth class, however, in which the young and the old resemble each other, there are many species (though by no means all), of which the young are bright-coloured, and as these form old groups, we may infer that their early progenitors were likewise bright. With this exception, if we look to the birds of the world, it appears that their beauty has been much increased since that period, of which their immature plumage gives us a partial record.

On the Colour of the Plumage in Relation to Protection

It will have been seen that I cannot follow Mr. Wallace in the belief that dull colours, when confined to the females, have been in most cases specially gained for the sake of protection. There can, however, be no doubt, as formerly remarked, that both sexes of many birds have had their colours modified, so as to escape the notice of their enemies; or in some instances, so as to approach their prey unobserved, just as owls have had their plumage rendered soft, that their flight may not be overheard. Mr. Wallace remarks (49. ‘Westminster Review,’ July 1867, p. 5.) that “it is only in the tropics, among forests which never lose their foliage, that we find whole groups of birds, whose chief colour is green.” It will be admitted by every one, who has ever tried, how difficult it is to distinguish parrots in a leaf-covered tree. Nevertheless, we must remember that many parrots are ornamented with crimson, blue, and orange tints, which can hardly be protective. Woodpeckers are eminently arboreal, but besides green species, there are many black, and black-and-white kinds—all the species being apparently exposed to nearly the same dangers. It is therefore probable that with tree-haunting birds, strongly-pronounced colours have been acquired through sexual selection, but that a green tint has been acquired oftener than any other, from the additional advantage of protection.

In regard to birds which live on the ground, every one admits that they are coloured so as to imitate the surrounding surface. How difficult it is to see a partridge, snipe, woodcock, certain plovers, larks, and night-jars when crouched on ground. Animals inhabiting deserts offer the most striking cases, for the bare surface affords no concealment, and nearly all the smaller quadrupeds, reptiles, and birds depend for safety on their colours. Mr. Tristram has remarked in regard to the inhabitants of the Sahara, that all are protected by their “isabelline or sand-colour.” (50. ‘Ibis,’ 1859, vol. i. p. 429, et seq. Dr. Rohlfs, however, remarks to me in a letter that according to his experience of the Sahara, this statement is too strong.) Calling to my recollection the desert-birds of South America, as well as most of the ground-birds of Great Britain, it appeared to me that both sexes in such cases are generally coloured nearly alike. Accordingly, I applied to Mr. Tristram with respect to the birds of the Sahara, and he has kindly given me the following information. There are twenty-six species belonging to fifteen genera, which manifestly have their plumage coloured in a protective manner; and this colouring is all the more striking, as with most of these birds it differs from that of their congeners. Both sexes of thirteen out of the twenty-six species are coloured in the same manner; but these belong to genera in which this rule commonly prevails, so that they tell us nothing about the protective colours being the same in both sexes of desert-birds. Of the other thirteen species, three belong to genera in which the sexes usually differ from each other, yet here they have the sexes alike. In the remaining ten species, the male differs from the female; but the difference is confined chiefly to the under surface of the plumage, which is concealed when the bird crouches on the ground; the head and back being of the same sand- coloured hue in the two sexes. So that in these ten species the upper surfaces of both sexes have been acted on and rendered alike, through natural selection, for the sake of protection; whilst the lower surfaces of the males alone have been diversified, through sexual selection, for the sake of ornament. Here, as both sexes are equally well protected, we clearly see that the females have not been prevented by natural selection from inheriting the colours of their male parents; so that we must look to the law of sexually-limited transmission.

In all parts of the world both sexes of many soft-billed birds, especially those which frequent reeds or sedges, are obscurely coloured. No doubt if their colours had been brilliant, they would have been much more conspicuous to their enemies; but whether their dull tints have been specially gained for the sake of protection seems, as far as I can judge, rather doubtful. It is still more doubtful whether such dull tints can have been gained for the sake of ornament. We must, however, bear in mind that male birds, though dull-coloured, often differ much from their females (as with the common sparrow), and this leads to the belief that such colours have been gained through sexual selection, from being attractive. Many of the soft-billed birds are songsters; and a discussion in a former chapter should not be forgotten, in which it was shewn that the best songsters are rarely ornamented with bright tints. It would appear that female birds, as a general rule, have selected their mates either for their sweet voices or gay colours, but not for both charms combined. Some species, which are manifestly coloured for the sake of protection, such as the jack-snipe, woodcock, and night-jar, are likewise marked and shaded, according to our standard of taste, with extreme elegance. In such cases we may conclude that both natural and sexual selection have acted conjointly for protection and ornament. Whether any bird exists which does not possess some special attraction, by which to charm the opposite sex, may be doubted. When both sexes are so obscurely coloured that it would be rash to assume the agency of sexual selection, and when no direct evidence can be advanced shewing that such colours serve as a protection, it is best to own complete ignorance of the cause, or, which comes to nearly the same thing, to attribute the result to the direct action of the conditions of life.

Both sexes of many birds are conspicuously, though not brilliantly coloured, such as the numerous black, white, or piebald species; and these colours are probably the result of sexual selection. With the common blackbird, capercailzie, blackcock, black scoter-duck (Oidemia), and even with one of the birds of paradise (Lophorina atra), the males alone are black, whilst the females are brown or mottled; and there can hardly be a doubt that blackness in these cases has been a sexually selected character. Therefore it is in some degree probable that the complete or partial blackness of both sexes in such birds as crows, certain cockatoos, storks, and swans, and many marine birds, is likewise the result of sexual selection, accompanied by equal transmission to both sexes; for blackness can hardly serve in any case as a protection. With several birds, in which the male alone is black, and in others in which both sexes are black, the beak or skin about the head is brightly coloured, and the contrast thus afforded adds much to their beauty; we see this in the bright yellow beak of the male blackbird, in the crimson skin over the eyes of the blackcock and capercailzie, in the brightly and variously coloured beak of the scoter-drake (Oidemia), in the red beak of the chough (Corvus graculus, Linn.), of the black swan, and the black stork. This leads me to remark that it is not incredible that toucans may owe the enormous size of their beaks to sexual selection, for the sake of displaying the diversified and vivid stripes of colour, with which these organs are ornamented. (51。 No satisfactory explanation has ever been offered of the immense size, and still less of the bright colours, of the toucan’s beak. 先生。 Bates (‘The Naturalist on the Amazons,’ vol. II。 1863。 341) states that they use their beaks for reaching fruit at the extreme tips of the branches; and likewise, as stated by other authors, for extracting eggs and young birds from the nests of other birds. 但是,作为先生。 Bates admits, the beak “can scarcely be considered a very perfectly-formed instrument for the end to which it is applied.” The great bulk of the beak, as shewn by its breadth, depth, as well as length, is not intelligible on the view, that it serves merely as an organ of prehension. 先生。 Belt believes (‘The Naturalist in Nicaragua,’ p. 197) that the principal use of the beak is as a defence against enemies, especially to the female whilst nesting in a hole in a tree.) The naked skin, also, at the base of the beak and round the eyes is likewise often brilliantly coloured; and Mr. Gould, in speaking of one species (52.

In the same manner, as the males alone of various species are black, the females being dull-coloured; so in a few cases the males alone are either wholly or partially white, as with the several bell-birds of South America (Chasmorhynchus), the Antarctic goose (Bernicla antarctica), the silver pheasant, etc., whilst the females are brown or obscurely mottled. Therefore, on the same principle as before, it is probable that both sexes of many birds, such as white cockatoos, several egrets with their beautiful plumes, certain ibises, gulls, terns, etc., have acquired their more or less completely white plumage through sexual selection. In some of these cases the plumage becomes white only at maturity. This is the case with certain gannets, tropic-birds, etc., and with the snow-goose (Anser hyperboreus). As the latter breeds on the “barren grounds,” when not covered with snow, and as it migrates southward during the winter, there is no reason to suppose that its snow-white adult plumage serves as a protection. In the Anastomus oscitans, we have still better evidence that the white plumage is a nuptial character, for it is developed only during the summer; the young in their immature state, and the adults in their winter dress, being grey and black. With many kinds of gulls (Larus), the head and neck become pure white during the summer, being grey or mottled during the winter and in the young state. On the other hand, with the smaller gulls, or sea-mews (Gavia), and with some terns (Sterna), exactly the reverse occurs; for the heads of the young birds during the first year, and of the adults during the winter, are either pure white, or much paler coloured than during the breeding-season. These latter cases offer another instance of the capricious manner in which sexual selection appears often to have acted. (53. On Larus, Gavia, and Sterna, see Macgillivray, ‘History of British Birds,’ vol. v. pp. 515, 584, 626. On the Anser hyperboreus, Audubon, ‘Ornithological Biography,’ vol. iv. p. 562. On the Anastomus, Mr. Blyth, in ‘Ibis,’ 1867, p. 173.)

That aquatic birds have acquired a white plumage so much oftener than terrestrial birds, probably depends on their large size and strong powers of flight, so that they can easily defend themselves or escape from birds of prey, to which moreover they are not much exposed. Consequently, sexual selection has not here been interfered with or guided for the sake of protection. No doubt with birds which roam over the open ocean, the males and females could find each other much more easily, when made conspicuous either by being perfectly white or intensely black; so that these colours may possibly serve the same end as the call-notes of many land-birds. (54. It may be noticed that with vultures, which roam far and wide high in the air, like marine birds over the ocean, three or four species are almost wholly or largely white, and that many others are black. So that here again conspicuous colours may possibly aid the sexes in finding each other during the breeding-season.) A white or black bird when it discovers and flies down to a carcase floating on the sea or cast up on the beach, will be seen from a great distance, and will guide other birds of the same and other species, to the prey; but as this would be a disadvantage to the first finders, the individuals which were the whitest or blackest would not thus procure more food than the less strongly coloured individuals. Hence conspicuous colours cannot have been gradually acquired for this purpose through natural selection.

As sexual selection depends on so fluctuating an element as taste, we can understand how it is that, within the same group of birds having nearly the same habits, there should exist white or nearly white, as well as black, or nearly black species,—for instance, both white and black cockatoos, storks, ibises, swans, terns, and petrels. Piebald birds likewise sometimes occur in the same groups together with black and white species; for instance, the black-necked swan, certain terns, and the common magpie. That a strong contrast in colour is agreeable to birds, we may conclude by looking through any large collection, for the sexes often differ from each other in the male having the pale parts of a purer white, and the variously coloured dark parts of still darker tints than the female.

It would even appear that mere novelty, or slight changes for the sake of change, have sometimes acted on female birds as a charm, like changes of fashion with us. Thus the males of some parrots can hardly be said to be more beautiful than the females, at least according to our taste, but they differ in such points, as in having a rose-coloured collar instead of “a bright emeraldine narrow green collar”; or in the male having a black collar instead of “a yellow demi-collar in front,” with a pale roseate instead of a plum-blue head. (55. See Jerdon on the genus Palaeornis, ‘Birds of India,’ vol. i. pp. 258-260.) As so many male birds have elongated tail-feathers or elongated crests for their chief ornament, the shortened tail, formerly described in the male of a humming-bird, and the shortened crest of the male goosander, seem like one of the many changes of fashion which we admire in our own dresses.

Some members of the heron family offer a still more curious case of novelty in colouring having, as it appears, been appreciated for the sake of novelty. The young of the Ardea asha are white, the adults being dark slate-coloured; and not only the young, but the adults in their winter plumage, of the allied Buphus coromandus are white, this colour changing into a rich golden-buff during the breeding-season. It is incredible that the young of these two species, as well as of some other members of the same family (56. The young of Ardea rufescens and A. caerulea of the United States are likewise white, the adults being coloured in accordance with their specific names. Audubon (‘Ornithological Biography,’ vol. iii. p. 416; vol. iv. p. 58) seems rather pleased at the thought that this remarkable change of plumage will greatly “disconcert the systematists.”), should for any special purpose have been rendered pure white and thus made conspicuous to their enemies; or that the adults of one of these two species should have been specially rendered white during the winter in a country which is never covered with snow. On the other hand we have good reason to believe that whiteness has been gained by many birds as a sexual ornament. We may therefore conclude that some early progenitor of the Ardea asha and the Buphus acquired a white plumage for nuptial purposes, and transmitted this colour to their young; so that the young and the old became white like certain existing egrets; and that the whiteness was afterwards retained by the young, whilst it was exchanged by the adults for more strongly-pronounced tints. But if we could look still further back to the still earlier progenitors of these two species, we should probably see the adults dark-coloured. I infer that this would be the case, from the analogy of many other birds, which are dark whilst young, and when adult are white; and more especially from the case of the Ardea gularis, the colours of which are the reverse of those of A. asha, for the young are dark-coloured and the adults white, the young having retained a former state of plumage. It appears therefore that, during a long line of descent, the adult progenitors of the Ardea asha, the Buphus, and of some allies, have undergone the following changes of colour: first, a dark shade; secondly, pure white; and thirdly, owing to another change of fashion (if I may so express myself), their present slaty, reddish, or golden-buff tints. These successive changes are intelligible only on the principle of novelty having been admired by birds for its own sake.

Several writers have objected to the whole theory of sexual selection, by assuming that with animals and savages the taste of the female for certain colours or other ornaments would not remain constant for many generations; that first one colour and then another would be admired, and consequently that no permanent effect could be produced. We may admit that taste is fluctuating, but it is not quite arbitrary. It depends much on habit, as we see in mankind; and we may infer that this would hold good with birds and other animals. Even in our own dress, the general character lasts long, and the changes are to a certain extent graduated. Abundant evidence will be given in two places in a future chapter, that savages of many races have admired for many generations the same cicatrices on the skin, the same hideously perforated lips, nostrils, or ears, distorted heads, etc.; and these deformities present some analogy to the natural ornaments of various animals. Nevertheless, with savages such fashions do not endure for ever, as we may infer from the differences in this respect between allied tribes on the same continent. So again the raisers of fancy animals certainly have admired for many generations and still admire the same breeds; they earnestly desire slight changes, which are considered as improvements, but any great or sudden change is looked at as the greatest blemish. With birds in a state of nature we have no reason to suppose that they would admire an entirely new style of coloration, even if great and sudden variations often occurred, which is far from being the case. We know that dovecot pigeons do not willingly associate with the variously coloured fancy breeds; that albino birds do not commonly get partners in marriage; and that the black ravens of the Feroe Islands chase away their piebald brethren. But this dislike of a sudden change would not preclude their appreciating slight changes, any more than it does in the case of man. Hence with respect to taste, which depends on many elements, but partly on habit and partly on a love of novelty, there seems no improbability in animals admiring for a very long period the same general style of ornamentation or other attractions, and yet appreciating slight changes in colours, form, or sound.

Summary of the Four Chapters on Birds

Most male birds are highly pugnacious during the breeding-season, and some possess weapons adapted for fighting with their rivals. But the most pugnacious and the best armed males rarely or never depend for success solely on their power to drive away or kill their rivals, but have special means for charming the female. With some it is the power of song, or of giving forth strange cries, or instrumental music, and the males in consequence differ from the females in their vocal organs, or in the structure of certain feathers. From the curiously diversified means for producing various sounds, we gain a high idea of the importance of this means of courtship. Many birds endeavour to charm the females by love- dances or antics, performed on the ground or in the air, and sometimes at prepared places. But ornaments of many kinds, the most brilliant tints, combs and wattles, beautiful plumes, elongated feathers, top-knots, and so forth, are by far the commonest means. In some cases mere novelty appears to have acted as a charm. The ornaments of the males must be highly important to them, for they have been acquired in not a few cases at the cost of increased danger from enemies, and even at some loss of power in fighting with their rivals. The males of very many species do not assume their ornamental dress until they arrive at maturity, or they assume it only during the breeding-season, or the tints then become more vivid. Certain ornamental appendages become enlarged, turgid, and brightly coloured during the act of courtship. The males display their charms with elaborate care and to the best effect; and this is done in the presence of the females. The courtship is sometimes a prolonged affair, and many males and females congregate at an appointed place. To suppose that the females do not appreciate the beauty of the males, is to admit that their splendid decorations, all their pomp and display, are useless; and this is incredible. Birds have fine powers of discrimination, and in some few instances it can be shewn that they have a taste for the beautiful. The females, moreover, are known occasionally to exhibit a marked preference or antipathy for certain individual males.

If it be admitted that the females prefer, or are unconsciously excited by the more beautiful males, then the males would slowly but surely be rendered more and more attractive through sexual selection. That it is this sex which has been chiefly modified, we may infer from the fact that, in almost every genus where the sexes differ, the males differ much more from one another than do the females; this is well shewn in certain closely-allied representative species, in which the females can hardly be distinguished, whilst the males are quite distinct. Birds in a state of nature offer individual differences which would amply suffice for the work of sexual selection; but we have seen that they occasionally present more strongly marked variations which recur so frequently that they would immediately be fixed, if they served to allure the female. The laws of variation must determine the nature of the initial changes, and will have largely influenced the final result. The gradations, which may be observed between the males of allied species, indicate the nature of the steps through which they have passed. They explain also in the most interesting manner how certain characters have originated, such as the indented ocelli on the tail-feathers of the peacock, and the ball-and-socket ocelli on the wing-feathers of the Argus pheasant. It is evident that the brilliant colours, top-knots, fine plumes, etc., of many male birds cannot have been acquired as a protection; indeed, they sometimes lead to danger. That they are not due to the direct and definite action of the conditions of life, we may feel assured, because the females have been exposed to the same conditions, and yet often differ from the males to an extreme degree. Although it is probable that changed conditions acting during a lengthened period have in some cases produced a definite effect on both sexes, or sometimes on one sex alone, the more important result will have been an increased tendency to vary or to present more strongly-marked individual differences; and such differences will have afforded an excellent ground- work for the action of sexual selection.

The laws of inheritance, irrespectively of selection, appear to have determined whether the characters acquired by the males for the sake of ornament, for producing various sounds, and for fighting together, have been transmitted to the males alone or to both sexes, either permanently, or periodically during certain seasons of the year. Why various characters should have been transmitted sometimes in one way and sometimes in another, is not in most cases known; but the period of variability seems often to have been the determining cause. When the two sexes have inherited all characters in common they necessarily resemble each other; but as the successive variations may be differently transmitted, every possible gradation may be found, even within the same genus, from the closest similarity to the widest dissimilarity between the sexes. With many closely-allied species, following nearly the same habits of life, the males have come to differ from each other chiefly through the action of sexual selection; whilst the females have come to differ chiefly from partaking more or less of the characters thus acquired by the males. The effects, moreover, of the definite action of the conditions of life, will not have been masked in the females, as in the males, by the accumulation through sexual selection of strongly-pronounced colours and other ornaments. The individuals of both sexes, however affected, will have been kept at each successive period nearly uniform by the free intercrossing of many individuals.

With species, in which the sexes differ in colour, it is possible or probable that some of the successive variations often tended to be transmitted equally to both sexes; but that when this occurred the females were prevented from acquiring the bright colours of the males, by the destruction which they suffered during incubation. There is no evidence that it is possible by natural selection to convert one form of transmission into another. But there would not be the least difficulty in rendering a female dull-coloured, the male being still kept bright- coloured, by the selection of successive variations, which were from the first limited in their transmission to the same sex. Whether the females of many species have actually been thus modified, must at present remain doubtful. When, through the law of the equal transmission of characters to both sexes, the females were rendered as conspicuously coloured as the males, their instincts appear often to have been modified so that they were led to build domed or concealed nests.

In one small and curious class of cases the characters and habits of the two sexes have been completely transposed, for the females are larger, stronger, more vociferous and brighter coloured than the males. They have, also, become so quarrelsome that they often fight together for the possession of the males, like the males of other pugnacious species for the possession of the females. If, as seems probable, such females habitually drive away their rivals, and by the display of their bright colours or other charms endeavour to attract the males, we can understand how it is that they have gradually been rendered, by sexual selection and sexually- limited transmission, more beautiful than the males—the latter being left unmodified or only slightly modified.

Whenever the law of inheritance at corresponding ages prevails but not that of sexually-limited transmission, then if the parents vary late in life— and we know that this constantly occurs with our poultry, and occasionally with other birds—the young will be left unaffected, whilst the adults of both sexes will be modified. If both these laws of inheritance prevail and either sex varies late in life, that sex alone will be modified, the other sex and the young being unaffected. When variations in brightness or in other conspicuous characters occur early in life, as no doubt often happens, they will not be acted on through sexual selection until the period of reproduction arrives; consequently if dangerous to the young, they will be eliminated through natural selection. Thus we can understand how it is that variations arising late in life have so often been preserved for the ornamentation of the males; the females and the young being left almost unaffected, and therefore like each other. With species having a distinct summer and winter plumage, the males of which either resemble or differ from the females during both seasons or during the summer alone, the degrees and kinds of resemblance between the young and the old are exceedingly complex; and this complexity apparently depends on characters, first acquired by the males, being transmitted in various ways and degrees, as limited by age, sex, and season.

As the young of so many species have been but little modified in colour and in other ornaments, we are enabled to form some judgment with respect to the plumage of their early progenitors; and we may infer that the beauty of our existing species, if we look to the whole class, has been largely increased since that period, of which the immature plumage gives us an indirect record. Many birds, especially those which live much on the ground, have undoubtedly been obscurely coloured for the sake of protection. In some instances the upper exposed surface of the plumage has been thus coloured in both sexes, whilst the lower surface in the males alone has been variously ornamented through sexual selection. Finally, from the facts given in these four chapters, we may conclude that weapons for battle, organs for producing sound, ornaments of many kinds, bright and conspicuous colours, have generally been acquired by the males through variation and sexual selection, and have been transmitted in various ways according to the several laws of inheritance—the females and the young being left comparatively but little modified. (57. I am greatly indebted to the kindness of Mr. Sclater for having looked over these four chapters on birds, and the two following ones on mammals. In this way I have been saved from making mistakes about the names of the species, and from stating anything as a fact which is known to this distinguished naturalist to be erroneous. But, of course, he is not at all answerable for the accuracy of the statements quoted by me from various authorities.)

第十七章 •10,900字
哺乳动物的第二性征

The law of battle—Special weapons, confined to the males—Cause of absence of weapons in the female—Weapons common to both sexes, yet primarily acquired by the male—Other uses of such weapons—Their high importance— Greater size of the male—Means of defence—On the preference shown by either sex in the pairing of quadrupeds.

With mammals the male appears to win the female much more through the law of battle than through the display of his charms. The most timid animals, not provided with any special weapons for fighting, engage in desperate conflicts during the season of love. Two male hares have been seen to fight together until one was killed; male moles often fight, and sometimes with fatal results; male squirrels engage in frequent contests, “and often wound each other severely”; as do male beavers, so that “hardly a skin is without scars.” (1. See Waterton’s account of two hares fighting, ‘Zoologist,’ vol. i. 1843, p. 211. On moles, Bell, ‘Hist. of British Quadrupeds,’ 1st ed., p. 100. On squirrels, Audubon and Bachman, Viviparous Quadrupeds of N. America, 1846, p. 269. On beavers, Mr. A.H. Green, in ‘Journal of Linnean Society, Zoology,’ vol. x. 1869, p. 362.) I observed the same fact with the hides of the guanacoes in Patagonia; and on one occasion several were so absorbed in fighting that they fearlessly rushed close by me. Livingstone speaks of the males of the many animals in Southern Africa as almost invariably shewing the scars received in former contests.

The law of battle prevails with aquatic as with terrestrial mammals. It is notorious how desperately male seals fight, both with their teeth and claws, during the breeding-season; and their hides are likewise often covered with scars. Male sperm-whales are very jealous at this season; and in their battles “they often lock their jaws together, and turn on their sides and twist about”; so that their lower jaws often become distorted. (2. On the battles of seals, see Capt. C. Abbott in ‘Proc. Zool. Soc.’ 1868, p. 191; Mr. R. Brown, ibid. 1868, p. 436; also L. Lloyd, ‘Game Birds of Sweden,’ 1867, p. 412; also Pennant. On the sperm-whale see Mr. J.H. Thompson, in ‘Proc. Zool. Soc.’ 1867, p. 246.)

All male animals which are furnished with special weapons for fighting, are well known to engage in fierce battles. The courage and the desperate conflicts of stags have often been described; their skeletons have been found in various parts of the world, with the horns inextricably locked together, shewing how miserably the victor and vanquished had perished. (3. See Scrope (‘Art of Deer-stalking,’ p. 17) on the locking of the horns with the Cervus elaphus. Richardson, in ‘Fauna Bor. Americana,’ 1829, p. 252, says that the wapiti, moose, and reindeer have been found thus locked together. Sir A. Smith found at the Cape of Good Hope the skeletons of two gnus in the same condition.) No animal in the world is so dangerous as an elephant in must. Lord Tankerville has given me a graphic description of the battles between the wild bulls in Chillingham Park, the descendants, degenerated in size but not in courage, of the gigantic Bos primigenius. In 1861 several contended for mastery; and it was observed that two of the younger bulls attacked in concert the old leader of the herd, overthrew and disabled him, so that he was believed by the keepers to be lying mortally wounded in a neighbouring wood. But a few days afterwards one of the young bulls approached the wood alone; and then the “monarch of the chase,” who had been lashing himself up for vengeance, came out and, in a short time, killed his antagonist. He then quietly joined the herd, and long held undisputed sway. Admiral Sir B.J. Sulivan informs me that, when he lived in the Falkland Islands, he imported a young English stallion, which frequented the hills near Port William with eight mares. On these hills there were two wild stallions, each with a small troop of mares; “and it is certain that these stallions would never have approached each other without fighting. Both had tried singly to fight the English horse and drive away his mares, but had failed. One day they came in TOGETHER and attacked him. This was seen by the capitan who had charge of the horses, and who, on riding to the spot, found one of the two stallions engaged with the English horse, whilst the other was driving away the mares, and had already separated four from the rest. The capitan settled the matter by driving the whole party into the corral, for the wild stallions would not leave the mares.”

Male animals which are provided with efficient cutting or tearing teeth for the ordinary purposes of life, such as the carnivora, insectivora, and rodents, are seldom furnished with weapons especially adapted for fighting with their rivals. The case is very different with the males of many other animals. We see this in the horns of stags and of certain kinds of antelopes in which the females are hornless. With many animals the canine teeth in the upper or lower jaw, or in both, are much larger in the males than in the females, or are absent in the latter, with the exception sometimes of a hidden rudiment. Certain antelopes, the musk-deer, camel, horse, boar, various apes, seals, and the walrus, offer instances. In the females of the walrus the tusks are sometimes quite absent. (4. Mr. Lamont (‘Seasons with the Sea-Horses,’ 1861, p. 143) says that a good tusk of the male walrus weighs 4 pounds, and is longer than that of the female, which weighs about 3 pounds. The males are described as fighting ferociously. On the occasional absence of the tusks in the female, see Mr. R. Brown, ‘Proceedings, Zoological Society,’ 1868, p. 429.) In the male elephant of India and in the male dugong (5. Owen, ‘Anatomy of Vertebrates,’ vol. iii. p. 283.) the upper incisors form offensive weapons. In the male narwhal the left canine alone is developed into the well-known, spirally-twisted, so-called horn, which is sometimes from nine to ten feet in length. It is believed that the males use these horns for fighting together; for “an unbroken one can rarely be got, and occasionally one may be found with the point of another jammed into the broken place.” (6. Mr. R. Brown, in ‘Proc. Zool. Soc.’ 1869, p. 553. See Prof. Turner, in ‘Journal of Anat. and Phys.’ 1872, p. 76, on the homological nature of these tusks. Also Mr. J.W. Clarke on two tusks being developed in the males, in ‘Proceedings of the Zoological Society,’ 1871, p. 42.) The tooth on the opposite side of the head in the male consists of a rudiment about ten inches in length, which is embedded in the jaw; but sometimes, though rarely, both are equally developed on the two sides. In the female both are always rudimentary. The male cachalot has a larger head than that of the female, and it no doubt aids him in his aquatic battles. Lastly, the adult male ornithorhynchus is provided with a remarkable apparatus, namely a spur on the foreleg, closely resembling the poison-fang of a venomous snake; but according to Harting, the secretion from the gland is not poisonous; and on the leg of the female there is a hollow, apparently for the reception of the spur. (7. Owen on the cachalot and Ornithorhynchus, ibid. vol. iii. pp. 638, 641. Harting is quoted by Dr. Zouteveen in the Dutch translation of this work, vol. ii. p. 292.)

When the males are provided with weapons which in the females are absent, there can be hardly a doubt that these serve for fighting with other males; and that they were acquired through sexual selection, and were transmitted to the male sex alone. It is not probable, at least in most cases, that the females have been prevented from acquiring such weapons, on account of their being useless, superfluous, or in some way injurious. On the contrary, as they are often used by the males for various purposes, more especially as a defence against their enemies, it is a surprising fact that they are so poorly developed, or quite absent, in the females of so many animals. With female deer the development during each recurrent season of great branching horns, and with female elephants the development of immense tusks, would be a great waste of vital power, supposing that they were of no use to the females. Consequently, they would have tended to be eliminated in the female through natural selection; that is, if the successive variations were limited in their transmission to the female sex, for otherwise the weapons of the males would have been injuriously affected, and this would have been a greater evil. On the whole, and from the consideration of the following facts, it seems probable that when the various weapons differ in the two sexes, this has generally depended on the kind of transmission which has prevailed.

As the reindeer is the one species in the whole family of Deer, in which the female is furnished with horns, though they are somewhat smaller, thinner, and less branched than in the male, it might naturally be thought that, at least in this case, they must be of some special service to her. The female retains her horns from the time when they are fully developed, namely, in September, throughout the winter until April or May, when she brings forth her young. Mr. Crotch made particular enquiries for me in Norway, and it appears that the females at this season conceal themselves for about a fortnight in order to bring forth their young, and then reappear, generally hornless. In Nova Scotia, however, as I hear from Mr. H. Reeks, the female sometimes retains her horns longer. The male on the other hand casts his horns much earlier, towards the end of November. As both sexes have the same requirements and follow the same habits of life, and as the male is destitute of horns during the winter, it is improbable that they can be of any special service to the female during this season, which includes the larger part of the time during which she is horned. Nor is it probable that she can have inherited horns from some ancient progenitor of the family of deer, for, from the fact of the females of so many species in all quarters of the globe not having horns, we may conclude that this was the primordial character of the group. (8. On the structure and shedding of the horns of the reindeer, Hoffberg, ‘Amoenitates Acad.’ vol. iv. 1788, p. 149. See Richardson, ‘Fauna Bor. Americana,’ p. 241, in regard to the American variety or species: also Major W. Ross King, ‘The Sportsman in Canada,’ 1866, p. 80.

The horns of the reindeer are developed at a most unusually early age; but what the cause of this may be is not known. The effect has apparently been the transference of the horns to both sexes. We should bear in mind that horns are always transmitted through the female, and that she has a latent capacity for their development, as we see in old or diseased females. (9. Isidore Geoffroy St.-Hilaire, ‘Essais de Zoolog. Générale,’ 1841, p. 513. Other masculine characters, besides the horns, are sometimes similarly transferred to the female; thus Mr. Boner, in speaking of an old female chamois (‘Chamois Hunting in the Mountains of Bavaria,’ 1860, 2nd ed., p. 363), says, “not only was the head very male-looking, but along the back there was a ridge of long hair, usually to be found only in bucks.”) Moreover the females of some other species of deer exhibit, either normally or occasionally, rudiments of horns; thus the female of Cervulus moschatus has “bristly tufts, ending in a knob, instead of a horn”; and “in most specimens of the female wapiti (Cervus canadensis) there is a sharp bony protuberance in the place of the horn.” (10. On the Cervulus, Dr. Gray, ‘Catalogue of Mammalia in the British Museum,’ part iii. p. 220. On the Cervus canadensis or wapiti, see Hon. J.D. Caton, ‘Ottawa Academy of Nat. Sciences,’ May 1868, p. 9.) From these several considerations we may conclude that the possession of fairly well-developed horns by the female reindeer, is due to the males having first acquired them as weapons for fighting with other males; and secondarily to their development from some unknown cause at an unusually early age in the males, and their consequent transference to both sexes.

Turning to the sheath-horned ruminants: with antelopes a graduated series can be formed, beginning with species, the females of which are completely destitute of horns—passing on to those which have horns so small as to be almost rudimentary (as with the Antilocapra americana, in which species they are present in only one out of four or five females (11. I am indebted to Dr. Canfield for this information; see also his paper in the ‘Proceedings of the Zoological Society,’ 1866, p. 105.))—to those which have fairly developed horns, but manifestly smaller and thinner than in the male and sometimes of a different shape (12. For instance the horns of the female Ant. euchore resemble those of a distinct species, viz. the Ant. dorcas var. Corine, see Desmarest, ‘Mammalogie,’ p. 455.),—and ending with those in which both sexes have horns of equal size. As with the reindeer, so with antelopes, there exists, as previously shewn, a relation between the period of the development of the horns and their transmission to one or both sexes; it is therefore probable that their presence or absence in the females of some species, and their more or less perfect condition in the females of other species, depends, not on their being of any special use, but simply on inheritance. It accords with this view that even in the same restricted genus both sexes of some species, and the males alone of others, are thus provided. It is also a remarkable fact that, although the females of Antilope bezoartica are normally destitute of horns, Mr. Blyth has seen no less than three females thus furnished; and there was no reason to suppose that they were old or diseased.

In all the wild species of goats and sheep the horns are larger in the male than in the female, and are sometimes quite absent in the latter. (13. Gray, ‘Catalogue of Mammalia, the British Museum,’ part iii. 1852, p. 160.) In several domestic breeds of these two animals, the males alone are furnished with horns; and in some breeds, for instance, in the sheep of North Wales, though both sexes are properly horned, the ewes are very liable to be hornless. I have been informed by a trustworthy witness, who purposely inspected a flock of these same sheep during the lambing season, that the horns at birth are generally more fully developed in the male than in the female. Mr. J. Peel crossed his Lonk sheep, both sexes of which always bear horns, with hornless Leicesters and hornless Shropshire Downs; and the result was that the male offspring had their horns considerably reduced, whilst the females were wholly destitute of them. These several facts indicate that, with sheep, the horns are a much less firmly fixed character in the females than in the males; and this leads us to look at the horns as properly of masculine origin.

With the adult musk-ox (Ovibos moschatus) the horns of the male are larger than those of the female, and in the latter the bases do not touch. (14. Richardson, ‘Fauna Bor. Americana,’ p. 278.) In regard to ordinary cattle Mr. Blyth remarks: “In most of the wild bovine animals the horns are both longer and thicker in the bull than in the cow, and in the cow-banteng (Bos sondaicus) the horns are remarkably small, and inclined much backwards. In the domestic races of cattle, both of the humped and humpless types, the horns are short and thick in the bull, longer and more slender in the cow and ox; and in the Indian buffalo, they are shorter and thicker in the bull, longer and more slender in the cow. In the wild gaour (B. gaurus) the horns are mostly both longer and thicker in the bull than in the cow.” (15. ‘Land and Water,’ 1867, p. 346.) Dr. Forsyth Major also informs me that a fossil skull, believed to be that of the female Bos etruscus, has been found in Val d’Arno, which is wholly without horns. In the Rhinoceros simus, as I may add, the horns of the female are generally longer but less powerful than in the male; and in some other species of rhinoceros they are said to be shorter in the female. (16. Sir Andrew Smith, ‘Zoology of S. Africa,’ pl. xix. Owen, ‘Anatomy of Vertebrates,’ vol. iii. p. 624.) From these various facts we may infer as probable that horns of all kinds, even when they are equally developed in the two sexes, were primarily acquired by the male in order to conquer other males, and have been transferred more or less completely to the female.

The effects of castration deserve notice, as throwing light on this same point. Stags after the operation never renew their horns. The male reindeer, however, must be excepted, as after castration he does renew them. This fact, as well as the possession of horns by both sexes, seems at first to prove that the horns in this species do not constitute a sexual character (17. This is the conclusion of Seidlitz, ‘Die Darwinsche Theorie,’ 1871, p. 47.); but as they are developed at a very early age, before the sexes differ in constitution, it is not surprising that they should be unaffected by castration, even if they were aboriginally acquired by the male. With sheep both sexes properly bear horns; and I am informed that with Welch sheep the horns of the males are considerably reduced by castration; but the degree depends much on the age at which the operation is performed, as is likewise the case with other animals. Merino rams have large horns, whilst the ewes “generally speaking are without horns”; and in this breed castration seems to produce a somewhat greater effect, so that if performed at an early age the horns “remain almost undeveloped.” (18. I am much obliged to Prof. Victor Carus, for having made enquiries for me in Saxony on this subject. H. von Nathusius (‘Viehzucht,’ 1872, p. 64) says that the horns of sheep castrated at an early period, either altogether disappear or remain as mere rudiments; but I do not know whether he refers to merinos or to ordinary breeds.) On the Guinea coast there is a breed in which the females never bear horns, and, as Mr. Winwood Reade informs me, the rams after castration are quite destitute of them. With cattle, the horns of the males are much altered by castration; for instead of being short and thick, they become longer than those of the cow, but otherwise resemble them. The Antilope bezoartica offers a somewhat analogous case: the males have long straight spiral horns, nearly parallel to each other, and directed backwards; the females occasionally bear horns, but these when present are of a very different shape, for they are not spiral, and spreading widely, bend round with the points forwards. Now it

is a remarkable fact that, in the castrated male, as Mr. Blyth informs me, the horns are of the same peculiar shape as in the female, but longer and thicker. If we may judge from analogy, the female probably shews us, in these two cases of cattle and the antelope, the former condition of the horns in some early progenitor of each species. But why castration should lead to the reappearance of an early condition of the horns cannot be explained with any certainty. Nevertheless, it seems probable, that in nearly the same manner as the constitutional disturbance in the offspring, caused by a cross between two distinct species or races, often leads to the reappearance of long-lost characters (19. I have given various experiments and other evidence proving that this is the case, in my ‘Variation of Animals and Plants under Domestication,’ vol. ii. 1868, pp. 39-47.); so here, the disturbance in the constitution of the individual, resulting from castration, produces the same effect.

The tusks of the elephant, in the different species or races, differ according to sex, nearly as do the horns of ruminants. In India and Malacca the males alone are provided with well-developed tusks. The elephant of Ceylon is considered by most naturalists as a distinct race, but by some as a distinct species, and here “not one in a hundred is found with tusks, the few that possess them being exclusively males.” (20. Sir J. Emerson Tennent, ‘Ceylon,’ 1859, vol. ii. p. 274. For Malacca, ‘Journal of Indian Archipelago,’ vol. iv. p. 357.) The African elephant is undoubtedly distinct, and the female has large well-developed tusks, though not so large as those of the male.

These differences in the tusks of the several races and species of elephants—the great variability of the horns of deer, as notably in the wild reindeer—the occasional presence of horns in the female Antilope Bezoartica, and their frequent absence in the female of Antilocapra americana—the presence of two tusks in some few male narwhals—the complete absence of tusks in some female walruses—are all instances of the extreme variability of secondary sexual characters, and of their liability to differ in closely-allied forms.

Although tusks and horns appear in all cases to have been primarily developed as sexual weapons, they often serve other purposes. The elephant uses his tusks in attacking the tiger; according to Bruce, he scores the trunks of trees until they can be thrown down easily, and he likewise thus extracts the farinaceous cores of palms; in Africa he often uses one tusk, always the same, to probe the ground and thus ascertain whether it will bear his weight. The common bull defends the herd with his horns; and the elk in Sweden has been known, according to Lloyd, to strike a wolf dead with a single blow of his great horns. Many similar facts could be given. One of the most curious secondary uses to which the horns of an animal may be occasionally put is that observed by Captain Hutton (21. ‘Calcutta Journal of Natural History,’ vol. ii, 1843, p. 526.) with the wild goat (Capra aegagrus) of the Himalayas and, as it is also said with the ibex, namely that when the male accidentally falls from a height he bends inwards his head, and by alighting on his massive horns, breaks the shock. The female cannot thus use her horns, which are smaller, but from her more quiet disposition she does not need this strange kind of shield so much.

Each male animal uses his weapons in his own peculiar fashion. The common ram makes a charge and butts with such force with the bases of his horns, that I have seen a powerful man knocked over like a child. Goats and certain species of sheep, for instance the Ovis cycloceros of Afghanistan (22. Mr. Blyth, in ‘Land and Water,’ March, 1867, p. 134, on the authority of Capt. Hutton and others. For the wild Pembrokeshire goats, see the ‘Field,’ 1869, p. 150.), rear on their hind legs, and then not only butt, but “make a cut down and a jerk up, with the ribbed front of their scimitar-shaped horn, as with a sabre. When the O. cycloceros attacked a large domestic ram, who was a noted bruiser, he conquered him by the sheer novelty of his mode of fighting, always closing at once with his adversary, and catching him across the face and nose with a sharp drawing jerk of the head, and then bounding out of the way before the blow could be returned.” In Pembrokeshire a male goat, the master of a flock which during several generations had run wild, was known to have killed several males in single combat; this goat possessed enormous horns, measuring thirty-nine inches in a straight line from tip to tip. The common bull, as every one knows, gores and tosses his opponent; but the Italian buffalo is said never to use his horns: he gives a tremendous blow with his convex forehead, and then tramples on his fallen enemy with his knees—an instinct which the common bull does not possess. (23. M. E.M. Bailly, “Sur l’usage des cornes,” etc., .Annal des Sciences Nat.’ tom. ii. 1824, p. 369.) Hence a dog who pins a buffalo by the nose is immediately crushed. We must, however, remember that the Italian buffalo has been long domesticated, and it is by no means certain that the wild parent-form had similar horns. Mr. Bartlett informs me that when a female Cape buffalo (Bubalus caffer) was turned into an enclosure with a bull of the same species, she attacked him, and he in return pushed her about with great violence. But it was manifest to Mr. Bartlett that, had not the bull shewn dignified forbearance, he could easily have killed her by a single lateral thrust with his immense horns. The giraffe uses his short, hair-covered horns, which are rather longer in the male than in the female, in a curious manner; for, with his long neck, he swings his head to either side, almost upside down, with such force that I have seen a hard plank deeply indented by a single blow.

[Fig. 63. Oryx leucoryx, male (from the Knowsley Menagerie).]

With antelopes it is sometimes difficult to imagine how they can possibly use their curiously-shaped horns; thus the springboc (Ant. euchore) has rather short upright horns, with the sharp points bent inwards almost at right angles, so as to face each other; Mr. Bartlett does not know how they are used, but suggests that they would inflict a fearful wound down each side of the face of an antagonist. The slightly-curved horns of the Oryx leucoryx (Fig. 63) are directed backwards, and are of such length that their points reach beyond the middle of the back, over which they extend in almost parallel lines. Thus they seem singularly ill-fitted for fighting; but Mr. Bartlett informs me that when two of these animals prepare for battle, they kneel down, with their heads between their fore legs, and in this attitude the horns stand nearly parallel and close to the ground, with the points directed forwards and a little upwards. The combatants then gradually approach each other, and each endeavours to get the upturned points under the body of the other; if one succeeds in doing this, he suddenly springs up, throwing up his head at the same time, and can thus wound or perhaps even transfix his antagonist. Both animals always kneel down, so as to guard as far as possible against this manoeuvre. It has been recorded that one of these antelopes has used his horn with effect even against a lion; yet from being forced to place his head between the forelegs in order to bring the points of the horns forward, he would generally be under a great disadvantage when attacked by any other animal. It is, therefore, not probable that the horns have been modified into their present great length and peculiar position, as a protection against beasts of prey. We can however see that, as soon as some ancient male progenitor of the Oryx acquired moderately long horns, directed a little backwards, he would be compelled, in his battles with rival males, to bend his head somewhat inwards or downwards, as is now done by certain stags; and it is not improbable that he might have acquired the habit of at first occasionally and afterwards of regularly kneeling down. In this case it is almost certain that the males which possessed the longest horns would have had a great advantage over others with shorter horns; and then the horns would gradually have been rendered longer and longer, through sexual selection, until they acquired their present extraordinary length and position.

With stags of many kinds the branches of the horns offer a curious case of difficulty; for certainly a single straight point would inflict a much more serious wound than several diverging ones. In Sir Philip Egerton’s museum there is a horn of the red-deer (Cervus elaphus), thirty inches in length, with “not fewer than fifteen snags or branches”; and at Moritzburg there is still preserved a pair of antlers of a red-deer, shot in 1699 by Frederick I., one of which bears the astonishing number of thirty-three branches and the other twenty-seven, making altogether sixty branches. Richardson figures a pair of antlers of the wild reindeer with twenty-nine points. (24。 On the horns of red-deer, Owen, ‘British Fossil Mammals,’ 1846, p. 478; Richardson on the horns of the reindeer, ‘Fauna Bor. Americana,’ 1829, p. 240. I am indebted to Prof. Victor Carus, for the Moritzburg case.) From the manner in which the horns are branched, and more especially from deer being known occasionally to fight together by kicking with their fore- feet (25. 提问。 JD Caton (‘Ottawa Acad. of Nat. Science,’ May 1868, p. 9) says that the American deer fight with their fore-feet, after “the question of superiority has been once settled and acknowledged in the herd.” Bailly, ‘Sur l’Usage des cornes,’ ‘Annales des Sciences Nat.’ tom. II。 1824。 371.), M. Bailly actually comes to the conclusion that their horns are more injurious than useful to them. But this author overlooks the pitched battles between rival males. As I felt much perplexed about the use or advantage of the branches, I applied to Mr. McNeill of Colonsay, who has long and carefully observed the habits of red-deer, and he informs me that he has never seen some of the branches brought into use, but that the brow antlers, from inclining downwards, are a great protection to the forehead, and their points are likewise used in attack. Sir Philip Egerton also informs me both as to red-deer and fallow-deer that, in fighting, they suddenly dash together, and getting their horns fixed against each other’s bodies, a desperate struggle ensues. When one is at last forced to yield and turn round, the victor endeavours to plunge his brow antlers into his defeated foe. It thus appears that the upper branches are used chiefly or exclusively for pushing and fencing. Nevertheless in some species the upper branches are used as weapons of offence; when a man was attacked by a wapiti deer (Cervus canadensis) in Judge Caton’s park in Ottawa, and several men tried to rescue him, the stag “never raised his head from the ground; in fact he kept his face almost flat on the ground, with his nose nearly between his fore feet, except when he rolled his head to one side to take a new observation preparatory to a plunge.” In this position the ends of the horns were directed against his adversaries. “In rolling his head he necessarily raised it somewhat, because his antlers were so long that he could not roll his head without raising them on one side, while, on the other side they touched the ground.” The stag by this procedure gradually drove the party of rescuers backwards to a distance of 150 or 200 feet; and the attacked man was killed. (26。 See a most interesting account in the Appendix to Hon. JD

[Fig. 64. Strepsiceros Kudu (from Sir Andrew Smith’s ‘Zoology of South
Africa.’]

Although the horns of stags are efficient weapons, there can, I think, be no doubt that a single point would have been much more dangerous than a branched antler; and Judge Caton, who has had large experience with deer, fully concurs in this conclusion. Nor do the branching horns, though highly important as a means of defence against rival stags, appear perfectly well adapted for this purpose, as they are liable to become interlocked. The suspicion has therefore crossed my mind that they may serve in part as ornaments. That the branched antlers of stags as well as the elegant lyrated horns of certain antelopes, with their graceful double curvature (Fig. 64), are ornamental in our eyes, no one will dispute. If, then, the horns, like the splendid accoutrements of the knights of old, add to the noble appearance of stags and antelopes, they may have been modified partly for this purpose, though mainly for actual service in battle; but I have no evidence in favour of this belief.

An interesting case has lately been published, from which it appears that the horns of a deer in one district in the United States are now being modified through sexual and natural selection. A writer in an excellent American Journal (27. The ‘American Naturalist,’ Dec. 1869, p. 552.) says, that he has hunted for the last twenty-one years in the Adirondacks, where the Cervus virginianus abounds. About fourteen years ago he first heard of SPIKE-HORN BUCKS. These became from year to year more common; about five years ago he shot one, and afterwards another, and now they are frequently killed. “The spike-horn differs greatly from the common antler of the C. virginianus. It consists of a single spike, more slender than the antler, and scarcely half so long, projecting forward from the brow, and terminating in a very sharp point. It gives a considerable advantage to its possessor over the common buck. Besides enabling him to run more swiftly through the thick woods and underbrush (every hunter knows that does and yearling bucks run much more rapidly than the large bucks when armed with their cumbrous antlers), the spike-horn is a more effective weapon than the common antler. With this advantage the spike-horn bucks are gaining upon the common bucks, and may, in time, entirely supersede them in the Adirondacks. Undoubtedly, the first spike-horn buck was merely an accidental freak of nature. But his spike-horns gave him an advantage, and enabled him to propagate his peculiarity. His descendants having a like advantage, have propagated the peculiarity in a constantly increasing ratio, till they are slowly crowding the antlered deer from the region they inhabit.” A critic has well objected to this account by asking, why, if the simple horns are now so advantageous, were the branched antlers of the parent-form ever developed? To this I can only answer by remarking, that a new mode of attack with new weapons might be a great advantage, as shewn by the case of the Ovis cycloceros, who thus conquered a domestic ram famous for his fighting power. Though the branched antlers of a stag are well adapted for fighting with his rivals, and though it might be an advantage to the prong-horned variety slowly to acquire long and branched horns, if he had to fight only with others of the same kind, yet it by no means follows that branched horns would be the best fitted for conquering a foe differently armed. In the foregoing case of the Oryx leucoryx, it is almost certain that the victory would rest with an antelope having short horns, and who therefore did not need to kneel down, though an oryx might profit by having still longer horns, if he fought only with his proper rivals.

Male quadrupeds, which are furnished with tusks, use them in various ways, as in the case of horns. The boar strikes laterally and upwards; the musk- deer downwards with serious effect. (28. Pallas, ‘Spicilegia Zoologica,’ fasc. xiii. 1779, p. 18.) The walrus, though having so short a neck and so unwieldy a body, “can strike either upwards, or downwards, or sideways, with equal dexterity.” (29. Lamont, ‘Seasons with the Sea-Horses,’ 1861, p. 141.) I was informed by the late Dr. Falconer, that the Indian elephant fights in a different manner according to the position and curvature of his tusks. When they are directed forwards and upwards he is able to fling a tiger to a great distance—it is said to even thirty feet; when they are short and turned downwards he endeavours suddenly to pin the tiger to the ground and, in consequence, is dangerous to the rider, who is liable to be jerked off the howdah. (30. See also Corse (‘Philosophical Transactions,’ 1799, p. 212) on the manner in which the short-tusked Mooknah variety attacks other elephants.)

Very few male quadrupeds possess weapons of two distinct kinds specially adapted for fighting with rival males. The male muntjac-deer (Cervulus), however, offers an exception, as he is provided with horns and exserted canine teeth. But we may infer from what follows that one form of weapon has often been replaced in the course of ages by another. With ruminants the development of horns generally stands in an inverse relation with that of even moderately developed canine teeth. Thus camels, guanacoes, chevrotains, and musk-deer, are hornless, and they have efficient canines; these teeth being “always of smaller size in the females than in the males.” The Camelidae have, in addition to their true canines, a pair of canine-shaped incisors in their upper jaws. (31. Owen, ‘Anatomy of Vertebrates,’ vol. iii. p. 349.) Male deer and antelopes, on the other hand, possess horns, and they rarely have canine teeth; and these, when present, are always of small size, so that it is doubtful whether they are of any service in their battles. In Antilope montana they exist only as rudiments in the young male, disappearing as he grows old; and they are absent in the female at all ages; but the females of certain other antelopes and of certain deer have been known occasionally to exhibit rudiments of these teeth. (32. See Ruppell (in ‘Proc. Zoolog. Soc.’ Jan. 12, 1836, p. 3) on the canines in deer and antelopes, with a note by Mr. Martin on a female American deer. See also Falconer (‘Palaeont. Memoirs and Notes,’ vol. i. 1868, p. 576) on canines in an adult female deer. In old males of the musk-deer the canines (Pallas, ‘Spic. Zoolog.’ fasc. xiii. 1779, p. 18) sometimes grow to the length of three inches, whilst in old females a rudiment projects scarcely half an inch above the gums.) Stallions have small canine teeth, which are either quite absent or rudimentary in the mare; but they do not appear to be used in fighting, for stallions bite with their incisors, and do not open their mouths wide like camels and guanacoes. Whenever the adult male possesses canines, now inefficient, whilst the female has either none or mere rudiments, we may conclude that the early male progenitor of the species was provided with efficient canines, which have been partially transferred to the females. The reduction of these teeth in the males seems to have followed from some change in their manner of fighting, often (but not in the horse) caused by the development of new weapons.

Tusks and horns are manifestly of high importance to their possessors, for their development consumes much organised matter. A single tusk of the Asiatic elephant—one of the extinct woolly species—and of the African elephant, have been known to weigh respectively 150, 160, and 180 pounds; and even greater weights have been given by some authors. (33. Emerson Tennent, ‘Ceylon,’ 1859, vol. ii. p. 275; Owen, ‘British Fossil Mammals,’ 1846, p. 245.) With deer, in which the horns are periodically renewed, the drain on the constitution must be greater; the horns, for instance, of the moose weigh from fifty to sixty pounds, and those of the extinct Irish elk from sixty to seventy pounds—the skull of the latter weighing on an average only five pounds and a quarter. Although the horns are not periodically renewed in sheep, yet their development, in the opinion of many agriculturists, entails a sensible loss to the breeder. Stags, moreover, in escaping from beasts of prey are loaded with an additional weight for the race, and are greatly retarded in passing through a woody country. The moose, for instance, with horns extending five and a half feet from tip to tip, although so skilful in their use that he will not touch or break a twig when walking quietly, cannot act so dexterously whilst rushing away from a pack of wolves. “During his progress he holds his nose up, so as to lay the horns horizontally back; and in this attitude cannot see the ground distinctly.” (34. Richardson, ‘Fauna Bor. Americana,’ on the moose, Alces palmata, pp. 236, 237; on the expanse of the horns, ‘Land and Water,’ 1869, p. 143. See also Owen, ‘British Fossil Mammals,’ on the Irish elk, pp. 447, 455.) The tips of the horns of the great Irish elk were actually eight feet apart! Whilst the horns are covered with velvet, which lasts with red-deer for about twelve weeks, they are extremely sensitive to a blow; so that in Germany the stags at this time somewhat change their habits, and avoiding dense forests, frequent young woods and low thickets. (35. ‘Forest Creatures,’ by C. Boner, 1861, p. 60.) These facts remind us that male birds have acquired ornamental plumes at the cost of retarded flight, and other ornaments at the cost of some loss of power in their battles with rival males.

With mammals, when, as is often the case, the sexes differ in size, the males are almost always larger and stronger. I am informed by Mr. Gould that this holds good in a marked manner with the marsupials of Australia, the males of which appear to continue growing until an unusually late age. But the most extraordinary case is that of one of the seals (Callorhinus ursinus), a full-grown female weighing less than one-sixth of a full-grown male. (36. See the very interesting paper by Mr. J.A. Allen in ‘Bull. Mus. Comp. Zoology of Cambridge, United States,’ vol. ii. No. 1, p. 82. The weights were ascertained by a careful observer, Capt. Bryant. Dr. Gill in ‘The American Naturalist,’ January, 1871, Prof. Shaler on the relative size of the sexes of whales, ‘American Naturalist,’ January, 1873.) Dr. Gill remarks that it is with the polygamous seals, the males of which are well known to fight savagely together, that the sexes differ much in size; the monogamous species differing but little. Whales also afford evidence of the relation existing between the pugnacity of the males and their large size compared with that of the female; the males of the right-whales do not fight together, and they are not larger, but rather smaller, than their females; on the other hand, male sperm-whales fight much together, and their bodies are “often found scarred with the imprint of their rival’s teeth,” and they are double the size of the females. The greater strength of the male, as Hunter long ago remarked (37. ‘Animal Economy,’ p. 45.), is invariably displayed in those parts of the body which are brought into action in fighting with rival males—for instance, in the massive neck of the bull. Male quadrupeds are also more courageous and pugnacious than the females. There can be little doubt that these characters have been gained, partly through sexual selection, owing to a long series of victories, by the stronger and more courageous males over the weaker, and partly through the inherited effects of use. It is probable that the successive variations in strength, size, and courage, whether due to mere variability or to the effects of use, by the accumulation of which male quadrupeds have acquired these characteristic qualities, occurred rather late in life, and were consequently to a large extent limited in their transmission to the same sex.

From these considerations I was anxious to obtain information as to the Scotch deer-hound, the sexes of which differ more in size than those of any other breed (though blood-hounds differ considerably), or than in any wild canine species known to me. Accordingly, I applied to Mr. Cupples, well known for his success with this breed, who has weighed and measured many of his own dogs, and who has with great kindness collected for me the following facts from various sources. Fine male dogs, measured at the shoulder, range from 28 inches, which is low, to 33 or even 34 inches in height; and in weight from 80 pounds, which is light, to 120 pounds, or even more. The females range in height from 23 to 27, or even to 28 inches; and in weight from 50 to 70, or even 80 pounds. (38。 See also Richardson’s ‘Manual on the Dog,’ p. 59. Much valuable information on the Scottish deer-hound is given by Mr. McNeill, who first called attention to the inequality in size between the sexes, in Scrope’s ‘Art of Deer- Stalking.’ I hope that Mr. Cupples will keep to his intention of publishing a full account and history of this famous breed.) Mr. Cupples concludes that from 95 to 100 pounds for the male, and 70 for the female, would be a safe average; but there is reason to believe that formerly both sexes attained a greater weight. 先生。 Cupples has weighed puppies when a fortnight old; in one litter the average weight of four males exceeded that of two females by six and a half ounces; in another litter the average weight of four males exceeded that of one female by less than one ounce; the same males when three weeks old, exceeded the female by seven and a half ounces, and at the age of six weeks by nearly fourteen ounces. 先生。 Wright of Yeldersley House, in a letter to Mr. Cupples, says: “I have taken notes on the sizes and weights of puppies of many litters, and as far as my experience goes, dog-puppies as a rule differ very little from bitches till they arrive at about five or six months old; and then the dogs begin to increase, gaining upon the bitches both in weight and size. At birth, and for several weeks afterwards, a bitch-puppy will occasionally be larger than any of the dogs, but they are invariably beaten by them later.” Mr. McNeill, of Colonsay, concludes that “the males do not attain their full growth till over two years old, though the females attain it sooner.” According to Mr. Cupples’ experience, male dogs go on growing in stature till they are from twelve to eighteen months old, and in weight till from eighteen to twenty-four months old; whilst the females cease increasing in stature at the age of from nine to fourteen or fifteen months, and in weight at the age of from twelve to fifteen months. From these various statements it is clear that the full difference in size between the male and female Scotch deer-hound is not acquired until rather late in life. The males almost exclusively are used for coursing, for, as Mr. McNeill informs me, the females have not sufficient strength and weight to pull down a full-grown deer. From the names used in old legends, it appears, as I hear from Mr. Cupples, that, at a very ancient period, the males were the most celebrated, the females being mentioned only as the mothers of famous dogs. Hence, during many generations, it is the male which has been chiefly tested for strength, size, speed, and courage, and the best will have been bred from.

[Fig. 65. Head of Common wild boar, in prime of life (from Brehm).]

The males of some few quadrupeds possess organs or parts developed solely as a means of defence against the attacks of other males. Some kinds of deer use, as we have seen, the upper branches of their horns chiefly or exclusively for defending themselves; and the Oryx antelope, as I am informed by Mr. Bartlett, fences most skilfully with his long, gently curved horns; but these are likewise used as organs of offence. The same observer remarks that rhinoceroses in fighting, parry each other’s sidelong blows with their horns, which clatter loudly together, as do the tusks of boars. Although wild boars fight desperately, they seldom, according to Brehm, receive fatal wounds, as the blows fall on each other’s tusks, or on the layer of gristly skin covering the shoulder, called by the German hunters, the shield; and here we have a part specially modified for defence. With boars in the prime of life (Fig. 65) the tusks in the lower jaw are used for fighting, but they become in old age, as Brehm states, so much curved inwards and upwards over the snout that they can no longer be used in this way. They may, however, still serve, and even more effectively, as a means of defence. In compensation for the loss of the lower tusks as weapons of offence, those in the upper jaw, which always project a little laterally, increase in old age so much in length and curve so much upwards that they can be used for attack. Nevertheless, an old boar is not so dangerous to man as one at the age of six or seven years. (39. Brehm, ‘Thierleben,’ B. ii. ss. 729-732.)

[Fig. 66. Skull of the Babirusa Pig (from Wallace’s ‘Malay Archipelago’).]

In the full-grown male Babirusa pig of Celebes (Fig. 66), the lower tusks are formidable weapons, like those of the European boar in the prime of life, whilst the upper tusks are so long and have their points so much curled inwards, sometimes even touching the forehead, that they are utterly useless as weapons of attack. They more nearly resemble horns than teeth, and are so manifestly useless as teeth that the animal was formerly supposed to rest his head by hooking them on to a branch! Their convex surfaces, however, if the head were held a little laterally, would serve as an excellent guard; and hence, perhaps, it is that in old animals they “are generally broken off, as if by fighting.” (40. See Mr. Wallace’s interesting account of this animal, ‘The Malay Archipelago,’ 1869, vol. i. p. 435.) Here, then, we have the curious case of the upper tusks of the Babirusa regularly assuming during the prime of life a structure which apparently renders them fitted only for defence; whilst in the European boar the lower tusks assume in a less degree and only during old age nearly the same form, and then serve in like manner solely for defence.

[Fig. 67. Head of female Aethiopian wart-hog, from ‘Proc. Zool. Soc.’ 1869, shewing the same characters as the male, though on a reduced scale. N.B. When the engraving was first made, I was under the impression that it represented the male.]

In the wart-hog (see Phacochoerus aethiopicus, Fig. 67) the tusks in the upper jaw of the male curve upwards during the prime of life, and from being pointed serve as formidable weapons. The tusks in the lower jaw are sharper than those in the upper, but from their shortness it seems hardly possible that they can be used as weapons of attack. They must, however, greatly strengthen those in the upper jaw, from being ground so as to fit closely against their bases. Neither the upper nor the lower tusks appear to have been specially modified to act as guards, though no doubt they are to a certain extent used for this purpose. But the wart-hog is not destitute of other special means of protection, for it has, on each side of the face, beneath the eyes, a rather stiff, yet flexible, cartilaginous, oblong pad (Fig. 67), which projects two or three inches outwards; and it appeared to Mr. Bartlett and myself, when viewing the living animal, that these pads, when struck from beneath by the tusks of an opponent, would be turned upwards, and would thus admirably protect the somewhat prominent eyes. I may add, on the authority of Mr. Bartlett, that these boars when fighting stand directly face to face.

Lastly, the African river-hog (Potomochoerus penicillatus) has a hard cartilaginous knob on each side of the face beneath the eyes, which answers to the flexible pad of the wart-hog; it has also two bony prominences on the upper jaw above the nostrils. A boar of this species in the Zoological Gardens recently broke into the cage of the wart-hog. They fought all night long, and were found in the morning much exhausted, but not seriously wounded. It is a significant fact, as shewing the purposes of the above- described projections and excrescences, that these were covered with blood, and were scored and abraded in an extraordinary manner.

Although the males of so many members of the pig family are provided with weapons, and as we have just seen with means of defence, these weapons seem to have been acquired within a rather late geological period. Dr. Forsyth Major specifies (41. ‘Atti della Soc. Italiana di Sc. Nat.’ 1873, vol. xv. fasc. iv.) several miocene species, in none of which do the tusks appear to have been largely developed in the males; and Professor Rutimeyer was formerly struck with this same fact.

The mane of the lion forms a good defence against the attacks of rival lions, the one danger to which he is liable; for the males, as Sir A. Smith informs me, engage in terrible battles, and a young lion dares not approach an old one. In 1857 a tiger at Bromwich broke into the cage of a lion and a fearful scene ensued: “the lion’s mane saved his neck and head from being much injured, but the tiger at last succeeded in ripping up his belly, and in a few minutes he was dead.” (42. ‘The Times,’ Nov. 10, 1857. In regard to the Canada lynx, see Audubon and Bachman, ‘Quadrupeds of North America,’ 1846, p. 139.) The broad ruff round the throat and chin of the Canadian lynx (Felis canadensis) is much longer in the male than in the female; but whether it serves as a defence I do not know. Male seals are well known to fight desperately together, and the males of certain kinds (Otaria jubata) (43. Dr. Murie, on Otaria, ‘Proc. Zoolog. Soc.’ 1869, p. 109. Mr. J.A. Allen, in the paper above quoted (p. 75), doubts whether the hair, which is longer on the neck in the male than in the female, deserves to be called a mane.) have great manes, whilst the females have small ones or none. The male baboon of the Cape of Good Hope (Cynocephalus porcarius) has a much longer mane and larger canine teeth than the female; and the mane probably serves as a protection, for, on asking the keepers in the Zoological Gardens, without giving them any clue to my object, whether any of the monkeys especially attacked each other by the nape of the neck, I was answered that this was not the case, except with the above baboon. In the Hamadryas baboon, Ehrenberg compares the mane of the adult male to that of a young lion, whilst in the young of both sexes and in the female the mane is almost absent.

It appeared to me probable that the immense woolly mane of the male American bison, which reaches almost to the ground, and is much more developed in the males than in the females, served as a protection to them in their terrible battles; but an experienced hunter told Judge Caton that he had never observed anything which favoured this belief. The stallion has a thicker and fuller mane than the mare; and I have made particular inquiries of two great trainers and breeders, who have had charge of many entire horses, and am assured that they “invariably endeavour to seize one another by the neck.” It does not, however, follow from the foregoing statements, that when the hair on the neck serves as a defence, that it was originally developed for this purpose, though this is probable in some cases, as in that of the lion. I am informed by Mr. McNeill that the long hairs on the throat of the stag (Cervus elaphus) serve as a great protection to him when hunted, for the dogs generally endeavour to seize him by the throat; but it is not probable that these hairs were specially developed for this purpose; otherwise the young and the females would have been equally protected.

Choice in Pairing by Either Sex of Quadrupeds

Before describing in the next chapter, the differences between the sexes in voice, odours emitted, and ornaments, it will be convenient here to consider whether the sexes exert any choice in their unions. Does the female prefer any particular male, either before or after the males may have fought together for supremacy; or does the male, when not a polygamist, select any particular female? The general impression amongst breeders seems to be that the male accepts any female; and this owing to his eagerness, is, in most cases, probably the truth. Whether the female as a general rule indifferently accepts any male is much more doubtful. In the fourteenth chapter, on Birds, a considerable body of direct and indirect evidence was advanced, shewing that the female selects her partner; and it would be a strange anomaly if female quadrupeds, which stand higher in the scale and have higher mental powers, did not generally, or at least often, exert some choice. The female could in most cases escape, if wooed by a male that did not please or excite her; and when pursued by several males, as commonly occurs, she would often have the opportunity, whilst they were fighting together, of escaping with some one male, or at least of temporarily pairing with him. This latter contingency has often been observed in Scotland with female red-deer, as I am informed by Sir Philip Egerton and others. (44. Mr. Boner, in his excellent description of the habits of the red-deer in Germany (‘Forest Creatures,’ 1861, p. 81) says, “while the stag is defending his rights against one intruder, another invades the sanctuary of his harem, and carries off trophy after trophy.” Exactly the same thing occurs with seals; see Mr. J.A. Allen, ibid. p. 100.)

It is scarcely possible that much should be known about female quadrupeds in a state of nature making any choice in their marriage unions. The following curious details on the courtship of one of the eared seals (Callorhinus ursinus) are given (45. Mr. J.A. Allen in ‘Bull. Mus. Comp. Zoolog. of Cambridge, United States,’ vol. ii. No. 1, p. 99.) on the authority of Capt. Bryant, who had ample opportunities for observation. He says, “Many of the females on their arrival at the island where they breed appear desirous of returning to some particular male, and frequently climb the outlying rocks to overlook the rookeries, calling out and listening as if for a familiar voice. Then changing to another place they do the same again…As soon as a female reaches the shore, the nearest male goes down to meet her, making meanwhile a noise like the clucking of a hen to her chickens. He bows to her and coaxes her until he gets between her and the water so that she cannot escape him. Then his manner changes, and with a harsh growl he drives her to a place in his harem. This continues until the lower row of harems is nearly full. Then the males higher up select the time when their more fortunate neighbours are off their guard to steal their wives. This they do by taking them in their mouths and lifting them over the heads of the other females, and carefully placing them in their own harem, carrying them as cats do their kittens. Those still higher up pursue the same method until the whole space is occupied. Frequently a struggle ensues between two males for the possession of the same female, and both seizing her at once pull her in two or terribly lacerate her with their teeth. When the space is all filled, the old male walks around complacently reviewing his family, scolding those who crowd or disturb the others, and fiercely driving off all intruders. This surveillance always keeps him actively occupied.”

As so little is known about the courtship of animals in a state of nature, I have endeavoured to discover how far our domesticated quadrupeds evince any choice in their unions. Dogs offer the best opportunity for observation, as they are carefully attended to and well understood. Many breeders have expressed a strong opinion on this head. Thus, Mr. Mayhew remarks, “The females are able to bestow their affections; and tender recollections are as potent over them as they are known to be in other cases, where higher animals are concerned. Bitches are not always prudent in their loves, but are apt to fling themselves away on curs of low degree. If reared with a companion of vulgar appearance, there often springs up between the pair a devotion which no time can afterwards subdue. The passion, for such it really is, becomes of a more than romantic endurance.” Mr. Mayhew, who attended chiefly to the smaller breeds, is convinced that the females are strongly attracted by males of a large size. (46. ‘Dogs: their Management,’ by E. Mayhew, M.R.C.V.S., 2nd ed., 1864, pp. 187-192.) The well-known veterinary Blaine states (47. Quoted by Alex. Walker, ‘On Intermarriage,’ 1838, p. 276; see also p. 244.) that his own female pug dog became so attached to a spaniel, and a female setter to a cur, that in neither case would they pair with a dog of their own breed until several weeks had elapsed. Two similar and trustworthy accounts have been given me in regard to a female retriever and a spaniel, both of which became enamoured with terrier-dogs.

Mr. Cupples informs me that he can personally vouch for the accuracy of the following more remarkable case, in which a valuable and wonderfully- intelligent female terrier loved a retriever belonging to a neighbour to such a degree, that she had often to be dragged away from him. After their permanent separation, although repeatedly shewing milk in her teats, she would never acknowledge the courtship of any other dog, and to the regret of her owner never bore puppies. Mr. Cupples also states, that in 1868, a female deerhound in his kennel thrice produced puppies, and on each occasion shewed a marked preference for one of the largest and handsomest, but not the most eager, of four deerhounds living with her, all in the prime of life. Mr. Cupples has observed that the female generally favours a dog whom she has associated with and knows; her shyness and timidity at first incline her against a strange dog. The male, on the contrary, seems rather inclined towards strange females. It appears to be rare when the male refuses any particular female, but Mr. Wright, of Yeldersley House, a great breeder of dogs, informs me that he has known some instances; he cites the case of one of his own deerhounds, who would not take any notice of a particular female mastiff, so that another deerhound had to be employed. It would be superfluous to give, as I could, other instances, and I will only add that Mr. Barr, who has carefully bred many bloodhounds, states that in almost every instance particular individuals of opposite sexes shew a decided preference for each other. Finally, Mr. Cupples, after attending to this subject for another year, has written to me, “I have had full confirmation of my former statement, that dogs in breeding form decided preferences for each other, being often influenced by size, bright colour, and individual characters, as well as by the degree of their previous familiarity.”

In regard to horses, Mr. Blenkiron, the greatest breeder of race-horses in the world, informs me that stallions are so frequently capricious in their choice, rejecting one mare and without any apparent cause taking to another, that various artifices have to be habitually used. The famous Monarque, for instance, would never consciously look at the dam of Gladiateur, and a trick had to be practised. We can partly see the reason why valuable race-horse stallions, which are in such demand as to be exhausted, should be so particular in their choice. Mr. Blenkiron has never known a mare reject a horse; but this has occurred in Mr. Wright’s stable, so that the mare had to be cheated. Prosper Lucas (48. ‘Traité de l’Héréd. Nat.’ tom. ii. 1850, p. 296.) quotes various statements from French authorities, and remarks, “On voit des étalons qui s’eprennent d’une jument, et negligent toutes les autres.” He gives, on the authority of Baelen, similar facts in regard to bulls; and Mr. H. Reeks assures me that a famous short-horn bull belonging to his father “invariably refused to be matched with a black cow.” Hoffberg, in describing the domesticated reindeer of Lapland says, “Foeminae majores et fortiores mares prae caeteris admittunt, ad eos confugiunt, a junioribus agitatae, qui hos in fugam conjiciunt.” (49. ‘Amoenitates Acad.’ vol. iv. 1788, p. 160.) A clergyman, who has bred many pigs, asserts that sows often reject one boar and immediately accept another.

From these facts there can be no doubt that, with most of our domesticated quadrupeds, strong individual antipathies and preferences are frequently exhibited, and much more commonly by the female than by the male. This being the case, it is improbable that the unions of quadrupeds in a state of nature should be left to mere chance. It is much more probable that the females are allured or excited by particular males, who possess certain characters in a higher degree than other males; but what these characters are, we can seldom or never discover with certainty.

第十八章 •11,200字
哺乳动物的第二性征——续

Voice—Remarkable sexual peculiarities in seals—Odour—Development of the hair—Colour of the hair and skin—Anomalous case of the female being more ornamented than the male—Colour and ornaments due to sexual selection— Colour acquired for the sake of protection—Colour, though common to both sexes, often due to sexual selection—On the disappearance of spots and stripes in adult quadrupeds—On the colours and ornaments of the Quadrumana—Summary.

Quadrupeds use their voices for various purposes, as a signal of danger, as a call from one member of a troop to another, or from the mother to her lost offspring, or from the latter for protection to their mother; but such uses need not here be considered. We are concerned only with the difference between the voices of the sexes, for instance between that of the lion and lioness, or of the bull and cow. Almost all male animals use their voices much more during the rutting-season than at any other time; and some, as the giraffe and porcupine (1. Owen, ‘Anatomy of Vertebrates,’ vol. iii. p. 585.), are said to be completely mute excepting at this season. As the throats (i.e. the larynx and thyroid bodies (2. Ibid. p. 595.)) of stags periodically become enlarged at the beginning of the breeding-season, it might be thought that their powerful voices must be somehow of high importance to them; but this is very doubtful. From information given to me by two experienced observers, Mr. McNeill and Sir P. Egerton, it seems that young stags under three years old do not roar or bellow; and that the old ones begin bellowing at the commencement of the breeding-season, at first only occasionally and moderately, whilst they restlessly wander about in search of the females. Their battles are prefaced by loud and prolonged bellowing, but during the actual conflict they are silent. Animals of all kinds which habitually use their voices utter various noises under any strong emotion, as when enraged and preparing to fight; but this may merely be the result of nervous excitement, which leads to the spasmodic contraction of almost all the muscles of the body, as when a man grinds his teeth and clenches his fists in rage or agony. No doubt stags challenge each other to mortal combat by bellowing; but those with the more powerful voices, unless at the same time the stronger, better-armed, and more courageous, would not gain any advantage over their rivals.

It is possible that the roaring of the lion may be of some service to him by striking terror into his adversary; for when enraged he likewise erects his mane and thus instinctively tries to make himself appear as terrible as possible. But it can hardly be supposed that the bellowing of the stag, even if it be of service to him in this way, can have been important enough to have led to the periodical enlargement of the throat. Some writers suggest that the bellowing serves as a call to the female; but the experienced observers above quoted inform me that female deer do not search for the male, though the males search eagerly for the females, as indeed might be expected from what we know of the habits of other male quadrupeds. The voice of the female, on the other hand, quickly brings to her one or more stags (3. See, for instance, Major W. Ross King (‘The Sportsman in Canada,’ 1866, pp. 53, 131) on the habits of the moose and wild reindeer.), as is well known to the hunters who in wild countries imitate her cry. If we could believe that the male had the power to excite or allure the female by his voice, the periodical enlargement of his vocal organs would be intelligible on the principle of sexual selection, together with inheritance limited to the same sex and season; but we have no evidence in favour of this view. As the case stands, the loud voice of the stag during the breeding-season does not seem to be of any special service to him, either during his courtship or battles, or in any other way. But may we not believe that the frequent use of the voice, under the strong excitement of love, jealousy, and rage, continued during many generations, may at last have produced an inherited effect on the vocal organs of the stag, as well as of other male animals? This appears to me, in our present state of knowledge, the most probable view.

The voice of the adult male gorilla is tremendous, and he is furnished with a laryngeal sack, as is the adult male orang. (4. Owen ‘Anatomy of Vertebrates,’ vol. iii. p. 600.) The gibbons rank among the noisiest of monkeys, and the Sumatra species (Hylobates syndactylus) is also furnished with an air sack; but Mr. Blyth, who has had opportunities for observation, does not believe that the male is noisier than the female. Hence, these latter monkeys probably use their voices as a mutual call; and this is certainly the case with some quadrupeds, for instance the beaver. (5. Mr. Green, in ‘Journal of Linnean Society,’ vol. x. ‘Zoology,’ 1869, note 362.) Another gibbon, the H. agilis, is remarkable, from having the power of giving a complete and correct octave of musical notes (6. C.L. Martin, ‘General Introduction to the Natural History of Mamm. Animals,’ 1841, p. 431.), which we may reasonably suspect serves as a sexual charm; but I shall have to recur to this subject in the next chapter. The vocal organs of the American Mycetes caraya are one-third larger in the male than in the female, and are wonderfully powerful. These monkeys in warm weather make the forests resound at morning and evening with their overwhelming voices. The males begin the dreadful concert, and often continue it during many hours, the females sometimes joining in with their less powerful voices. An excellent observer, Rengger (7. ‘Naturgeschichte der Säugethiere von Paraguay,’ 1830, ss. 15, 21.), could not perceive that they were excited to begin by any special cause; he thinks that, like many birds, they delight in their own music, and try to excel each other. Whether most of the foregoing monkeys have acquired their powerful voices in order to beat their rivals and charm the females—or whether the vocal organs have been strengthened and enlarged through the inherited effects of long-continued use without any particular good being thus gained—I will not pretend to say; but the former view, at least in the case of the Hylobates agilis, seems the most probable.

I may here mention two very curious sexual peculiarities occurring in seals, because they have been supposed by some writers to affect the voice. The nose of the male sea-elephant (Macrorhinus proboscideus) becomes greatly elongated during the breeding-season, and can then be erected. In this state it is sometimes a foot in length. The female is not thus provided at any period of life. The male makes a wild, hoarse, gurgling noise, which is audible at a great distance and is believed to be strengthened by the proboscis; the voice of the female being different. Lesson compares the erection of the proboscis, with the swelling of the wattles of male gallinaceous birds whilst courting the females. In another allied kind of seal, the bladder-nose (Cystophora cristata), the head is covered by a great hood or bladder. This is supported by the septum of the nose, which is produced far backwards and rises into an internal crest seven inches in height. The hood is clothed with short hair, and is muscular; can be inflated until it more than equals the whole head in size! The males when rutting, fight furiously on the ice, and their roaring “is said to be sometimes so loud as to be heard four miles off.” When attacked they likewise roar or bellow; and whenever irritated the bladder is inflated and quivers. Some naturalists believe that the voice is thus strengthened, but various other uses have been assigned to this extraordinary structure. Mr. R. Brown thinks that it serves as a protection against accidents of all kinds; but this is not probable, for, as I am assured by Mr. Lamont who killed 600 of these animals, the hood is rudimentary in the females, and it is not developed in the males during youth. (8. On the sea-elephant, see an article by Lesson, in ‘Dict. Class. Hist. Nat.’ tom. xiii. p. 418. For the Cystophora, or Stemmatopus, see Dr. Dekay, ‘Annals of Lyceum of Nat. Hist.’ New York, vol. i. 1824, p. 94. Pennant has also collected information from the sealers on this animal. The fullest account is given by Mr. Brown, in ‘Proc. Zoolog. Soc.’ 1868, p. 435.)

气味

With some animals, as with the notorious skunk of America, the overwhelming odour which they emit appears to serve exclusively as a defence. With shrew-mice (Sorex) both sexes possess abdominal scent-glands, and there can be little doubt, from the rejection of their bodies by birds and beasts of prey, that the odour is protective; nevertheless, the glands become enlarged in the males during the breeding-season. In many other quadrupeds the glands are of the same size in both sexes (9. As with the castoreum of the beaver, see Mr. L.H. Morgan’s most interesting work, ‘The American Beaver,’ 1868, p. 300. Pallas (‘Spic. Zoolog.’ fasc. viii. 1779, p. 23) has well discussed the odoriferous glands of mammals. Owen (‘Anat. of Vertebrates,’ vol. iii. p. 634) also gives an account of these glands, including those of the elephant, and (p. 763) those of shrew-mice. On bats, Mr. Dobson in ‘Proceedings of the Zoological Society’ 1873, p. 241.), but their uses are not known. In other species the glands are confined to the males, or are more developed than in the females; and they almost always become more active during the rutting-season. At this period the glands on the sides of the face of the male elephant enlarge, and emit a secretion having a strong musky odour. The males, and rarely the females, of many kinds of bats have glands and protrudable sacks situated in various parts; and it is believed that these are odoriferous.

The rank effluvium of the male goat is well known, and that of certain male deer is wonderfully strong and persistent. On the banks of the Plata I perceived the air tainted with the odour of the male Cervus campestris, at half a mile to leeward of a herd; and a silk handkerchief, in which I carried home a skin, though often used and washed, retained, when first unfolded, traces of the odour for one year and seven months. This animal does not emit its strong odour until more than a year old, and if castrated whilst young never emits it. (10. Rengger, ‘Naturgeschichte der Säugethiere von Paraguay,’ 1830, s. 355. This observer also gives some curious particulars in regard to the odour.) Besides the general odour, permeating the whole body of certain ruminants (for instance, Bos moschatus) in the breeding-season, many deer, antelopes, sheep, and goats possess odoriferous glands in various situations, more especially on their faces. The so-called tear-sacks, or suborbital pits, come under this head. These glands secrete a semi-fluid fetid matter which is sometimes so copious as to stain the whole face, as I have myself seen in an antelope. They are “usually larger in the male than in the female, and their development is checked by castration.” (11. Owen, ‘Anatomy of Vertebrates,’ vol. iii. p. 632. See also Dr. Murie’s observations on those glands in the ‘Proc. Zoolog. Soc.’ 1870, p. 340. Desmarest, ‘On the Antilope subgutturosa, ‘Mammalogie,’ 1820, p. 455.) According to Desmarest they are altogether absent in the female of Antilope subgutturosa. Hence, there can be no doubt that they stand in close relation with the reproductive functions. They are also sometimes present, and sometimes absent, in nearly allied forms. In the adult male musk-deer (Moschus moschiferus), a naked space round the tail is bedewed with an odoriferous fluid, whilst in the adult female, and in the male until two years old, this space is covered with hair and is not odoriferous. The proper musk- sack of this deer is from its position necessarily confined to the male, and forms an additional scent-organ. It is a singular fact that the matter secreted by this latter gland, does not, according to Pallas, change in consistence, or increase in quantity, during the rutting-season; nevertheless this naturalist admits that its presence is in some way connected with the act of reproduction. He gives, however, only a conjectural and unsatisfactory explanation of its use. (12. Pallas, ‘Spicilegia Zoolog.’ fasc. xiii. 1799, p. 24; Desmoulins, ‘Dict. Class. d’Hist. Nat.’ tom. iii. p. 586.)

In most cases, when only the male emits a strong odour during the breeding- season, it probably serves to excite or allure the female. We must not judge on this head by our own taste, for it is well known that rats are enticed by certain essential oils, and cats by valerian, substances far from agreeable to us; and that dogs, though they will not eat carrion, sniff and roll on it. From the reasons given when discussing the voice of the stag, we may reject the idea that the odour serves to bring the females from a distance to the males. Active and long-continued use cannot here have come into play, as in the case of the vocal organs. The odour emitted must be of considerable importance to the male, inasmuch as large and complex glands, furnished with muscles for everting the sack, and for closing or opening the orifice, have in some cases been developed. The development of these organs is intelligible through sexual selection, if the most odoriferous males are the most successful in winning the females, and in leaving offspring to inherit their gradually perfected glands and odours.

Development of the Hair

We have seen that male quadrupeds often have the hair on their necks and shoulders much more developed than the females; and many additional instances could be given. This sometimes serves as a defence to the male during his battles; but whether the hair in most cases has been specially developed for this purpose, is very doubtful. We may feel almost certain that this is not the case, when only a thin and narrow crest runs along the back; for a crest of this kind would afford scarcely any protection, and the ridge of the back is not a place likely to be injured; nevertheless such crests are sometimes confined to the males, or are much more developed in them than in the females. Two antelopes, the Tragelaphus scriptus (13. Dr. Gray, ‘Gleanings from the Menagerie at Knowsley,’ pl. 28.) (Fig. 70) and Portax picta may be given as instances. When stags, and the males of the wild goat, are enraged or terrified, these crests stand erect (14. Judge Caton on the Wapiti, ‘Transact. Ottawa Acad. Nat. Sciences,’ 1868, pp. 36, 40; Blyth, ‘Land and Water,’ on Capra aegagrus 1867, p. 37.); but it cannot be supposed that they have been developed merely for the sake of exciting fear in their enemies. One of the above-named antelopes, the Portax picta, has a large well-defined brush of black hair on the throat, and this is much larger in the male than in the female. In the Ammotragus tragelaphus of North Africa, a member of the sheep-family, the fore-legs are almost concealed by an extraordinary growth of hair, which depends from the neck and upper halves of the legs; but Mr. Bartlett does not believe that this mantle is of the least use to the male, in whom it is much more developed than in the female.

[Fig. 68. Pithecia satanas, male (from Brehm).]

Male quadrupeds of many kinds differ from the females in having more hair, or hair of a different character, on certain parts of their faces. Thus the bull alone has curled hair on the forehead. (15. Hunter’s ‘Essays and Observations,’ edited by Owen, 1861. vol. i. p. 236.) In three closely- allied sub-genera of the goat family, only the males possess beards, sometimes of large size; in two other sub-genera both sexes have a beard, but it disappears in some of the domestic breeds of the common goat; and neither sex of the Hemitragus has a beard. In the ibex the beard is not developed during the summer, and is so small at other times that it may be called rudimentary. (16. See Dr. Gray’s ‘Catalogue of Mammalia in the British Museum,’ part iii. 1852, p. 144.) With some monkeys the beard is confined to the male, as in the orang; or is much larger in the male than in the female, as in the Mycetes caraya and Pithecia satanas (Fig. 68). So it is with the whiskers of some species of Macacus (17. Rengger, ‘Säugethiere,’ etc., s. 14; Desmarest, ‘Mammalogie,’ p. 86.), and, as we have seen, with the manes of some species of baboons. But with most kinds of monkeys the various tufts of hair about the face and head are alike in both sexes.

The males of various members of the ox family (Bovidae), and of certain antelopes, are furnished with a dewlap, or great fold of skin on the neck, which is much less developed in the female.

Now, what must we conclude with respect to such sexual differences as these? No one will pretend that the beards of certain male goats, or the dewlaps of the bull, or the crests of hair along the backs of certain male antelopes, are of any use to them in their ordinary habits. It is possible that the immense beard of the male Pithecia, and the large beard of the male orang, may protect their throats when fighting; for the keepers in the Zoological Gardens inform me that many monkeys attack each other by the throat; but it is not probable that the beard has been developed for a distinct purpose from that served by the whiskers, moustache, and other tufts of hair on the face; and no one will suppose that these are useful as a protection. Must we attribute all these appendages of hair or skin to mere purposeless variability in the male? It cannot be denied that this is possible; for in many domesticated quadrupeds, certain characters, apparently not derived through reversion from any wild parent form, are confined to the males, or are more developed in them than in the females— for instance, the hump on the male zebu-cattle of India, the tail of fat- tailed rams, the arched outline of the forehead in the males of several breeds of sheep, and lastly, the mane, the long hairs on the hind legs, and the dewlap of the male of the Berbura goat. (18. See the chapters on these several animals in vol. i. of my ‘Variation of Animals under Domestication;’ also vol. ii. p. 73; also chap. xx. on the practice of selection by semi-civilised people. For the Berbura goat, see Dr. Gray, ‘Catalogue,’ ibid. p. 157.) The mane, which occurs only in the rams of an African breed of sheep, is a true secondary sexual character, for, as I hear from Mr. Winwood Reade, it is not developed if the animal be castrated. Although we ought to be extremely cautious, as shewn in my work on ‘Variation under Domestication,’ in concluding that any character, even with animals kept by semi-civilised people, has not been subjected to selection by man, and thus augmented, yet in the cases just specified this is improbable; more especially as the characters are confined to the males, or are more strongly developed in them than in the females. If it were positively known that the above African ram is a descendant of the same primitive stock as the other breeds of sheep, and if the Berbura male-goat with his mane, dewlap, etc., is descended from the same stock as other goats, then, assuming that selection has not been applied to these characters, they must be due to simple variability, together with sexually- limited inheritance.

Hence it appears reasonable to extend this same view to all analogous cases with animals in a state of nature. Nevertheless I cannot persuade myself that it generally holds good, as in the case of the extraordinary development of hair on the throat and fore-legs of the male Ammotragus, or in that of the immense beard of the male Pithecia. Such study as I have been able to give to nature makes me believe that parts or organs which are highly developed, were acquired at some period for a special purpose. With those antelopes in which the adult male is more strongly-coloured than the female, and with those monkeys in which the hair on the face is elegantly arranged and coloured in a diversified manner, it seems probable that the crests and tufts of hair were gained as ornaments; and this I know is the opinion of some naturalists. If this be correct, there can be little doubt that they were gained or at least modified through sexual selection; but how far the same view may be extended to other mammals is doubtful.

Colour of the Hair and of the Naked Skin

I will first give briefly all the cases known to me of male quadrupeds differing in colour from the females. With Marsupials, as I am informed by Mr. Gould, the sexes rarely differ in this respect; but the great red kangaroo offers a striking exception, “delicate blue being the prevailing tint in those parts of the female which in the male are red.” (19. Osphranter rufus, Gould, ‘Mammals of Australia,’ 1863, vol. ii. On the Didelphis, Desmarest, ‘Mammalogie,’ p. 256.) In the Didelphis opossum of Cayenne the female is said to be a little more red than the male. Of the Rodents, Dr. Gray remarks: “African squirrels, especially those found in the tropical regions, have the fur much brighter and more vivid at some seasons of the year than at others, and the fur of the male is generally brighter than that of the female.” (20. ‘Annals and Magazine of Natural History,’ Nov. 1867, p. 325. On the Mus minutus, Desmarest, ‘Mammalogie,’ p. 304.) Dr. Gray informs me that he specified the African squirrels, because, from their unusually bright colours, they best exhibit this difference. The female of the Mus minutus of Russia is of a paler and dirtier tint than the male. In a large number of bats the fur of the male is lighter than in the female. (21. J.A. Allen, in ‘Bulletin of Mus. Comp. Zoolog. of Cambridge, United States,’ 1869, p. 207. Mr. Dobson on sexual characters in the Chiroptera, ‘Proceedings of the Zoological Society,’ 1873, p. 241. Dr. Gray on Sloths, ibid. 1871, p. 436.) Mr. Dobson also remarks, with respect to these animals: “Differences, depending partly or entirely on the possession by the male of fur of a much more brilliant hue, or distinguished by different markings or by the greater length of certain portions, are met only, to any appreciable extent, in the frugivorous bats in which the sense of sight is well developed.” This last remark deserves attention, as bearing on the question whether bright colours are serviceable to male animals from being ornamental. In one genus of sloths, it is now established, as Dr. Gray states, “that the males are ornamented differently from the females—that is to say, that they have a patch of soft short hair between the shoulders, which is generally of a more or less orange colour, and in one species pure white. The females, on the contrary, are destitute of this mark.”

The terrestrial Carnivora and Insectivora rarely exhibit sexual differences of any kind, including colour. The ocelot (Felis pardalis), however, is exceptional, for the colours of the female, compared with those of the male, are “moins apparentes, le fauve, étant plus terne, le blanc moins pur, les raies ayant moins de largeur et les taches moins de diamètre.” (22. Desmarest, ‘Mammalogie,’ 1820, p. 220. On Felis mitis, Rengger, ibid. s. 194.) The sexes of the allied Felis mitis also differ, but in a less degree; the general hues of the female being rather paler than in the male, with the spots less black. The marine Carnivora or seals, on the other hand, sometimes differ considerably in colour, and they present, as we have already seen, other remarkable sexual differences. Thus the male of the Otaria nigrescens of the southern hemisphere is of a rich brown shade above; whilst the female, who acquires her adult tints earlier in life than the male, is dark-grey above, the young of both sexes being of a deep chocolate colour. The male of the northern Phoca groenlandica is tawny grey, with a curious saddle-shaped dark mark on the back; the female is much smaller, and has a very different appearance, being “dull white or yellowish straw-colour, with a tawny hue on the back”; the young at first are pure white, and can “hardly be distinguished among the icy hummocks and snow, their colour thus acting as a protection.” (23. Dr. Murie on the Otaria, ‘Proceedings Zoological Society,’ 1869, p. 108. Mr. R. Brown on the P. groenlandica, ibid. 1868, p. 417. See also on the colours of seals, Desmarest, ibid. pp. 243, 249.)

With Ruminants sexual differences of colour occur more commonly than in any other order. A difference of this kind is general in the Strepsicerene antelopes; thus the male nilghau (Portax picta) is bluish-grey and much darker than the female, with the square white patch on the throat, the white marks on the fetlocks, and the black spots on the ears all much more distinct. We have seen that in this species the crests and tufts of hair are likewise more developed in the male than in the hornless female. I am informed by Mr. Blyth that the male, without shedding his hair, periodically becomes darker during the breeding-season. Young males cannot be distinguished from young females until about twelve months old; and if the male is emasculated before this period, he never, according to the same authority, changes colour. The importance of this latter fact, as evidence that the colouring of the Portax is of sexual origin, becomes obvious, when we hear (24. Judge Caton, in ‘Transactions of the Ottawa Academy of Natural Sciences,’ 1868, p. 4.) that neither the red summer-coat nor the blue winter-coat of the Virginian deer is at all affected by emasculation. With most or all of the highly-ornamented species of Tragelaphus the males are darker than the hornless females, and their crests of hair are more fully developed. In the male of that magnificent antelope, the Derbyan eland, the body is redder, the whole neck much blacker, and the white band which separates these colours broader than in the female. In the Cape eland, also, the male is slightly darker than the female. (25. Dr. Gray, ‘Cat. of Mamm. in Brit. Mus.’ part iii. 1852, pp. 134-142; also Dr. Gray, ‘Gleanings from the Menagerie of Knowsley,’ in which there is a splendid drawing of the Oreas derbianus: see the text on Tragelaphus. For the Cape eland (Oreas canna), see Andrew Smith, ‘Zoology of S. Africa,’ pl. 41 and 42. There are also many of these Antelopes in the Zoological Gardens.)

In the Indian black-buck (A. bezoartica), which belongs to another tribe of antelopes, the male is very dark, almost black; whilst the hornless female is fawn-coloured. We meet in this species, as Mr. Blyth informs me, with an exactly similar series of facts, as in the Portax picta, namely, in the male periodically changing colour during the breeding-season, in the effects of emasculation on this change, and in the young of both sexes being indistinguishable from each other. In the Antilope niger the male is black, the female, as well as the young of both sexes, being brown; in A. sing-sing the male is much brighter coloured than the hornless female, and his chest and belly are blacker; in the male A. caama, the marks and lines which occur on various parts of the body are black, instead of brown as in the female; in the brindled gnu (A. gorgon) “the colours of the male are nearly the same as those of the female, only deeper and of a brighter hue.” (26. On the Ant. niger, see ‘Proc. Zool. Soc.’ 1850, p. 133. With respect to an allied species, in which there is an equal sexual difference in colour, see Sir S. Baker, ‘The Albert Nyanza,’ 1866, vol. ii. p. 627. For the A. sing-sing, Gray, ‘Cat. B. Mus.’ p. 100. Desmarest, ‘Mammalogie,’ p. 468, on the A. caama. Andrew Smith, ‘Zoology of S. Africa,’ on the Gnu.) Other analogous cases could be added.

The Banteng bull (Bos sondaicus) of the Malayan Archipelago is almost black, with white legs and buttocks; the cow is of a bright dun, as are the young males until about the age of three years, when they rapidly change colour. The emasculated bull reverts to the colour of the female. The female Kemas goat is paler, and both it and the female Capra aegagrus are said to be more uniformly tinted than their males. Deer rarely present any sexual differences in colour. Judge Caton, however, informs me that in the males of the wapiti deer (Cervus canadensis) the neck, belly, and legs are much darker than in the female; but during the winter the darker tints gradually fade away and disappear. I may here mention that Judge Caton has in his park three races of the Virginian deer, which differ slightly in colour, but the differences are almost exclusively confined to the blue winter or breeding-coat; so that this case may be compared with those given in a previous chapter of closely-allied or representative species of birds, which differ from each other only in their breeding plumage. (27. ‘Ottawa Academy of Sciences,’ May 21, 1868, pp. 3, 5.) The females of Cervus paludosus of S. America, as well as the young of both sexes, do not possess the black stripes on the nose and the blackish-brown line on the breast, which are characteristic of the adult males. (28. S. Muller, on the Banteng, ‘Zoog. Indischen Archipel.’ 1839-1844, tab. 35; see also Raffles, as quoted by Mr. Blyth, in ‘Land and Water,’ 1867, p. 476. On goats, Dr. Gray, ‘Catalogue of the British Museum,’ p. 146; Desmarest, ‘Mammalogie,’ p. 482. On the Cervus paludosus, Rengger, ibid. s. 345.) Lastly, as I am informed by Mr. Blyth, the mature male of the beautifully coloured and spotted axis deer is considerably darker than the female: and this hue the castrated male never acquires.

The last Order which we need consider is that of the Primates. The male of the Lemur macaco is generally coal-black, whilst the female is brown. (29. Sclater, ‘Proc. Zool. Soc.’ 1866, p. i. The same fact has also been fully ascertained by MM. Pollen and van Dam. See, also, Dr. Gray in ‘Annals and Magazine of Natural History,’ May 1871, p. 340.) Of the Quadrumana of the New World, the females and young of Mycetes caraya are greyish-yellow and like each other; in the second year the young male becomes reddish-brown; in the third, black, excepting the stomach, which, however, becomes quite black in the fourth or fifth year. There is also a strongly-marked difference in colour between the sexes of Mycetes seniculus and Cebus capucinus; the young of the former, and I believe of the latter species, resembling the females. With Pithecia leucocephala the young likewise resemble the females, which are brownish-black above and light rusty-red beneath, the adult males being black. The ruff of hair round the face of Ateles marginatus is tinted yellow in the male and white in the female. Turning to the Old World, the males of Hylobates hoolock are always black, with the exception of a white band over the brows; the females vary from whity-brown to a dark tint mixed with black, but are never wholly black. (30. On Mycetes, Rengger, ibid. s. 14; and Brehm, ‘Thierleben,’ B. i. s. 96, 107. On Ateles Desmarest, ‘Mammalogie,’ p. 75. On Hylobates, Blyth, ‘Land and Water,’ 1867, p. 135. On the Semnopithecus, S. Muller, ‘Zoog. Indischen Archipel.’ tab. x.) In the beautiful Cercopithecus diana, the head of the adult male is of an intense black, whilst that of the female is dark grey; in the former the fur between the thighs is of an elegant fawn- colour, in the latter it is paler. In the beautiful and curious moustache monkey (Cercopithecus cephus) the only difference between the sexes is that the tail of the male is chestnut and that of the female grey; but Mr. Bartlett informs me that all the hues become more pronounced in the male when adult, whilst in the female they remain as they were during youth. According to the coloured figures given by Solomon Muller, the male of Semnopithecus chrysomelas is nearly black, the female being pale brown. In the Cercopithecus cynosurus and griseo-viridis one part of the body, which is confined to the male sex, is of the most brilliant blue or green, and contrasts strikingly with the naked skin on the hinder part of the body, which is vivid red.

[Fig. 69. Head of male Mandrill (from Gervais, ‘Hist. Nat. des
Mammifères’).]

Lastly, in the baboon family, the adult male of Cynocephalus hamadryas differs from the female not only by his immense mane, but slightly in the colour of the hair and of the naked callosities. In the drill (C. leucophaeus) the females and young are much paler-coloured, with less green, than the adult males. No other member in the whole class of mammals is coloured in so extraordinary a manner as the adult male mandrill (C. mormon). The face at this age becomes of a fine blue, with the ridge and tip of the nose of the most brilliant red. According to some authors, the face is also marked with whitish stripes, and is shaded in parts with black, but the colours appear to be variable. On the forehead there is a crest of hair, and on the chin a yellow beard. “Toutes les parties supérieures de leurs cuisses et le grand espace nu de leurs fesses sont également colorés du rouge le plus vif, avec un mélange de bleu qui ne manque reellement pas d’élégance.” (31. Gervais, ‘Hist. Nat. des Mammifères,’ 1854, p. 103. Figures are given of the skull of the male. Also Desmarest, ‘Mammalogie,’ p. 70. Geoffroy St.-Hilaire and F. Cuvier, ‘Hist. Nat. des Mammifères,’ 1824, tom. i.) When the animal is excited all the naked parts become much more vividly tinted. Several authors have used the strongest expressions in describing these resplendent colours, which they compare with those of the most brilliant birds. Another remarkable peculiarity is that when the great canine teeth are fully developed, immense protuberances of bone are formed on each cheek, which are deeply furrowed longitudinally, and the naked skin over them is brilliantly- coloured, as just-described. (Fig. 69.) In the adult females and in the young of both sexes these protuberances are scarcely perceptible; and the naked parts are much less bright coloured, the face being almost black, tinged with blue. In the adult female, however, the nose at certain regular intervals of time becomes tinted with red.

In all the cases hitherto given the male is more strongly or brighter coloured than the female, and differs from the young of both sexes. But as with some few birds it is the female which is brighter coloured than the male, so with the Rhesus monkey (Macacus rhesus), the female has a large surface of naked skin round the tail, of a brilliant carmine red, which, as I was assured by the keepers in the Zoological Gardens, periodically becomes even yet more vivid, and her face also is pale red. On the other hand, in the adult male and in the young of both sexes (as I saw in the Gardens), neither the naked skin at the posterior end of the body, nor the face, shew a trace of red. It appears, however, from some published accounts, that the male does occasionally, or during certain seasons, exhibit some traces of the red. Although he is thus less ornamented than the female, yet in the larger size of his body, larger canine teeth, more developed whiskers, more prominent superciliary ridges, he follows the common rule of the male excelling the female.

I have now given all the cases known to me of a difference in colour between the sexes of mammals. Some of these may be the result of variations confined to one sex and transmitted to the same sex, without any good being gained, and therefore without the aid of selection. We have instances of this with our domesticated animals, as in the males of certain cats being rusty-red, whilst the females are tortoise-shell coloured. Analogous cases occur in nature: Mr. Bartlett has seen many black varieties of the jaguar, leopard, vulpine phalanger, and wombat; and he is certain that all, or nearly all these animals, were males. On the other hand, with wolves, foxes, and apparently American squirrels, both sexes are occasionally born black. Hence it is quite possible that with some mammals a difference in colour between the sexes, especially when this is congenital, may simply be the result, without the aid of selection, of the occurrence of one or more variations, which from the first were sexually limited in their transmission. Nevertheless it is improbable that the diversified, vivid, and contrasted colours of certain quadrupeds, for instance, of the above monkeys and antelopes, can thus be accounted for. We should bear in mind that these colours do not appear in the male at birth, but only at or near maturity; and that unlike ordinary variations, they are lost if the male be emasculated. It is on the whole probable that the strongly-marked colours and other ornamental characters of male quadrupeds are beneficial to them in their rivalry with other males, and have consequently been acquired through sexual selection. This view is strengthened by the differences in colour between the sexes occurring almost exclusively, as may be collected from the previous details, in those groups and sub-groups of mammals which present other and strongly-marked secondary sexual characters; these being likewise due to sexual selection.

Quadrupeds manifestly take notice of colour. Sir S. Baker repeatedly observed that the African elephant and rhinoceros attacked white or grey horses with special fury. I have elsewhere shewn (32. The ‘Variation of Animals and Plants under Domestication,’ 1868, vol. ii. pp. 102, 103.) that half-wild horses apparently prefer to pair with those of the same colour, and that herds of fallow-deer of different colours, though living together, have long kept distinct. It is a more significant fact that a female zebra would not admit the addresses of a male ass until he was painted so as to resemble a zebra, and then, as John Hunter remarks, “she received him very readily. In this curious fact, we have instinct excited by mere colour, which had so strong an effect as to get the better of everything else. But the male did not require this, the female being an animal somewhat similar to himself, was sufficient to rouse him.” (33. ‘Essays and Observations,’ by J. Hunter, edited by Owen, 1861, vol. i. p. 194.)

In an earlier chapter we have seen that the mental powers of the higher animals do not differ in kind, though greatly in degree, from the corresponding powers of man, especially of the lower and barbarous races; and it would appear that even their taste for the beautiful is not widely different from that of the Quadrumana. As the negro of Africa raises the flesh on his face into parallel ridges “or cicatrices, high above the natural surface, which unsightly deformities are considered great personal attractions” (34. Sir S. Baker, ‘The Nile Tributaries of Abyssinia,’ 1867.);—as negroes and savages in many parts of the world paint their faces with red, blue, white, or black bars,—so the male mandrill of Africa appears to have acquired his deeply-furrowed and gaudily-coloured face from having been thus rendered attractive to the female. No doubt it is to us a most grotesque notion that the posterior end of the body should be coloured for the sake of ornament even more brilliantly than the face; but this is not more strange than that the tails of many birds should be especially decorated.

With mammals we do not at present possess any evidence that the males take pains to display their charms before the female; and the elaborate manner in which this is performed by male birds and other animals is the strongest argument in favour of the belief that the females admire, or are excited by, the ornaments and colours displayed before them. There is, however, a striking parallelism between mammals and birds in all their secondary sexual characters, namely in their weapons for fighting with rival males, in their ornamental appendages, and in their colours. In both classes, when the male differs from the female, the young of both sexes almost always resemble each other, and in a large majority of cases resemble the adult female. In both classes the male assumes the characters proper to his sex shortly before the age of reproduction; and if emasculated at an early period, loses them. In both classes the change of colour is sometimes seasonal, and the tints of the naked parts sometimes become more vivid during the act of courtship. In both classes the male is almost always more vividly or strongly coloured than the female, and is ornamented with larger crests of hair or feathers, or other such appendages. In a few exceptional cases the female in both classes is more highly ornamented than the male. With many mammals, and at least in the case of one bird, the male is more odoriferous than the female. In both classes the voice of the male is more powerful than that of the female. Considering this parallelism, there can be little doubt that the same cause, whatever it may be, has acted on mammals and birds; and the result, as far as ornamental characters are concerned, may be attributed, as it appears to me, to the long-continued preference of the individuals of one sex for certain individuals of the opposite sex, combined with their success in leaving a larger number of offspring to inherit their superior attractions.

Equal Transmission of Ornamental Characters to Both Sexes

With many birds, ornaments, which analogy leads us to believe were primarily acquired by the males, have been transmitted equally, or almost equally, to both sexes; and we may now enquire how far this view applies to mammals. With a considerable number of species, especially of the smaller kinds, both sexes have been coloured, independently of sexual selection, for the sake of protection; but not, as far as I can judge, in so many cases, nor in so striking a manner, as in most of the lower classes. Audubon remarks that he often mistook the musk-rat (35. Fiber zibethicus, Audubon and Bachman, ‘The Quadrupeds of North America,’ 1846, p. 109.), whilst sitting on the banks of a muddy stream, for a clod of earth, so complete was the resemblance. The hare on her form is a familiar instance of concealment through colour; yet this principle partly fails in a closely-allied species, the rabbit, for when running to its burrow, it is made conspicuous to the sportsman, and no doubt to all beasts of prey, by its upturned white tail. No one doubts that the quadrupeds inhabiting snow-clad regions have been rendered white to protect them from their enemies, or to favour their stealing on their prey. In regions where snow never lies for long, a white coat would be injurious; consequently, species of this colour are extremely rare in the hotter parts of the world. It deserves notice that many quadrupeds inhabiting moderately cold regions, although they do not assume a white winter dress, become paler during this season; and this apparently is the direct result of the conditions to which they have long been exposed. Pallas (36. ‘Novae species Quadrupedum e Glirium ordine,’ 1778, p. 7. What I have called the roe is the Capreolus sibiricus subecaudatus of Pallas.) states that in Siberia a change of this nature occurs with the wolf, two species of Mustela, the domestic horse, the Equus hemionus, the domestic cow, two species of antelopes, the musk- deer, the roe, elk, and reindeer. The roe, for instance, has a red summer and a greyish-white winter coat; and the latter may perhaps serve as a protection to the animal whilst wandering through the leafless thickets, sprinkled with snow and hoar-frost. If the above-named animals were gradually to extend their range into regions perpetually covered with snow, their pale winter-coats would probably be rendered through natural selection, whiter and whiter, until they became as white as snow.

Mr. Reeks has given me a curious instance of an animal profiting by being peculiarly coloured. He raised from fifty to sixty white and brown piebald rabbits in a large walled orchard; and he had at the same time some similarly coloured cats in his house. Such cats, as I have often noticed, are very conspicuous during day; but as they used to lie in watch during the dusk at the mouths of the burrows, the rabbits apparently did not distinguish them from their parti-coloured brethren. The result was that, within eighteen months, every one of these parti-coloured rabbits was destroyed; and there was evidence that this was effected by the cats. Colour seems to be advantageous to another animal, the skunk, in a manner of which we have had many instances in other classes. No animal will voluntarily attack one of these creatures on account of the dreadful odour which it emits when irritated; but during the dusk it would not easily be recognised and might be attacked by a beast of prey. Hence it is, as Mr. Belt believes (37. ‘The Naturalist in Nicaragua,’ p. 249.), that the skunk is provided with a great white bushy tail, which serves as a conspicuous warning.

[Fig. 70. Tragelaphus scriptus, male (from the Knowsley Menagerie).

Fig. 71. Damalis pygarga, male (from the Knowsley Menagerie).]

Although we must admit that many quadrupeds have received their present tints either as a protection, or as an aid in procuring prey, yet with a host of species, the colours are far too conspicuous and too singularly arranged to allow us to suppose that they serve for these purposes. We may take as an illustration certain antelopes; when we see the square white patch on the throat, the white marks on the fetlocks, and the round black spots on the ears, all more distinct in the male of the Portax picta, than in the female;—when we see that the colours are more vivid, that the narrow white lines on the flank and the broad white bar on the shoulder are more distinct in the male Oreas derbyanus than in the female;—when we see a similar difference between the sexes of the curiously-ornamented Tragelaphus scriptus (Fig. 70),—we cannot believe that differences of this kind are of any service to either sex in their daily habits of life. It seems a much more probable conclusion that the various marks were first acquired by the males and their colours intensified through sexual selection, and then partially transferred to the females. If this view be admitted, there can be little doubt that the equally singular colours and marks of many other antelopes, though common to both sexes, have been gained and transmitted in a like manner. Both sexes, for instance, of the koodoo (Strepsiceros kudu) (Fig. 64) have narrow white vertical lines on their hind flanks, and an elegant angular white mark on their foreheads. Both sexes in the genus Damalis are very oddly coloured; in D. pygarga the back and neck are purplish-red, shading on the flanks into black; and these colours are abruptly separated from the white belly and from a large white space on the buttocks; the head is still more oddly coloured, a large oblong white mask, narrowly-edged with black, covers the face up to the eyes (Fig. 71); there are three white stripes on the forehead, and the ears are marked with white. The fawns of this species are of a uniform pale yellowish-brown. In Damalis albifrons the colouring of the head differs from that in the last species in a single white stripe replacing the three stripes, and in the ears being almost wholly white. (38. See the fine plates in A. Smith’s ‘Zoology of South Africa,’ and Dr. Gray’s ‘Gleanings from the Menagerie of Knowsley.’) After having studied to the best of my ability the sexual differences of animals belonging to all classes, I cannot avoid the conclusion that the curiously-arranged colours of many antelopes, though common to both sexes, are the result of sexual selection primarily applied to the male.

The same conclusion may perhaps be extended to the tiger, one of the most beautiful animals in the world, the sexes of which cannot be distinguished by colour, even by the dealers in wild beasts. Mr. Wallace believes (39. ‘Westminster Review,’ July 1, 1867, p. 5.) that the striped coat of the tiger “so assimilates with the vertical stems of the bamboo, as to assist greatly in concealing him from his approaching prey.” But this view does not appear to me satisfactory. We have some slight evidence that his beauty may be due to sexual selection, for in two species of Felis the analogous marks and colours are rather brighter in the male than in the female. The zebra is conspicuously striped, and stripes cannot afford any protection in the open plains of South Africa. Burchell (40. ‘Travels in South Africa,’ 1824, vol. ii. p. 315.) in describing a herd says, “their sleek ribs glistened in the sun, and the brightness and regularity of their striped coats presented a picture of extraordinary beauty, in which probably they are not surpassed by any other quadruped.” But as throughout the whole group of the Equidae the sexes are identical in colour, we have here no evidence of sexual selection. Nevertheless he who attributes the white and dark vertical stripes on the flanks of various antelopes to this process, will probably extend the same view to the Royal Tiger and beautiful Zebra.

We have seen in a former chapter that when young animals belonging to any class follow nearly the same habits of life as their parents, and yet are coloured in a different manner, it may be inferred that they have retained the colouring of some ancient and extinct progenitor. In the family of pigs, and in the tapirs, the young are marked with longitudinal stripes, and thus differ from all the existing adult species in these two groups. With many kinds of deer the young are marked with elegant white spots, of which their parents exhibit not a trace. A graduated series can be followed from the axis deer, both sexes of which at all ages and during all seasons are beautifully spotted (the male being rather more strongly coloured than the female), to species in which neither the old nor the young are spotted. I will specify some of the steps in this series. The Mantchurian deer (Cervus mantchuricus) is spotted during the whole year, but, as I have seen in the Zoological Gardens, the spots are much plainer during the summer, when the general colour of the coat is lighter, than during the winter, when the general colour is darker and the horns are fully developed. In the hog-deer (Hyelaphus porcinus) the spots are extremely conspicuous during the summer when the coat is reddish-brown, but quite disappear during the winter when the coat is brown. (41。 Dr. Gray, ‘Gleanings from the Menagerie of Knowsley,’ p. 64. 先生。 Blyth, in speaking (‘Land and Water,’ 1869, p. 42) of the hog-deer of Ceylon, says it is more brightly spotted with white than the common hog-deer, at the season when it renews its horns.) In both these species the young are spotted. In the Virginian deer the young are likewise spotted, and about five per cent. of the adult animals living in Judge Caton’s park, as I am informed by him, temporarily exhibit at the period when the red summer coat is being replaced by the bluish winter coat, a row of spots on each flank, which are always the same in number, though very variable in distinctness. From this condition there is but a very small step to the complete absence of spots in the adults at all seasons; and, lastly, to their absence at all ages and seasons, as occurs with certain species. From the existence of this perfect series, and more especially from the fawns of so many species being spotted, we may conclude that the now living members of the deer family are the descendants of some ancient species which, like the axis deer, was spotted at all ages and seasons. A still more ancient progenitor probably somewhat resembled the Hyomoschus aquaticus—for this animal is spotted, and the hornless males have large exserted canine teeth, of which some few true deer still retain rudiments. Hyomoschus, also, offers one of those interesting cases of a form linking together two groups, for it is intermediate in certain osteological characters between the pachyderms and ruminants, which were formerly thought to be quite distinct. (42。 Falconer and Cautley, ‘Proc. Geolog. Soc.’ 1843; and Falconer’s ‘Pal. Memoirs,’ vol. i. p.

A curious difficulty here arises. If we admit that coloured spots and stripes were first acquired as ornaments, how comes it that so many existing deer, the descendants of an aboriginally spotted animal, and all the species of pigs and tapirs, the descendants of an aboriginally striped animal, have lost in their adult state their former ornaments? I cannot satisfactorily answer this question. We may feel almost sure that the spots and stripes disappeared at or near maturity in the progenitors of our existing species, so that they were still retained by the young; and, owing to the law of inheritance at corresponding ages, were transmitted to the young of all succeeding generations. It may have been a great advantage to the lion and puma, from the open nature of their usual haunts, to have lost their stripes, and to have been thus rendered less conspicuous to their prey; and if the successive variations, by which this end was gained, occurred rather late in life, the young would have retained their stripes, as is now the case. As to deer, pigs, and tapirs, Fritz Müller has suggested to me that these animals, by the removal of their spots or stripes through natural selection, would have been less easily seen by their enemies; and that they would have especially required this protection, as soon as the carnivora increased in size and number during the tertiary periods. This may be the true explanation, but it is rather strange that the young should not have been thus protected, and still more so that the adults of some species should have retained their spots, either partially or completely, during part of the year. We know that, when the domestic ass varies and becomes reddish-brown, grey, or black, the stripes on the shoulders and even on the spine frequently disappear, though we cannot explain the cause. Very few horses, except dun-coloured kinds, have stripes on any part of their bodies, yet we have good reason to believe that the aboriginal horse was striped on the legs and spine, and probably on the shoulders. (43。 The ‘Variation of Animals and Plants under Domestication,’ 1868, vol. i. 第 61-64.) Hence the disappearance of the spots and stripes in our adult existing deer, pigs, and tapirs, may be due to a change in the general colour of their coats; but whether this change was effected through sexual or natural selection, or was due to the direct action of the conditions of life, or to some other unknown cause, it is impossible to decide. An observation made by Mr. Sclater well illustrates our ignorance of the laws which regulate the appearance and disappearance of stripes; the species of Asinus which inhabit the Asiatic continent are destitute of stripes, not having even the cross shoulder-stripe, whilst those which inhabit Africa are conspicuously striped, with the partial exception of A. taeniopus, which has only the cross shoulder-stripe and generally some faint bars on the legs; and this species inhabits the almost intermediate region of Upper Egypt and Abyssinia. (44。 ‘Proc. 动物园。 苏格拉底。” 1862,p。 164. See, also, Dr. Hartmann, ‘Ann. d. Landw.’ Bd. 十四、 s.

Quadrumana

[Fig. 72. Head of Semnopithecus rubicundus. This and the following figures (from Prof. Gervais) are given to shew the odd arrangement and development of the hair on the head.

Fig. 73. Head of Semnopithecus comatus.

Fig. 74. Head of Cebus capucinus.

Fig. 75. Head of Ateles marginatus.

Fig. 76. Head of Cebus vellerosus.]

Before we conclude, it will be well to add a few remarks on the ornaments of monkeys. In most of the species the sexes resemble each other in colour, but in some, as we have seen, the males differ from the females, especially in the colour of the naked parts of the skin, in the development of the beard, whiskers, and mane. Many species are coloured either in so extraordinary or so beautiful a manner, and are furnished with such curious and elegant crests of hair, that we can hardly avoid looking at these characters as having been gained for the sake of ornament. The accompanying figures (Figs. 72 to 76) serve to shew the arrangement of the hair on the face and head in several species. It is scarcely conceivable that these crests of hair, and the strongly contrasted colours of the fur and skin, can be the result of mere variability without the aid of selection; and it is inconceivable that they can be of use in any ordinary way to these animals. If so, they have probably been gained through sexual selection, though transmitted equally, or almost equally, to both sexes. With many of the Quadrumana, we have additional evidence of the action of sexual selection in the greater size and strength of the males, and in the greater development of their canine teeth, in comparison with the females.

[Fig. 77. Cercopithecus petaurista (from Brehm).]

A few instances will suffice of the strange manner in which both sexes of some species are coloured, and of the beauty of others. The face of the Cercopithecus petaurista (Fig. 77) is black, the whiskers and beard being white, with a defined, round, white spot on the nose, covered with short white hair, which gives to the animal an almost ludicrous aspect. The Semnopithecus frontatus likewise has a blackish face with a long black beard, and a large naked spot on the forehead of a bluish-white colour. The face of Macacus lasiotus is dirty flesh-coloured, with a defined red spot on each cheek. The appearance of Cercocebus aethiops is grotesque, with its black face, white whiskers and collar, chestnut head, and a large naked white spot over each eyelid. In very many species, the beard, whiskers, and crests of hair round the face are of a different colour from the rest of the head, and when different, are always of a lighter tint (45. I observed this fact in the Zoological Gardens; and many cases may be seen in the coloured plates in Geoffroy St.-Hilaire and F. Cuvier, ‘Histoire Nat. des Mammifères,’ tom. i. 1824.), being often pure white, sometimes bright yellow, or reddish. The whole face of the South American Brachyurus calvus is of a “glowing scarlet hue”; but this colour does not appear until the animal is nearly mature. (46. Bates, ‘The Naturalist on the Amazons,’ 1863, vol. ii. p. 310.) The naked skin of the face differs wonderfully in colour in the various species. It is often brown or flesh-colour, with parts perfectly white, and often as black as that of the most sooty negro. In the Brachyurus the scarlet tint is brighter than that of the most blushing Caucasian damsel. It is sometimes more distinctly orange than in any Mongolian, and in several species it is blue, passing into violet or grey. In all the species known to Mr. Bartlett, in which the adults of both sexes have strongly-coloured faces, the colours are dull or absent during early youth. This likewise holds good with the mandrill and Rhesus, in which the face and the posterior parts of the body are brilliantly coloured in one sex alone. In these latter cases we have reason to believe that the colours were acquired through sexual selection; and we are naturally led to extend the same view to the foregoing species, though both sexes when adult have their faces coloured in the same manner.

[Fig. 78. Cercopithecus diana (from Brehm).]

Although many kinds of monkeys are far from beautiful according to our taste, other species are universally admired for their elegant appearance and bright colours. The Semnopithecus nemaeus, though peculiarly coloured, is described as extremely pretty; the orange-tinted face is surrounded by long whiskers of glossy whiteness, with a line of chestnut-red over the eyebrows; the fur on the back is of a delicate grey, with a square patch on the loins, the tail and the fore-arms being of a pure white; a gorget of chestnut surmounts the chest; the thighs are black, with the legs chestnut- red. I will mention only two other monkeys for their beauty; and I have selected these as presenting slight sexual differences in colour, which renders it in some degree probable that both sexes owe their elegant appearance to sexual selection. In the moustache-monkey (Cercopithecus cephus) the general colour of the fur is mottled-greenish with the throat white; in the male the end of the tail is chestnut, but the face is the most ornamented part, the skin being chiefly bluish-grey, shading into a blackish tint beneath the eyes, with the upper lip of a delicate blue, clothed on the lower edge with a thin black moustache; the whiskers are orange-coloured, with the upper part black, forming a band which extends backwards to the ears, the latter being clothed with whitish hairs. In the Zoological Society’s Gardens I have often overheard visitors admiring the beauty of another monkey, deservedly called Cercopithecus diana (Fig. 78); the general colour of the fur is grey; the chest and inner surface of the forelegs are white; a large triangular defined space on the hinder part of the back is rich chestnut; in the male the inner sides of the thighs and the abdomen are delicate fawn-coloured, and the top of the head is black; the face and ears are intensely black, contrasting finely with a white transverse crest over the eyebrows and a long white peaked beard, of which the basal portion is black. (47. I have seen most of the above monkeys in the Zoological Society’s Gardens. The description of the Semnopithecus nemaeus is taken from Mr. W.C. Martin’s ‘Natural History of Mammalia,’ 1841, p. 460; see also pp. 475, 523.)

In these and many other monkeys, the beauty and singular arrangement of their colours, and still more the diversified and elegant arrangement of the crests and tufts of hair on their heads, force the conviction on my mind that these characters have been acquired through sexual selection exclusively as ornaments.

总结

The law of battle for the possession of the female appears to prevail throughout the whole great class of mammals. Most naturalists will admit that the greater size, strength, courage, and pugnacity of the male, his special weapons of offence, as well as his special means of defence, have been acquired or modified through that form of selection which I have called sexual. This does not depend on any superiority in the general struggle for life, but on certain individuals of one sex, generally the male, being successful in conquering other males, and leaving a larger number of offspring to inherit their superiority than do the less successful males.

There is another and more peaceful kind of contest, in which the males endeavour to excite or allure the females by various charms. This is probably carried on in some cases by the powerful odours emitted by the males during the breeding-season; the odoriferous glands having been acquired through sexual selection. Whether the same view can be extended to the voice is doubtful, for the vocal organs of the males must have been strengthened by use during maturity, under the powerful excitements of love, jealousy or rage, and will consequently have been transmitted to the same sex. Various crests, tufts, and mantles of hair, which are either confined to the male, or are more developed in this sex than in the female, seem in most cases to be merely ornamental, though they sometimes serve as a defence against rival males. There is even reason to suspect that the branching horns of stags, and the elegant horns of certain antelopes, though properly serving as weapons of offence or defence, have been partly modified for ornament.

When the male differs in colour from the female, he generally exhibits darker and more strongly-contrasted tints. We do not in this class meet with the splendid red, blue, yellow, and green tints, so common with male birds and many other animals. The naked parts, however, of certain Quadrumana must be excepted; for such parts, often oddly situated, are brilliantly coloured in some species. The colours of the male in other cases may be due to simple variation, without the aid of selection. But when the colours are diversified and strongly pronounced, when they are not developed until near maturity, and when they are lost after emasculation, we can hardly avoid the conclusion that they have been acquired through sexual selection for the sake of ornament, and have been transmitted exclusively, or almost exclusively, to the same sex. When both sexes are coloured in the same manner, and the colours are conspicuous or curiously arranged, without being of the least apparent use as a protection, and especially when they are associated with various other ornamental appendages, we are led by analogy to the same conclusion, namely, that they have been acquired through sexual selection, although transmitted to both sexes. That conspicuous and diversified colours, whether confined to the males or common to both sexes, are as a general rule associated in the same groups and sub-groups with other secondary sexual characters serving for war or for ornament, will be found to hold good, if we look back to the various cases given in this and the last chapter.

The law of the equal transmission of characters to both sexes, as far as colour and other ornaments are concerned, has prevailed far more extensively with mammals than with birds; but weapons, such as horns and tusks, have often been transmitted either exclusively or much more perfectly to the males than to the females. This is surprising, for, as the males generally use their weapons for defence against enemies of all kinds, their weapons would have been of service to the females. As far as we can see, their absence in this sex can be accounted for only by the form of inheritance which has prevailed. Finally, with quadrupeds the contest between the individuals of the same sex, whether peaceful or bloody, has, with the rarest exceptions, been confined to the males; so that the latter have been modified through sexual selection, far more commonly than the females, either for fighting with each other or for alluring the opposite sex.

第三部分·与人类相关的性选择及其结论

第十九章 •13,400字
男人的第二性征

Differences between man and woman—Causes of such differences and of certain characters common to both sexes—Law of battle—Differences in mental powers, and voice—On the influence of beauty in determining the marriages of mankind—Attention paid by savages to ornaments—Their ideas of beauty in woman—The tendency to exaggerate each natural peculiarity.

With mankind the differences between the sexes are greater than in most of the Quadrumana, but not so great as in some, for instance, the mandrill. Man on an average is considerably taller, heavier, and stronger than woman, with squarer shoulders and more plainly-pronounced muscles. Owing to the relation which exists between muscular development and the projection of the brows (1. Schaaffhausen, translation in ‘Anthropological Review,’ Oct. 1868, pp. 419, 420, 427.), the superciliary ridge is generally more marked in man than in woman. His body, and especially his face, is more hairy, and his voice has a different and more powerful tone. In certain races the women are said to differ slightly in tint from the men. For instance, Schweinfurth, in speaking of a negress belonging to the Monbuttoos, who inhabit the interior of Africa a few degrees north of the equator, says, “Like all her race, she had a skin several shades lighter than her husband’s, being something of the colour of half-roasted coffee.” (2. ‘The Heart of Africa,’ English transl. 1873, vol i. p. 544.) As the women labour in the fields and are quite unclothed, it is not likely that they differ in colour from the men owing to less exposure to the weather. European women are perhaps the brighter coloured of the two sexes, as may be seen when both have been equally exposed.

Man is more courageous, pugnacious and energetic than woman, and has a more inventive genius. His brain is absolutely larger, but whether or not proportionately to his larger body, has not, I believe, been fully ascertained. In woman the face is rounder; the jaws and the base of the skull smaller; the outlines of the body rounder, in parts more prominent; and her pelvis is broader than in man (3. Ecker, translation, in ‘Anthropological Review,’ Oct. 1868, pp. 351-356. The comparison of the form of the skull in men and women has been followed out with much care by Welcker.); but this latter character may perhaps be considered rather as a primary than a secondary sexual character. She comes to maturity at an earlier age than man.

As with animals of all classes, so with man, the distinctive characters of the male sex are not fully developed until he is nearly mature; and if emasculated they never appear. The beard, for instance, is a secondary

sexual character, and male children are beardless, though at an early age they have abundant hair on the head. It is probably due to the rather late appearance in life of the successive variations whereby man has acquired his masculine characters, that they are transmitted to the male sex alone. Male and female children resemble each other closely, like the young of so many other animals in which the adult sexes differ widely; they likewise resemble the mature female much more closely than the mature male. The female, however, ultimately assumes certain distinctive characters, and in the formation of her skull, is said to be intermediate between the child and the man. (4. Ecker and Welcker, ibid. pp. 352, 355; Vogt, ‘Lectures on Man,’ Eng. translat. p. 81.) Again, as the young of closely allied though distinct species do not differ nearly so much from each other as do the adults, so it is with the children of the different races of man. Some have even maintained that race-differences cannot be detected in the infantile skull. (5. Schaaffhausen, ‘Anthropolog. Review,’ ibid. p. 429.) In regard to colour, the new-born negro child is reddish nut-brown, which soon becomes slaty-grey; the black colour being fully developed within a year in the Soudan, but not until three years in Egypt. The eyes of the negro are at first blue, and the hair chestnut-brown rather than black, being curled only at the ends. The children of the Australians immediately after birth are yellowish-brown, and become dark at a later age. Those of the Guaranys of Paraguay are whitish-yellow, but they acquire in the course of a few weeks the yellowish-brown tint of their parents. Similar observations have been made in other parts of America. (6. Pruner-Bey, on negro infants as quoted by Vogt, ‘Lectures on Man,’ Eng. translat. 1864, p. 189: for further facts on negro infants, as quoted from Winterbottom and Camper, see Lawrence, ‘Lectures on Physiology,’ etc. 1822, p. 451. For the infants of the Guaranys, see Rengger, ‘Säugethiere,’ etc. s. 3. See also Godron, ‘De l’Espèce,’ tom. ii. 1859, p. 253. For the Australians, Waitz, ‘Introduction to Anthropology,’ Eng. translat. 1863, p. 99.)

I have specified the foregoing differences between the male and female sex in mankind, because they are curiously like those of the Quadrumana. With these animals the female is mature at an earlier age than the male; at least this is certainly the case in Cebus azarae. (7。 Rengger, ‘Säugethiere,’ etc., 1830, s. 49.) The males of most species are larger and stronger than the females, of which fact the gorilla affords a well- known instance. Even in so trifling a character as the greater prominence of the superciliary ridge, the males of certain monkeys differ from the females (8. As in Macacus cynomolgus (Desmarest, ‘Mammalogie,’ p. 65), and in Hylobates agilis (Geoffroy St.-Hilaire and F. Cuvier, ‘Histoire Nat. des Mammifères,’ 1824, tom. i. p. 2).), and agree in this respect with mankind. In the gorilla and certain other monkeys, the cranium of the adult male presents a strongly-marked sagittal crest, which is absent in the female; and Ecker found a trace of a similar difference between the two sexes in the Australians. (9。 ‘Anthropological Review,’ Oct. 1868。 353.) With monkeys when there is any difference in the voice, that of the male is the more powerful. We have seen that certain male monkeys have a well- developed beard, which is quite deficient, or much less developed in the female. No instance is known of the beard, whiskers, or moustache being larger in the female than in the male monkey. Even in the colour of the beard there is a curious parallelism between man and the Quadrumana, for with man when the beard differs in colour from the hair of the head, as is commonly the case, it is, I believe, almost always of a lighter tint, being often reddish. I have repeatedly observed this fact in England; but two gentlemen have lately written to me, saying that they form an exception to the rule. One of these gentlemen accounts for the fact by the wide difference in colour of the hair on the paternal and maternal sides of his family. Both had been long aware of this peculiarity (one of them having often been accused of dyeing his beard), and had been thus led to observe other men, and were convinced that the exceptions were very rare. Dr. Hooker attended to this little point for me in Russia, and found no exception to the rule. In Calcutta, Mr. J. Scott, of the Botanic Gardens, was so kind as to observe the many races of men to be seen there, as well as in some other parts of India, namely, two races of Sikhim, the Bhoteas, Hindoos, Burmese, and Chinese, most of which races have very little hair on the face; and he always found that when there was any difference in colour between the hair of the head and the beard, the latter was invariably lighter. Now with monkeys, as has already been stated, the beard frequently differs strikingly in colour from the hair of the head, and in such cases it is always of a lighter hue, being often pure white, sometimes yellow or reddish. (10。 先生。 Blyth informs me that he has only seen one instance of the beard, whiskers, etc., in a monkey becoming white with old age, as is so commonly the case with us. This, however, occurred in an aged Macacus cynomolgus, kept in confinement whose moustaches were “remarkably long and human-like.” Altogether this old monkey presented a ludicrous resemblance to one of the reigning monarchs of Europe, after whom he was universally nick-named. In certain races of man the hair on the head hardly ever becomes grey; thus Mr. D.

In regard to the general hairiness of the body, the women in all races are less hairy than the men; and in some few Quadrumana the under side of the body of the female is less hairy than that of the male. (11. This is the case with the females of several species of Hylobates; see Geoffroy St.- Hilaire and F. Cuvier, ‘Hist. Nat. des Mamm.’ tom. i. See also, on H. lar, ‘Penny Cyclopedia,’ vol. ii. pp. 149, 150.) Lastly, male monkeys, like men, are bolder and fiercer than the females. They lead the troop, and when there is danger, come to the front. We thus see how close is the parallelism between the sexual differences of man and the Quadrumana. With some few species, however, as with certain baboons, the orang and the gorilla, there is a considerably greater difference between the sexes, as in the size of the canine teeth, in the development and colour of the hair, and especially in the colour of the naked parts of the skin, than in mankind.

All the secondary sexual characters of man are highly variable, even within the limits of the same race; and they differ much in the several races. These two rules hold good generally throughout the animal kingdom. In the excellent observations made on board the Novara (12. The results were deduced by Dr. Weisbach from the measurements made by Drs. K. Scherzer and Schwarz, see ‘Reise der Novara: Anthropolog. Theil,’ 1867, ss. 216, 231, 234, 236, 239, 269.), the male Australians were found to exceed the females by only 65 millim. in height, whilst with the Javans the average excess was 218 millim.; so that in this latter race the difference in height between the sexes is more than thrice as great as with the Australians. Numerous measurements were carefully made of the stature, the circumference of the neck and chest, the length of the back-bone and of the arms, in various races; and nearly all these measurements shew that the males differ much more from one another than do the females. This fact indicates that, as far as these characters are concerned, it is the male which has been chiefly modified, since the several races diverged from their common stock.

The development of the beard and the hairiness of the body differ remarkably in the men of distinct races, and even in different tribes or families of the same race. We Europeans see this amongst ourselves. In the Island of St. Kilda, according to Martin (13. ‘Voyage to St. Kilda’ (3rd ed. 1753), p. 37.), the men do not acquire beards until the age of thirty or upwards, and even then the beards are very thin. On the Europaeo-Asiatic continent, beards prevail until we pass beyond India; though with the natives of Ceylon they are often absent, as was noticed in ancient times by Diodorus. (14. Sir J.E. Tennent, ‘Ceylon,’ vol. ii. 1859, p. 107.) Eastward of India beards disappear, as with the Siamese, Malays, Kalmucks, Chinese, and Japanese; nevertheless, the Ainos (15. Quatrefages, ‘Revue des Cours Scientifiques,’ Aug. 29, 1868, p. 630; Vogt, ‘Lectures on Man,’ Eng. trans. p. 127.), who inhabit the northernmost islands of the Japan Archipelago, are the hairiest men in the world. With negroes the beard is scanty or wanting, and they rarely have whiskers; in both sexes the body is frequently almost destitute of fine down. (16. On the beards of negroes, Vogt, ‘Lectures,’ etc. p. 127; Waitz, ‘Introduct. to Anthropology,’ Engl. translat. 1863, vol. i. p. 96. It is remarkable that in the United States (‘Investigations in Military and Anthropological Statistics of American Soldiers,’ 1869, p. 569) the pure negroes and their crossed offspring seem to have bodies almost as hairy as Europeans.) On the other hand, the Papuans of the Malay Archipelago, who are nearly as black as negroes, possess well-developed beards. (17. Wallace, ‘The Malay Arch.’ vol. ii. 1869, p. 178.) In the Pacific Ocean the inhabitants of the Fiji Archipelago have large bushy beards, whilst those of the not distant archipelagoes of Tonga and Samoa are beardless; but these men belong to distinct races. In the Ellice group all the inhabitants belong to the same race; yet on one island alone, namely Nunemaya, “the men have splendid beards”; whilst on the other islands “they have, as a rule, a dozen straggling hairs for a beard.” (18. Dr. J. Barnard Davis on Oceanic Races, in ‘Anthropological Review,’ April 1870, pp. 185, 191.)

Throughout the great American continent the men may be said to be beardless; but in almost all the tribes a few short hairs are apt to appear on the face, especially in old age. With the tribes of North America, Catlin estimates that eighteen out of twenty men are completely destitute by nature of a beard; but occasionally there may be seen a man, who has neglected to pluck out the hairs at puberty, with a soft beard an inch or two in length. The Guaranys of Paraguay differ from all the surrounding tribes in having a small beard, and even some hair on the body, but no whiskers. (19. Catlin, ‘North American Indians,’ 3rd. ed. 1842, vol. ii. p. 227. On the Guaranys, see Azara, ‘Voyages dans l’Amérique Merid.’ tom. ii. 1809, p. 85; also Rengger, ‘Säugethiere von Paraguay,’ s. 3.) I am informed by Mr. D. Forbes, who particularly attended to this point, that the Aymaras and Quichuas of the Cordillera are remarkably hairless, yet in old age a few straggling hairs occasionally appear on the chin. The men of these two tribes have very little hair on the various parts of the body where hair grows abundantly in Europeans, and the women have none on the corresponding parts. The hair on the head, however, attains an extraordinary length in both sexes, often reaching almost to the ground; and this is likewise the case with some of the N. American tribes. In the amount of hair, and in the general shape of the body, the sexes of the American aborigines do not differ so much from each other, as in most other races. (20. Prof. and Mrs. Agassiz (‘Journey in Brazil,’ p. 530) remark that the sexes of the American Indians differ less than those of the negroes and of the higher races. See also Rengger, ibid. p. 3, on the Guaranys.) This fact is analogous with what occurs with some closely allied monkeys; thus the sexes of the chimpanzee are not as different as those of the orang or gorilla. (21. Rutimeyer, ‘Die Grenzen der Thierwelt; eine Betrachtung zu Darwin’s Lehre,’ 1868, s. 54.)

In the previous chapters we have seen that with mammals, birds, fishes, insects, etc., many characters, which there is every reason to believe were primarily gained through sexual selection by one sex, have been transferred to the other. As this same form of transmission has apparently prevailed much with mankind, it will save useless repetition if we discuss the origin of characters peculiar to the male sex together with certain other characters common to both sexes.

Law of Battle

With savages, for instance, the Australians, the women are the constant cause of war both between members of the same tribe and between distinct tribes. So no doubt it was in ancient times; “nam fuit ante Helenam mulier teterrima belli causa.” With some of the North American Indians, the contest is reduced to a system. That excellent observer, Hearne (22. ‘A Journey from Prince of Wales Fort,’ 8vo. ed. Dublin, 1796, p. 104. Sir J. Lubbock (‘Origin of Civilisation,’ 1870, p. 69) gives other and similar cases in North America. For the Guanas of South America see Azara, ‘Voyages,’ etc. tom. ii. p. 94.), says:—”It has ever been the custom among these people for the men to wrestle for any woman to whom they are attached; and, of course, the strongest party always carries off the prize. A weak man, unless he be a good hunter, and well-beloved, is seldom permitted to keep a wife that a stronger man thinks worth his notice. This custom prevails throughout all the tribes, and causes a great spirit of emulation among their youth, who are upon all occasions, from their childhood, trying their strength and skill in wrestling.” With the Guanas of South America, Azara states that the men rarely marry till twenty years old or more, as before that age they cannot conquer their rivals.

Other similar facts could be given; but even if we had no evidence on this head, we might feel almost sure, from the analogy of the higher Quadrumana (23. On the fighting of the male gorillas, see Dr. Savage, in ‘Boston Journal of Natural History,’ vol. v. 1847, p. 423. On Presbytis entellus, see the ‘Indian Field,’ 1859, p. 146.), that the law of battle had prevailed with man during the early stages of his development. The occasional appearance at the present day of canine teeth which project above the others, with traces of a diastema or open space for the reception of the opposite canines, is in all probability a case of reversion to a former state, when the progenitors of man were provided with these weapons, like so many existing male Quadrumana. It was remarked in a former chapter that as man gradually became erect, and continually used his hands and arms for fighting with sticks and stones, as well as for the other purposes of life, he would have used his jaws and teeth less and less. The jaws, together with their muscles, would then have been reduced through disuse, as would the teeth through the not well understood principles of correlation and economy of growth; for we everywhere see that parts, which are no longer of service, are reduced in size. By such steps the original inequality between the jaws and teeth in the two sexes of mankind would ultimately have been obliterated. The case is almost parallel with that of many male Ruminants, in which the canine teeth have been reduced to mere rudiments, or have disappeared, apparently in consequence of the development of horns. As the prodigious difference between the skulls of the two sexes in the orang and gorilla stands in close relation with the development of the immense canine teeth in the males, we may infer that the reduction of the jaws and teeth in the early male progenitors of man must have led to a most striking and favourable change in his appearance.

There can be little doubt that the greater size and strength of man, in comparison with woman, together with his broader shoulders, more developed muscles, rugged outline of body, his greater courage and pugnacity, are all due in chief part to inheritance from his half-human male ancestors. These characters would, however, have been preserved or even augmented during the long ages of man’s savagery, by the success of the strongest and boldest men, both in the general struggle for life and in their contests for wives; a success which would have ensured their leaving a more numerous progeny than their less favoured brethren. It is not probable that the greater strength of man was primarily acquired through the inherited effects of his having worked harder than woman for his own subsistence and that of his family; for the women in all barbarous nations are compelled to work at least as hard as the men. With civilised people the arbitrament of battle for the possession of the women has long ceased; on the other hand, the men, as a general rule, have to work harder than the women for their joint subsistence, and thus their greater strength will have been kept up.

Difference in the Mental Powers of the Two Sexes

With respect to differences of this nature between man and woman, it is probable that sexual selection has played a highly important part. I am aware that some writers doubt whether there is any such inherent difference; but this is at least probable from the analogy of the lower animals which present other secondary sexual characters. No one disputes that the bull differs in disposition from the cow, the wild-boar from the sow, the stallion from the mare, and, as is well known to the keepers of menageries, the males of the larger apes from the females. Woman seems to differ from man in mental disposition, chiefly in her greater tenderness and less selfishness; and this holds good even with savages, as shewn by a well-known passage in Mungo Park’s Travels, and by statements made by many other travellers. Woman, owing to her maternal instincts, displays these qualities towards her infants in an eminent degree; therefore it is likely that she would often extend them towards her fellow-creatures. Man is the rival of other men; he delights in competition, and this leads to ambition which passes too easily into selfishness. These latter qualities seem to be his natural and unfortunate birthright. It is generally admitted that with woman the powers of intuition, of rapid perception, and perhaps of imitation, are more strongly marked than in man; but some, at least, of these faculties are characteristic of the lower races, and therefore of a past and lower state of civilisation.

The chief distinction in the intellectual powers of the two sexes is shewn by man’s attaining to a higher eminence, in whatever he takes up, than can woman—whether requiring deep thought, reason, or imagination, or merely the use of the senses and hands. If two lists were made of the most eminent men and women in poetry, painting, sculpture, music (inclusive both of composition and performance), history, science, and philosophy, with half-a-dozen names under each subject, the two lists would not bear comparison. We may also infer, from the law of the deviation from averages, so well illustrated by Mr. Galton, in his work on ‘Hereditary Genius,’ that if men are capable of a decided pre-eminence over women in many subjects, the average of mental power in man must be above that of woman.

Amongst the half-human progenitors of man, and amongst savages, there have been struggles between the males during many generations for the possession of the females. But mere bodily strength and size would do little for victory, unless associated with courage, perseverance, and determined energy. With social animals, the young males have to pass through many a contest before they win a female, and the older males have to retain their females by renewed battles. They have, also, in the case of mankind, to defend their females, as well as their young, from enemies of all kinds, and to hunt for their joint subsistence. But to avoid enemies or to attack them with success, to capture wild animals, and to fashion weapons, requires the aid of the higher mental faculties, namely, observation, reason, invention, or imagination. These various faculties will thus have been continually put to the test and selected during manhood; they will, moreover, have been strengthened by use during this same period of life. Consequently in accordance with the principle often alluded to, we might expect that they would at least tend to be transmitted chiefly to the male offspring at the corresponding period of manhood.

Now, when two men are put into competition, or a man with a woman, both possessed of every mental quality in equal perfection, save that one has higher energy, perseverance, and courage, the latter will generally become more eminent in every pursuit, and will gain the ascendancy. (24. J. Stuart Mill remarks (‘The Subjection of Women,’ 1869, p. 122), “The things in which man most excels woman are those which require most plodding, and long hammering at single thoughts.” What is this but energy and perseverance?) He may be said to possess genius—for genius has been declared by a great authority to be patience; and patience, in this sense, means unflinching, undaunted perseverance. But this view of genius is perhaps deficient; for without the higher powers of the imagination and reason, no eminent success can be gained in many subjects. These latter faculties, as well as the former, will have been developed in man, partly through sexual selection,—that is, through the contest of rival males, and partly through natural selection, that is, from success in the general struggle for life; and as in both cases the struggle will have been during maturity, the characters gained will have been transmitted more fully to the male than to the female offspring. It accords in a striking manner with this view of the modification and re-inforcement of many of our mental faculties by sexual selection, that, firstly, they notoriously undergo a considerable change at puberty (25. Maudsley, ‘Mind and Body,’ p. 31.), and, secondly, that eunuchs remain throughout life inferior in these same qualities. Thus, man has ultimately become superior to woman. It is, indeed, fortunate that the law of the equal transmission of characters to both sexes prevails with mammals; otherwise, it is probable that man would have become as superior in mental endowment to woman, as the peacock is in ornamental plumage to the peahen.

It must be borne in mind that the tendency in characters acquired by either sex late in life, to be transmitted to the same sex at the same age, and of early acquired characters to be transmitted to both sexes, are rules which, though general, do not always hold. If they always held good, we might conclude (but I here exceed my proper bounds) that the inherited effects of the early education of boys and girls would be transmitted equally to both sexes; so that the present inequality in mental power between the sexes would not be effaced by a similar course of early training; nor can it have been caused by their dissimilar early training. In order that woman should reach the same standard as man, she ought, when nearly adult, to be trained to energy and perseverance, and to have her reason and imagination exercised to the highest point; and then she would probably transmit these qualities chiefly to her adult daughters. All women, however, could not be thus raised, unless during many generations those who excelled in the above robust virtues were married, and produced offspring in larger numbers than other women. As before remarked of bodily strength, although men do not now fight for their wives, and this form of selection has passed away, yet during manhood, they generally undergo a severe struggle in order to maintain themselves and their families; and this will tend to keep up or even increase their mental powers, and, as a consequence, the present inequality between the sexes. (26. An observation by Vogt bears on this subject: he says, “It is a remarkable circumstance, that the difference between the sexes, as regards the cranial cavity, increases with the development of the race, so that the male European excels much more the female, than the negro the negress. Welcker confirms this statement of Huschke from his measurements of negro and German skulls.” But Vogt admits (‘Lectures on Man,’ Eng. translat. 1864, p. 81) that more observations are requisite on this point.

Voice and Musical Powers

In some species of Quadrumana there is a great difference between the adult sexes, in the power of their voices and in the development of the vocal organs; and man appears to have inherited this difference from his early progenitors. His vocal cords are about one-third longer than in woman, or than in boys; and emasculation produces the same effect on him as on the lower animals, for it “arrests that prominent growth of the thyroid, etc., which accompanies the elongation of the cords.” (27. Owen, ‘Anatomy of Vertebrates,’ vol. iii. p. 603.) With respect to the cause of this difference between the sexes, I have nothing to add to the remarks in the last chapter on the probable effects of the long-continued use of the vocal organs by the male under the excitement of love, rage and jealousy. According to Sir Duncan Gibb (28. ‘Journal of the Anthropological Society,’ April 1869, p. lvii. and lxvi.), the voice and the form of the larynx differ in the different races of mankind; but with the Tartars, Chinese, etc., the voice of the male is said not to differ so much from that of the female, as in most other races.

The capacity and love for singing or music, though not a sexual character in man, must not here be passed over. Although the sounds emitted by animals of all kinds serve many purposes, a strong case can be made out, that the vocal organs were primarily used and perfected in relation to the propagation of the species. Insects and some few spiders are the lowest animals which voluntarily produce any sound; and this is generally effected by the aid of beautifully constructed stridulating organs, which are often confined to the males. The sounds thus produced consist, I believe in all cases, of the same note, repeated rhythmically (29. Dr. Scudder, ‘Notes on Stridulation,’ in ‘Proc. Boston Soc. of Nat. Hist.’ vol. xi. April 1868.); and this is sometimes pleasing even to the ears of man. The chief and, in some cases, exclusive purpose appears to be either to call or charm the opposite sex.

The sounds produced by fishes are said in some cases to be made only by the males during the breeding-season. All the air-breathing Vertebrata necessarily possess an apparatus for inhaling and expelling air, with a pipe capable of being closed at one end. Hence when the primeval members of this class were strongly excited and their muscles violently contracted, purposeless sounds would almost certainly have been produced; and these, if they proved in any way serviceable, might readily have been modified or intensified by the preservation of properly adapted variations. The lowest Vertebrates which breathe air are Amphibians; and of these, frogs and toads possess vocal organs, which are incessantly used during the breeding- season, and which are often more highly developed in the male than in the female. The male alone of the tortoise utters a noise, and this only during the season of love. Male alligators roar or bellow during the same season. Every one knows how much birds use their vocal organs as a means of courtship; and some species likewise perform what may be called instrumental music.

In the class of Mammals, with which we are here more particularly concerned, the males of almost all the species use their voices during the breeding-season much more than at any other time; and some are absolutely mute excepting at this season. With other species both sexes, or only the females, use their voices as a love-call. Considering these facts, and that the vocal organs of some quadrupeds are much more largely developed in the male than in the female, either permanently or temporarily during the breeding-season; and considering that in most of the lower classes the sounds produced by the males, serve not only to call but to excite or allure the female, it is a surprising fact that we have not as yet any good evidence that these organs are used by male mammals to charm the females. The American Mycetes caraya perhaps forms an exception, as does the Hylobates agilis, an ape allied to man. This gibbon has an extremely loud but musical voice. Mr. Waterhouse states (30. Given in W.C.L. Martin’s ‘General Introduction to Natural History of Mamm. Animals,’ 1841, p. 432; Owen, ‘Anatomy of Vertebrates,’ vol. iii, p. 600.), “It appeared to me that in ascending and descending the scale, the intervals were always exactly half-tones; and I am sure that the highest note was the exact octave to the lowest. The quality of the notes is very musical; and I do not doubt that a good violinist would be able to give a correct idea of the gibbon’s composition, excepting as regards its loudness.” Mr. Waterhouse then gives the notes. Professor Owen, who is a musician, confirms the foregoing statement, and remarks, though erroneously, that this gibbon “alone of brute mammals may be said to sing.” It appears to be much excited after its performance. Unfortunately, its habits have never been closely observed in a state of nature; but from the analogy of other animals, it is probable that it uses its musical powers more especially during the season of courtship.

This gibbon is not the only species in the genus which sings, for my son, Francis Darwin, attentively listened in the Zoological Gardens to H. leuciscus whilst singing a cadence of three notes, in true musical intervals and with a clear musical tone. It is a more surprising fact that certain rodents utter musical sounds. Singing mice have often been mentioned and exhibited, but imposture has commonly been suspected. We have, however, at last a clear account by a well-known observer, the Rev. S. Lockwood (31. The ‘American Naturalist,’ 1871, p. 761.), of the musical powers of an American species, the Hesperomys cognatus, belonging to a genus distinct from that of the English mouse. This little animal was kept in confinement, and the performance was repeatedly heard. In one of the two chief songs, “the last bar would frequently be prolonged to two or three; and she would sometimes change from C sharp and D, to C natural and D, then warble on these two notes awhile, and wind up with a quick chirp on C sharp and D. The distinctness between the semitones was very marked, and easily appreciable to a good ear.” Mr. Lockwood gives both songs in musical notation; and adds that though this little mouse “had no ear for time, yet she would keep to the key of B (two flats) and strictly in a major key.”…”Her soft clear voice falls an octave with all the precision possible; then at the wind up, it rises again into a very quick trill on C sharp and D.”

A critic has asked how the ears of man, and he ought to have added of other animals, could have been adapted by selection so as to distinguish musical notes. But this question shews some confusion on the subject; a noise is the sensation resulting from the co-existence of several aerial “simple vibrations” of various periods, each of which intermits so frequently that its separate existence cannot be perceived. It is only in the want of continuity of such vibrations, and in their want of harmony inter se, that a noise differs from a musical note. Thus an ear to be capable of discriminating noises—and the high importance of this power to all animals is admitted by every one—must be sensitive to musical notes. We have evidence of this capacity even low down in the animal scale: thus Crustaceans are provided with auditory hairs of different lengths, which have been seen to vibrate when the proper musical notes are struck. (32. Helmholtz, ‘Theorie Phys. de la Musique,’ 1868, p. 187.) As stated in a previous chapter, similar observations have been made on the hairs of the antennae of gnats. It has been positively asserted by good observers that spiders are attracted by music. It is also well known that some dogs howl when hearing particular tones. (33. Several accounts have been published to this effect. Mr. Peach writes to me that an old dog of his howls when B flat is sounded on the flute, and to no other note. I may add another instance of a dog always whining, when one note on a concertina, which was out of tune, was played.) Seals apparently appreciate music, and their fondness for it “was well known to the ancients, and is often taken advantage of by the hunters at the present day.” (34. Mr. R. Brown, in ‘Proc. Zool. Soc.’ 1868, p. 410.)

Therefore, as far as the mere perception of musical notes is concerned, there seems no special difficulty in the case of man or of any other animal. Helmholtz has explained on physiological principles why concords are agreeable, and discords disagreeable to the human ear; but we are little concerned with these, as music in harmony is a late invention. We are more concerned with melody, and here again, according to Helmholtz, it is intelligible why the notes of our musical scale are used. The ear analyses all sounds into their component “simple vibrations,” although we are not conscious of this analysis. In a musical note the lowest in pitch of these is generally predominant, and the others which are less marked are the octave, the twelfth, the second octave, etc., all harmonies of the fundamental predominant note; any two notes of our scale have many of these harmonic over-tones in common. It seems pretty clear then, that if an animal always wished to sing precisely the same song, he would guide himself by sounding those notes in succession, which possess many over- tones in common—that is, he would choose for his song, notes which belong to our musical scale.

But if it be further asked why musical tones in a certain order and rhythm give man and other animals pleasure, we can no more give the reason than for the pleasantness of certain tastes and smells. That they do give pleasure of some kind to animals, we may infer from their being produced during the season of courtship by many insects, spiders, fishes, amphibians, and birds; for unless the females were able to appreciate such sounds and were excited or charmed by them, the persevering efforts of the males, and the complex structures often possessed by them alone, would be useless; and this it is impossible to believe.

Human song is generally admitted to be the basis or origin of instrumental music. As neither the enjoyment nor the capacity of producing musical notes are faculties of the least use to man in reference to his daily habits of life, they must be ranked amongst the most mysterious with which he is endowed. They are present, though in a very rude condition, in men of all races, even the most savage; but so different is the taste of the several races, that our music gives no pleasure to savages, and their music is to us in most cases hideous and unmeaning. Dr. Seemann, in some interesting remarks on this subject (35. ‘Journal of Anthropological Society,’ Oct. 1870, p. clv. See also the several later chapters in Sir John Lubbock’s ‘Prehistoric Times,’ 2nd ed. 1869, which contain an admirable account of the habits of savages.), “doubts whether even amongst the nations of Western Europe, intimately connected as they are by close and frequent intercourse, the music of the one is interpreted in the same sense by the others. By travelling eastwards we find that there is certainly a different language of music. Songs of joy and dance- accompaniments are no longer, as with us, in the major keys, but always in the minor.” Whether or not the half-human progenitors of man possessed, like the singing gibbons, the capacity of producing, and therefore no doubt of appreciating, musical notes, we know that man possessed these faculties at a very remote period. M. Lartet has described two flutes made out of the bones and horns of the reindeer, found in caves together with flint tools and the remains of extinct animals. The arts of singing and of dancing are also very ancient, and are now practised by all or nearly all the lowest races of man. Poetry, which may be considered as the offspring of song, is likewise so ancient, that many persons have felt astonished that it should have arisen during the earliest ages of which we have any record.

We see that the musical faculties, which are not wholly deficient in any race, are capable of prompt and high development, for Hottentots and Negroes have become excellent musicians, although in their native countries they rarely practise anything that we should consider music. Schweinfurth, however, was pleased with some of the simple melodies which he heard in the interior of Africa. But there is nothing anomalous in the musical faculties lying dormant in man: some species of birds which never naturally sing, can without much difficulty be taught to do so; thus a house-sparrow has learnt the song of a linnet. As these two species are closely allied, and belong to the order of Insessores, which includes nearly all the singing-birds in the world, it is possible that a progenitor of the sparrow may have been a songster. It is more remarkable that parrots, belonging to a group distinct from the Insessores, and having differently constructed vocal organs, can be taught not only to speak, but to pipe or whistle tunes invented by man, so that they must have some musical capacity. Nevertheless it would be very rash to assume that parrots are descended from some ancient form which was a songster. Many cases could be advanced of organs and instincts originally adapted for one purpose, having been utilised for some distinct purpose. (36. Since this chapter was printed, I have seen a valuable article by Mr. Chauncey Wright (‘North American Review,’ Oct. 1870, page 293), who, in discussing the above subject, remarks, “There are many consequences of the ultimate laws or uniformities of nature, through which the acquisition of one useful power will bring with it many resulting advantages as well as limiting disadvantages, actual or possible, which the principle of utility may not have comprehended in its action.” As I have attempted to shew in an early chapter of this work, this principle has an important bearing on the acquisition by man of some of his mental characteristics.) Hence the capacity for high musical development which the savage races of man possess, may be due either to the practice by our semi-human progenitors of some rude form of music, or simply to their having acquired the proper vocal organs for a different purpose. But in this latter case we must assume, as in the above instance of parrots, and as seems to occur with many animals, that they already possessed some sense of melody.

Music arouses in us various emotions, but not the more terrible ones of horror, fear, rage, etc. It awakens the gentler feelings of tenderness and love, which readily pass into devotion. In the Chinese annals it is said, “Music hath the power of making heaven descend upon earth.” It likewise stirs up in us the sense of triumph and the glorious ardour for war. These powerful and mingled feelings may well give rise to the sense of sublimity. We can concentrate, as Dr. Seemann observes, greater intensity of feeling in a single musical note than in pages of writing. It is probable that nearly the same emotions, but much weaker and far less complex, are felt by birds when the male pours forth his full volume of song, in rivalry with other males, to captivate the female. Love is still the commonest theme of our songs. As Herbert Spencer remarks, “music arouses dormant sentiments of which we had not conceived the possibility, and do not know the meaning; or, as Richter says, tells us of things we have not seen and shall not see.” Conversely, when vivid emotions are felt and expressed by the orator, or even in common speech, musical cadences and rhythm are instinctively used. The negro in Africa when excited often bursts forth in song; “another will reply in song, whilst the company, as if touched by a musical wave, murmur a chorus in perfect unison.” (37. Winwood Reade, ‘The Martyrdom of Man,’ 1872, p. 441, and ‘African Sketch Book,’ 1873, vol. ii. p. 313.) Even monkeys express strong feelings in different tones— anger and impatience by low,—fear and pain by high notes. (38. Rengger, ‘Säugethiere von Paraguay,’ s. 49.) The sensations and ideas thus excited in us by music, or expressed by the cadences of oratory, appear from their vagueness, yet depth, like mental reversions to the emotions and thoughts of a long-past age.

All these facts with respect to music and impassioned speech become intelligible to a certain extent, if we may assume that musical tones and rhythm were used by our half-human ancestors, during the season of courtship, when animals of all kinds are excited not only by love, but by the strong passions of jealousy, rivalry, and triumph. From the deeply- laid principle of inherited associations, musical tones in this case would be likely to call up vaguely and indefinitely the strong emotions of a long-past age. As we have every reason to suppose that articulate speech is one of the latest, as it certainly is the highest, of the arts acquired by man, and as the instinctive power of producing musical notes and rhythms is developed low down in the animal series, it would be altogether opposed to the principle of evolution, if we were to admit that man’s musical capacity has been developed from the tones used in impassioned speech. We must suppose that the rhythms and cadences of oratory are derived from previously developed musical powers. (39. See the very interesting discussion on the ‘Origin and Function of Music,’ by Mr. Herbert Spencer, in his collected ‘Essays,’ 1858, p. 359. Mr. Spencer comes to an exactly opposite conclusion to that at which I have arrived. He concludes, as did Diderot formerly, that the cadences used in emotional speech afford the foundation from which music has been developed; whilst I conclude that musical notes and rhythm were first acquired by the male or female progenitors of mankind for the sake of charming the opposite sex. Thus musical tones became firmly associated with some of the strongest passions an animal is capable of feeling, and are consequently used instinctively, or through association when strong emotions are expressed in speech. Mr. Spencer does not offer any satisfactory explanation, nor can I, why high or deep notes should be expressive, both with man and the lower animals, of certain emotions. Mr. Spencer gives also an interesting discussion on the relations between poetry, recitative and song.) We can thus understand how it is that music, dancing, song, and poetry are such very ancient arts. We may go even further than this, and, as remarked in a former chapter, believe that musical sounds afforded one of the bases for the development of language. (40. I find in Lord Monboddo’s ‘Origin of Language,’ vol. i. 1774, p. 469, that Dr. Blacklock likewise thought “that the first language among men was music, and that before our ideas were expressed by articulate sounds, they were communicated by tones varied according to different degrees of gravity and acuteness.”)

As the males of several quadrumanous animals have their vocal organs much more developed than in the females, and as a gibbon, one of the anthropomorphous apes, pours forth a whole octave of musical notes and may be said to sing, it appears probable that the progenitors of man, either the males or females or both sexes, before acquiring the power of expressing their mutual love in articulate language, endeavoured to charm each other with musical notes and rhythm. So little is known about the use of the voice by the Quadrumana during the season of love, that we have no means of judging whether the habit of singing was first acquired by our male or female ancestors. Women are generally thought to possess sweeter voices than men, and as far as this serves as any guide, we may infer that they first acquired musical powers in order to attract the other sex. (41. See an interesting discussion on this subject by Haeckel, ‘Generelle Morphologie,’ B. ii. 1866, s. 246.) But if so, this must have occurred long ago, before our ancestors had become sufficiently human to treat and value their women merely as useful slaves. The impassioned orator, bard, or musician, when with his varied tones and cadences he excites the strongest emotions in his hearers, little suspects that he uses the same means by which his half-human ancestors long ago aroused each other’s ardent passions, during their courtship and rivalry.

The Influence of Beauty in Determining the Marriages of Mankind

In civilised life man is largely, but by no means exclusively, influenced in the choice of his wife by external appearance; but we are chiefly concerned with primeval times, and our only means of forming a judgment on this subject is to study the habits of existing semi-civilised and savage nations. If it can be shewn that the men of different races prefer women having various characteristics, or conversely with the women, we have then to enquire whether such choice, continued during many generations, would produce any sensible effect on the race, either on one sex or both according to the form of inheritance which has prevailed.

It will be well first to shew in some detail that savages pay the greatest attention to their personal appearance. (42. A full and excellent account of the manner in which savages in all parts of the world ornament themselves, is given by the Italian traveller, Professor Mantegazza, ‘Rio de la Plata, Viaggi e Studi,’ 1867, pp. 525-545; all the following statements, when other references are not given, are taken from this work. See, also, Waitz, ‘Introduction to Anthropology,’ Eng. translat. vol. i. 1863, p. 275, et passim. Lawrence also gives very full details in his ‘Lectures on Physiology,’ 1822. Since this chapter was written Sir J. Lubbock has published his ‘Origin of Civilisation,’ 1870, in which there is an interesting chapter on the present subject, and from which (pp. 42, 48) I have taken some facts about savages dyeing their teeth and hair, and piercing their teeth.) That they have a passion for ornament is notorious; and an English philosopher goes so far as to maintain, that clothes were first made for ornament and not for warmth. As Professor Waitz remarks, “however poor and miserable man is, he finds a pleasure in adorning himself.” The extravagance of the naked Indians of South America in decorating themselves is shewn “by a man of large stature gaining with difficulty enough by the labour of a fortnight to procure in exchange the chica necessary to paint himself red.” (43. Humboldt, ‘Personal Narrative,’ Eng. translat. vol. iv. p. 515; on the imagination shewn in painting the body, p. 522; on modifying the form of the calf of the leg, p. 466.) The ancient barbarians of Europe during the Reindeer period brought to their caves any brilliant or singular objects which they happened to find. Savages at the present day everywhere deck themselves with plumes, necklaces, armlets, ear-rings, etc. They paint themselves in the most diversified manner. “If painted nations,” as Humboldt observes, “had been examined with the same attention as clothed nations, it would have been perceived that the most fertile imagination and the most mutable caprice have created the fashions of painting, as well as those of garments.”

In one part of Africa the eyelids are coloured black; in another the nails are coloured yellow or purple. In many places the hair is dyed of various tints. In different countries the teeth are stained black, red, blue, etc., and in the Malay Archipelago it is thought shameful to have white teeth “like those of a dog.” Not one great country can be named, from the polar regions in the north to New Zealand in the south, in which the aborigines do not tattoo themselves. This practice was followed by the Jews of old, and by the ancient Britons. In Africa some of the natives tattoo themselves, but it is a much more common practice to raise protuberances by rubbing salt into incisions made in various parts of the body; and these are considered by the inhabitants of Kordofan and Darfur “to be great personal attractions.” In the Arab countries no beauty can be perfect until the cheeks “or temples have been gashed.” (44. ‘The Nile Tributaries,’ 1867; ‘The Albert N’yanza,’ 1866, vol. i. p. 218.) In South America, as Humboldt remarks, “a mother would be accused of culpable indifference towards her children, if she did not employ artificial means to shape the calf of the leg after the fashion of the country.” In the Old and New Worlds the shape of the skull was formerly modified during infancy in the most extraordinary manner, as is still the case in many places, and such deformities are considered ornamental. For instance, the savages of Colombia (45. Quoted by Prichard, ‘Physical History of Mankind,’ 4th ed. vol. i. 1851, p. 321.) deem a much flattened head “an essential point of beauty.”

The hair is treated with especial care in various countries; it is allowed to grow to full length, so as to reach to the ground, or is combed into “a compact frizzled mop, which is the Papuan’s pride and glory.” (46. On the Papuans, Wallace, ‘The Malay Archipelago,’ vol. ii. p. 445. On the coiffure of the Africans, Sir S. Baker, ‘The Albert N’yanza,’ vol. i. p. 210.) In northern Africa “a man requires a period of from eight to ten years to perfect his coiffure.” With other nations the head is shaved, and in parts of South America and Africa even the eyebrows and eyelashes are eradicated. The natives of the Upper Nile knock out the four front teeth, saying that they do not wish to resemble brutes. Further south, the Batokas knock out only the two upper incisors, which, as Livingstone (47. ‘Travels,’ p. 533.) remarks, gives the face a hideous appearance, owing to the prominence of the lower jaw; but these people think the presence of the incisors most unsightly, and on beholding some Europeans, cried out, “Look at the great teeth!” The chief Sebituani tried in vain to alter this fashion. In various parts of Africa and in the Malay Archipelago the natives file the incisors into points like those of a saw, or pierce them with holes, into which they insert studs.

As the face with us is chiefly admired for its beauty, so with savages it is the chief seat of mutilation. In all quarters of the world the septum, and more rarely the wings of the nose are pierced; rings, sticks, feathers, and other ornaments being inserted into the holes. The ears are everywhere pierced and similarly ornamented, and with the Botocudos and Lenguas of South America the hole is gradually so much enlarged that the lower edge touches the shoulder. In North and South America and in Africa either the upper or lower lip is pierced; and with the Botocudos the hole in the lower lip is so large that a disc of wood, four inches in diameter, is placed in it. Mantegazza gives a curious account of the shame felt by a South American native, and of the ridicule which he excited, when he sold his tembeta,—the large coloured piece of wood which is passed through the hole. In Central Africa the women perforate the lower lip and wear a crystal, which, from the movement of the tongue, has “a wriggling motion, indescribably ludicrous during conversation.” The wife of the chief of Latooka told Sir S. Baker (49. ‘The Albert N’yanza,’ 1866, vol. i. p. 217.) that Lady Baker “would be much improved if she would extract her four front teeth from the lower jaw, and wear the long pointed polished crystal in her under lip.” Further south with the Makalolo, the upper lip is perforated, and a large metal and bamboo ring, called a pelele, is worn in the hole. “This caused the lip in one case to project two inches beyond the tip of the nose; and when the lady smiled, the contraction of the muscles elevated it over the eyes. ‘Why do the women wear these things?’ the venerable chief, Chinsurdi, was asked. Evidently surprised at such a stupid question, he replied, ‘For beauty! They are the only beautiful things women have; men have beards, women have none. What kind of a person would she be without the pelele? She would not be a woman at all with a mouth like a man, but no beard.'” (49. Livingstone, ‘British Association,’ 1860; report given in the ‘Athenaeum,’ July 7, 1860, p. 29.)

Hardly any part of the body, which can be unnaturally modified, has escaped. The amount of suffering thus caused must have been extreme, for many of the operations require several years for their completion, so that the idea of their necessity must be imperative. The motives are various; the men paint their bodies to make themselves appear terrible in battle; certain mutilations are connected with religious rites, or they mark the age of puberty, or the rank of the man, or they serve to distinguish the tribes. Amongst savages the same fashions prevail for long periods (50. Sir S. Baker (ibid. vol. i. p. 210) speaking of the natives of Central Africa says, “every tribe has a distinct and unchanging fashion for dressing the hair.” See Agassiz (‘Journey in Brazil,’ 1868, p. 318) on invariability of the tattooing of Amazonian Indians.), and thus mutilations, from whatever cause first made, soon come to be valued as distinctive marks. But self-adornment, vanity, and the admiration of others, seem to be the commonest motives. In regard to tattooing, I was told by the missionaries in New Zealand that when they tried to persuade some girls to give up the practice, they answered, “We must just have a few lines on our lips; else when we grow old we shall be so very ugly.” With the men of New Zealand, a most capable judge (51. Rev. R. Taylor, ‘New Zealand and its Inhabitants,’ 1855, p. 152.) says, “to have fine tattooed faces was the great ambition of the young, both to render themselves attractive to the ladies, and conspicuous in war.” A star tattooed on the forehead and a spot on the chin are thought by the women in one part of Africa to be irresistible attractions. (52. Mantegazza, ‘Viaggi e Studi,’ p. 542.) In most, but not all parts of the world, the men are more ornamented than the women, and often in a different manner; sometimes, though rarely, the women are hardly at all ornamented. As the women are made by savages to perform the greatest share of the work, and as they are not allowed to eat the best kinds of food, so it accords with the characteristic selfishness of man that they should not be allowed to obtain, or use the finest ornaments. Lastly, it is a remarkable fact, as proved by the foregoing quotations, that the same fashions in modifying the shape of the head, in ornamenting the hair, in painting, tattooing, in perforating the nose, lips, or ears, in removing or filing the teeth, etc., now prevail, and have long prevailed, in the most distant quarters of the world. It is extremely improbable that these practices, followed by so many distinct nations, should be due to tradition from any common source. They indicate the close similarity of the mind of man, to whatever race he may belong, just as do the almost universal habits of dancing, masquerading, and making rude pictures.

Having made these preliminary remarks on the admiration felt by savages for various ornaments, and for deformities most unsightly in our eyes, let us see how far the men are attracted by the appearance of their women, and what are their ideas of beauty. I have heard it maintained that savages are quite indifferent about the beauty of their women, valuing them solely as slaves; it may therefore be well to observe that this conclusion does not at all agree with the care which the women take in ornamenting themselves, or with their vanity. Burchell (53. ‘Travels in South Africa,’ 1824, vol. i. p. 414.) gives an amusing account of a Bush-woman who used as much grease, red ochre, and shining powder “as would have ruined any but a very rich husband.” She displayed also “much vanity and too evident a consciousness of her superiority.” Mr. Winwood Reade informs me that the negroes of the West Coast often discuss the beauty of their women. Some competent observers have attributed the fearfully common practice of infanticide partly to the desire felt by the women to retain their good looks. (54. See, for references, Gerland, ‘Ueber das Aussterben der Naturvölker,’ 1868, ss. 51, 53, 55; also Azara, ‘Voyages,’ etc., tom. ii. p. 116.) In several regions the women wear charms and use love-philters to gain the affections of the men; and Mr. Brown enumerates four plants used for this purpose by the women of North-Western America. (55. On the vegetable productions used by the North-Western American Indians, see ‘Pharmaceutical Journal,’ vol. x.)

Hearne (56. ‘A Journey from Prince of Wales Fort,’ 8vo. ed. 1796, p. 89.), an excellent observer, who lived many years with the American Indians, says, in speaking of the women, “Ask a Northern Indian what is beauty, and he will answer, a broad flat face, small eyes, high cheek-bones, three or four broad black lines across each cheek, a low forehead, a large broad chin, a clumsy hook nose, a tawny hide, and breasts hanging down to the belt.” Pallas, who visited the northern parts of the Chinese empire, says, “those women are preferred who have the Mandschu form; that is to say, a broad face, high cheek-bones, very broad noses, and enormous ears”(57. Quoted by Prichard, ‘Physical History of Mankind,’ 3rd ed. vol. iv. 1844, p. 519; Vogt, ‘Lectures on Man,’ Eng. translat. p. 129. On the opinion of the Chinese on the Cingalese, E. Tennent, ‘Ceylon,’ 1859, vol. ii. p. 107.); and Vogt remarks that the obliquity of the eye, which is proper to the Chinese and Japanese, is exaggerated in their pictures for the purpose, as it “seems, of exhibiting its beauty, as contrasted with the eye of the red-haired barbarians.” It is well known, as Huc repeatedly remarks, that the Chinese of the interior think Europeans hideous, with their white skins and prominent noses. The nose is far from being too prominent, according to our ideas, in the natives of Ceylon; yet “the Chinese in the seventh century, accustomed to the flat features of the Mongol races, were surprised at the prominent noses of the Cingalese; and Thsang described them as having ‘the beak of a bird, with the body of a man.'”

Finlayson, after minutely describing the people of Cochin China, says that their rounded heads and faces are their chief characteristics; and, he adds, “the roundness of the whole countenance is more striking in the women, who are reckoned beautiful in proportion as they display this form of face.” The Siamese have small noses with divergent nostrils, a wide mouth, rather thick lips, a remarkably large face, with very high and broad cheek-bones. It is, therefore, not wonderful that “beauty, according to our notion, is a stranger to them. Yet they consider their own females to be much more beautiful than those of Europe.” (58. Prichard, as taken from Crawfurd and Finlayson, ‘Phys. Hist. of Mankind,’ vol. iv. pp. 534, 535.)

It is well known that with many Hottentot women the posterior part of the body projects in a wonderful manner; they are steatopygous; and Sir Andrew Smith is certain that this peculiarity is greatly admired by the men. (59. Idem illustrissimus viator dixit mihi praecinctorium vel tabulam foeminae, quod nobis teterrimum est, quondam permagno aestimari ab hominibus in hac gente. Nunc res mutata est, et censent talem conformationem minime optandam esse.) He once saw a woman who was considered a beauty, and she was so immensely developed behind, that when seated on level ground she could not rise, and had to push herself along until she came to a slope. Some of the women in various negro tribes have the same peculiarity; and, according to Burton, the Somal men are said to choose their wives by ranging them in a line, and by picking her out who projects farthest a tergo. Nothing can be more hateful to a negro than the opposite form.” (60. The ‘Anthropological Review,’ November 1864, p. 237. For additional references, see Waitz, ‘Introduction to Anthropology,’ Eng. translat., 1863, vol. i. p. 105.)

With respect to colour, the negroes rallied Mungo Park on the whiteness of his skin and the prominence of his nose, both of which they considered as “unsightly and unnatural conformations.” He in return praised the glossy jet of their skins and the lovely depression of their noses; this they said was “honeymouth,” nevertheless they gave him food. The African Moors, also, “knitted their brows and seemed to shudder” at the whiteness of his skin. On the eastern coast, the negro boys when they saw Burton, cried out, “Look at the white man; does he not look like a white ape?” On the western coast, as Mr. Winwood Reade informs me, the negroes admire a very black skin more than one of a lighter tint. But their horror of whiteness may be attributed, according to this same traveller, partly to the belief held by most negroes that demons and spirits are white, and partly to their thinking it a sign of ill-health.

The Banyai of the more southern part of the continent are negroes, but “a great many of them are of a light coffee-and-milk colour, and, indeed, this colour is considered handsome throughout the whole country”; so that here we have a different standard of taste. With the Kaffirs, who differ much from negroes, “the skin, except among the tribes near Delagoa Bay, is not usually black, the prevailing colour being a mixture of black and red, the most common shade being chocolate. Dark complexions, as being most common, are naturally held in the highest esteem. To be told that he is light- coloured, or like a white man, would be deemed a very poor compliment by a Kaffir. I have heard of one unfortunate man who was so very fair that no girl would marry him.” One of the titles of the Zulu king is, “You who are black.” (61. Mungo Park’s ‘Travels in Africa,’ 4to. 1816, pp. 53, 131. Burton’s statement is quoted by Schaaffhausen, ‘Archiv. fur Anthropologie,’ 1866, s. 163. On the Banyai, Livingstone, ‘Travels,’ p. 64. On the Kaffirs, the Rev. J. Shooter, ‘The Kafirs of Natal and the Zulu Country,’ 1857, p. 1.) Mr. Galton, in speaking to me about the natives of S. Africa, remarked that their ideas of beauty seem very different from ours; for in one tribe two slim, slight, and pretty girls were not admired by the natives.

Turning to other quarters of the world; in Java, a yellow, not a white girl, is considered, according to Madame Pfeiffer, a beauty. A man of Cochin China “spoke with contempt of the wife of the English Ambassador, that she had white teeth like a dog, and a rosy colour like that of potato- flowers.” We have seen that the Chinese dislike our white skin, and that the N. Americans admire “a tawny hide.” In S. America, the Yuracaras, who inhabit the wooded, damp slopes of the eastern Cordillera, are remarkably pale-coloured, as their name in their own language expresses; nevertheless they consider European women as very inferior to their own. (62. For the Javans and Cochin-Chinese, see Waitz, ‘Introduct. to Anthropology,’ Eng. translat. vol. i. p. 305. On the Yuracaras, A. d’Orbigny, as quoted in Prichard, ‘Physical History of Mankind,’ vol. v. 3rd ed. p. 476.)

In several of the tribes of North America the hair on the head grows to a wonderful length; and Catlin gives a curious proof how much this is esteemed, for the chief of the Crows was elected to this office from having the longest hair of any man in the tribe, namely ten feet and seven inches. The Aymaras and Quichuas of S. America, likewise have very long hair; and this, as Mr. D. Forbes informs me, is so much valued as a beauty, that cutting it off was the severest punishment which he could inflict on them. In both the Northern and Southern halves of the continent the natives sometimes increase the apparent length of their hair by weaving into it fibrous substances. Although the hair on the head is thus cherished, that on the face is considered by the North American Indians “as very vulgar,” and every hair is carefully eradicated. This practice prevails throughout the American continent from Vancouver’s Island in the north to Tierra del Fuego in the south. When York Minster, a Fuegian on board the “Beagle,” was taken back to his country, the natives told him be ought to pull out the few short hairs on his face. They also threatened a young missionary, who was left for a time with them, to strip him naked, and pluck the hair from his face and body, yet he was far from being a hairy man. This fashion is carried so far that the Indians of Paraguay eradicate their eyebrows and eyelashes, saying that they do not wish to be like horses. (63. ‘North American Indians,’ by G. Catlin, 3rd ed., 1842, vol. i. p. 49; vol. ii, p. 227. On the natives of Vancouver’s Island, see Sproat, ‘Scenes and Studies of Savage Life,’ 1868, p. 25. On the Indians of Paraguay, Azara, ‘Voyages,’ tom. ii. p. 105.)

It is remarkable that throughout the world the races which are almost completely destitute of a beard dislike hairs on the face and body, and take pains to eradicate them. The Kalmucks are beardless, and they are well known, like the Americans, to pluck out all straggling hairs; and so it is with the Polynesians, some of the Malays, and the Siamese. Mr. Veitch states that the Japanese ladies “all objected to our whiskers, considering them very ugly, and told us to cut them off, and be like Japanese men.” The New Zealanders have short, curled beards; yet they formerly plucked out the hairs on the face. They had a saying that “there is no woman for a hairy man;” but it would appear that the fashion has changed in New Zealand, perhaps owing to the presence of Europeans, and I am assured that beards are now admired by the Maories. (64. On the Siamese, Prichard, ibid. vol. iv. p. 533. On the Japanese, Veitch in ‘Gardeners’ Chronicle,’ 1860, p. 1104. On the New Zealanders, Mantegazza, ‘Viaggi e Studi,’ 1867, p. 526. For the other nations mentioned, see references in Lawrence, ‘Lectures on Physiology,’ etc., 1822, p. 272.)

On the other hand, bearded races admire and greatly value their beards; among the Anglo-Saxons every part of the body had a recognised value; “the loss of the beard being estimated at twenty shillings, while the breaking of a thigh was fixed at only twelve.” (65. Lubbock, ‘Origin of Civilisation,’ 1870, p. 321.) In the East men swear solemnly by their beards. We have seen that Chinsurdi, the chief of the Makalolo in Africa, thought that beards were a great ornament. In the Pacific the Fijian’s beard is “profuse and bushy, and is his greatest pride”; whilst the inhabitants of the adjacent archipelagoes of Tonga and Samoa are “beardless, and abhor a rough chin.” In one island alone of the Ellice group “the men are heavily bearded, and not a little proud thereof.” (66. Dr. Barnard Davis quotes Mr. Prichard and others for these facts in regard to the Polynesians, in ‘Anthropolog. Review,’ April 1870, pp. 185, 191.)

We thus see how widely the different races of man differ in their taste for the beautiful. In every nation sufficiently advanced to have made effigies of their gods or of their deified rulers, the sculptors no doubt have endeavoured to express their highest ideal of beauty and grandeur. (67. Ch. Comte has remarks to this effect in his ‘Traité de Législation,’ 3rd ed. 1837, p. 136.) Under this point of view it is well to compare in our mind the Jupiter or Apollo of the Greeks with the Egyptian or Assyrian statues; and these with the hideous bas-reliefs on the ruined buildings of Central America.

I have met with very few statements opposed to this conclusion. Mr. Winwood Reade, however, who has had ample opportunities for observation, not only with the negroes of the West Coast of Africa, but with those of the interior who have never associated with Europeans, is convinced that their ideas of beauty are ON THE WHOLE the same as ours; and Dr. Rohlfs writes to me to the same effect with respect to Bornu and the countries inhabited by the Pullo tribes. Mr. Reade found that he agreed with the negroes in their estimation of the beauty of the native girls; and that their appreciation of the beauty of European women corresponded with ours. They admire long hair, and use artificial means to make it appear abundant; they admire also a beard, though themselves very scantily provided. Mr. Reade feels doubtful what kind of nose is most appreciated; a girl has been heard to say, “I do not want to marry him, he has got no nose”; and this shews that a very flat nose is not admired. We should, however, bear in mind that the depressed, broad noses and projecting jaws of the negroes of the West Coast are exceptional types with the inhabitants of Africa. Notwithstanding the foregoing statements, Mr. Reade admits that negroes “do not like the colour of our skin; they look on blue eyes with aversion, and they think our noses too long and our lips too thin.” He does not think it probable that negroes would ever prefer the most beautiful European woman, on the mere grounds of physical admiration, to a good-looking negress. (68. The ‘African Sketch Book,’ vol. ii. 1873, pp. 253, 394, 521. The Fuegians, as I have been informed by a missionary who long resided with them, consider European women as extremely beautiful; but from what we have seen of the judgment of the other aborigines of America, I cannot but think that this must be a mistake, unless indeed the statement refers to the few Fuegians who have lived for some time with Europeans, and who must consider us as superior beings. I should add that a most experienced observer, Capt. Burton, believes that a woman whom we consider beautiful is admired throughout the world. ‘Anthropological Review,’ March, 1864, p. 245.)

The general truth of the principle, long ago insisted on by Humboldt (69. ‘Personal Narrative,’ Eng. translat. vol. iv. p. 518, and elsewhere. Mantegazza, in his ‘Viaggi e Studi,’ strongly insists on this same principle.), that man admires and often tries to exaggerate whatever characters nature may have given him, is shewn in many ways. The practice of beardless races extirpating every trace of a beard, and often all the hairs on the body affords one illustration. The skull has been greatly modified during ancient and modern times by many nations; and there can be little doubt that this has been practised, especially in N. and S. America, in order to exaggerate some natural and admired peculiarity. Many American Indians are known to admire a head so extremely flattened as to appear to us idiotic. The natives on the north-western coast compress the head into a pointed cone; and it is their constant practice to gather the hair into a knot on the top of the head, for the sake, as Dr. Wilson remarks, “of increasing the apparent elevation of the favourite conoid form.” The inhabitants of Arakhan admire a broad, smooth forehead, and in order to produce it, they fasten a plate of lead on the heads of the new-born children. On the other hand, “a broad, well-rounded occiput is considered a great beauty” by the natives of the Fiji Islands. (70. On the skulls of the American tribes, see Nott and Gliddon, ‘Types of Mankind,’ 1854, p. 440; Prichard, ‘Physical History of Mankind,’ vol. i. 3rd ed. p. 321; on the natives of Arakhan, ibid. vol. iv. p. 537. Wilson, ‘Physical Ethnology,’ Smithsonian Institution, 1863, p. 288; on the Fijians, p. 290. Sir J. Lubbock (‘Prehistoric Times,’ 2nd ed. 1869, p. 506) gives an excellent resume on this subject.)

As with the skull, so with the nose; the ancient Huns during the age of Attila were accustomed to flatten the noses of their infants with bandages, “for the sake of exaggerating a natural conformation.” With the Tahitians, to be called LONG-NOSE is considered as an insult, and they compress the noses and foreheads of their children for the sake of beauty. The same holds with the Malays of Sumatra, the Hottentots, certain Negroes, and the natives of Brazil. (71. On the Huns, Godron, ‘De l’Espèce,’ tom. ii. 1859, p. 300. On the Tahitians, Waitz, ‘Anthropology,’ Eng. translat. vol. i. p. 305. Marsden, quoted by Prichard, ‘Phys. Hist. of Mankind,’ 3rd edit. vol. v. p. 67. Lawrence, ‘Lectures on Physiology,’ p. 337.) The Chinese have by nature unusually small feet (72. This fact was ascertained in the ‘Reise der Novara: Anthropolog. Theil.’ Dr. Weisbach, 1867, s. 265.); and it is well known that the women of the upper classes distort their feet to make them still smaller. Lastly, Humboldt thinks that the American Indians prefer colouring their bodies with red paint in order to exaggerate their natural tint; and until recently European women added to their naturally bright colours by rouge and white cosmetics; but it may be doubted whether barbarous nations have generally had any such intention in painting themselves.

In the fashions of our own dress we see exactly the same principle and the same desire to carry every point to an extreme; we exhibit, also, the same spirit of emulation. But the fashions of savages are far more permanent than ours; and whenever their bodies are artificially modified, this is necessarily the case. The Arab women of the Upper Nile occupy about three days in dressing their hair; they never imitate other tribes, “but simply vie with each other in the superlativeness of their own style.” Dr. Wilson, in speaking of the compressed skulls of various American races, adds, “such usages are among the least eradicable, and long survive the shock of revolutions that change dynasties and efface more important national peculiarities.” (73. ‘Smithsonian Institution,’ 1863, p. 289. On the fashions of Arab women, Sir S. Baker, ‘The Nile Tributaries,’ 1867, p. 121.) The same principle comes into play in the art of breeding; and we can thus understand, as I have elsewhere explained (74. The ‘Variation of Animals and Plants under Domestication,’ vol. i. p. 214; vol. ii. p. 240.), the wonderful development of the many races of animals and plants, which have been kept merely for ornament. Fanciers always wish each character to be somewhat increased; they do not admire a medium standard; they certainly do not desire any great and abrupt change in the character of their breeds; they admire solely what they are accustomed to, but they ardently desire to see each characteristic feature a little more developed.

The senses of man and of the lower animals seem to be so constituted that brilliant colours and certain forms, as well as harmonious and rhythmical sounds, give pleasure and are called beautiful; but why this should be so we know not. It is certainly not true that there is in the mind of man any universal standard of beauty with respect to the human body. It is, however, possible that certain tastes may in the course of time become inherited, though there is no evidence in favour of this belief: and if so, each race would possess its own innate ideal standard of beauty. It has been argued (75. Schaaffhausen, ‘Archiv. für Anthropologie,’ 1866, s. 164.) that ugliness consists in an approach to the structure of the lower animals, and no doubt this is partly true with the more civilised nations, in which intellect is highly appreciated; but this explanation will hardly apply to all forms of ugliness. The men of each race prefer what they are accustomed to; they cannot endure any great change; but they like variety, and admire each characteristic carried to a moderate extreme. (76. Mr. Bain has collected (‘Mental and Moral Science,’ 1868, pp. 304-314) about a dozen more or less different theories of the idea of beauty; but none is quite the same as that here given.) Men accustomed to a nearly oval face, to straight and regular features, and to bright colours, admire, as we Europeans know, these points when strongly developed. On the other hand, men accustomed to a broad face, with high cheek-bones, a depressed nose, and a black skin, admire these peculiarities when strongly marked. No doubt characters of all kinds may be too much developed for beauty. Hence a perfect beauty, which implies many characters modified in a particular manner, will be in every race a prodigy. As the great anatomist Bichat long ago said, if every one were cast in the same mould, there would be no such thing as beauty. If all our women were to become as beautiful as the Venus de’ Medici, we should for a time be charmed; but we should soon wish for variety; and as soon as we had obtained variety, we should wish to see certain characters a little exaggerated beyond the then existing common standard.

第二十章 •9,800字
男人的第二性征——续

On the effects of the continued selection of women according to a different standard of beauty in each race—On the causes which interfere with sexual selection in civilised and savage nations—Conditions favourable to sexual selection during primeval times—On the manner of action of sexual selection with mankind—On the women in savage tribes having some power to choose their husbands—Absence of hair on the body, and development of the beard—Colour of the skin—Summary.

We have seen in the last chapter that with all barbarous races ornaments, dress, and external appearance are highly valued; and that the men judge of the beauty of their women by widely different standards. We must next inquire whether this preference and the consequent selection during many generations of those women, which appear to the men of each race the most attractive, has altered the character either of the females alone, or of both sexes. With mammals the general rule appears to be that characters of all kinds are inherited equally by the males and females; we might therefore expect that with mankind any characters gained by the females or by the males through sexual selection would commonly be transferred to the offspring of both sexes. If any change has thus been effected, it is almost certain that the different races would be differently modified, as each has its own standard of beauty.

With mankind, especially with savages, many causes interfere with the action of sexual selection as far as the bodily frame is concerned. Civilised men are largely attracted by the mental charms of women, by their wealth, and especially by their social position; for men rarely marry into a much lower rank. The men who succeed in obtaining the more beautiful women will not have a better chance of leaving a long line of descendants than other men with plainer wives, save the few who bequeath their fortunes according to primogeniture. With respect to the opposite form of selection, namely, of the more attractive men by the women, although in civilised nations women have free or almost free choice, which is not the case with barbarous races, yet their choice is largely influenced by the social position and wealth of the men; and the success of the latter in life depends much on their intellectual powers and energy, or on the fruits of these same powers in their forefathers. No excuse is needed for treating this subject in some detail; for, as the German philosopher Schopenhauer remarks, “the final aim of all love intrigues, be they comic or tragic, is really of more importance than all other ends in human life. What it all turns upon is nothing less than the composition of the next generation…It is not the weal or woe of any one individual, but that of the human race to come, which is here at stake.” (1. ‘Schopenhauer and Darwinism,’ in ‘Journal of Anthropology,’ Jan. 1871, p. 323.

There is, however, reason to believe that in certain civilised and semi- civilised nations sexual selection has effected something in modifying the bodily frame of some of the members. Many persons are convinced, as it appears to me with justice, that our aristocracy, including under this term all wealthy families in which primogeniture has long prevailed, from having chosen during many generations from all classes the more beautiful women as their wives, have become handsomer, according to the European standard, than the middle classes; yet the middle classes are placed under equally favourable conditions of life for the perfect development of the body. Cook remarks that the superiority in personal appearance “which is observable in the erees or nobles in all the other islands (of the Pacific) is found in the Sandwich Islands”; but this may be chiefly due to their better food and manner of life.

The old traveller Chardin, in describing the Persians, says their “blood is now highly refined by frequent intermixtures with the Georgians and Circassians, two nations which surpass all the world in personal beauty. There is hardly a man of rank in Persia who is not born of a Georgian or Circassian mother.” He adds that they inherit their beauty, “not from their ancestors, for without the above mixture, the men of rank in Persia, who are descendants of the Tartars, would be extremely ugly.” (2. These quotations are taken from Lawrence (‘Lectures on Physiology,’ etc., 1822, p. 393), who attributes the beauty of the upper classes in England to the men having long selected the more beautiful women.) Here is a more curious case; the priestesses who attended the temple of Venus Erycina at San- Giuliano in Sicily, were selected for their beauty out of the whole of Greece; they were not vestal virgins, and Quatrefages (3. ‘Anthropologie,’ ‘Revue des Cours Scientifiques,’ Oct. 1868, p. 721.), who states the foregoing fact, says that the women of San-Giuliano are now famous as the most beautiful in the island, and are sought by artists as models. But it is obvious that the evidence in all the above cases is doubtful.

The following case, though relating to savages, is well worth giving for its curiosity. Mr. Winwood Reade informs me that the Jollofs, a tribe of negroes on the west coast of Africa, “are remarkable for their uniformly fine appearance.” A friend of his asked one of these men, “How is it that every one whom I meet is so fine looking, not only your men but your women?” The Jollof answered, “It is very easily explained: it has always been our custom to pick out our worst-looking slaves and to sell them.” It need hardly be added that with all savages, female slaves serve as concubines. That this negro should have attributed, whether rightly or wrongly, the fine appearance of his tribe to the long-continued elimination of the ugly women is not so surprising as it may at first appear; for I have elsewhere shewn (4. ‘Variation of Animals and Plants under Domestication,’ vol. i. p. 207.) that negroes fully appreciate the importance of selection in the breeding of their domestic animals, and I could give from Mr. Reade additional evidence on this head.

The Causes Which Prevent or Check the Action of Sexual Selection with Savages

The chief causes are, first, so-called communal marriages or promiscuous intercourse; secondly, the consequences of female infanticide; thirdly, early betrothals; and lastly, the low estimation in which women are held, as mere slaves. These four points must be considered in some detail.

It is obvious that as long as the pairing of man, or of any other animal, is left to mere chance, with no choice exerted by either sex, there can be no sexual selection; and no effect will be produced on the offspring by certain individuals having had an advantage over others in their courtship. Now it is asserted that there exist at the present day tribes which practise what Sir J. Lubbock by courtesy calls communal marriages; that is, all the men and women in the tribe are husbands and wives to one another. The licentiousness of many savages is no doubt astonishing, but it seems to me that more evidence is requisite, before we fully admit that their intercourse is in any case promiscuous. Nevertheless all those who have most closely studied the subject (5. Sir J. Lubbock, ‘The Origin of Civilisation,’ 1870, chap. iii. especially pp. 60-67. Mr. M’Lennan, in his extremely valuable work on ‘Primitive Marriage,’ 1865, p. 163, speaks of the union of the sexes “in the earliest times as loose, transitory, and in some degree promiscuous.” Mr. M’Lennan and Sir J. Lubbock have collected much evidence on the extreme licentiousness of savages at the present time. Mr. L.H. Morgan, in his interesting memoir of the classificatory system of relationship. (‘Proceedings of the American Academy of Sciences,’ vol. vii. Feb. 1868, p. 475), concludes that polygamy and all forms of marriage during primeval times were essentially unknown. It appears also, from Sir J. Lubbock’s work, that Bachofen likewise believes that communal intercourse originally prevailed.), and whose judgment is worth much more than mine, believe that communal marriage (this expression being variously guarded) was the original and universal form throughout the world, including therein the intermarriage of brothers and sisters. The late Sir A. Smith, who had travelled widely in S. Africa, and knew much about the habits of savages there and elsewhere, expressed to me the strongest opinion that no race exists in which woman is considered as the property of the community. I believe that his judgment was largely determined by what is implied by the term marriage. Throughout the following discussion I use the term in the same sense as when naturalists speak of animals as monogamous, meaning thereby that the male is accepted by or chooses a single female, and lives with her either during the breeding-season or for the whole year, keeping possession of her by the law of might; or, as when they speak of a polygamous species, meaning that the male lives with several females. This kind of marriage is all that concerns us here, as it suffices for the work of sexual selection. But I know that some of the writers above referred to imply by the term marriage a recognised right protected by the tribe.

The indirect evidence in favour of the belief of the former prevalence of communal marriages is strong, and rests chiefly on the terms of relationship which are employed between the members of the same tribe, implying a connection with the tribe, and not with either parent. But the subject is too large and complex for even an abstract to be here given, and I will confine myself to a few remarks. It is evident in the case of such marriages, or where the marriage tie is very loose, that the relationship of the child to its father cannot be known. But it seems almost incredible that the relationship of the child to its mother should ever be completely ignored, especially as the women in most savage tribes nurse their infants for a long time. Accordingly, in many cases the lines of descent are traced through the mother alone, to the exclusion of the father. But in other cases the terms employed express a connection with the tribe alone, to the exclusion even of the mother. It seems possible that the connection between the related members of the same barbarous tribe, exposed to all sorts of danger, might be so much more important, owing to the need of mutual protection and aid, than that between the mother and her child, as to lead to the sole use of terms expressive of the former relationships; but Mr. Morgan is convinced that this view is by no means sufficient.

The terms of relationship used in different parts of the world may be divided, according to the author just quoted, into two great classes, the classificatory and descriptive, the latter being employed by us. It is the classificatory system which so strongly leads to the belief that communal and other extremely loose forms of marriage were originally universal. But as far as I can see, there is no necessity on this ground for believing in absolutely promiscuous intercourse; and I am glad to find that this is Sir J. Lubbock’s view. Men and women, like many of the lower animals, might formerly have entered into strict though temporary unions for each birth, and in this case nearly as much confusion would have arisen in the terms of relationship as in the case of promiscuous intercourse. As far as sexual selection is concerned, all that is required is that choice should be exerted before the parents unite, and it signifies little whether the unions last for life or only for a season.

Besides the evidence derived from the terms of relationship, other lines of reasoning indicate the former wide prevalence of communal marriage. Sir J. Lubbock accounts for the strange and widely-extended habit of exogamy—that is, the men of one tribe taking wives from a distinct tribe,—by communism having been the original form of intercourse; so that a man never obtained a wife for himself unless he captured her from a neighbouring and hostile tribe, and then she would naturally have become his sole and valuable property. Thus the practice of capturing wives might have arisen; and from the honour so gained it might ultimately have become the universal habit. According to Sir J. Lubbock (6. ‘Address to British Association On the Social and Religious Condition of the Lower Races of Man,’ 1870, p. 20.), we can also thus understand “the necessity of expiation for marriage as an infringement of tribal rites, since according to old ideas, a man had no right to appropriate to himself that which belonged to the whole tribe.” Sir J. Lubbock further gives a curious body of facts shewing that in old times high honour was bestowed on women who were utterly licentious; and this, as he explains, is intelligible, if we admit that promiscuous intercourse was the aboriginal, and therefore long revered custom of the tribe. (7. ‘Origin of Civilisation,’ 1870, p. 86. In the several works above quoted, there will be found copious evidence on relationship through the females alone, or with the tribe alone.)

Although the manner of development of the marriage tie is an obscure subject, as we may infer from the divergent opinions on several points between the three authors who have studied it most closely, namely, Mr. Morgan, Mr. M’Lennan, and Sir J. Lubbock, yet from the foregoing and several other lines of evidence it seems probable (8. Mr. C. Staniland Wake argues strongly (‘Anthropologia,’ March, 1874, p. 197) against the views held by these three writers on the former prevalence of almost promiscuous intercourse; and he thinks that the classificatory system of relationship can be otherwise explained.) that the habit of marriage, in any strict sense of the word, has been gradually developed; and that almost promiscuous or very loose intercourse was once extremely common throughout the world. Nevertheless, from the strength of the feeling of jealousy all through the animal kingdom, as well as from the analogy of the lower animals, more particularly of those which come nearest to man, I cannot believe that absolutely promiscuous intercourse prevailed in times past, shortly before man attained to his present rank in the zoological scale. Man, as I have attempted to shew, is certainly descended from some ape-like creature. With the existing Quadrumana, as far as their habits are known, the males of some species are monogamous, but live during only a part of the year with the females: of this the orang seems to afford an instance. Several kinds, for example some of the Indian and American monkeys, are strictly monogamous, and associate all the year round with their wives. Others are polygamous, for example the gorilla and several American species, and each family lives separate. Even when this occurs, the families inhabiting the same district are probably somewhat social; the chimpanzee, for instance, is occasionally met with in large bands. Again, other species are polygamous, but several males, each with his own females, live associated in a body, as with several species of baboons. (9. Brehm (‘Thierleben,’ B. i. p. 77) says Cynocephalus hamadryas lives in great troops containing twice as many adult females as adult males. See Rengger on American polygamous species, and Owen (‘Anatomy of Vertebrates,’ vol. iii. p. 746) on American monogamous species. Other references might be added.) We may indeed conclude from what we know of the jealousy of all male quadrupeds, armed, as many of them are, with special weapons for battling with their rivals, that promiscuous intercourse in a state of nature is extremely improbable. The pairing may not last for life, but only for each birth; yet if the males which are the strongest and best able to defend or otherwise assist their females and young, were to select the more attractive females, this would suffice for sexual selection.

Therefore, looking far enough back in the stream of time, and judging from the social habits of man as he now exists, the most probable view is that he aboriginally lived in small communities, each with a single wife, or if powerful with several, whom he jealously guarded against all other men. Or he may not have been a social animal, and yet have lived with several wives, like the gorilla; for all the natives “agree that but one adult male is seen in a band; when the young male grows up, a contest takes place for mastery, and the strongest, by killing and driving out the others, establishes himself as the head of the community.” (10. Dr. Savage, in ‘Boston Journal of Natural History,’ vol. v. 1845-47, p. 423.) The younger males, being thus expelled and wandering about, would, when at last successful in finding a partner, prevent too close interbreeding within the limits of the same family.

Although savages are now extremely licentious, and although communal marriages may formerly have largely prevailed, yet many tribes practise some form of marriage, but of a far more lax nature than that of civilised nations. Polygamy, as just stated, is almost universally followed by the leading men in every tribe. Nevertheless there are tribes, standing almost at the bottom of the scale, which are strictly monogamous. This is the case with the Veddahs of Ceylon: they have a saying, according to Sir J. Lubbock (11. ‘Prehistoric Times,’ 1869, p. 424.), “that death alone can separate husband and wife.” An intelligent Kandyan chief, of course a polygamist, “was perfectly scandalised at the utter barbarism of living with only one wife, and never parting until separated by death.” It was, he said, “just like the Wanderoo monkeys.” Whether savages who now enter into some form of marriage, either polygamous or monogamous, have retained this habit from primeval times, or whether they have returned to some form of marriage, after passing through a stage of promiscuous intercourse, I will not pretend to conjecture.

杀婴

This practice is now very common throughout the world, and there is reason to believe that it prevailed much more extensively during former times. (12. Mr. M’Lennan, ‘Primitive Marriage,’ 1865. See especially on exogamy and infanticide, pp. 130, 138, 165.) Barbarians find it difficult to support themselves and their children, and it is a simple plan to kill their infants. In South America some tribes, according to Azara, formerly destroyed so many infants of both sexes that they were on the point of extinction. In the Polynesian Islands women have been known to kill from four or five, to even ten of their children; and Ellis could not find a single woman who had not killed at least one. In a village on the eastern frontier of India Colonel MacCulloch found not a single female child. Wherever infanticide (13. Dr. Gerland (‘Ueber das Aussterben der Naturvölker,’ 1868) has collected much information on infanticide, see especially ss. 27, 51, 54. Azara (‘Voyages,’ etc., tom. ii. pp. 94, 116) enters in detail on the motives. See also M’Lennan (ibid. p. 139) for cases in India. In the former reprints of the 2nd edition of this book an incorrect quotation from Sir G. Grey was unfortunately given in the above passage and has now been removed from the text.) prevails the struggle for existence will be in so far less severe, and all the members of the tribe will have an almost equally good chance of rearing their few surviving children. In most cases a larger number of female than of male infants are destroyed, for it is obvious that the latter are of more value to the tribe, as they will, when grown up, aid in defending it, and can support themselves. But the trouble experienced by the women in rearing children, their consequent loss of beauty, the higher estimation set on them when few, and their happier fate, are assigned by the women themselves, and by various observers, as additional motives for infanticide.

When, owing to female infanticide, the women of a tribe were few, the habit of capturing wives from neighbouring tribes would naturally arise. Sir J. Lubbock, however, as we have seen, attributes the practice in chief part to the former existence of communal marriage, and to the men having consequently captured women from other tribes to hold as their sole property. Additional causes might be assigned, such as the communities being very small, in which case, marriageable women would often be deficient. That the habit was most extensively practised during former times, even by the ancestors of civilised nations, is clearly shewn by the preservation of many curious customs and ceremonies, of which Mr. M’Lennan has given an interesting account. In our own marriages the “best man” seems originally to have been the chief abettor of the bridegroom in the act of capture. Now as long as men habitually procured their wives through violence and craft, they would have been glad to seize on any woman, and would not have selected the more attractive ones. But as soon as the practice of procuring wives from a distinct tribe was effected through barter, as now occurs in many places, the more attractive women would generally have been purchased. The incessant crossing, however, between tribe and tribe, which necessarily follows from any form of this habit, would tend to keep all the people inhabiting the same country nearly uniform in character; and this would interfere with the power of sexual selection in differentiating the tribes.

The scarcity of women, consequent on female infanticide, leads, also, to another practice, that of polyandry, still common in several parts of the world, and which formerly, as Mr. M’Lennan believes, prevailed almost universally: but this latter conclusion is doubted by Mr. Morgan and Sir J. Lubbock. (14. ‘Primitive Marriage,’ p. 208; Sir J. Lubbock, ‘Origin of Civilisation,’ p. 100. See also Mr. Morgan, loc. cit., on the former prevalence of polyandry.) Whenever two or more men are compelled to marry one woman, it is certain that all the women of the tribe will get married, and there will be no selection by the men of the more attractive women. But under these circumstances the women no doubt will have the power of choice, and will prefer the more attractive men. Azara, for instance, describes how carefully a Guana woman bargains for all sorts of privileges, before accepting some one or more husbands; and the men in consequence take unusual care of their personal appearance. So amongst the Todas of India, who practise polyandry, the girls can accept or refuse any man. (15. Azara, ‘Voyages,’ etc., tom. ii. pp. 92-95; Colonel Marshall, ‘Amongst the Todas,’ p. 212.) A very ugly man in these cases would perhaps altogether fail in getting a wife, or get one later in life; but the handsomer men, although more successful in obtaining wives, would not, as far as we can see, leave more offspring to inherit their beauty than the less handsome husbands of the same women.

Early Betrothals and Slavery of Women

With many savages it is the custom to betroth the females whilst mere infants; and this would effectually prevent preference being exerted on either side according to personal appearance. But it would not prevent the more attractive women from being afterwards stolen or taken by force from their husbands by the more powerful men; and this often happens in Australia, America, and elsewhere. The same consequences with reference to sexual selection would to a certain extent follow, when women are valued almost solely as slaves or beasts of burden, as is the case with many savages. The men, however, at all times would prefer the handsomest slaves according to their standard of beauty.

We thus see that several customs prevail with savages which must greatly interfere with, or completely stop, the action of sexual selection. On the other hand, the conditions of life to which savages are exposed, and some of their habits, are favourable to natural selection; and this comes into play at the same time with sexual selection. Savages are known to suffer severely from recurrent famines; they do not increase their food by artificial means; they rarely refrain from marriage (16. Burchell says (‘Travels in S. Africa,’ vol. ii. 1824, p. 58), that among the wild nations of Southern Africa, neither men nor women ever pass their lives in a state of celibacy. Azara (‘Voyages dans l’Amérique Merid.’ tom. ii. 1809, p. 21) makes precisely the same remark in regard to the wild Indians of South America.), and generally marry whilst young. Consequently they must be subjected to occasional hard struggles for existence, and the favoured individuals will alone survive.

At a very early period, before man attained to his present rank in the scale, many of his conditions would be different from what now obtains amongst savages. Judging from the analogy of the lower animals, he would then either live with a single female, or be a polygamist. The most powerful and able males would succeed best in obtaining attractive females. They would also succeed best in the general struggle for life, and in defending their females, as well as their offspring, from enemies of all kinds. At this early period the ancestors of man would not be sufficiently advanced in intellect to look forward to distant contingencies; they would not foresee that the rearing of all their children, especially their female children, would make the struggle for life severer for the tribe. They would be governed more by their instincts and less by their reason than are savages at the present day. They would not at that period have partially lost one of the strongest of all instincts, common to all the lower animals, namely the love of their young offspring; and consequently they would not have practised female infanticide. Women would not have been thus rendered scarce, and polyandry would not have been practised; for hardly any other cause, except the scarcity of women seems sufficient to break down the natural and widely prevalent feeling of jealousy, and the desire of each male to possess a female for himself. Polyandry would be a natural stepping-stone to communal marriages or almost promiscuous intercourse; though the best authorities believe that this latter habit preceded polyandry. During primordial times there would be no early betrothals, for this implies foresight. Nor would women be valued merely as useful slaves or beasts of burthen. Both sexes, if the females as well as the males were permitted to exert any choice, would choose their partners not for mental charms, or property, or social position, but almost solely from external appearance. All the adults would marry or pair, and all the offspring, as far as that was possible, would be reared; so that the struggle for existence would be periodically excessively severe. Thus during these times all the conditions for sexual selection would have been more favourable than at a later period, when man had advanced in his intellectual powers but had retrograded in his instincts. Therefore, whatever influence sexual selection may have had in producing the differences between the races of man, and between man and the higher Quadrumana, this influence would have been more powerful at a remote period than at the present day, though probably not yet wholly lost.

The Manner of Action of Sexual Selection with Mankind

With primeval man under the favourable conditions just stated, and with those savages who at the present time enter into any marriage tie, sexual selection has probably acted in the following manner, subject to greater or less interference from female infanticide, early betrothals, etc. The strongest and most vigorous men—those who could best defend and hunt for their families, who were provided with the best weapons and possessed the most property, such as a large number of dogs or other animals,—would succeed in rearing a greater average number of offspring than the weaker and poorer members of the same tribes. There can, also, be no doubt that such men would generally be able to select the more attractive women. At present the chiefs of nearly every tribe throughout the world succeed in obtaining more than one wife. I hear from Mr. Mantell that, until recently, almost every girl in New Zealand who was pretty, or promised to be pretty, was tapu to some chief. With the Kafirs, as Mr. C. Hamilton states (17. ‘Anthropological Review,’ Jan. 1870, p. xvi.), “the chiefs generally have the pick of the women for many miles round, and are most persevering in establishing or confirming their privilege.” We have seen that each race has its own style of beauty, and we know that it is natural to man to admire each characteristic point in his domestic animals, dress, ornaments, and personal appearance, when carried a little beyond the average. If then the several foregoing propositions be admitted, and I cannot see that they are doubtful, it would be an inexplicable circumstance if the selection of the more attractive women by the more powerful men of each tribe, who would rear on an average a greater number of children, did not after the lapse of many generations somewhat modify the character of the tribe.

When a foreign breed of our domestic animals is introduced into a new country, or when a native breed is long and carefully attended to, either for use or ornament, it is found after several generations to have undergone a greater or less amount of change whenever the means of comparison exist. This follows from unconscious selection during a long series of generations—that is, the preservation of the most approved individuals—without any wish or expectation of such a result on the part of the breeder. So again, if during many years two careful breeders rear animals of the same family, and do not compare them together or with a common standard, the animals are found to have become, to the surprise of their owners, slightly different. (18. The ‘Variation of Animals and Plants under Domestication,’ vol. ii. pp. 210-217.) Each breeder has impressed, as von Nathusius well expresses it, the character of his own mind—his own taste and judgment—on his animals. What reason, then, can be assigned why similar results should not follow from the long-continued selection of the most admired women by those men of each tribe who were able to rear the greatest number of children? This would be unconscious selection, for an effect would be produced, independently of any wish or expectation on the part of the men who preferred certain women to others.

Let us suppose the members of a tribe, practising some form of marriage, to spread over an unoccupied continent, they would soon split up into distinct hordes, separated from each other by various barriers, and still more effectually by the incessant wars between all barbarous nations. The hordes would thus be exposed to slightly different conditions and habits of life, and would sooner or later come to differ in some small degree. As soon as this occurred, each isolated tribe would form for itself a slightly different standard of beauty (19. An ingenious writer argues, from a comparison of the pictures of Raphael, Rubens, and modern French artists, that the idea of beauty is not absolutely the same even throughout Europe: see the ‘Lives of Haydn and Mozart,’ by Bombet (otherwise M. Beyle), English translation, p. 278.); and then unconscious selection would come into action through the more powerful and leading men preferring certain women to others. Thus the differences between the tribes, at first very slight, would gradually and inevitably be more or less increased.

With animals in a state of nature, many characters proper to the males, such as size, strength, special weapons, courage and pugnacity, have been acquired through the law of battle. The semi-human progenitors of man, like their allies the Quadrumana, will almost certainly have been thus modified; and, as savages still fight for the possession of their women, a similar process of selection has probably gone on in a greater or less degree to the present day. Other characters proper to the males of the lower animals, such as bright colours and various ornaments, have been acquired by the more attractive males having been preferred by the females. There are, however, exceptional cases in which the males are the selectors, instead of having been the selected. We recognise such cases by the females being more highly ornamented than the males,—their ornamental characters having been transmitted exclusively or chiefly to their female offspring. One such case has been described in the order to which man belongs, that of the Rhesus monkey.

Man is more powerful in body and mind than woman, and in the savage state he keeps her in a far more abject state of bondage than does the male of any other animal; therefore it is not surprising that he should have gained the power of selection. Women are everywhere conscious of the value of their own beauty; and when they have the means, they take more delight in decorating themselves with all sorts of ornaments than do men. They borrow the plumes of male birds, with which nature has decked this sex, in order to charm the females. As women have long been selected for beauty, it is not surprising that some of their successive variations should have been transmitted exclusively to the same sex; consequently that they should have transmitted beauty in a somewhat higher degree to their female than to their male offspring, and thus have become more beautiful, according to general opinion, than men. Women, however, certainly transmit most of their characters, including some beauty, to their offspring of both sexes; so that the continued preference by the men of each race for the more attractive women, according to their standard of taste, will have tended to modify in the same manner all the individuals of both sexes belonging to the race.

With respect to the other form of sexual selection (which with the lower animals is much the more common), namely, when the females are the selectors, and accept only those males which excite or charm them most, we have reason to believe that it formerly acted on our progenitors. Man in all probability owes his beard, and perhaps some other characters, to inheritance from an ancient progenitor who thus gained his ornaments. But this form of selection may have occasionally acted during later times; for in utterly barbarous tribes the women have more power in choosing, rejecting, and tempting their lovers, or of afterwards changing their husbands, than might have been expected. As this is a point of some importance, I will give in detail such evidence as I have been able to collect.

Hearne describes how a woman in one of the tribes of Arctic America repeatedly ran away from her husband and joined her lover; and with the Charruas of S. America, according to Azara, divorce is quite optional. Amongst the Abipones, a man on choosing a wife bargains with the parents about the price. But “it frequently happens that the girl rescinds what has been agreed upon between the parents and the bridegroom, obstinately rejecting the very mention of marriage.” She often runs away, hides herself, and thus eludes the bridegroom. Captain Musters who lived with the Patagonians, says that their marriages are always settled by inclination; “if the parents make a match contrary to the daughter’s will, she refuses and is never compelled to comply.” In Tierra del Fuego a young man first obtains the consent of the parents by doing them some service, and then he attempts to carry off the girl; “but if she is unwilling, she hides herself in the woods until her admirer is heartily tired of looking for her, and gives up the pursuit; but this seldom happens.” In the Fiji Islands the man seizes on the woman whom he wishes for his wife by actual or pretended force; but “on reaching the home of her abductor, should she not approve of the match, she runs to some one who can protect her; if, however, she is satisfied, the matter is settled forthwith.” With the Kalmucks there is a regular race between the bride and bridegroom, the former having a fair start; and Clarke “was assured that no instance occurs of a girl being caught, unless she has a partiality to the pursuer.” Amongst the wild tribes of the Malay Archipelago there is also a racing match; and it appears from M. Bourien’s account, as Sir J. Lubbock remarks, that “the race, ‘is not to the swift, nor the battle to the strong,’ but to the young man who has the good fortune to please his intended bride.” A similar custom, with the same result, prevails with the Koraks of North- Eastern Asia.

Turning to Africa: the Kafirs buy their wives, and girls are severely beaten by their fathers if they will not accept a chosen husband; but it is manifest from many facts given by the Rev. Mr. Shooter, that they have considerable power of choice. Thus very ugly, though rich men, have been known to fail in getting wives. The girls, before consenting to be betrothed, compel the men to shew themselves off first in front and then behind, and “exhibit their paces.” They have been known to propose to a man, and they not rarely run away with a favoured lover. So again, Mr. Leslie, who was intimately acquainted with the Kafirs, says, “it is a mistake to imagine that a girl is sold by her father in the same manner, and with the same authority, with which he would dispose of a cow.” Amongst the degraded Bushmen of S. Africa, “when a girl has grown up to womanhood without having been betrothed, which, however, does not often happen, her lover must gain her approbation, as well as that of the parents.” (20. Azara, ‘Voyages,’ etc., tom. ii. p. 23. Dobrizhoffer, ‘An Account of the Abipones,’ vol. ii. 1822, p. 207. Capt. Musters, in ‘Proc. R. Geograph. Soc.’ vol. xv. p. 47. Williams on the Fiji Islanders, as quoted by Lubbock, ‘Origin of Civilisation,’ 1870, p. 79. On the Fuegians, King and Fitzroy, ‘Voyages of the “Adventure” and “Beagle,”‘ vol. ii. 1839, p. 182. On the Kalmucks, quoted by M’Lennan, ‘Primitive Marriage,’ 1865, p. 32. On the Malays, Lubbock, ibid. p. 76. The Rev. J. Shooter, ‘On the Kafirs of Natal,’ 1857, pp. 52-60. Mr. D. Leslie, ‘Kafir Character and Customs,’ 1871, p. 4. On the Bush-men, Burchell, ‘Travels in S. Africa,’ ii. 1824, p. 59. On the Koraks by McKennan, as quoted by Mr. Wake, in ‘Anthropologia,’ Oct. 1873, p. 75.) Mr. Winwood Reade made inquiries for me with respect to the negroes of Western Africa, and he informs me that “the women, at least among the more intelligent Pagan tribes, have no difficulty in getting the husbands whom they may desire, although it is considered unwomanly to ask a man to marry them. They are quite capable of falling in love, and of forming tender, passionate, and faithful attachments.” Additional cases could be given.

We thus see that with savages the women are not in quite so abject a state in relation to marriage as has often been supposed. They can tempt the men whom they prefer, and can sometimes reject those whom they dislike, either before or after marriage. Preference on the part of the women, steadily acting in any one direction, would ultimately affect the character of the tribe; for the women would generally choose not merely the handsomest men, according to their standard of taste, but those who were at the same time best able to defend and support them. Such well-endowed pairs would commonly rear a larger number of offspring than the less favoured. The same result would obviously follow in a still more marked manner if there was selection on both sides; that is, if the more attractive, and at the same time more powerful men were to prefer, and were preferred by, the more attractive women. And this double form of selection seems actually to have occurred, especially during the earlier periods of our long history.

We will now examine a little more closely some of the characters which distinguish the several races of man from one another and from the lower animals, namely, the greater or less deficiency of hair on the body, and the colour of the skin. We need say nothing about the great diversity in the shape of the features and of the skull between the different races, as we have seen in the last chapter how different is the standard of beauty in these respects. These characters will therefore probably have been acted on through sexual selection; but we have no means of judging whether they have been acted on chiefly from the male or female side. The musical faculties of man have likewise been already discussed.

Absence of Hair on the Body, And Its Development on the Face and Head

From the presence of the woolly hair or lanugo on the human foetus, and of rudimentary hairs scattered over the body during maturity, we may infer that man is descended from some animal which was born hairy and remained so during life. The loss of hair is an inconvenience and probably an injury to man, even in a hot climate, for he is thus exposed to the scorching of the sun, and to sudden chills, especially during wet weather. As Mr. Wallace remarks, the natives in all countries are glad to protect their naked backs and shoulders with some slight covering. No one supposes that the nakedness of the skin is any direct advantage to man; his body therefore cannot have been divested of hair through natural selection. (21. ‘Contributions to the Theory of Natural Selection,’ 1870, p. 346. Mr. Wallace believes (p. 350) “that some intelligent power has guided or determined the development of man”; and he considers the hairless condition of the skin as coming under this head. The Rev. T.R. Stebbing, in commenting on this view (‘Transactions of Devonshire Association for Science,’ 1870) remarks, that had Mr. Wallace “employed his usual ingenuity on the question of man’s hairless skin, he might have seen the possibility of its selection through its superior beauty or the health attaching to superior cleanliness.”) Nor, as shewn in a former chapter, have we any evidence that this can be due to the direct action of climate, or that it is the result of correlated development.

The absence of hair on the body is to a certain extent a secondary sexual character; for in all parts of the world women are less hairy than men. Therefore we may reasonably suspect that this character has been gained through sexual selection. We know that the faces of several species of monkeys, and large surfaces at the posterior end of the body of other species, have been denuded of hair; and this we may safely attribute to sexual selection, for these surfaces are not only vividly coloured, but sometimes, as with the male mandrill and female rhesus, much more vividly in the one sex than in the other, especially during the breeding-season. I am informed by Mr. Bartlett that, as these animals gradually reach maturity, the naked surfaces grow larger compared with the size of their bodies. The hair, however, appears to have been removed, not for the sake of nudity, but that the colour of the skin may be more fully displayed. So again with many birds, it appears as if the head and neck had been divested of feathers through sexual selection, to exhibit the brightly-coloured skin.

As the body in woman is less hairy than in man, and as this character is common to all races, we may conclude that it was our female semi-human ancestors who were first divested of hair, and that this occurred at an extremely remote period before the several races had diverged from a common stock. Whilst our female ancestors were gradually acquiring this new character of nudity, they must have transmitted it almost equally to their offspring of both sexes whilst young; so that its transmission, as with the ornaments of many mammals and birds, has not been limited either by sex or age. There is nothing surprising in a partial loss of hair having been esteemed as an ornament by our ape-like progenitors, for we have seen that innumerable strange characters have been thus esteemed by animals of all kinds, and have consequently been gained through sexual selection. Nor is it surprising that a slightly injurious character should have been thus acquired; for we know that this is the case with the plumes of certain birds, and with the horns of certain stags.

The females of some of the anthropoid apes, as stated in a former chapter, are somewhat less hairy on the under surface than the males; and here we have what might have afforded a commencement for the process of denudation. With respect to the completion of the process through sexual selection, it is well to bear in mind the New Zealand proverb, “There is no woman for a hairy man.” All who have seen photographs of the Siamese hairy family will admit how ludicrously hideous is the opposite extreme of excessive hairiness. And the king of Siam had to bribe a man to marry the first hairy woman in the family; and she transmitted this character to her young offspring of both sexes. (22. The ‘Variation of Animals and Plants under Domestication,’ vol. ii. 1868, p. 237.)

Some races are much more hairy than others, especially the males; but it must not be assumed that the more hairy races, such as the European, have retained their primordial condition more completely than the naked races, such as the Kalmucks or Americans. It is more probable that the hairiness of the former is due to partial reversion; for characters which have been at some former period long inherited are always apt to return. We have seen that idiots are often very hairy, and they are apt to revert in other characters to a lower animal type. It does not appear that a cold climate has been influential in leading to this kind of reversion; excepting perhaps with the negroes, who have been reared during several generations in the United States (23. ‘Investigations into Military and Anthropological Statistics of American Soldiers,’ by B.A. Gould, 1869, p. 568:—Observations were carefully made on the hairiness of 2129 black and coloured soldiers, whilst they were bathing; and by looking to the published table, “it is manifest at a glance that there is but little, if any, difference between the white and the black races in this respect.” It is, however, certain that negroes in their native and much hotter land of Africa, have remarkably smooth bodies. It should be particularly observed, that both pure blacks and mulattoes were included in the above enumeration; and this is an unfortunate circumstance, as in accordance with a principle, the truth of which I have elsewhere proved, crossed races of man would be eminently liable to revert to the primordial hairy character of their early ape-like progenitors.), and possibly with the Ainos, who inhabit the northern islands of the Japan archipelago. But the laws of inheritance are so complex that we can seldom understand their action. If the greater hairiness of certain races be the result of reversion, unchecked by any form of selection, its extreme variability, even within the limits of the same race, ceases to be remarkable. (24. Hardly any view advanced in this work has met with so much disfavour (see for instance, Sprengel, ‘Die Fortschritte des Darwinismus,’ 1874, p. 80) as the above explanation of the loss of hair in mankind through sexual selection; but none of the opposed arguments seem to me of much weight, in comparison with the facts shewing that the nudity of the skin is to a certain extent a secondary sexual character in man and in some of the Quadrumana.)

With respect to the beard in man, if we turn to our best guide, the Quadrumana, we find beards equally developed in both sexes of many species, but in some, either confined to the males, or more developed in them than in the females. From this fact and from the curious arrangement, as well as the bright colours of the hair about the heads of many monkeys, it is highly probable, as before explained, that the males first acquired their beards through sexual selection as an ornament, transmitting them in most cases, equally or nearly so, to their offspring of both sexes. We know from Eschricht (25. ‘Ueber die Richtung der Haare am Menschlichen Körper,’ in Müller’s ‘Archiv. für Anat. und Phys.’ 1837, s. 40.) that with mankind the female as well as the male foetus is furnished with much hair on the face, especially round the mouth; and this indicates that we are descended from progenitors of whom both sexes were bearded. It appears therefore at first sight probable that man has retained his beard from a very early period, whilst woman lost her beard at the same time that her body became almost completely divested of hair. Even the colour of our beards seems to have been inherited from an ape-like progenitor; for when there is any difference in tint between the hair of the head and the beard, the latter is lighter coloured in all monkeys and in man. In those Quadrumana in which the male has a larger beard than that of the female, it is fully developed only at maturity, just as with mankind; and it is possible that only the later stages of development have been retained by man. In opposition to this view of the retention of the beard from an early period is the fact of its great variability in different races, and even within the same race; for this indicates reversion,—long lost characters being very apt to vary on re-appearance.

Nor must we overlook the part which sexual selection may have played in later times; for we know that with savages the men of the beardless races take infinite pains in eradicating every hair from their faces as something odious, whilst the men of the bearded races feel the greatest pride in their beards. The women, no doubt, participate in these feelings, and if so sexual selection can hardly have failed to have effected something in the course of later times. It is also possible that the long-continued habit of eradicating the hair may have produced an inherited effect. Dr. Brown-Sequard has shewn that if certain animals are operated on in a particular manner, their offspring are affected. Further evidence could be given of the inheritance of the effects of mutilations; but a fact lately ascertained by Mr. Salvin (26. On the tail-feathers of Motmots, ‘Proceedings of the Zoological Society,’ 1873, p. 429.) has a more direct bearing on the present question; for he has shewn that the motmots, which are known habitually to bite off the barbs of the two central tail- feathers, have the barbs of these feathers naturally somewhat reduced. (27. Mr. Sproat has suggested (‘Scenes and Studies of Savage Life,’ 1868, p. 25) this same view. Some distinguished ethnologists, amongst others M. Gosse of Geneva, believe that artificial modifications of the skull tend to be inherited.) Nevertheless, with mankind the habit of eradicating the beard and the hairs on the body would probably not have arisen until these had already become by some means reduced.

It is difficult to form any judgment as to how the hair on the head became developed to its present great length in many races. Eschricht (28. ‘Ueber die Richtung,’ ibid. s. 40.) states that in the human foetus the hair on the face during the fifth month is longer than that on the head; and this indicates that our semi-human progenitors were not furnished with long tresses, which must therefore have been a late acquisition. This is likewise indicated by the extraordinary difference in the length of the hair in the different races; in the negro the hair forms a mere curly mat; with us it is of great length, and with the American natives it not rarely reaches to the ground. Some species of Semnopithecus have their heads covered with moderately long hair, and this probably serves as an ornament and was acquired through sexual selection. The same view may perhaps be extended to mankind, for we know that long tresses are now and were formerly much admired, as may be observed in the works of almost every poet; St. Paul says, “if a woman have long hair, it is a glory to her;” and we have seen that in North America a chief was elected solely from the length of his hair.

Colour of the Skin

The best kind of evidence that in man the colour of the skin has been modified through sexual selection is scanty; for in most races the sexes do not differ in this respect, and only slightly, as we have seen, in others. We know, however, from the many facts already given that the colour of the skin is regarded by the men of all races as a highly important element in their beauty; so that it is a character which would be likely to have been modified through selection, as has occurred in innumerable instances with the lower animals. It seems at first sight a monstrous supposition that the jet-blackness of the negro should have been gained through sexual selection; but this view is supported by various analogies, and we know that negroes admire their own colour. With mammals, when the sexes differ in colour, the male is often black or much darker than the female; and it depends merely on the form of inheritance whether this or any other tint is transmitted to both sexes or to one alone. The resemblance to a negro in miniature of Pithecia satanas with his jet black skin, white rolling eyeballs, and hair parted on the top of the head, is almost ludicrous.

The colour of the face differs much more widely in the various kinds of monkeys than it does in the races of man; and we have some reason to believe that the red, blue, orange, almost white and black tints of their skin, even when common to both sexes, as well as the bright colours of their fur, and the ornamental tufts about the head, have all been acquired through sexual selection. As the order of development during growth, generally indicates the order in which the characters of a species have been developed and modified during previous generations; and as the newly- born infants of the various races of man do not differ nearly as much in colour as do the adults, although their bodies are as completely destitute of hair, we have some slight evidence that the tints of the different races were acquired at a period subsequent to the removal of the hair, which must have occurred at a very early period in the history of man.

总结

We may conclude that the greater size, strength, courage, pugnacity, and energy of man, in comparison with woman, were acquired during primeval times, and have subsequently been augmented, chiefly through the contests of rival males for the possession of the females. The greater intellectual vigour and power of invention in man is probably due to natural selection, combined with the inherited effects of habit, for the most able men will have succeeded best in defending and providing for themselves and for their wives and offspring. As far as the extreme intricacy of the subject permits us to judge, it appears that our male ape-like progenitors acquired their beards as an ornament to charm or excite the opposite sex, and transmitted them only to their male offspring. The females apparently first had their bodies denuded of hair, also as a sexual ornament; but they transmitted this character almost equally to both sexes. It is not improbable that the females were modified in other respects for the same purpose and by the same means; so that women have acquired sweeter voices and become more beautiful than men.

It deserves attention that with mankind the conditions were in many respects much more favourable for sexual selection, during a very early period, when man had only just attained to the rank of manhood, than during later times. For he would then, as we may safely conclude, have been guided more by his instinctive passions, and less by foresight or reason. He would have jealously guarded his wife or wives. He would not have practised infanticide; nor valued his wives merely as useful slaves; nor have been betrothed to them during infancy. Hence we may infer that the races of men were differentiated, as far as sexual selection is concerned, in chief part at a very remote epoch; and this conclusion throws light on the remarkable fact that at the most ancient period, of which we have not as yet any record, the races of man had already come to differ nearly or quite as much as they do at the present day.

The views here advanced, on the part which sexual selection has played in the history of man, want scientific precision. He who does not admit this agency in the case of the lower animals, will disregard all that I have written in the later chapters on man. We cannot positively say that this character, but not that, has been thus modified; it has, however, been shewn that the races of man differ from each other and from their nearest allies, in certain characters which are of no service to them in their daily habits of life, and which it is extremely probable would have been modified through sexual selection. We have seen that with the lowest savages the people of each tribe admire their own characteristic qualities,—the shape of the head and face, the squareness of the cheek- bones, the prominence or depression of the nose, the colour of the skin, the length of the hair on the head, the absence of hair on the face and body, or the presence of a great beard, and so forth. Hence these and other such points could hardly fail to be slowly and gradually exaggerated, from the more powerful and able men in each tribe, who would succeed in rearing the largest number of offspring, having selected during many generations for their wives the most strongly characterised and therefore most attractive women. For my own part I conclude that of all the causes which have led to the differences in external appearance between the races of man, and to a certain extent between man and the lower animals, sexual selection has been the most efficient.

第二十一章 •7,900字
总体总结和结论

Main conclusion that man is descended from some lower form—Manner of development—Genealogy of man—Intellectual and moral faculties—Sexual Selection—Concluding remarks.

A brief summary will be sufficient to recall to the reader’s mind the more salient points in this work. Many of the views which have been advanced are highly speculative, and some no doubt will prove erroneous; but I have in every case given the reasons which have led me to one view rather than to another. It seemed worth while to try how far the principle of evolution would throw light on some of the more complex problems in the natural history of man. False facts are highly injurious to the progress of science, for they often endure long; but false views, if supported by some evidence, do little harm, for every one takes a salutary pleasure in proving their falseness: and when this is done, one path towards error is closed and the road to truth is often at the same time opened.

The main conclusion here arrived at, and now held by many naturalists who are well competent to form a sound judgment, is that man is descended from some less highly organised form. The grounds upon which this conclusion rests will never be shaken, for the close similarity between man and the lower animals in embryonic development, as well as in innumerable points of structure and constitution, both of high and of the most trifling importance,—the rudiments which he retains, and the abnormal reversions to which he is occasionally liable,—are facts which cannot be disputed. They have long been known, but until recently they told us nothing with respect to the origin of man. Now when viewed by the light of our knowledge of the whole organic world, their meaning is unmistakable. The great principle of evolution stands up clear and firm, when these groups or facts are considered in connection with others, such as the mutual affinities of the members of the same group, their geographical distribution in past and present times, and their geological succession. It is incredible that all these facts should speak falsely. He who is not content to look, like a savage, at the phenomena of nature as disconnected, cannot any longer believe that man is the work of a separate act of creation. He will be forced to admit that the close resemblance of the embryo of man to that, for instance, of a dog—the construction of his skull, limbs and whole frame on the same plan with that of other mammals, independently of the uses to which the parts may be put—the occasional re-appearance of various structures, for instance of several muscles, which man does not normally possess, but which are common to the Quadrumana—and a crowd of analogous facts—all point in the plainest manner to the conclusion that man is the co-descendant with other mammals of a common progenitor.

We have seen that man incessantly presents individual differences in all parts of his body and in his mental faculties. These differences or variations seem to be induced by the same general causes, and to obey the same laws as with the lower animals. In both cases similar laws of inheritance prevail. Man tends to increase at a greater rate than his means of subsistence; consequently he is occasionally subjected to a severe struggle for existence, and natural selection will have effected whatever lies within its scope. A succession of strongly-marked variations of a similar nature is by no means requisite; slight fluctuating differences in the individual suffice for the work of natural selection; not that we have any reason to suppose that in the same species, all parts of the organisation tend to vary to the same degree. We may feel assured that the inherited effects of the long-continued use or disuse of parts will have done much in the same direction with natural selection. Modifications formerly of importance, though no longer of any special use, are long- inherited. When one part is modified, other parts change through the principle of correlation, of which we have instances in many curious cases of correlated monstrosities. Something may be attributed to the direct and definite action of the surrounding conditions of life, such as abundant food, heat or moisture; and lastly, many characters of slight physiological importance, some indeed of considerable importance, have been gained through sexual selection.

No doubt man, as well as every other animal, presents structures, which seem to our limited knowledge, not to be now of any service to him, nor to have been so formerly, either for the general conditions of life, or in the relations of one sex to the other. Such structures cannot be accounted for by any form of selection, or by the inherited effects of the use and disuse of parts. We know, however, that many strange and strongly-marked peculiarities of structure occasionally appear in our domesticated productions, and if their unknown causes were to act more uniformly, they would probably become common to all the individuals of the species. We may hope hereafter to understand something about the causes of such occasional modifications, especially through the study of monstrosities: hence the labours of experimentalists, such as those of M. Camille Dareste, are full of promise for the future. In general we can only say that the cause of each slight variation and of each monstrosity lies much more in the constitution of the organism, than in the nature of the surrounding conditions; though new and changed conditions certainly play an important part in exciting organic changes of many kinds.

Through the means just specified, aided perhaps by others as yet undiscovered, man has been raised to his present state. But since he attained to the rank of manhood, he has diverged into distinct races, or as they may be more fitly called, sub-species. Some of these, such as the Negro and European, are so distinct that, if specimens had been brought to a naturalist without any further information, they would undoubtedly have been considered by him as good and true species. Nevertheless all the races agree in so many unimportant details of structure and in so many mental peculiarities that these can be accounted for only by inheritance from a common progenitor; and a progenitor thus characterised would probably deserve to rank as man.

It must not be supposed that the divergence of each race from the other races, and of all from a common stock, can be traced back to any one pair of progenitors. On the contrary, at every stage in the process of modification, all the individuals which were in any way better fitted for their conditions of life, though in different degrees, would have survived in greater numbers than the less well-fitted. The process would have been like that followed by man, when he does not intentionally select particular individuals, but breeds from all the superior individuals, and neglects the inferior. He thus slowly but surely modifies his stock, and unconsciously forms a new strain. So with respect to modifications acquired independently of selection, and due to variations arising from the nature of the organism and the action of the surrounding conditions, or from changed habits of life, no single pair will have been modified much more than the other pairs inhabiting the same country, for all will have been continually blended through free intercrossing.

By considering the embryological structure of man,—the homologies which he presents with the lower animals,—the rudiments which he retains,—and the reversions to which he is liable, we can partly recall in imagination the former condition of our early progenitors; and can approximately place them in their proper place in the zoological series. We thus learn that man is descended from a hairy, tailed quadruped, probably arboreal in its habits, and an inhabitant of the Old World. This creature, if its whole structure had been examined by a naturalist, would have been classed amongst the Quadrumana, as surely as the still more ancient progenitor of the Old and New World monkeys. The Quadrumana and all the higher mammals are probably derived from an ancient marsupial animal, and this through a long line of diversified forms, from some amphibian-like creature, and this again from some fish-like animal. In the dim obscurity of the past we can see that the early progenitor of all the Vertebrata must have been an aquatic animal, provided with branchiae, with the two sexes united in the same individual, and with the most important organs of the body (such as the brain and heart) imperfectly or not at all developed. This animal seems to have been more like the larvae of the existing marine Ascidians than any other known form.

The high standard of our intellectual powers and moral disposition is the greatest difficulty which presents itself, after we have been driven to this conclusion on the origin of man. But every one who admits the principle of evolution, must see that the mental powers of the higher animals, which are the same in kind with those of man, though so different in degree, are capable of advancement. Thus the interval between the mental powers of one of the higher apes and of a fish, or between those of an ant and scale-insect, is immense; yet their development does not offer any special difficulty; for with our domesticated animals, the mental faculties are certainly variable, and the variations are inherited. No one doubts that they are of the utmost importance to animals in a state of nature. Therefore the conditions are favourable for their development through natural selection. The same conclusion may be extended to man; the intellect must have been all-important to him, even at a very remote period, as enabling him to invent and use language, to make weapons, tools, traps, etc., whereby with the aid of his social habits, he long ago became the most dominant of all living creatures.

A great stride in the development of the intellect will have followed, as soon as the half-art and half-instinct of language came into use; for the continued use of language will have reacted on the brain and produced an inherited effect; and this again will have reacted on the improvement of language. As Mr. Chauncey Wright (1. ‘On the Limits of Natural Selection,’ in the ‘North American Review,’ Oct. 1870, p. 295.) has well remarked, the largeness of the brain in man relatively to his body, compared with the lower animals, may be attributed in chief part to the early use of some simple form of language,—that wonderful engine which affixes signs to all sorts of objects and qualities, and excites trains of thought which would never arise from the mere impression of the senses, or if they did arise could not be followed out. The higher intellectual powers of man, such as those of ratiocination, abstraction, self- consciousness, etc., probably follow from the continued improvement and exercise of the other mental faculties.

The development of the moral qualities is a more interesting problem. The foundation lies in the social instincts, including under this term the family ties. These instincts are highly complex, and in the case of the lower animals give special tendencies towards certain definite actions; but the more important elements are love, and the distinct emotion of sympathy. Animals endowed with the social instincts take pleasure in one another’s company, warn one another of danger, defend and aid one another in many ways. These instincts do not extend to all the individuals of the species, but only to those of the same community. As they are highly beneficial to the species, they have in all probability been acquired through natural selection.

A moral being is one who is capable of reflecting on his past actions and their motives—of approving of some and disapproving of others; and the fact that man is the one being who certainly deserves this designation, is the greatest of all distinctions between him and the lower animals. But in the fourth chapter I have endeavoured to shew that the moral sense follows, firstly, from the enduring and ever-present nature of the social instincts; secondly, from man’s appreciation of the approbation and disapprobation of his fellows; and thirdly, from the high activity of his mental faculties, with past impressions extremely vivid; and in these latter respects he differs from the lower animals. Owing to this condition of mind, man cannot avoid looking both backwards and forwards, and comparing past impressions. Hence after some temporary desire or passion has mastered his social instincts, he reflects and compares the now weakened impression of such past impulses with the ever-present social instincts; and he then feels that sense of dissatisfaction which all unsatisfied instincts leave behind them, he therefore resolves to act differently for the future,—and this is conscience. Any instinct, permanently stronger or more enduring than another, gives rise to a feeling which we express by saying that it ought to be obeyed. A pointer dog, if able to reflect on his past conduct, would say to himself, I ought (as indeed we say of him) to have pointed at that hare and not have yielded to the passing temptation of hunting it.

Social animals are impelled partly by a wish to aid the members of their community in a general manner, but more commonly to perform certain definite actions. Man is impelled by the same general wish to aid his fellows; but has few or no special instincts. He differs also from the lower animals in the power of expressing his desires by words, which thus become a guide to the aid required and bestowed. The motive to give aid is likewise much modified in man: it no longer consists solely of a blind instinctive impulse, but is much influenced by the praise or blame of his fellows. The appreciation and the bestowal of praise and blame both rest on sympathy; and this emotion, as we have seen, is one of the most important elements of the social instincts. Sympathy, though gained as an instinct, is also much strengthened by exercise or habit. As all men desire their own happiness, praise or blame is bestowed on actions and motives, according as they lead to this end; and as happiness is an essential part of the general good, the greatest-happinesss principle indirectly serves as a nearly safe standard of right and wrong. As the reasoning powers advance and experience is gained, the remoter effects of certain lines of conduct on the character of the individual, and on the general good, are perceived; and then the self-regarding virtues come within the scope of public opinion, and receive praise, and their opposites blame. But with the less civilised nations reason often errs, and many bad customs and base superstitions come within the same scope, and are then esteemed as high virtues, and their breach as heavy crimes.

The moral faculties are generally and justly esteemed as of higher value than the intellectual powers. But we should bear in mind that the activity of the mind in vividly recalling past impressions is one of the fundamental though secondary bases of conscience. This affords the strongest argument for educating and stimulating in all possible ways the intellectual faculties of every human being. No doubt a man with a torpid mind, if his social affections and sympathies are well developed, will be led to good actions, and may have a fairly sensitive conscience. But whatever renders the imagination more vivid and strengthens the habit of recalling and comparing past impressions, will make the conscience more sensitive, and may even somewhat compensate for weak social affections and sympathies.

The moral nature of man has reached its present standard, partly through the advancement of his reasoning powers and consequently of a just public opinion, but especially from his sympathies having been rendered more tender and widely diffused through the effects of habit, example, instruction, and reflection. It is not improbable that after long practice virtuous tendencies may be inherited. With the more civilised races, the conviction of the existence of an all-seeing Deity has had a potent influence on the advance of morality. Ultimately man does not accept the praise or blame of his fellows as his sole guide, though few escape this influence, but his habitual convictions, controlled by reason, afford him the safest rule. His conscience then becomes the supreme judge and monitor. Nevertheless the first foundation or origin of the moral sense lies in the social instincts, including sympathy; and these instincts no doubt were primarily gained, as in the case of the lower animals, through natural selection.

The belief in God has often been advanced as not only the greatest, but the most complete of all the distinctions between man and the lower animals. It is however impossible, as we have seen, to maintain that this belief is innate or instinctive in man. On the other hand a belief in all-pervading spiritual agencies seems to be universal; and apparently follows from a considerable advance in man’s reason, and from a still greater advance in his faculties of imagination, curiosity and wonder. I am aware that the assumed instinctive belief in God has been used by many persons as an argument for His existence. But this is a rash argument, as we should thus be compelled to believe in the existence of many cruel and malignant spirits, only a little more powerful than man; for the belief in them is far more general than in a beneficent Deity. The idea of a universal and beneficent Creator does not seem to arise in the mind of man, until he has been elevated by long-continued culture.

He who believes in the advancement of man from some low organised form, will naturally ask how does this bear on the belief in the immortality of the soul. The barbarous races of man, as Sir J. Lubbock has shewn, possess no clear belief of this kind; but arguments derived from the primeval beliefs of savages are, as we have just seen, of little or no avail. Few persons feel any anxiety from the impossibility of determining at what precise period in the development of the individual, from the first trace of a minute germinal vesicle, man becomes an immortal being; and there is no greater cause for anxiety because the period cannot possibly be determined in the gradually ascending organic scale. (2. The Rev. J.A. Picton gives a discussion to this effect in his ‘New Theories and the Old Faith,’ 1870.)

I am aware that the conclusions arrived at in this work will be denounced by some as highly irreligious; but he who denounces them is bound to shew why it is more irreligious to explain the origin of man as a distinct species by descent from some lower form, through the laws of variation and natural selection, than to explain the birth of the individual through the laws of ordinary reproduction. The birth both of the species and of the individual are equally parts of that grand sequence of events, which our minds refuse to accept as the result of blind chance. The understanding revolts at such a conclusion, whether or not we are able to believe that every slight variation of structure,—the union of each pair in marriage, the dissemination of each seed,—and other such events, have all been ordained for some special purpose.

Sexual selection has been treated at great length in this work; for, as I have attempted to shew, it has played an important part in the history of the organic world. I am aware that much remains doubtful, but I have endeavoured to give a fair view of the whole case. In the lower divisions of the animal kingdom, sexual selection seems to have done nothing: such animals are often affixed for life to the same spot, or have the sexes combined in the same individual, or what is still more important, their perceptive and intellectual faculties are not sufficiently advanced to allow of the feelings of love and jealousy, or of the exertion of choice. When, however, we come to the Arthropoda and Vertebrata, even to the lowest classes in these two great Sub-Kingdoms, sexual selection has effected much.

In the several great classes of the animal kingdom,—in mammals, birds, reptiles, fishes, insects, and even crustaceans,—the differences between the sexes follow nearly the same rules. The males are almost always the wooers; and they alone are armed with special weapons for fighting with their rivals. They are generally stronger and larger than the females, and are endowed with the requisite qualities of courage and pugnacity. They are provided, either exclusively or in a much higher degree than the females, with organs for vocal or instrumental music, and with odoriferous glands. They are ornamented with infinitely diversified appendages, and with the most brilliant or conspicuous colours, often arranged in elegant patterns, whilst the females are unadorned. When the sexes differ in more important structures, it is the male which is provided with special sense- organs for discovering the female, with locomotive organs for reaching her, and often with prehensile organs for holding her. These various structures for charming or securing the female are often developed in the male during only part of the year, namely the breeding-season. They have in many cases been more or less transferred to the females; and in the latter case they often appear in her as mere rudiments. They are lost or never gained by the males after emasculation. Generally they are not developed in the male during early youth, but appear a short time before the age for reproduction. Hence in most cases the young of both sexes resemble each other; and the female somewhat resembles her young offspring throughout life. In almost every great class a few anomalous cases occur, where there has been an almost complete transposition of the characters proper to the two sexes; the females assuming characters which properly belong to the males. This surprising uniformity in the laws regulating the differences between the sexes in so many and such widely separated classes, is intelligible if we admit the action of one common cause, namely sexual selection.

Sexual selection depends on the success of certain individuals over others of the same sex, in relation to the propagation of the species; whilst natural selection depends on the success of both sexes, at all ages, in relation to the general conditions of life. The sexual struggle is of two kinds; in the one it is between individuals of the same sex, generally the males, in order to drive away or kill their rivals, the females remaining passive; whilst in the other, the struggle is likewise between the individuals of the same sex, in order to excite or charm those of the opposite sex, generally the females, which no longer remain passive, but select the more agreeable partners. This latter kind of selection is closely analogous to that which man unintentionally, yet effectually, brings to bear on his domesticated productions, when he preserves during a long period the most pleasing or useful individuals, without any wish to modify the breed.

The laws of inheritance determine whether characters gained through sexual selection by either sex shall be transmitted to the same sex, or to both; as well as the age at which they shall be developed. It appears that variations arising late in life are commonly transmitted to one and the same sex. Variability is the necessary basis for the action of selection, and is wholly independent of it. It follows from this, that variations of the same general nature have often been taken advantage of and accumulated through sexual selection in relation to the propagation of the species, as well as through natural selection in relation to the general purposes of life. Hence secondary sexual characters, when equally transmitted to both sexes can be distinguished from ordinary specific characters only by the light of analogy. The modifications acquired through sexual selection are often so strongly pronounced that the two sexes have frequently been ranked as distinct species, or even as distinct genera. Such strongly-marked differences must be in some manner highly important; and we know that they have been acquired in some instances at the cost not only of inconvenience, but of exposure to actual danger.

The belief in the power of sexual selection rests chiefly on the following considerations. Certain characters are confined to one sex; and this alone renders it probable that in most cases they are connected with the act of reproduction. In innumerable instances these characters are fully developed only at maturity, and often during only a part of the year, which is always the breeding-season. The males (passing over a few exceptional cases) are the more active in courtship; they are the better armed, and are rendered the more attractive in various ways. It is to be especially observed that the males display their attractions with elaborate care in the presence of the females; and that they rarely or never display them excepting during the season of love. It is incredible that all this should be purposeless. Lastly we have distinct evidence with some quadrupeds and birds, that the individuals of one sex are capable of feeling a strong antipathy or preference for certain individuals of the other sex.

Bearing in mind these facts, and the marked results of man’s unconscious selection, when applied to domesticated animals and cultivated plants, it seems to me almost certain that if the individuals of one sex were during a long series of generations to prefer pairing with certain individuals of the other sex, characterised in some peculiar manner, the offspring would slowly but surely become modified in this same manner. I have not attempted to conceal that, excepting when the males are more numerous than the females, or when polygamy prevails, it is doubtful how the more attractive males succeed in leaving a large number of offspring to inherit their superiority in ornaments or other charms than the less attractive males; but I have shewn that this would probably follow from the females,— especially the more vigorous ones, which would be the first to breed,— preferring not only the more attractive but at the same time the more vigorous and victorious males.

Although we have some positive evidence that birds appreciate bright and beautiful objects, as with the bower-birds of Australia, and although they certainly appreciate the power of song, yet I fully admit that it is astonishing that the females of many birds and some mammals should be endowed with sufficient taste to appreciate ornaments, which we have reason to attribute to sexual selection; and this is even more astonishing in the case of reptiles, fish, and insects. But we really know little about the minds of the lower animals. It cannot be supposed, for instance, that male birds of paradise or peacocks should take such pains in erecting, spreading, and vibrating their beautiful plumes before the females for no purpose. We should remember the fact given on excellent authority in a former chapter, that several peahens, when debarred from an admired male, remained widows during a whole season rather than pair with another bird.

Nevertheless I know of no fact in natural history more wonderful than that the female Argus pheasant should appreciate the exquisite shading of the ball-and-socket ornaments and the elegant patterns on the wing-feather of the male. He who thinks that the male was created as he now exists must admit that the great plumes, which prevent the wings from being used for flight, and which are displayed during courtship and at no other time in a manner quite peculiar to this one species, were given to him as an ornament. If so, he must likewise admit that the female was created and endowed with the capacity of appreciating such ornaments. I differ only in the conviction that the male Argus pheasant acquired his beauty gradually, through the preference of the females during many generations for the more highly ornamented males; the aesthetic capacity of the females having been advanced through exercise or habit, just as our own taste is gradually improved. In the male through the fortunate chance of a few feathers being left unchanged, we can distinctly trace how simple spots with a little fulvous shading on one side may have been developed by small steps into the wonderful ball-and-socket ornaments; and it is probable that they were actually thus developed.

Everyone who admits the principle of evolution, and yet feels great difficulty in admitting that female mammals, birds, reptiles, and fish, could have acquired the high taste implied by the beauty of the males, and which generally coincides with our own standard, should reflect that the nerve-cells of the brain in the highest as well as in the lowest members of the Vertebrate series, are derived from those of the common progenitor of this great Kingdom. For we can thus see how it has come to pass that certain mental faculties, in various and widely distinct groups of animals, have been developed in nearly the same manner and to nearly the same degree.

The reader who has taken the trouble to go through the several chapters devoted to sexual selection, will be able to judge how far the conclusions at which I have arrived are supported by sufficient evidence. If he accepts these conclusions he may, I think, safely extend them to mankind; but it would be superfluous here to repeat what I have so lately said on the manner in which sexual selection apparently has acted on man, both on the male and female side, causing the two sexes to differ in body and mind, and the several races to differ from each other in various characters, as well as from their ancient and lowly-organised progenitors.

He who admits the principle of sexual selection will be led to the remarkable conclusion that the nervous system not only regulates most of the existing functions of the body, but has indirectly influenced the progressive development of various bodily structures and of certain mental qualities. Courage, pugnacity, perseverance, strength and size of body, weapons of all kinds, musical organs, both vocal and instrumental, bright colours and ornamental appendages, have all been indirectly gained by the one sex or the other, through the exertion of choice, the influence of love and jealousy, and the appreciation of the beautiful in sound, colour or form; and these powers of the mind manifestly depend on the development of the brain.

Man scans with scrupulous care the character and pedigree of his horses, cattle, and dogs before he matches them; but when he comes to his own marriage he rarely, or never, takes any such care. He is impelled by nearly the same motives as the lower animals, when they are left to their own free choice, though he is in so far superior to them that he highly values mental charms and virtues. On the other hand he is strongly attracted by mere wealth or rank. Yet he might by selection do something not only for the bodily constitution and frame of his offspring, but for their intellectual and moral qualities. Both sexes ought to refrain from marriage if they are in any marked degree inferior in body or mind; but such hopes are Utopian and will never be even partially realised until the laws of inheritance are thoroughly known. Everyone does good service, who aids towards this end. When the principles of breeding and inheritance are better understood, we shall not hear ignorant members of our legislature rejecting with scorn a plan for ascertaining whether or not consanguineous marriages are injurious to man.

The advancement of the welfare of mankind is a most intricate problem: all ought to refrain from marriage who cannot avoid abject poverty for their children; for poverty is not only a great evil, but tends to its own increase by leading to recklessness in marriage. On the other hand, as Mr. Galton has remarked, if the prudent avoid marriage, whilst the reckless marry, the inferior members tend to supplant the better members of society. Man, like every other animal, has no doubt advanced to his present high condition through a struggle for existence consequent on his rapid multiplication; and if he is to advance still higher, it is to be feared that he must remain subject to a severe struggle. Otherwise he would sink into indolence, and the more gifted men would not be more successful in the battle of life than the less gifted. Hence our natural rate of increase, though leading to many and obvious evils, must not be greatly diminished by any means. There should be open competition for all men; and the most able should not be prevented by laws or customs from succeeding best and rearing the largest number of offspring. Important as the struggle for existence has been and even still is, yet as far as the highest part of man’s nature is concerned there are other agencies more important. For the moral qualities are advanced, either directly or indirectly, much more through the effects of habit, the reasoning powers, instruction, religion, etc., than through natural selection; though to this latter agency may be safely attributed the social instincts, which afforded the basis for the development of the moral sense.

The main conclusion arrived at in this work, namely, that man is descended from some lowly organised form, will, I regret to think, be highly distasteful to many. But there can hardly be a doubt that we are descended from barbarians. The astonishment which I felt on first seeing a party of Fuegians on a wild and broken shore will never be forgotten by me, for the reflection at once rushed into my mind—such were our ancestors. These men were absolutely naked and bedaubed with paint, their long hair was tangled, their mouths frothed with excitement, and their expression was wild, startled, and distrustful. They possessed hardly any arts, and like wild animals lived on what they could catch; they had no government, and were merciless to every one not of their own small tribe. He who has seen a savage in his native land will not feel much shame, if forced to acknowledge that the blood of some more humble creature flows in his veins. For my own part I would as soon be descended from that heroic little monkey, who braved his dreaded enemy in order to save the life of his keeper, or from that old baboon, who descending from the mountains, carried away in triumph his young comrade from a crowd of astonished dogs—as from a savage who delights to torture his enemies, offers up bloody sacrifices, practices infanticide without remorse, treats his wives like slaves, knows no decency, and is haunted by the grossest superstitions.

Man may be excused for feeling some pride at having risen, though not through his own exertions, to the very summit of the organic scale; and the fact of his having thus risen, instead of having been aboriginally placed there, may give him hope for a still higher destiny in the distant future. But we are not here concerned with hopes or fears, only with the truth as far as our reason permits us to discover it; and I have given the evidence to the best of my ability. We must, however, acknowledge, as it seems to me, that man with all his noble qualities, with sympathy which feels for the most debased, with benevolence which extends not only to other men but to the humblest living creature, with his god-like intellect which has penetrated into the movements and constitution of the solar system—with all these exalted powers—Man still bears in his bodily frame the indelible stamp of his lowly origin.

Supplemental Note
On Sexual Selection in Relation to Monkeys

Reprinted from NATURE, November 2, 1876, p. 18.

In the discussion on Sexual Selection in my ‘Descent of Man,’ no case interested and perplexed me so much as the brightly-coloured hinder ends and adjoining parts of certain monkeys. As these parts are more brightly coloured in one sex than the other, and as they become more brilliant during the season of love, I concluded that the colours had been gained as a sexual attraction. I was well aware that I thus laid myself open to ridicule; though in fact it is not more surprising that a monkey should display his bright-red hinder end than that a peacock should display his magnificent tail. I had, however, at that time no evidence of monkeys exhibiting this part of their bodies during their courtship; and such display in the case of birds affords the best evidence that the ornaments of the males are of service to them by attracting or exciting the females. I have lately read an article by Joh. von Fischer, of Gotha, published in ‘Der Zoologische Garten,’ April 1876, on the expression of monkeys under various emotions, which is well worthy of study by any one interested in the subject, and which shews that the author is a careful and acute observer. In this article there is an account of the behaviour of a young male mandrill when he first beheld himself in a looking-glass, and it is added, that after a time he turned round and presented his red hinder end to the glass. Accordingly I wrote to Herr J. von Fischer to ask what he supposed was the meaning of this strange action, and he has sent me two long letters full of new and curious details, which will, I hope, be hereafter published. He says that he was himself at first perplexed by the above action, and was thus led carefully to observe several individuals of various other species of monkeys, which he has long kept in his house. He finds that not only the mandrill (Cynocephalus mormon) but the drill (C. leucophaeus) and three other kinds of baboons (C. hamadryas, sphinx, and babouin), also Cynopithecus niger, and Macacus rhesus and nemestrinus, turn this part of their bodies, which in all these species is more or less brightly coloured, to him when they are pleased, and to other persons as a sort of greeting. He took pains to cure a Macacus rhesus, which he had kept for five years, of this indecorous habit, and at last succeeded. These monkeys are particularly apt to act in this manner, grinning at the same time, when first introduced to a new monkey, but often also to their old monkey friends; and after this mutual display they begin to play together. The young mandrill ceased spontaneously after a time to act in this manner towards his master, von Fischer, but continued to do so towards persons who were strangers and to new monkeys. A young Cynopithecus niger never acted, excepting on one occasion, in this way towards his master, but frequently towards strangers, and continues to do so up to the present time. From these facts Von Fischer concludes that the monkeys which behaved in this manner before a looking-glass (viz., the mandrill, drill, Cynopithecus niger, Macacus rhesus and nemestrinus) acted as if their reflection were a new acquaintance. The mandrill and drill, which have their hinder ends especially ornamented, display it even whilst quite young, more frequently and more ostentatiously than do the other kinds. Next in order comes Cynocephalus hamadryas, whilst the other species act in this manner seldomer. The individuals, however, of the same species vary in this respect, and some which were very shy never displayed their hinder ends. It deserves especial attention that Von Fischer has never seen any species purposely exhibit the hinder part of its body, if not at all coloured. This remark applies to many individuals of Macacus cynomolgus and Cercocebus radiatus (which is closely allied to M. rhesus), to three species of Cercopithecus and several American monkeys. The habit of turning the hinder ends as a greeting to an old friend or new acquaintance, which seems to us so odd, is not really more so than the habits of many savages, for instance that of rubbing their bellies with their hands, or rubbing noses together.

With respect to the origin of the habit, Von Fischer remarks that his monkeys like to have their naked hinder ends patted or stroked, and that they then grunt with pleasure. They often also turn this part of their bodies to other monkeys to have bits of dirt picked off, and so no doubt it would be with respect to thorns. But the habit with adult animals is connected to a certain extent with sexual feelings, for Von Fischer watched through a glass door a female Cynopithecus niger, and she during several days, “umdrehte und dem Männchen mit gurgelnden Tönen die stark geröthete Sitzflache zeigte, was ich früher nie an diesem Thier bemerkt hatte. Beim Anblick dieses Gegenstandes erregte sich das Männchen sichtlich, denn es polterte heftig an den Stäben, ebenfalls gurgelnde Laute ausstossend.” As all the monkeys which have the hinder parts of their bodies more or less brightly coloured live, according to Von Fischer, in open rocky places, he thinks that these colours serve to render one sex conspicuous at a distance to the other; but, as monkeys are such gregarious animals, I should have thought that there was no need for the sexes to recognise each other at a distance. It seems to me more probable that the bright colours, whether on the face or hinder end, or, as in the mandrill, on both, serve as a sexual ornament and attraction. Anyhow, as we now know that monkeys have the habit of turning their hinder ends towards other monkeys, it ceases to be at all surprising that it should have been this part of their bodies which has been more or less decorated. The fact that it is only the monkeys thus characterised which, as far as at present known, act in this manner as a greeting towards other monkeys renders it doubtful whether the habit was first acquired from some independent cause, and that afterwards the parts in question were coloured as a sexual ornament; or whether the colouring and the habit of turning round were first acquired through variation and sexual selection, and that afterwards the habit was retained as a sign of pleasure or as a greeting, through the principle of inherited association. This principle apparently comes into play on many occasions: thus it is generally admitted that the songs of birds serve mainly as an attraction during the season of love, and that the leks, or great congregations of the black-grouse, are connected with their courtship; but the habit of singing has been retained by some birds when they feel happy, for instance by the common robin, and the habit of congregating has been retained by the black- grouse during other seasons of the year.

I beg leave to refer to one other point in relation to sexual selection. It has been objected that this form of selection, as far as the ornaments of the males are concerned, implies that all females within the same district must possess and exercise exactly the same taste. It should, however, be observed, in the first place, that although the range of variation of a species may be very large, it is by no means indefinite. I have elsewhere given a good instance of this fact in the pigeon, of which there are at least a hundred varieties differing widely in their colours, and at least a score of varieties of the fowl differing in the same kind of way; but the range of colour in these two species is extremely distinct. Therefore the females of natural species cannot have an unlimited scope for their taste. In the second place, I presume that no supporter of the principle of sexual selection believes that the females select particular points of beauty in the males; they are merely excited or attracted in a greater degree by one male than by another, and this seems often to depend, especially with birds, on brilliant colouring. Even man, excepting perhaps an artist, does not analyse the slight differences in the features of the woman whom he may admire, on which her beauty depends. The male mandrill has not only the hinder end of his body, but his face gorgeously coloured and marked with oblique ridges, a yellow beard, and other ornaments. We may infer from what we see of the variation of animals under domestication, that the above several ornaments of the mandrill were gradually acquired by one individual varying a little in one way, and another individual in another way. The males which were the handsomest or the most attractive in any manner to the females would pair oftenest, and would leave rather more offspring than other males. The offspring of the former, although variously intercrossed, would either inherit the peculiarities of their fathers or transmit an increased tendency to vary in the same manner. Consequently the whole body of males inhabiting the same country would tend from the effects of constant intercrossing to become modified almost uniformly, but sometimes a little more in one character and sometimes in another, though at an extremely slow rate; all ultimately being thus rendered more attractive to the females. The process is like that which I have called unconscious selection by man, and of which I have given several instances. In one country the inhabitants value a fleet or light dog or horse, and in another country a heavier and more powerful one; in neither country is there any selection of individual animals with lighter or stronger bodies and limbs; nevertheless after a considerable lapse of time the individuals are found to have been modified in the desired manner almost uniformly, though differently in each country. In two absolutely distinct countries inhabited by the same species, the individuals of which can never during long ages have intermigrated and intercrossed, and where, moreover, the variations will probably not have been identically the same, sexual selection might cause the males to differ. Nor does the belief appear to me altogether fanciful that two sets of females, surrounded by a very different environment, would be apt to acquire somewhat different tastes with respect to form, sound, or colour.

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