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diff --git a/2300-h/2300-h.htm b/2300-h/2300-h.htm new file mode 100644 index 0000000..353d1d2 --- /dev/null +++ b/2300-h/2300-h.htm @@ -0,0 +1,39457 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" +"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> +<head> +<meta http-equiv="Content-Type" content="text/html;charset=utf-8" /> +<meta http-equiv="Content-Style-Type" content="text/css" /> +<title>The Project Gutenberg eBook of The Descent of Man and Selection in Relation to Sex, by Charles Darwin</title> + +<style type="text/css" xml:space="preserve"> + +body { margin-left: 20%; + margin-right: 20%; + text-align: justify; } + +h1, h2, h3, h4, h5 {text-align: center; font-style: normal; font-weight: +normal; line-height: 1.5; margin-top: .5em; margin-bottom: .5em;} + +h1 {font-size: 300%; + margin-top: 0.6em; + margin-bottom: 0.6em; + letter-spacing: 0.12em; + word-spacing: 0.2em; + text-indent: 0em;} +h2 {font-size: 150%; margin-top: 2em; margin-bottom: 1em;} +h3 {font-size: 130%; margin-top: 1em;} +h4 {font-size: 120%;} +h5 {font-size: 110%;} + +.no-break {page-break-before: avoid;} /* for epubs */ + +div.chapter {page-break-before: always; margin-top: 4em;} + +hr {width: 80%; margin-top: 2em; margin-bottom: 2em;} + +p {text-indent: 1em; + margin-top: 0.25em; + margin-bottom: 0.25em; } + +p.letter {text-indent: 0%; + margin-left: 10%; + margin-right: 10%; + margin-top: 1em; + margin-bottom: 1em; } + +p.noindent {text-indent: 0% } + +p.center {text-align: center; + text-indent: 0em; + margin-top: 1em; + margin-bottom: 1em; } + +pre { font-style: italic; font-size: 90%; margin-left: 10%;} + +a:link {color:blue; text-decoration:none} +a:visited {color:blue; text-decoration:none} +a:hover {color:red} + +</style> +</head> +<body> + +<div style='text-align:center; font-size:1.2em; font-weight:bold'>The Project Gutenberg eBook of The Descent of Man, by Charles Darwin</div> +<div style='display:block; margin:1em 0'> +This eBook is for the use of anyone anywhere in the United States and +most other parts of the world at no cost and with almost no restrictions +whatsoever. You may copy it, give it away or re-use it under the terms +of the Project Gutenberg License included with this eBook or online +at <a href="https://www.gutenberg.org">www.gutenberg.org</a>. If you +are not located in the United States, you will have to check the laws of the +country where you are located before using this eBook. +</div> +<div style='display:block; margin-top:1em; margin-bottom:1em; margin-left:2em; text-indent:-2em'>Title: The Descent of Man</div> +<div style='display:block; margin-top:1em; margin-bottom:1em; margin-left:2em; text-indent:-2em'>Author: Charles Darwin</div> +<div style='display:block; margin:1em 0'>Release Date: November 28, 1999 [eBook #2300]<br /> +[Most recently updated: December 27, 2021]</div> +<div style='display:block; margin:1em 0'>Language: English</div> +<div style='display:block; margin:1em 0'>Character set encoding: UTF-8</div> +<div style='display:block; margin-left:2em; text-indent:-2em'>Produced by: Sue Asscher and David Widger</div> +<div style='margin-top:2em; margin-bottom:4em'>*** START OF THE PROJECT GUTENBERG EBOOK THE DESCENT OF MAN ***</div> + +<h1>THE DESCENT OF MAN AND SELECTION IN RELATION TO SEX</h1> + +<h2 class="no-break">By Charles Darwin</h2> + +<hr /> + +<h2>CONTENTS</h2> + +<table summary="" style=""> + +<tr> +<td> <a href="#link2H_PREF">PREFACE TO THE SECOND EDITION.</a></td> +</tr> + +<tr> +<td> <a href="#link2H_4_0002">DETAILED TABLE OF CONTENTS</a></td> +</tr> + +<tr> +<td> <a href="#link2H_4_0004"><b>THE DESCENT OF MAN; AND SELECTION IN RELATION TO SEX.</b></a></td> +</tr> + +<tr> +<td> <a href="#link2H_INTR">INTRODUCTION.</a><br /><br /></td> +</tr> + +<tr> +<td> <a href="#link2H_4_0006"><b>PART I. THE DESCENT OR ORIGIN OF MAN.</b></a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0001">CHAPTER I. THE EVIDENCE OF THE DESCENT OF MAN FROM SOME LOWER FORM.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0002">CHAPTER II. — ON THE MANNER OF DEVELOPMENT OF MAN FROM SOME LOWER FORM.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0003">CHAPTER III. — COMPARISON OF THE MENTAL POWERS OF MAN AND THE LOWER ANIMALS.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0004">CHAPTER IV. — COMPARISON OF THE MENTAL POWERS OF MAN AND THE LOWER ANIMALS, continued.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0005">CHAPTER V. — ON THE DEVELOPMENT OF THE INTELLECTUAL AND MORAL FACULTIES DURING PRIMEVAL AND CIVILISED TIMES.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0006">CHAPTER VI. — ON THE AFFINITIES AND GENEALOGY OF MAN.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0007">CHAPTER VII. — ON THE RACES OF MAN.</a><br /><br /></td> +</tr> + +<tr> +<td> <a href="#link2H_4_0014"><b>PART II. SEXUAL SELECTION.</b></a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0008">CHAPTER VIII. — PRINCIPLES OF SEXUAL SELECTION.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0009">CHAPTER IX. — SECONDARY SEXUAL CHARACTERS IN THE LOWER CLASSES OF THE ANIMAL KINGDOM.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0010">CHAPTER X. — SECONDARY SEXUAL CHARACTERS OF INSECTS.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0011">CHAPTER XI. — INSECTS, continued. ORDER LEPIDOPTERA. (BUTTERFLIES AND MOTHS.)</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0012">CHAPTER XII. — SECONDARY SEXUAL CHARACTERS OF FISHES, AMPHIBIANS, AND REPTILES.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0013">CHAPTER XIII. — SECONDARY SEXUAL CHARACTERS OF BIRDS.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0014">CHAPTER XIV. — BIRDS—continued.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0015">CHAPTER XV. — BIRDS—continued.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0016">CHAPTER XVI. — BIRDS—concluded.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0017">CHAPTER XVII. — SECONDARY SEXUAL CHARACTERS OF MAMMALS.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0018">CHAPTER XVIII. — SECONDARY SEXUAL CHARACTERS OF MAMMALS, continued.</a><br /><br /></td> +</tr> + +<tr> +<td> <a href="#link2H_4_0026"><b>PART III. — SEXUAL SELECTION IN RELATION TO MAN, AND CONCLUSION.</b></a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0019">CHAPTER XIX. — SECONDARY SEXUAL CHARACTERS OF MAN.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0020">CHAPTER XX. — SECONDARY SEXUAL CHARACTERS OF MAN, continued.</a></td> +</tr> + +<tr> +<td> <a href="#link2HCH0021">CHAPTER XXI. — GENERAL A SUMMARY AND CONCLUSION.</a></td> +</tr> + +</table> + +<hr /> + +<div class="chapter"> + +<h2><a name="link2H_PREF" id="link2H_PREF"></a> +PREFACE TO THE SECOND EDITION.</h2> + +<p> +During the successive reprints of the first edition of this work, published in +1871, I was able to introduce several important corrections; and now that more +time has elapsed, I have endeavoured to profit by the fiery ordeal through +which the book has passed, and have taken advantage of all the criticisms which +seem to me sound. I am also greatly indebted to a large number of +correspondents for the communication of a surprising number of new facts and +remarks. These have been so numerous, that I have been able to use only the +more important ones; and of these, as well as of the more important +corrections, I will append a list. Some new illustrations have been introduced, +and four of the old drawings have been replaced by better ones, done from life +by Mr. T.W. Wood. I must especially call attention to some observations which I +owe to the kindness of Prof. Huxley (given as a supplement at the end of Part +I.), on the nature of the differences between the brains of man and the higher +apes. I have been particularly glad to give these observations, because during +the last few years several memoirs on the subject have appeared on the +Continent, and their importance has been, in some cases, greatly exaggerated by +popular writers. +</p> + +<p> +I may take this opportunity of remarking that my critics frequently assume that +I attribute all changes of corporeal structure and mental power exclusively to +the natural selection of such variations as are often called spontaneous; +whereas, even in the first edition of the ‘Origin of Species,’ I +distinctly stated that great weight must be attributed to the inherited effects +of use and disuse, with respect both to the body and mind. I also attributed +some amount of modification to the direct and prolonged action of changed +conditions of life. Some allowance, too, must be made for occasional reversions +of structure; nor must we forget what I have called “correlated” +growth, meaning, thereby, that various parts of the organisation are in some +unknown manner so connected, that when one part varies, so do others; and if +variations in the one are accumulated by selection, other parts will be +modified. Again, it has been said by several critics, that when I found that +many details of structure in man could not be explained through natural +selection, I invented sexual selection; I gave, however, a tolerably clear +sketch of this principle in the first edition of the ‘Origin of +Species,’ and I there stated that it was applicable to man. This subject +of sexual selection has been treated at full length in the present work, simply +because an opportunity was here first afforded me. I have been struck with the +likeness of many of the half-favourable criticisms on sexual selection, with +those which appeared at first on natural selection; such as, that it would +explain some few details, but certainly was not applicable to the extent to +which I have employed it. My conviction of the power of sexual selection +remains unshaken; but it is probable, or almost certain, that several of my +conclusions will hereafter be found erroneous; this can hardly fail to be the +case in the first treatment of a subject. When naturalists have become familiar +with the idea of sexual selection, it will, as I believe, be much more largely +accepted; and it has already been fully and favourably received by several +capable judges. +</p> + +<p> +DOWN, BECKENHAM, KENT, September, 1874. +</p> + +<p> +First Edition February 24, 1871. Second Edition September, 1874. +</p> + +<hr /> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2H_4_0002" id="link2H_4_0002"></a> +DETAILED TABLE OF CONTENTS</h2> + +<p class="noindent"> +<a href="#link2H_INTR">INTRODUCTION.</a><br/><br/> +</p> + +<p class="center"> +<a href="#link2H_4_0004"><b>PART I. THE DESCENT OR ORIGIN OF MAN.</b></a><br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0001">CHAPTER I.</a><br/> +THE EVIDENCE OF THE DESCENT OF MAN FROM SOME LOWER FORM.<br/> +Nature of the evidence bearing on the origin of man—Homologous structures +in man and the lower animals—Miscellaneous points of +correspondence—Development—Rudimentary structures, muscles, +sense-organs, hair, bones, reproductive organs, etc.—The bearing of these +three great classes of facts on the origin of man.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0002">CHAPTER II.</a><br/> +ON THE MANNER OF DEVELOPMENT OF MAN FROM SOME LOWER FORM.<br/> +Variability of body and mind in man—Inheritance—Causes of +variability—Laws of variation the same in man as in the lower +animals—Direct action of the conditions of life—Effects of the +increased use and disuse of parts—Arrested +development—Reversion—Correlated variation—Rate of +increase—Checks to increase—Natural selection—Man the most +dominant animal in the world—Importance of his corporeal +structure—The causes which have led to his becoming +erect—Consequent changes of structure—Decrease in size of the +canine teeth—Increased size and altered shape of the +skull—Nakedness —Absence of a tail—Defenceless condition of +man.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0003">CHAPTER III.</a><br/> +COMPARISON OF THE MENTAL POWERS OF MAN AND THE LOWER ANIMALS.<br/> +The difference in mental power between the highest ape and the lowest savage, +immense—Certain instincts in common—The +emotions—Curiosity—Imitation—Attention—Memory— +Imagination—Reason—Progressive improvement —Tools and weapons +used by animals—Abstraction, +Self-consciousness—Language—Sense of beauty—Belief in God, +spiritual agencies, superstitions.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0004">CHAPTER IV.</a><br/> +COMPARISON OF THE MENTAL POWERS OF MAN AND THE LOWER ANIMALS, continued.<br/> +The moral sense—Fundamental proposition—The qualities of social +animals—Origin of sociability—Struggle between opposed +instincts—Man a social animal—The more enduring social instincts +conquer other less persistent instincts—The social virtues alone regarded +by savages—The self-regarding virtues acquired at a later stage of +development—The importance of the judgment of the members of the same +community on conduct—Transmission of moral tendencies—Summary.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0005">CHAPTER V.</a><br/> +ON THE DEVELOPMENT OF THE INTELLECTUAL AND MORAL FACULTIES DURING PRIMEVAL AND CIVILISED TIMES.<br/> +Advancement of the intellectual powers through natural +selection—Importance of imitation—Social and moral +faculties—Their development within the limits of the same +tribe—Natural selection as affecting civilised nations—Evidence +that civilised nations were once barbarous.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0006">CHAPTER VI.</a><br/> +ON THE AFFINITIES AND GENEALOGY OF MAN.<br/> +Position of man in the animal series—The natural system +genealogical—Adaptive characters of slight value—Various small +points of resemblance between man and the Quadrumana—Rank of man in the +natural system—Birthplace and antiquity of man—Absence of fossil +connecting-links—Lower stages in the genealogy of man, as inferred +firstly from his affinities and secondly from his structure—Early +androgynous condition of the Vertebrata —Conclusion.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0007">CHAPTER VII.</a><br/> +ON THE RACES OF MAN.<br/> +The nature and value of specific characters—Application to the races of +man—Arguments in favour of, and opposed to, ranking the so-called races +of man as distinct species—Sub-species—Monogenists and +polygenists—Convergence of character—Numerous points of resemblance +in body and mind between the most distinct races of man—The state of man +when he first spread over the earth—Each race not descended from a single +pair—The extinction of races—The formation of races—The +effects of crossing—Slight influence of the direct action of the +conditions of life—Slight or no influence of natural +selection—Sexual selection.<br/><br/> +</p> + +<p class="center"> +<a href="#link2H_4_0014"><b>PART II. SEXUAL SELECTION.</b></a><br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0008">CHAPTER VIII.</a><br/> +PRINCIPLES OF SEXUAL SELECTION.<br/> +Secondary sexual characters—Sexual selection—Manner of +action—Excess of males—Polygamy—The male alone generally +modified through sexual selection—Eagerness of the male—Variability +of the male—Choice exerted by the female—Sexual compared with +natural selection—Inheritance at corresponding periods of life, at +corresponding seasons of the year, and as limited by sex—Relations +between the several forms of inheritance—Causes why one sex and the young +are not modified through sexual selection—Supplement on the proportional +numbers of the two sexes throughout the animal kingdom—The proportion of +the sexes in relation to natural selection.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0009">CHAPTER IX.</a><br/> +SECONDARY SEXUAL CHARACTERS IN THE LOWER CLASSES OF THE ANIMAL KINGDOM.<br/> +These characters are 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.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0010">CHAPTER X.</a><br/> +SECONDARY SEXUAL CHARACTERS OF INSECTS.<br/> +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.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0011">CHAPTER XI.</a><br/> +INSECTS, continued. ORDER LEPIDOPTERA. (BUTTERFLIES AND MOTHS.)<br/> +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 character of insects—Birds and +insects compared.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0012">CHAPTER XII.</a><br/> +SECONDARY SEXUAL CHARACTERS OF FISHES, AMPHIBIANS, AND REPTILES.<br/> +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.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0013">CHAPTER XIII.</a><br/> +SECONDARY SEXUAL CHARACTERS OF BIRDS.<br/> +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.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0014">CHAPTER XIV.</a><br/> +BIRDS—continued.<br/> +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.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0015">CHAPTER XV.</a><br/> +BIRDS—continued.<br/> +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.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0016">CHAPTER XVI.</a><br/> +BIRDS—concluded.<br/> +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.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0017">CHAPTER XVII.</a><br/> +SECONDARY SEXUAL CHARACTERS OF MAMMALS.<br/> +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 shewn by either sex in the pairing of quadrupeds.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0018">CHAPTER XVIII.</a><br/> +SECONDARY SEXUAL CHARACTERS OF MAMMALS, continued.<br/> +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.<br/><br/> +</p> + +<p class="center"> +<a href="#link2H_4_0026"><b>PART III. SEXUAL SELECTION IN RELATION TO MAN, AND CONCLUSION.</b></a><br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0019">CHAPTER XIX.</a><br/> +SECONDARY SEXUAL CHARACTERS OF MAN.<br/> +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 women—The tendency to exaggerate each natural +peculiarity.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0020">CHAPTER XX.</a><br/> +SECONDARY SEXUAL CHARACTERS OF MAN, continued.<br/> +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.<br/><br/> +</p> + +<p class="noindent"> +<a href="#link2HCH0021">CHAPTER XXI.</a><br/> +GENERAL A SUMMARY AND CONCLUSION.<br/> +Main conclusion that man is descended from some lower form—Manner of +development—Genealogy of man—Intellectual and moral +faculties—Sexual selection—Concluding remarks. +</p> + +<hr /> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2H_4_0004" id="link2H_4_0004"></a> +THE DESCENT OF MAN; AND SELECTION IN RELATION TO SEX.</h2> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2H_INTR" id="link2H_INTR"></a> +INTRODUCTION.</h2> + +<p> +The nature of the following work will be best understood by a brief account of +how it came to be written. During many years I collected notes on the origin or +descent of man, without any intention of publishing on the subject, but rather +with the determination not to publish, as I thought that I should thus only add +to the prejudices against my views. It seemed to me sufficient to indicate, in +the first edition of my ‘Origin of Species,’ that by this work +“light would be thrown on the origin of man and his history;” and +this implies that man must be included with other organic beings in any general +conclusion respecting his manner of appearance on this earth. Now the case +wears a wholly different aspect. When a naturalist like Carl Vogt ventures to +say in his address as President of the National Institution of Geneva (1869), +“personne, en Europe au moins, n’ose plus soutenir la creation +indépendante et de toutes pièces, des espèces,” it is manifest that at +least a large number of naturalists must admit that species are the modified +descendants of other species; and this especially holds good with the younger +and rising naturalists. The greater number accept the agency of natural +selection; though some urge, whether with justice the future must decide, that +I have greatly overrated its importance. Of the older and honoured chiefs in +natural science, many unfortunately are still opposed to evolution in every +form. +</p> + +<p> +In consequence of the views now adopted by most naturalists, and which will +ultimately, as in every other case, be followed by others who are not +scientific, I have been led to put together my notes, so as to see how far the +general conclusions arrived at in my former works were applicable to man. This +seemed all the more desirable, as I had never deliberately applied these views +to a species taken singly. When we confine our attention to any one form, we +are deprived of the weighty arguments derived from the nature of the affinities +which connect together whole groups of organisms—their geographical +distribution in past and present times, and their geological succession. The +homological structure, embryological development, and rudimentary organs of a +species remain to be considered, whether it be man or any other animal, to +which our attention may be directed; but these great classes of facts afford, +as it appears to me, ample and conclusive evidence in favour of the principle +of gradual evolution. The strong support derived from the other arguments +should, however, always be kept before the mind. +</p> + +<p> +The sole object of this work is to consider, firstly, whether man, like every +other species, is descended from some pre-existing form; secondly, the manner +of his development; and thirdly, the value of the differences between the +so-called races of man. As I shall confine myself to these points, it will not +be necessary to describe in detail the differences between the several +races—an enormous subject which has been fully described in many valuable +works. The high antiquity of man has recently been demonstrated by the labours +of a host of eminent men, beginning with M. Boucher de Perthes; and this is the +indispensable basis for understanding his origin. I shall, therefore, take this +conclusion for granted, and may refer my readers to the admirable treatises of +Sir Charles Lyell, Sir John Lubbock, and others. Nor shall I have occasion to +do more than to allude to the amount of difference between man and the +anthropomorphous apes; for Prof. Huxley, in the opinion of most competent +judges, has conclusively shewn that in every visible character man differs less +from the higher apes, than these do from the lower members of the same order of +Primates. +</p> + +<p> +This work contains hardly any original facts in regard to man; but as the +conclusions at which I arrived, after drawing up a rough draft, appeared to me +interesting, I thought that they might interest others. It has often and +confidently been asserted, that man’s origin can never be known: but +ignorance more frequently begets confidence than does knowledge: it is those +who know little, and not those who know much, who so positively assert that +this or that problem will never be solved by science. The conclusion that man +is the co-descendant with other species of some ancient, lower, and extinct +form, is not in any degree new. Lamarck long ago came to this conclusion, which +has lately been maintained by several eminent naturalists and philosophers; for +instance, by Wallace, Huxley, Lyell, Vogt, Lubbock, Buchner, Rolle, etc. (1. As +the works of the first-named authors are so well known, I need not give the +titles; but as those of the latter are less well known in England, I will give +them:—‘Sechs Vorlesungen über die Darwin’sche Theorie:’ +zweite Auflage, 1868, von Dr L. Buchner; translated into French under the title +‘Conférences sur la Théorie Darwinienne,’ 1869. ‘Der Mensch +im Lichte der Darwin’sche Lehre,’ 1865, von Dr. F. Rolle. I will +not attempt to give references to all the authors who have taken the same side +of the question. Thus G. Canestrini has published (‘Annuario della Soc. +d. Nat.,’ Modena, 1867, page 81) a very curious paper on rudimentary +characters, as bearing on the origin of man. Another work has (1869) been +published by Dr. Francesco Barrago, bearing in Italian the title of “Man, +made in the image of God, was also made in the image of the ape.”), and +especially by Haeckel. This last naturalist, besides his great work, +‘Generelle Morphologie’ (1866), has recently (1868, with a second +edition in 1870), published his ‘Natürliche Schöpfungsgeschichte,’ +in which he fully discusses the genealogy of man. If this work had appeared +before my essay had been written, I should probably never have completed it. +Almost all the conclusions at which I have arrived I find confirmed by this +naturalist, whose knowledge on many points is much fuller than mine. Wherever I +have added any fact or view from Prof. Haeckel’s writings, I give his +authority in the text; other statements I leave as they originally stood in my +manuscript, occasionally giving in the foot-notes references to his works, as a +confirmation of the more doubtful or interesting points. +</p> + +<p> +During many years it has seemed to me highly probable that sexual selection has +played an important part in differentiating the races of man; but in my +‘Origin of Species’ (first edition, page 199) I contented myself by +merely alluding to this belief. When I came to apply this view to man, I found +it indispensable to treat the whole subject in full detail. (2. Prof. Haeckel +was the only author who, at the time when this work first appeared, had +discussed the subject of sexual selection, and had seen its full importance, +since the publication of the ‘Origin’; and this he did in a very +able manner in his various works.) Consequently the second part of the present +work, treating of sexual selection, has extended to an inordinate length, +compared with the first part; but this could not be avoided. +</p> + +<p> +I had intended adding to the present volumes an essay on the expression of the +various emotions by man and the lower animals. My attention was called to this +subject many years ago by Sir Charles Bell’s admirable work. This +illustrious anatomist maintains that man is endowed with certain muscles solely +for the sake of expressing his emotions. As this view is obviously opposed to +the belief that man is descended from some other and lower form, it was +necessary for me to consider it. I likewise wished to ascertain how far the +emotions are expressed in the same manner by the different races of man. But +owing to the length of the present work, I have thought it better to reserve my +essay for separate publication. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2H_4_0006" id="link2H_4_0006"></a> +PART I.<br /> +THE DESCENT OR ORIGIN OF MAN.</h2> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0001" id="link2HCH0001"></a> +CHAPTER I.<br /> +THE EVIDENCE OF THE DESCENT OF MAN FROM SOME LOWER FORM.</h2> + +<p class="letter"> +Nature of the evidence bearing on the origin of man—Homologous structures +in man and the lower animals—Miscellaneous points of +correspondence—Development—Rudimentary structures, muscles, sense- +organs, hair, bones, reproductive organs, etc.—The bearing of these three +great classes of facts on the origin of man. +</p> + +<p> +He who wishes to decide whether man is the modified descendant of some +pre-existing form, would probably first enquire whether man varies, however +slightly, in bodily structure and in mental faculties; and if so, whether the +variations are transmitted to his offspring in accordance with the laws which +prevail with the lower animals. Again, are the variations the result, as far as +our ignorance permits us to judge, of the same general causes, and are they +governed by the same general laws, as in the case of other organisms; for +instance, by correlation, the inherited effects of use and disuse, etc.? Is man +subject to similar malconformations, the result of arrested development, of +reduplication of parts, etc., and does he display in any of his anomalies +reversion to some former and ancient type of structure? It might also naturally +be enquired whether man, like so many other animals, has given rise to +varieties and sub-races, differing but slightly from each other, or to races +differing so much that they must be classed as doubtful species? How are such +races distributed over the world; and how, when crossed, do they react on each +other in the first and succeeding generations? And so with many other points. +</p> + +<p> +The enquirer would next come to the important point, whether man tends to +increase at so rapid a rate, as to lead to occasional severe struggles for +existence; and consequently to beneficial variations, whether in body or mind, +being preserved, and injurious ones eliminated. Do the races or species of men, +whichever term may be applied, encroach on and replace one another, so that +some finally become extinct? We shall see that all these questions, as indeed +is obvious in respect to most of them, must be answered in the affirmative, in +the same manner as with the lower animals. But the several considerations just +referred to may be conveniently deferred for a time: and we will first see how +far the bodily structure of man shews traces, more or less plain, of his +descent from some lower form. In succeeding chapters the mental powers of man, +in comparison with those of the lower animals, will be considered. +</p> + +<h3>THE BODILY STRUCTURE OF MAN.</h3> + +<p> +It is notorious that man is constructed on the same general type or model as +other mammals. All the bones in his skeleton can be compared with corresponding +bones in a monkey, bat, or seal. So it is with his muscles, nerves, +blood-vessels and internal viscera. The brain, the most important of all the +organs, follows the same law, as shewn by Huxley and other anatomists. Bischoff +(1. ‘Grosshirnwindungen des Menschen,’ 1868, s. 96. The conclusions +of this author, as well as those of Gratiolet and Aeby, concerning the brain, +will be discussed by Prof. Huxley in the Appendix alluded to in the Preface to +this edition.), who is a hostile witness, admits that every chief fissure and +fold in the brain of man has its analogy in that of the orang; but he adds that +at no period of development do their brains perfectly agree; nor could perfect +agreement be expected, for otherwise their mental powers would have been the +same. Vulpian (2. ‘Lec. sur la Phys.’ 1866, page 890, as quoted by +M. Dally, ‘L’Ordre des Primates et le Transformisme,’ 1868, +page 29.), remarks: “Les différences réelles qui existent entre +l’encephale de l’homme et celui des singes supérieurs, sont bien +minimes. Il ne faut pas se faire d’illusions a cet égard. L’homme +est bien plus près des singes anthropomorphes par les caractères anatomiques de +son cerveau que ceux-ci ne le sont non seulement des autres mammifères, mais +même de certains quadrumanes, des guenons et des macaques.” But it would +be superfluous here to give further details on the correspondence between man +and the higher mammals in the structure of the brain and all other parts of the +body. +</p> + +<p> +It may, however, be worth while to specify a few points, not directly or +obviously connected with structure, by which this correspondence or +relationship is well shewn. +</p> + +<p> +Man is liable to receive from the lower animals, and to communicate to them, +certain diseases, as hydrophobia, variola, the glanders, syphilis, cholera, +herpes, etc. (3. Dr. W. Lauder Lindsay has treated this subject at some length +in the ‘Journal of Mental Science,’ July 1871; and in the +‘Edinburgh Veterinary Review,’ July 1858.); and this fact proves +the close similarity (4. A Reviewer has criticised (‘British Quarterly +Review,’ Oct. 1st, 1871, page 472) what I have here said with much +severity and contempt; but as I do not use the term identity, I cannot see that +I am greatly in error. There appears to me a strong analogy between the same +infection or contagion producing the same result, or one closely similar, in +two distinct animals, and the testing of two distinct fluids by the same +chemical reagent.) of their tissues and blood, both in minute structure and +composition, far more plainly than does their comparison under the best +microscope, or by the aid of the best chemical analysis. Monkeys are liable to +many of the same non-contagious diseases as we are; thus Rengger (5. +‘Naturgeschichte der Säugethiere von Paraguay,’ 1830, s. 50.), who +carefully observed for a long time the Cebus Azarae in its native land, found +it liable to catarrh, with the usual symptoms, and which, when often recurrent, +led to consumption. These monkeys suffered also from apoplexy, inflammation of +the bowels, and cataract in the eye. The younger ones when shedding their +milk-teeth often died from fever. Medicines produced the same effect on them as +on us. Many kinds of monkeys have a strong taste for tea, coffee, and spiritous +liquors: they will also, as I have myself seen, smoke tobacco with pleasure. +(6. The same tastes are common to some animals much lower in the scale. Mr. A. +Nichols informs me that he kept in Queensland, in Australia, three individuals +of the Phaseolarctus cinereus; and that, without having been taught in any way, +they acquired a strong taste for rum, and for smoking tobacco.) Brehm asserts +that the natives of north-eastern Africa catch the wild baboons by exposing +vessels with strong beer, by which they are made drunk. He has seen some of +these animals, which he kept in confinement, in this state; and he gives a +laughable account of their behaviour and strange grimaces. On the following +morning they were very cross and dismal; they held their aching heads with both +hands, and wore a most pitiable expression: when beer or wine was offered them, +they turned away with disgust, but relished the juice of lemons. (7. Brehm, +‘Thierleben,’ B. i. 1864, s. 75, 86. On the Ateles, s. 105. For +other analogous statements, see s. 25, 107.) An American monkey, an Ateles, +after getting drunk on brandy, would never touch it again, and thus was wiser +than many men. These trifling facts prove how similar the nerves of taste must +be in monkeys and man, and how similarly their whole nervous system is +affected. +</p> + +<p> +Man is infested with internal parasites, sometimes causing fatal effects; and +is plagued by external parasites, all of which belong to the same genera or +families as those infesting other mammals, and in the case of scabies to the +same species. (8. Dr. W. Lauder Lindsay, ‘Edinburgh Vet. Review,’ +July 1858, page 13.) Man is subject, like other mammals, birds, and even +insects (9. With respect to insects see Dr. Laycock, “On a General Law of +Vital Periodicity,” ‘British Association,’ 1842. Dr. +Macculloch, ‘Silliman’s North American Journal of Science,’ +vol. XVII. page 305, has seen a dog suffering from tertian ague. Hereafter I +shall return to this subject.), to that mysterious law, which causes certain +normal processes, such as gestation, as well as the maturation and duration of +various diseases, to follow lunar periods. His wounds are repaired by the same +process of healing; and the stumps left after the amputation of his limbs, +especially during an early embryonic period, occasionally possess some power of +regeneration, as in the lowest animals. (10. I have given the evidence on this +head in my ‘Variation of Animals and Plants under Domestication,’ +vol. ii. page 15, and more could be added.) +</p> + +<p> +The whole process of that most important function, the reproduction of the +species, is strikingly the same in all mammals, from the first act of courtship +by the male (11. Mares e diversis generibus Quadrumanorum sine dubio dignoscunt +feminas humanas a maribus. Primum, credo, odoratu, postea aspectu. Mr. Youatt, +qui diu in 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 confirmaverunt. Sir Andrew Smith et Brehm notabant +idem in Cynocephalo. Illustrissimus Cuvier etiam narrat multa de hac re, qua ut +opinor, nihil turpius potest indicari inter omnia hominibus et Quadrumanis +communia. Narrat enim Cynocephalum quendam in furorem incidere aspectu +feminarum aliquarem, sed nequaquam accendi tanto furore ab omnibus. Semper +eligebat juniores, et dignoscebat in turba, et advocabat voce gestuque.), to +the birth and nurturing of the young. Monkeys are born in almost as helpless a +condition as our own infants; and in certain genera the young differ fully as +much in appearance from the adults, as do our children from their full-grown +parents. (12. This remark is made with respect to Cynocephalus and the +anthropomorphous apes by Geoffroy Saint-Hilaire and F. Cuvier, ‘Histoire +Nat. des Mammifères,’ tom. i. 1824.) It has been urged by some writers, +as an important distinction, that with man the young arrive at maturity at a +much later age than with any other animal: but if we look to the races of +mankind which inhabit tropical countries the difference is not great, for the +orang is believed not to be adult till the age of from ten to fifteen years. +(13. Huxley, ‘Man’s Place in Nature,’ 1863, p. 34.) Man +differs from woman in size, bodily strength, hairiness, etc., as well as in +mind, in the same manner as do the two sexes of many mammals. So that the +correspondence in general structure, in the minute structure of the tissues, in +chemical composition and in constitution, between man and the higher animals, +especially the anthropomorphous apes, is extremely close. +</p> + +<h3>EMBRYONIC DEVELOPMENT.</h3> + +<p> +[Fig. 1. Shows a human embryo, from Ecker, and a dog embryo, from Bischoff. +Labelled in each are: +</p> + +<p> +a. Fore-brain, cerebral hemispheres, etc. b. Mid-brain, corpora quadrigemina. +c. Hind-brain, cerebellum, medulla oblongata. d. Eye. e. Ear. f. First visceral +arch. g. Second visceral arch. H. Vertebral columns and muscles in process of +development. i. Anterior extremities. K. Posterior extremities. L. Tail or os +coccyx.] +</p> + +<p> +Man is developed from an ovule, about the 125th of an inch in diameter, which +differs in no respect from the ovules of other animals. The embryo itself at a +very early period can hardly be distinguished from that of other members of the +vertebrate kingdom. At this period the arteries run in arch-like branches, as +if to carry the blood to branchiae which are not present in the higher +Vertebrata, though the slits on the sides of the neck still remain (see f, g, +fig. 1), marking their former position. At a somewhat later period, when the +extremities are developed, “the feet of lizards and mammals,” as +the illustrious Von Baer remarks, “the wings and feet of birds, no less +than the hands and feet of man, all arise from the same fundamental +form.” It is, says Prof. Huxley (14. ‘Man’s Place in +Nature,’ 1863, p. 67.), “quite in the later stages of development +that the young human being presents marked differences from the young ape, +while the latter departs as much from the dog in its developments, as the man +does. Startling as this last assertion may appear to be, it is demonstrably +true.” +</p> + +<p> +As some of my readers may never have seen a drawing of an embryo, I have given +one of man and another of a dog, at about the same early stage of development, +carefully copied from two works of undoubted accuracy. (15. The human embryo +(upper fig.) is from Ecker, ‘Icones Phys.,’ 1851-1859, tab. xxx. +fig. 2. This embryo was ten lines in length, so that the drawing is much +magnified. The embryo of the dog is from Bischoff, +‘Entwicklungsgeschichte des Hunde-Eies,’ 1845, tab. xi. fig. 42B. +This drawing is five times magnified, the embryo being twenty-five days old. +The internal viscera have been omitted, and the uterine appendages in both +drawings removed. I was directed to these figures by Prof. Huxley, from whose +work, ‘Man’s Place in Nature,’ the idea of giving them was +taken. Haeckel has also given analogous drawings in his +‘Schopfungsgeschichte.’) +</p> + +<p> +After the foregoing statements made by such high authorities, it would be +superfluous on my part to give a number of borrowed details, shewing that the +embryo of man closely resembles that of other mammals. It may, however, be +added, that the human embryo likewise resembles certain low forms when adult in +various points of structure. For instance, the heart at first exists as a +simple pulsating vessel; the excreta are voided through a cloacal passage; and +the os coccyx projects like a true tail, “extending considerably beyond +the rudimentary legs.” (16. Prof. Wyman in ‘Proceedings of the +American Academy of Sciences,’ vol. iv. 1860, p. 17.) In the embryos of +all air-breathing vertebrates, certain glands, called the corpora Wolffiana, +correspond with, and act like the kidneys of mature fishes. (17. Owen, +‘Anatomy of Vertebrates,’ vol. i. p. 533.) Even at a later +embryonic period, some striking resemblances between man and the lower animals +may be observed. Bischoff says that “the convolutions of the brain in a +human foetus at the end of the seventh month reach about the same stage of +development as in a baboon when adult.” (18. ‘Die +Grosshirnwindungen des Menschen,’ 1868, s. 95.) The great toe, as +Professor Owen remarks (19. ‘Anatomy of Vertebrates,’ vol. ii. p. +553.), “which forms the fulcrum when standing or walking, is perhaps the +most characteristic peculiarity in the human structure;” but in an +embryo, about an inch in length, Prof. Wyman (20. ‘Proc. Soc. Nat. +Hist.’ Boston, 1863, vol. ix. p. 185.) found “that the great toe +was shorter than the others; and, instead of being parallel to them, projected +at an angle from the side of the foot, thus corresponding with the permanent +condition of this part in the quadrumana.” I will conclude with a +quotation from Huxley (21. ‘Man’s Place in Nature,’ p. 65.) +who after asking, does man originate in a different way from a dog, bird, frog +or fish? says, “the reply is not doubtful for a moment; without question, +the mode of origin, and the early stages of the development of man, are +identical with those of the animals immediately below him in the scale: without +a doubt in these respects, he is far nearer to apes than the apes are to the +dog.” +</p> + +<h3>RUDIMENTS.</h3> + +<p> +This subject, though not intrinsically more important than the two last, will +for several reasons be treated here more fully. (22. I had written a rough copy +of this chapter before reading a valuable paper, “Caratteri rudimentali +in ordine all’ origine dell’ uomo” (‘Annuario della +Soc. d. Naturalisti,’ Modena, 1867, p. 81), by G. Canestrini, to which +paper I am considerably indebted. Haeckel has given admirable discussions on +this whole subject, under the title of Dysteleology, in his ‘Generelle +Morphologie’ and ‘Schöpfungsgeschichte.’) Not one of the +higher animals can be named which does not bear some part in a rudimentary +condition; and man forms no exception to the rule. Rudimentary organs must be +distinguished from those that are nascent; though in some cases the distinction +is not easy. The former are either absolutely useless, such as the mammae of +male quadrupeds, or the incisor teeth of ruminants which never cut through the +gums; or they are of such slight service to their present possessors, that we +can hardly suppose that they were developed under the conditions which now +exist. Organs in this latter state are not strictly rudimentary, but they are +tending in this direction. Nascent organs, on the other hand, though not fully +developed, are of high service to their possessors, and are capable of further +development. Rudimentary organs are eminently variable; and this is partly +intelligible, as they are useless, or nearly useless, and consequently are no +longer subjected to natural selection. They often become wholly suppressed. +When this occurs, they are nevertheless liable to occasional reappearance +through reversion—a circumstance well worthy of attention. +</p> + +<p> +The chief agents in causing organs to become rudimentary seem to have been +disuse at that period of life when the organ is chiefly used (and this is +generally during maturity), and also inheritance at a corresponding period of +life. The term “disuse” does not relate merely to the lessened +action of muscles, but includes a diminished flow of blood to a part or organ, +from being subjected to fewer alternations of pressure, or from becoming in any +way less habitually active. Rudiments, however, may occur in one sex of those +parts which are normally present in the other sex; and such rudiments, as we +shall hereafter see, have often originated in a way distinct from those here +referred to. In some cases, organs have been reduced by means of natural +selection, from having become injurious to the species under changed habits of +life. The process of reduction is probably often aided through the two +principles of compensation and economy of growth; but the later stages of +reduction, after disuse has done all that can fairly be attributed to it, and +when the saving to be effected by the economy of growth would be very small +(23. Some good criticisms on this subject have been given by Messrs. Murie and +Mivart, in ‘Transact. Zoological Society,’ 1869, vol. vii. p. 92.), +are difficult to understand. The final and complete suppression of a part, +already useless and much reduced in size, in which case neither compensation +nor economy can come into play, is perhaps intelligible by the aid of the +hypothesis of pangenesis. But as the whole subject of rudimentary organs has +been discussed and illustrated in my former works (24. ‘Variation of +Animals and Plants under Domestication,’ vol. ii pp. 317 and 397. See +also ‘Origin of Species,’ 5th Edition p. 535.), I need here say no +more on this head. +</p> + +<p> +Rudiments of various muscles have been observed in many parts of the human body +(25. For instance, M. Richard (‘Annales des Sciences Nat.,’ 3rd +series, Zoolog. 1852, tom. xviii. p. 13) describes and figures rudiments of +what he calls the “muscle pedieux de la main,” which he says is +sometimes “infiniment petit.” Another muscle, called “le +tibial posterieur,” is generally quite absent in the hand, but appears +from time to time in a more or less rudimentary condition.); and not a few +muscles, which are regularly present in some of the lower animals can +occasionally be detected in man in a greatly reduced condition. Every one must +have noticed the power which many animals, especially horses, possess of moving +or twitching their skin; and this is effected by the panniculus carnosus. +Remnants of this muscle in an efficient state are found in various parts of our +bodies; for instance, the muscle on the forehead, by which the eyebrows are +raised. The platysma myoides, which is well developed on the neck, belongs to +this system. Prof. Turner, of Edinburgh, has occasionally detected, as he +informs me, muscular fasciculi in five different situations, namely in the +axillae, near the scapulae, etc., all of which must be referred to the system +of the panniculus. He has also shewn (26. Prof. W. Turner, ‘Proceedings +of the Royal Society of Edinburgh,’ 1866-67, p. 65.) that the musculus +sternalis or sternalis brutorum, which is not an extension of the rectus +abdominalis, but is closely allied to the panniculus, occurred in the +proportion of about three per cent. in upwards of 600 bodies: he adds, that +this muscle affords “an excellent illustration of the statement that +occasional and rudimentary structures are especially liable to variation in +arrangement.” +</p> + +<p> +Some few persons have the power of contracting the superficial muscles on their +scalps; and these muscles are in a variable and partially rudimentary +condition. M. A. de Candolle has communicated to me a curious instance of the +long-continued persistence or inheritance of this power, as well as of its +unusual development. He knows a family, in which one member, the present head +of the family, could, when a youth, pitch several heavy books from his head by +the movement of the scalp alone; and he won wagers by performing this feat. His +father, uncle, grandfather, and his three children possess the same power to +the same unusual degree. This family became divided eight generations ago into +two branches; so that the head of the above-mentioned branch is cousin in the +seventh degree to the head of the other branch. This distant cousin resides in +another part of France; and on being asked whether he possessed the same +faculty, immediately exhibited his power. This case offers a good illustration +how persistent may be the transmission of an absolutely useless faculty, +probably derived from our remote semi-human progenitors; since many monkeys +have, and frequently use the power, of largely moving their scalps up and down. +(27. See my ‘Expression of the Emotions in Man and Animals,’ 1872, +p. 144.) +</p> + +<p> +The extrinsic muscles which serve to move the external ear, and the intrinsic +muscles which move the different parts, are in a rudimentary condition in man, +and they all belong to the system of the panniculus; they are also variable in +development, or at least in function. I have seen one man who could draw the +whole ear forwards; other men can draw it upwards; another who could draw it +backwards (28. Canestrini quotes Hyrtl. (‘Annuario della Soc. dei +Naturalisti,’ Modena, 1867, p. 97) to the same effect.); and from what +one of these persons told me, it is probable that most of us, by often touching +our ears, and thus directing our attention towards them, could recover some +power of movement by repeated trials. The power of erecting and directing the +shell of the ears to the various points of the compass, is no doubt of the +highest service to many animals, as they thus perceive the direction of danger; +but I have never heard, on sufficient evidence, of a man who possessed this +power, the one which might be of use to him. The whole external shell may be +considered a rudiment, together with the various folds and prominences (helix +and anti-helix, tragus and anti-tragus, etc.) which in the lower animals +strengthen and support the ear when erect, without adding much to its weight. +Some authors, however, suppose that the cartilage of the shell serves to +transmit vibrations to the acoustic nerve; but Mr. Toynbee (29. ‘The +Diseases of the Ear,’ by J. Toynbee, F.R.S., 1860, p. 12. A distinguished +physiologist, Prof. Preyer, informs me that he had lately been experimenting on +the function of the shell of the ear, and has come to nearly the same +conclusion as that given here.), after collecting all the known evidence on +this head, concludes that the external shell is of no distinct use. The ears of +the chimpanzee and orang are curiously like those of man, and the proper +muscles are likewise but very slightly developed. (30. Prof. A. Macalister, +‘Annals and Magazine of Natural History,’ vol. vii. 1871, p. 342.) +I am also assured by the keepers in the Zoological Gardens that these animals +never move or erect their ears; so that they are in an equally rudimentary +condition with those of man, as far as function is concerned. Why these +animals, as well as the progenitors of man, should have lost the power of +erecting their ears, we cannot say. It may be, though I am not satisfied with +this view, that owing to their arboreal habits and great strength they were but +little exposed to danger, and so during a lengthened period moved their ears +but little, and thus gradually lost the power of moving them. This would be a +parallel case with that of those large and heavy birds, which, from inhabiting +oceanic islands, have not been exposed to the attacks of beasts of prey, and +have consequently lost the power of using their wings for flight. The inability +to move the ears in man and several apes is, however, partly compensated by the +freedom with which they can move the head in a horizontal plane, so as to catch +sounds from all directions. It has been asserted that the ear of man alone +possesses a lobule; but “a rudiment of it is found in the gorilla” +(31. Mr. St. George Mivart, ‘Elementary Anatomy,’ 1873, p. 396.); +and, as I hear from Prof. Preyer, it is not rarely absent in the negro. +</p> + +<p> +[Fig. 2. Human Ear, modelled and drawn by Mr. Woolner. The projecting point is +labelled a.] +</p> + +<p> +The celebrated sculptor, Mr. Woolner, informs me of one little peculiarity in +the external ear, which he has often observed both in men and women, and of +which he perceived the full significance. His attention was first called to the +subject whilst at work on his figure of Puck, to which he had given pointed +ears. He was thus led to examine the ears of various monkeys, and subsequently +more carefully those of man. The peculiarity consists in a little blunt point, +projecting from the inwardly folded margin, or helix. When present, it is +developed at birth, and, according to Prof. Ludwig Meyer, more frequently in +man than in woman. Mr. Woolner made an exact model of one such case, and sent +me the accompanying drawing. (Fig. 2). These points not only project inwards +towards the centre of the ear, but often a little outwards from its plane, so +as to be visible when the head is viewed from directly in front or behind. They +are variable in size, and somewhat in position, standing either a little higher +or lower; and they sometimes occur on one ear and not on the other. They are +not confined to mankind, for I observed a case in one of the spider-monkeys +(Ateles beelzebuth) in our Zoological Gardens; and Mr. E. Ray Lankester informs +me of another case in a chimpanzee in the gardens at Hamburg. The helix +obviously consists of the extreme margin of the ear folded inwards; and this +folding appears to be in some manner connected with the whole external ear +being permanently pressed backwards. In many monkeys, which do not stand high +in the order, as baboons and some species of macacus (32. See also some +remarks, and the drawings of the ears of the Lemuroidea, in Messrs. Murie and +Mivart’s excellent paper in ‘Transactions of the Zoological +Society,’ vol. vii. 1869, pp. 6 and 90.), the upper portion of the ear is +slightly pointed, and the margin is not at all folded inwards; but if the +margin were to be thus folded, a slight point would necessarily project inwards +towards the centre, and probably a little outwards from the plane of the ear; +and this I believe to be their origin in many cases. On the other hand, Prof. +L. Meyer, in an able paper recently published (33. ‘Über das +Darwin’sche Spitzohr,’ Archiv fur Path. Anat. und Phys., 1871, p. +485.), maintains that the whole case is one of mere variability; and that the +projections are not real ones, but are due to the internal cartilage on each +side of the points not having been fully developed. I am quite ready to admit +that this is the correct explanation in many instances, as in those figured by +Prof. Meyer, in which there are several minute points, or the whole margin is +sinuous. I have myself seen, through the kindness of Dr. L. Down, the ear of a +microcephalous idiot, on which there is a projection on the outside of the +helix, and not on the inward folded edge, so that this point can have no +relation to a former apex of the ear. Nevertheless in some cases, my original +view, that the points are vestiges of the tips of formerly erect and pointed +ears, still seems to me probable. I think so from the frequency of their +occurrence, and from the general correspondence in position with that of the +tip of a pointed ear. In one case, of which a photograph has been sent me, the +projection is so large, that supposing, in accordance with Prof. Meyer’s +view, the ear to be made perfect by the equal development of the cartilage +throughout the whole extent of the margin, it would have covered fully +one-third of the whole ear. Two cases have been communicated to me, one in +North America, and the other in England, in which the upper margin is not at +all folded inwards, but is pointed, so that it closely resembles the pointed +ear of an ordinary quadruped in outline. In one of these cases, which was that +of a young child, the father compared the ear with the drawing which I have +given (34. ‘The Expression of the Emotions,’ p. 136.) of the ear of +a monkey, the Cynopithecus niger, and says that their outlines are closely +similar. If, in these two cases, the margin had been folded inwards in the +normal manner, an inward projection must have been formed. I may add that in +two other cases the outline still remains somewhat pointed, although the margin +of the upper part of the ear is normally folded inwards—in one of them, +however, very narrowly. [Fig.3. Foetus of an Orang(?). Exact copy of a +photograph, shewing the form of the ear at this early age.] The following +woodcut (No. 3) is an accurate copy of a photograph of the foetus of an orang +(kindly sent me by Dr. Nitsche), in which it may be seen how different the +pointed outline of the ear is at this period from its adult condition, when it +bears a close general resemblance to that of man. It is evident that the +folding over of the tip of such an ear, unless it changed greatly during its +further development, would give rise to a point projecting inwards. On the +whole, it still seems to me probable that the points in question are in some +cases, both in man and apes, vestiges of a former condition. +</p> + +<p> +The nictitating membrane, or third eyelid, with its accessory muscles and other +structures, is especially well developed in birds, and is of much functional +importance to them, as it can be rapidly drawn across the whole eye-ball. It is +found in some reptiles and amphibians, and in certain fishes, as in sharks. It +is fairly well developed in the two lower divisions of the mammalian series, +namely, in the monotremata and marsupials, and in some few of the higher +mammals, as in the walrus. But in man, the quadrumana, and most other mammals, +it exists, as is admitted by all anatomists, as a mere rudiment, called the +semilunar fold. (35. Muller’s ‘Elements of Physiology,’ Eng. +translat. 1842, vol. ii. p. 1117. Owen, ‘Anatomy of Vertebrates,’ +vol. iii. p. 260; ibid. on the Walrus, ‘Proceedings of the Zoological +Society,’ November 8, 1854. See also R. Knox, ‘Great Artists and +Anatomists,’ p. 106. This rudiment apparently is somewhat larger in +Negroes and Australians than in Europeans, see Carl Vogt, ‘Lectures on +Man,’ Eng. translat. p. 129.) +</p> + +<p> +The sense of smell is of the highest importance to the greater number of +mammals—to some, as the ruminants, in warning them of danger; to others, +as the Carnivora, in finding their prey; to others, again, as the wild boar, +for both purposes combined. But the sense of smell is of extremely slight +service, if any, even to the dark coloured races of men, in whom it is much +more highly developed than in the white and civilised races. (36. The account +given by Humboldt of the power of smell possessed by the natives of South +America is well known, and has been confirmed by others. M. Houzeau +(‘Études sur les Facultés Mentales,’ etc., tom. i. 1872, p. 91) +asserts that he repeatedly made experiments, and proved that Negroes and +Indians could recognise persons in the dark by their odour. Dr. W. Ogle has +made some curious observations on the connection between the power of smell and +the colouring matter of the mucous membrane of the olfactory region as well as +of the skin of the body. I have, therefore, spoken in the text of the +dark-coloured races having a finer sense of smell than the white races. See his +paper, ‘Medico-Chirurgical Transactions,’ London, vol. liii. 1870, +p. 276.) Nevertheless it does not warn them of danger, nor guide them to their +food; nor does it prevent the Esquimaux from sleeping in the most fetid +atmosphere, nor many savages from eating half-putrid meat. In Europeans the +power differs greatly in different individuals, as I am assured by an eminent +naturalist who possesses this sense highly developed, and who has attended to +the subject. Those who believe in the principle of gradual evolution, will not +readily admit that the sense of smell in its present state was originally +acquired by man, as he now exists. He inherits the power in an enfeebled and so +far rudimentary condition, from some early progenitor, to whom it was highly +serviceable, and by whom it was continually used. In those animals which have +this sense highly developed, such as dogs and horses, the recollection of +persons and of places is strongly associated with their odour; and we can thus +perhaps understand how it is, as Dr. Maudsley has truly remarked (37. +‘The Physiology and Pathology of Mind,’ 2nd ed. 1868, p. 134.), +that the sense of smell in man “is singularly effective in recalling +vividly the ideas and images of forgotten scenes and places.” +</p> + +<p> +Man differs conspicuously from all the other primates in being almost naked. +But a few short straggling hairs are found over the greater part of the body in +the man, and fine down on that of the woman. The different races differ much in +hairiness; and in the individuals of the same race the hairs are highly +variable, not only in abundance, but likewise in position: thus in some +Europeans the shoulders are quite naked, whilst in others they bear thick tufts +of hair. (38. Eschricht, Über die Richtung der Haare am menschlichen Körper, +Muller’s ‘Archiv fur Anat. und Phys.’ 1837, s. 47. I shall +often have to refer to this very curious paper.) There can be little doubt that +the hairs thus scattered over the body are the rudiments of the uniform hairy +coat of the lower animals. This view is rendered all the more probable, as it +is known that fine, short, and pale-coloured hairs on the limbs and other parts +of the body, occasionally become developed into “thickset, long, and +rather coarse dark hairs,” when abnormally nourished near old-standing +inflamed surfaces. (39. Paget, ‘Lectures on Surgical Pathology,’ +1853, vol. i. p. 71.) +</p> + +<p> +I am informed by Sir James Paget that often several members of a family have a +few hairs in their eyebrows much longer than the others; so that even this +slight peculiarity seems to be inherited. These hairs, too, seem to have their +representatives; for in the chimpanzee, and in certain species of Macacus, +there are scattered hairs of considerable length rising from the naked skin +above the eyes, and corresponding to our eyebrows; similar long hairs project +from the hairy covering of the superciliary ridges in some baboons. +</p> + +<p> +The fine wool-like hair, or so-called lanugo, with which the human foetus +during the sixth month is thickly covered, offers a more curious case. It is +first developed, during the fifth month, on the eyebrows and face, and +especially round the mouth, where it is much longer than that on the head. A +moustache of this kind was observed by Eschricht (40. Eschricht, ibid. s. 40, +47.) on a female foetus; but this is not so surprising a circumstance as it may +at first appear, for the two sexes generally resemble each other in all +external characters during an early period of growth. The direction and +arrangement of the hairs on all parts of the foetal body are the same as in the +adult, but are subject to much variability. The whole surface, including even +the forehead and ears, is thus thickly clothed; but it is a significant fact +that the palms of the hands and the soles of the feet are quite naked, like the +inferior surfaces of all four extremities in most of the lower animals. As this +can hardly be an accidental coincidence, the woolly covering of the foetus +probably represents the first permanent coat of hair in those mammals which are +born hairy. Three or four cases have been recorded of persons born with their +whole bodies and faces thickly covered with fine long hairs; and this strange +condition is strongly inherited, and is correlated with an abnormal condition +of the teeth. (41. See my ‘Variation of Animals and Plants under +Domestication,’ vol. ii. p. 327. Prof. Alex. Brandt has recently sent me +an additional case of a father and son, born in Russia, with these +peculiarities. I have received drawings of both from Paris.) Prof. Alex. Brandt +informs me that he has compared the hair from the face of a man thus +characterised, aged thirty-five, with the lanugo of a foetus, and finds it +quite similar in texture; therefore, as he remarks, the case may be attributed +to an arrest of development in the hair, together with its continued growth. +Many delicate children, as I have been assured by a surgeon to a hospital for +children, have their backs covered by rather long silky hairs; and such cases +probably come under the same head. +</p> + +<p> +It appears as if the posterior molar or wisdom-teeth were tending to become +rudimentary in the more civilised races of man. These teeth are rather smaller +than the other molars, as is likewise the case with the corresponding teeth in +the chimpanzee and orang; and they have only two separate fangs. They do not +cut through the gums till about the seventeenth year, and I have been assured +that they are much more liable to decay, and are earlier lost than the other +teeth; but this is denied by some eminent dentists. They are also much more +liable to vary, both in structure and in the period of their development, than +the other teeth. (42. Dr. Webb, ‘Teeth in Man and the Anthropoid +Apes,’ as quoted by Dr. C. Carter Blake in Anthropological Review, July +1867, p. 299.) In the Melanian races, on the other hand, the wisdom-teeth are +usually furnished with three separate fangs, and are generally sound; they also +differ from the other molars in size, less than in the Caucasian races. (43. +Owen, ‘Anatomy of Vertebrates,’ vol. iii. pp. 320, 321, and 325.) +Prof. Schaaffhausen accounts for this difference between the races by +“the posterior dental portion of the jaw being always shortened” in +those that are civilised (44. ‘On the Primitive Form of the Skull,’ +Eng. translat., in ‘Anthropological Review,’ Oct. 1868, p. 426), +and this shortening may, I presume, be attributed to civilised men habitually +feeding on soft, cooked food, and thus using their jaws less. I am informed by +Mr. Brace that it is becoming quite a common practice in the United States to +remove some of the molar teeth of children, as the jaw does not grow large +enough for the perfect development of the normal number. (45. Prof. Montegazza +writes to me from Florence, that he has lately been studying the last molar +teeth in the different races of man, and has come to the same conclusion as +that given in my text, viz., that in the higher or civilised races they are on +the road towards atrophy or elimination.) +</p> + +<p> +With respect to the alimentary canal, I have met with an account of only a +single rudiment, namely the vermiform appendage of the caecum. The caecum is a +branch or diverticulum of the intestine, ending in a cul-de-sac, and is +extremely long in many of the lower vegetable-feeding mammals. In the marsupial +koala it is actually more than thrice as long as the whole body. (46. Owen, +‘Anatomy of Vertebrates,’ vol. iii. pp. 416, 434, 441.) It is +sometimes produced into a long gradually-tapering point, and is sometimes +constricted in parts. It appears as if, in consequence of changed diet or +habits, the caecum had become much shortened in various animals, the vermiform +appendage being left as a rudiment of the shortened part. That this appendage +is a rudiment, we may infer from its small size, and from the evidence which +Prof. Canestrini (47. ‘Annuario della Soc. d. Nat.’ Modena, 1867, +p. 94.) has collected of its variability in man. It is occasionally quite +absent, or again is largely developed. The passage is sometimes completely +closed for half or two-thirds of its length, with the terminal part consisting +of a flattened solid expansion. In the orang this appendage is long and +convoluted: in man it arises from the end of the short caecum, and is commonly +from four to five inches in length, being only about the third of an inch in +diameter. Not only is it useless, but it is sometimes the cause of death, of +which fact I have lately heard two instances: this is due to small hard bodies, +such as seeds, entering the passage, and causing inflammation. (48. M. C. +Martins (“De l’Unité Organique,” in ‘Revue des Deux +Mondes,’ June 15, 1862, p. 16) and Haeckel (‘Generelle +Morphologie,’ B. ii. s. 278), have both remarked on the singular fact of +this rudiment sometimes causing death.) +</p> + +<p> +In some of the lower Quadrumana, in the Lemuridae and Carnivora, as well as in +many marsupials, there is a passage near the lower end of the humerus, called +the supra-condyloid foramen, through which the great nerve of the fore limb and +often the great artery pass. Now in the humerus of man, there is generally a +trace of this passage, which is sometimes fairly well developed, being formed +by a depending hook-like process of bone, completed by a band of ligament. Dr. +Struthers (49. With respect to inheritance, see Dr. Struthers in the +‘Lancet,’ Feb. 15, 1873, and another important paper, ibid. Jan. +24, 1863, p. 83. Dr. Knox, as I am informed, was the first anatomist who drew +attention to this peculiar structure in man; see his ‘Great Artists and +Anatomists,’ p. 63. See also an important memoir on this process by Dr. +Gruber, in the ‘Bulletin de l’Acad. Imp. de St. Petersbourg,’ +tom. xii. 1867, p. 448.), who has closely attended to the subject, has now +shewn that this peculiarity is sometimes inherited, as it has occurred in a +father, and in no less than four out of his seven children. When present, the +great nerve invariably passes through it; and this clearly indicates that it is +the homologue and rudiment of the supra-condyloid foramen of the lower animals. +Prof. Turner estimates, as he informs me, that it occurs in about one per cent. +of recent skeletons. But if the occasional development of this structure in man +is, as seems probable, due to reversion, it is a return to a very ancient state +of things, because in the higher Quadrumana it is absent. +</p> + +<p> +There is another foramen or perforation in the humerus, occasionally present in +man, which may be called the inter-condyloid. This occurs, but not constantly, +in various anthropoid and other apes (50. Mr. St. George Mivart, +‘Transactions Phil. Soc.’ 1867, p. 310.), and likewise in many of +the lower animals. It is remarkable that this perforation seems to have been +present in man much more frequently during ancient times than recently. Mr. +Busk (51. “On the Caves of Gibraltar,” ‘Transactions of the +International Congress of Prehistoric Archaeology,’ Third Session, 1869, +p. 159. Prof. Wyman has lately shewn (Fourth Annual Report, Peabody Museum, +1871, p. 20), that this perforation is present in thirty-one per cent. of some +human remains from ancient mounds in the Western United States, and in Florida. +It frequently occurs in the negro.) has collected the following evidence on +this head: Prof. Broca “noticed the perforation in four and a half per +cent. of the arm-bones collected in the ‘Cimetière du Sud,’ at +Paris; and in the Grotto of Orrony, the contents of which are referred to the +Bronze period, as many as eight humeri out of thirty-two were perforated; but +this extraordinary proportion, he thinks, might be due to the cavern having +been a sort of ‘family vault.’ Again, M. Dupont found thirty per +cent. of perforated bones in the caves of the Valley of the Lesse, belonging to +the Reindeer period; whilst M. Leguay, in a sort of dolmen at Argenteuil, +observed twenty-five per cent. to be perforated; and M. Pruner-Bey found +twenty-six per cent. in the same condition in bones from Vaureal. Nor should it +be left unnoticed that M. Pruner-Bey states that this condition is common in +Guanche skeletons.” It is an interesting fact that ancient races, in this +and several other cases, more frequently present structures which resemble +those of the lower animals than do the modern. One chief cause seems to be that +the ancient races stand somewhat nearer in the long line of descent to their +remote animal-like progenitors. +</p> + +<p> +In man, the os coccyx, together with certain other vertebrae hereafter to be +described, though functionless as a tail, plainly represent this part in other +vertebrate animals. At an early embryonic period it is free, and projects +beyond the lower extremities; as may be seen in the drawing (Fig. 1.) of a +human embryo. Even after birth it has been known, in certain rare and anomalous +cases (52. Quatrefages has lately collected the evidence on this subject. +‘Revue des Cours Scientifiques,’ 1867-1868, p. 625. In 1840 +Fleischmann exhibited a human foetus bearing a free tail, which, as is not +always the case, included vertebral bodies; and this tail was critically +examined by the many anatomists present at the meeting of naturalists at +Erlangen (see Marshall in Niederlandischen Archiv für Zoologie, December +1871).), to form a small external rudiment of a tail. The os coccyx is short, +usually including only four vertebrae, all anchylosed together: and these are +in a rudimentary condition, for they consist, with the exception of the basal +one, of the centrum alone. (53. Owen, ‘On the Nature of Limbs,’ +1849, p. 114.) They are furnished with some small muscles; one of which, as I +am informed by Prof. Turner, has been expressly described by Theile as a +rudimentary repetition of the extensor of the tail, a muscle which is so +largely developed in many mammals. +</p> + +<p> +The spinal cord in man extends only as far downwards as the last dorsal or +first lumbar vertebra; but a thread-like structure (the filum terminale) runs +down the axis of the sacral part of the spinal canal, and even along the back +of the coccygeal bones. The upper part of this filament, as Prof. Turner +informs me, is undoubtedly homologous with the spinal cord; but the lower part +apparently consists merely of the pia mater, or vascular investing membrane. +Even in this case the os coccyx may be said to possess a vestige of so +important a structure as the spinal cord, though no longer enclosed within a +bony canal. The following fact, for which I am also indebted to Prof. Turner, +shews how closely the os coccyx corresponds with the true tail in the lower +animals: Luschka has recently discovered at the extremity of the coccygeal +bones a very peculiar convoluted body, which is continuous with the middle +sacral artery; and this discovery led Krause and Meyer to examine the tail of a +monkey (Macacus), and of a cat, in both of which they found a similarly +convoluted body, though not at the extremity. +</p> + +<p> +The reproductive system offers various rudimentary structures; but these differ +in one important respect from the foregoing cases. Here we are not concerned +with the vestige of a part which does not belong to the species in an efficient +state, but with a part efficient in the one sex, and represented in the other +by a mere rudiment. Nevertheless, the occurrence of such rudiments is as +difficult to explain, on the belief of the separate creation of each species, +as in the foregoing cases. Hereafter I shall have to recur to these rudiments, +and shall shew that their presence generally depends merely on inheritance, +that is, on parts acquired by one sex having been partially transmitted to the +other. I will in this place only give some instances of such rudiments. It is +well known that in the males of all mammals, including man, rudimentary mammae +exist. These in several instances have become well developed, and have yielded +a copious supply of milk. Their essential identity in the two sexes is likewise +shewn by their occasional sympathetic enlargement in both during an attack of +the measles. The vesicula prostatica, which has been observed in many male +mammals, is now universally acknowledged to be the homologue of the female +uterus, together with the connected passage. It is impossible to read +Leuckart’s able description of this organ, and his reasoning, without +admitting the justness of his conclusion. This is especially clear in the case +of those mammals in which the true female uterus bifurcates, for in the males +of these the vesicula likewise bifurcates. (54. Leuckart, in Todd’s +‘Cyclopaedia of Anatomy’ 1849-52, vol. iv. p. 1415. In man this +organ is only from three to six lines in length, but, like so many other +rudimentary parts, it is variable in development as well as in other +characters.) Some other rudimentary structures belonging to the reproductive +system might have been here adduced. (55. See, on this subject, Owen, +‘Anatomy of Vertebrates,’ vol. iii. pp. 675, 676, 706.) +</p> + +<p> +The bearing of the three great classes of facts now given is unmistakeable. But +it would be superfluous fully to recapitulate the line of argument given in +detail in my ‘Origin of Species.’ The homological construction of +the whole frame in the members of the same class is intelligible, if we admit +their descent from a common progenitor, together with their subsequent +adaptation to diversified conditions. On any other view, the similarity of +pattern between the hand of a man or monkey, the foot of a horse, the flipper +of a seal, the wing of a bat, etc., is utterly inexplicable. (56. Prof. +Bianconi, in a recently published work, illustrated by admirable engravings +(‘La Théorie Darwinienne et la création dite indépendante,’ 1874), +endeavours to shew that homological structures, in the above and other cases, +can be fully explained on mechanical principles, in accordance with their uses. +No one has shewn so well, how admirably such structures are adapted for their +final purpose; and this adaptation can, as I believe, be explained through +natural selection. In considering the wing of a bat, he brings forward (p. 218) +what appears to me (to use Auguste Comte’s words) a mere metaphysical +principle, namely, the preservation “in its integrity of the mammalian +nature of the animal.” In only a few cases does he discuss rudiments, and +then only those parts which are partially rudimentary, such as the little hoofs +of the pig and ox, which do not touch the ground; these he shews clearly to be +of service to the animal. It is unfortunate that he did not consider such cases +as the minute teeth, which never cut through the jaw in the ox, or the mammae +of male quadrupeds, or the wings of certain beetles, existing under the +soldered wing-covers, or the vestiges of the pistil and stamens in various +flowers, and many other such cases. Although I greatly admire Prof. +Bianconi’s work, yet the belief now held by most naturalists seems to me +left unshaken, that homological structures are inexplicable on the principle of +mere adaptation.) It is no scientific explanation to assert that they have all +been formed on the same ideal plan. With respect to development, we can clearly +understand, on the principle of variations supervening at a rather late +embryonic period, and being inherited at a corresponding period, how it is that +the embryos of wonderfully different forms should still retain, more or less +perfectly, the structure of their common progenitor. No other explanation has +ever been given of the marvellous fact that the embryos of a man, dog, seal, +bat, reptile, etc., can at first hardly be distinguished from each other. In +order to understand the existence of rudimentary organs, we have only to +suppose that a former progenitor possessed the parts in question in a perfect +state, and that under changed habits of life they became greatly reduced, +either from simple disuse, or through the natural selection of those +individuals which were least encumbered with a superfluous part, aided by the +other means previously indicated. +</p> + +<p> +Thus we can understand how it has come to pass that man and all other +vertebrate animals have been constructed on the same general model, why they +pass through the same early stages of development, and why they retain certain +rudiments in common. Consequently we ought frankly to admit their community of +descent: to take any other view, is to admit that our own structure, and that +of all the animals around us, is a mere snare laid to entrap our judgment. This +conclusion is greatly strengthened, if we look to the members of the whole +animal series, and consider the evidence derived from their affinities or +classification, their geographical distribution and geological succession. It +is only our natural prejudice, and that arrogance which made our forefathers +declare that they were descended from demi-gods, which leads us to demur to +this conclusion. But the time will before long come, when it will be thought +wonderful that naturalists, who were well acquainted with the comparative +structure and development of man, and other mammals, should have believed that +each was the work of a separate act of creation. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0002" id="link2HCH0002"></a> +CHAPTER II.<br /> +ON THE MANNER OF DEVELOPMENT OF MAN FROM SOME LOWER FORM.</h2> + +<p class="letter"> +Variability of body and mind in man—Inheritance—Causes of +variability—Laws of variation the same in man as in the lower +animals—Direct action of the conditions of life—Effects of the +increased use and disuse of parts—Arrested +development—Reversion—Correlated variation—Rate of +increase—Checks to increase—Natural selection—Man the most +dominant animal in the world—Importance of his corporeal +structure—The causes which have led to his becoming +erect—Consequent changes of structure—Decrease in size of the +canine teeth—Increased size and altered shape of the +skull—Nakedness —Absence of a tail—Defenceless condition of +man. +</p> + +<p> +It is manifest that man is now subject to much variability. No two individuals +of the same race are quite alike. We may compare millions of faces, and each +will be distinct. There is an equally great amount of diversity in the +proportions and dimensions of the various parts of the body; the length of the +legs being one of the most variable points. (1. ‘Investigations in +Military and Anthropological Statistics of American Soldiers,’ by B.A. +Gould, 1869, p. 256.) Although in some quarters of the world an elongated +skull, and in other quarters a short skull prevails, yet there is great +diversity of shape even within the limits of the same race, as with the +aborigines of America and South Australia—the latter a race +“probably as pure and homogeneous in blood, customs, and language as any +in existence”—and even with the inhabitants of so confined an area +as the Sandwich Islands. (2. With respect to the “Cranial forms of the +American aborigines,” see Dr. Aitken Meigs in ‘Proc. Acad. Nat. +Sci.’ Philadelphia, May 1868. On the Australians, see Huxley, in +Lyell’s ‘Antiquity of Man,’ 1863, p. 87. On the Sandwich +Islanders, Prof. J. Wyman, ‘Observations on Crania,’ Boston, 1868, +p. 18.) An eminent dentist assures me that there is nearly as much diversity in +the teeth as in the features. The chief arteries so frequently run in abnormal +courses, that it has been found useful for surgical purposes to calculate from +1040 corpses how often each course prevails. (3. ‘Anatomy of the +Arteries,’ by R. Quain. Preface, vol. i. 1844.) The muscles are eminently +variable: thus those of the foot were found by Prof. Turner (4. +‘Transactions of the Royal Society of Edinburgh,’ vol. xxiv. pp. +175, 189.) not to be strictly alike in any two out of fifty bodies; and in some +the deviations were considerable. He adds, that the power of performing the +appropriate movements must have been modified in accordance with the several +deviations. Mr. J. Wood has recorded (5. ‘Proceedings Royal +Society,’ 1867, p. 544; also 1868, pp. 483, 524. There is a previous +paper, 1866, p. 229.) the occurrence of 295 muscular variations in thirty-six +subjects, and in another set of the same number no less than 558 variations, +those occurring on both sides of the body being only reckoned as one. In the +last set, not one body out of the thirty-six was “found totally wanting +in departures from the standard descriptions of the muscular system given in +anatomical text books.” A single body presented the extraordinary number +of twenty-five distinct abnormalities. The same muscle sometimes varies in many +ways: thus Prof. Macalister describes (6. ‘Proc. R. Irish Academy,’ +vol. x. 1868, p. 141.) no less than twenty distinct variations in the palmaris +accessorius. +</p> + +<p> +The famous old anatomist, Wolff (7. ‘Act. Acad. St. Petersburg,’ +1778, part ii. p. 217.), insists that the internal viscera are more variable +than the external parts: Nulla particula est quae non aliter et aliter in aliis +se habeat hominibus. He has even written a treatise on the choice of typical +examples of the viscera for representation. A discussion on the beau-ideal of +the liver, lungs, kidneys, etc., as of the human face divine, sounds strange in +our ears. +</p> + +<p> +The variability or diversity of the mental faculties in men of the same race, +not to mention the greater differences between the men of distinct races, is so +notorious that not a word need here be said. So it is with the lower animals. +All who have had charge of menageries admit this fact, and we see it plainly in +our dogs and other domestic animals. Brehm especially insists that each +individual monkey of those which he kept tame in Africa had its own peculiar +disposition and temper: he mentions one baboon remarkable for its high +intelligence; and the keepers in the Zoological Gardens pointed out to me a +monkey, belonging to the New World division, equally remarkable for +intelligence. Rengger, also, insists on the diversity in the various mental +characters of the monkeys of the same species which he kept in Paraguay; and +this diversity, as he adds, is partly innate, and partly the result of the +manner in which they have been treated or educated. (8. Brehm, +‘Thierleben,’ B. i. ss. 58, 87. Rengger, ‘Säugethiere von +Paraguay,’ s. 57.) +</p> + +<p> +I have elsewhere (9. ‘Variation of Animals and Plants under +Domestication,’ vol. ii. chap. xii.) so fully discussed the subject of +Inheritance, that I need here add hardly anything. A greater number of facts +have been collected with respect to the transmission of the most trifling, as +well as of the most important characters in man, than in any of the lower +animals; though the facts are copious enough with respect to the latter. So in +regard to mental qualities, their transmission is manifest in our dogs, horses, +and other domestic animals. Besides special tastes and habits, general +intelligence, courage, bad and good temper, etc., are certainly transmitted. +With man we see similar facts in almost every family; and we now know, through +the admirable labours of Mr. Galton (10. ‘Hereditary Genius: an Inquiry +into its Laws and Consequences,’ 1869.), that genius which implies a +wonderfully complex combination of high faculties, tends to be inherited; and, +on the other hand, it is too certain that insanity and deteriorated mental +powers likewise run in families. +</p> + +<p> +With respect to the causes of variability, we are in all cases very ignorant; +but we can see that in man as in the lower animals, they stand in some relation +to the conditions to which each species has been exposed, during several +generations. Domesticated animals vary more than those in a state of nature; +and this is apparently due to the diversified and changing nature of the +conditions to which they have been subjected. In this respect the different +races of man resemble domesticated animals, and so do the individuals of the +same race, when inhabiting a very wide area, like that of America. We see the +influence of diversified conditions in the more civilised nations; for the +members belonging to different grades of rank, and following different +occupations, present a greater range of character than do the members of +barbarous nations. But the uniformity of savages has often been exaggerated, +and in some cases can hardly be said to exist. (11. Mr. Bates remarks +(‘The Naturalist on the Amazons,’ 1863, vol. ii p. 159), with +respect to the Indians of the same South American tribe, “no two of them +were at all similar in the shape of the head; one man had an oval visage with +fine features, and another was quite Mongolian in breadth and prominence of +cheek, spread of nostrils, and obliquity of eyes.”) It is, nevertheless, +an error to speak of man, even if we look only to the conditions to which he +has been exposed, as “far more domesticated” (12. Blumenbach, +‘Treatises on Anthropology.’ Eng. translat., 1865, p. 205.) than +any other animal. Some savage races, such as the Australians, are not exposed +to more diversified conditions than are many species which have a wide range. +In another and much more important respect, man differs widely from any +strictly domesticated animal; for his breeding has never long been controlled, +either by methodical or unconscious selection. No race or body of men has been +so completely subjugated by other men, as that certain individuals should be +preserved, and thus unconsciously selected, from somehow excelling in utility +to their masters. Nor have certain male and female individuals been +intentionally picked out and matched, except in the well-known case of the +Prussian grenadiers; and in this case man obeyed, as might have been expected, +the law of methodical selection; for it is asserted that many tall men were +reared in the villages inhabited by the grenadiers and their tall wives. In +Sparta, also, a form of selection was followed, for it was enacted that all +children should be examined shortly after birth; the well-formed and vigorous +being preserved, the others left to perish. (13. Mitford’s ‘History +of Greece,’ vol. i. p. 282. It appears also from a passage in +Xenophon’s ‘Memorabilia,’ B. ii. 4 (to which my attention has +been called by the Rev. J.N. Hoare), that it was a well recognised principle +with the Greeks, that men ought to select their wives with a view to the health +and vigour of their children. The Grecian poet, Theognis, who lived 550 B.C., +clearly saw how important selection, if carefully applied, would be for the +improvement of mankind. He saw, likewise, that wealth often checks the proper +action of sexual selection. He thus writes: +</p> + +<pre> + “With kine and horses, Kurnus! we proceed + By reasonable rules, and choose a breed + For profit and increase, at any price: + Of a sound stock, without defect or vice. + But, in the daily matches that we make, + The price is everything: for money’s sake, + Men marry: women are in marriage given + The churl or ruffian, that in wealth has thriven, + May match his offspring with the proudest race: + Thus everything is mix’d, noble and base! + If then in outward manner, form, and mind, + You find us a degraded, motley kind, + Wonder no more, my friend! the cause is plain, + And to lament the consequence is vain.” +</pre> + +<p> +(The Works of J. Hookham Frere, vol. ii. 1872, p. 334.)) +</p> + +<p> +If we consider all the races of man as forming a single species, his range is +enormous; but some separate races, as the Americans and Polynesians, have very +wide ranges. It is a well-known law that widely-ranging species are much more +variable than species with restricted ranges; and the variability of man may +with more truth be compared with that of widely-ranging species, than with that +of domesticated animals. +</p> + +<p> +Not only does variability appear to be induced in man and the lower animals by +the same general causes, but in both the same parts of the body are affected in +a closely analogous manner. This has been proved in such full detail by Godron +and Quatrefages, that I need here only refer to their works. (14. Godron, +‘De l’Espèce,’ 1859, tom. ii. livre 3. Quatrefages, +‘Unité de l’Espèce Humaine,’ 1861. Also Lectures on +Anthropology, given in the ‘Revue des Cours Scientifiques,’ +1866-1868.) Monstrosities, which graduate into slight variations, are likewise +so similar in man and the lower animals, that the same classification and the +same terms can be used for both, as has been shewn by Isidore Geoffroy +St.-Hilaire. (15. ‘Hist. Gen. et Part. des Anomalies de +l’Organisation,’ in three volumes, tom. i. 1832.) In my work on the +variation of domestic animals, I have attempted to arrange in a rude fashion +the laws of variation under the following heads:—The direct and definite +action of changed conditions, as exhibited by all or nearly all the individuals +of the same species, varying in the same manner under the same circumstances. +The effects of the long-continued use or disuse of parts. The cohesion of +homologous parts. The variability of multiple parts. Compensation of growth; +but of this law I have found no good instance in the case of man. The effects +of the mechanical pressure of one part on another; as of the pelvis on the +cranium of the infant in the womb. Arrests of development, leading to the +diminution or suppression of parts. The reappearance of long-lost characters +through reversion. And lastly, correlated variation. All these so-called laws +apply equally to man and the lower animals; and most of them even to plants. It +would be superfluous here to discuss all of them (16. I have fully discussed +these laws in my ‘Variation of Animals and Plants under +Domestication,’ vol. ii. chap. xxii. and xxiii. M. J.P. Durand has lately +(1868) published a valuable essay, ‘De l’Influence des +Milieux,’ etc. He lays much stress, in the case of plants, on the nature +of the soil.); but several are so important, that they must be treated at +considerable length. +</p> + +<h3>THE DIRECT AND DEFINITE ACTION OF CHANGED CONDITIONS.</h3> + +<p> +This is a most perplexing subject. It cannot be denied that changed conditions +produce some, and occasionally a considerable effect, on organisms of all +kinds; and it seems at first probable that if sufficient time were allowed this +would be the invariable result. But I have failed to obtain clear evidence in +favour of this conclusion; and valid reasons may be urged on the other side, at +least as far as the innumerable structures are concerned, which are adapted for +special ends. There can, however, be no doubt that changed conditions induce an +almost indefinite amount of fluctuating variability, by which the whole +organisation is rendered in some degree plastic. +</p> + +<p> +In the United States, above 1,000,000 soldiers, who served in the late war, +were measured, and the States in which they were born and reared were recorded. +(17. ‘Investigations in Military and Anthrop. Statistics,’ etc., +1869, by B.A. Gould, pp. 93, 107, 126, 131, 134.) From this astonishing number +of observations it is proved that local influences of some kind act directly on +stature; and we further learn that “the State where the physical growth +has in great measure taken place, and the State of birth, which indicates the +ancestry, seem to exert a marked influence on the stature.” For instance, +it is established, “that residence in the Western States, during the +years of growth, tends to produce increase of stature.” On the other +hand, it is certain that with sailors, their life delays growth, as shewn +“by the great difference between the statures of soldiers and sailors at +the ages of seventeen and eighteen years.” Mr. B.A. Gould endeavoured to +ascertain the nature of the influences which thus act on stature; but he +arrived only at negative results, namely that they did not relate to climate, +the elevation of the land, soil, nor even “in any controlling +degree” to the abundance or the need of the comforts of life. This latter +conclusion is directly opposed to that arrived at by Villerme, from the +statistics of the height of the conscripts in different parts of France. When +we compare the differences in stature between the Polynesian chiefs and the +lower orders within the same islands, or between the inhabitants of the fertile +volcanic and low barren coral islands of the same ocean (18. For the +Polynesians, see Prichard’s ‘Physical History of Mankind,’ +vol. v. 1847, pp. 145, 283. Also Godron, ‘De l’Espèce,’ tom. +ii. p. 289. There is also a remarkable difference in appearance between the +closely-allied Hindoos inhabiting the Upper Ganges and Bengal; see +Elphinstone’s ‘History of India,’ vol. i. p. 324.) or again +between the Fuegians on the eastern and western shores of their country, where +the means of subsistence are very different, it is scarcely possible to avoid +the conclusion that better food and greater comfort do influence stature. But +the preceding statements shew how difficult it is to arrive at any precise +result. Dr. Beddoe has lately proved that, with the inhabitants of Britain, +residence in towns and certain occupations have a deteriorating influence on +height; and he infers that the result is to a certain extent inherited, as is +likewise the case in the United States. Dr. Beddoe further believes that +wherever a “race attains its maximum of physical development, it rises +highest in energy and moral vigour.” (19. ‘Memoirs, Anthropological +Society,’ vol. iii. 1867-69, pp. 561, 565, 567.) +</p> + +<p> +Whether external conditions produce any other direct effect on man is not +known. It might have been expected that differences of climate would have had a +marked influence, inasmuch as the lungs and kidneys are brought into activity +under a low temperature, and the liver and skin under a high one. (20. Dr. +Brakenridge, ‘Theory of Diathesis,’ ‘Medical Times,’ +June 19 and July 17, 1869.) It was formerly thought that the colour of the skin +and the character of the hair were determined by light or heat; and although it +can hardly be denied that some effect is thus produced, almost all observers +now agree that the effect has been very small, even after exposure during many +ages. But this subject will be more properly discussed when we treat of the +different races of mankind. With our domestic animals there are grounds for +believing that cold and damp directly affect the growth of the hair; but I have +not met with any evidence on this head in the case of man. +</p> + +<h3>EFFECTS OF THE INCREASED USE AND DISUSE OF A PARTS.</h3> + +<p> +It is well known that use strengthens the muscles in the individual, and +complete disuse, or the destruction of the proper nerve, weakens them. When the +eye is destroyed, the optic nerve often becomes atrophied. When an artery is +tied, the lateral channels increase not only in diameter, but in the thickness +and strength of their coats. When one kidney ceases to act from disease, the +other increases in size, and does double work. Bones increase not only in +thickness, but in length, from carrying a greater weight. (21. I have given +authorities for these several statements in my ‘Variation of Animals and +Plants under Domestication,’ vol. ii. pp. 297-300. Dr. Jaeger, +“Über das Langenwachsthum der Knochen,” ‘Jenäischen +Zeitschrift,’ B. v. Heft. i.) Different occupations, habitually followed, +lead to changed proportions in various parts of the body. Thus it was +ascertained by the United States Commission (22. ‘Investigations,’ +etc., by B.A. Gould, 1869, p. 288.) that the legs of the sailors employed in +the late war were longer by 0.217 of an inch than those of the soldiers, though +the sailors were on an average shorter men; whilst their arms were shorter by +1.09 of an inch, and therefore, out of proportion, shorter in relation to their +lesser height. This shortness of the arms is apparently due to their greater +use, and is an unexpected result: but sailors chiefly use their arms in +pulling, and not in supporting weights. With sailors, the girth of the neck and +the depth of the instep are greater, whilst the circumference of the chest, +waist, and hips is less, than in soldiers. +</p> + +<p> +Whether the several foregoing modifications would become hereditary, if the +same habits of life were followed during many generations, is not known, but it +is probable. Rengger (23. ‘Säugethiere von Paraguay,’ 1830, s. 4.) +attributes the thin legs and thick arms of the Payaguas Indians to successive +generations having passed nearly their whole lives in canoes, with their lower +extremities motionless. Other writers have come to a similar conclusion in +analogous cases. According to Cranz (24. ‘History of Greenland,’ +Eng. translat., 1767, vol. i. p. 230.), who lived for a long time with the +Esquimaux, “the natives believe that ingenuity and dexterity in +seal-catching (their highest art and virtue) is hereditary; there is really +something in it, for the son of a celebrated seal-catcher will distinguish +himself, though he lost his father in childhood.” But in this case it is +mental aptitude, quite as much as bodily structure, which appears to be +inherited. It is asserted that the hands of English labourers are at birth +larger than those of the gentry. (25. ‘Intermarriage,’ by Alex. +Walker, 1838, p. 377.) From the correlation which exists, at least in some +cases (26. ‘The Variation of Animals under Domestication,’ vol. i. +p. 173.), between the development of the extremities and of the jaws, it is +possible that in those classes which do not labour much with their hands and +feet, the jaws would be reduced in size from this cause. That they are +generally smaller in refined and civilised men than in hard-working men or +savages, is certain. But with savages, as Mr. Herbert Spencer (27. +‘Principles of Biology,’ vol. i. p. 455.) has remarked, the greater +use of the jaws in chewing coarse, uncooked food, would act in a direct manner +on the masticatory muscles, and on the bones to which they are attached. In +infants, long before birth, the skin on the soles of the feet is thicker than +on any other part of the body; (28. Paget, ‘Lectures on Surgical +Pathology,’ vol. ii, 1853, p. 209.) and it can hardly be doubted that +this is due to the inherited effects of pressure during a long series of +generations. +</p> + +<p> +It is familiar to every one that watchmakers and engravers are liable to be +short-sighted, whilst men living much out of doors, and especially savages, are +generally long-sighted. (29. It is a singular and unexpected fact that sailors +are inferior to landsmen in their mean distance of distinct vision. Dr. B.A. +Gould (‘Sanitary Memoirs of the War of the Rebellion,’ 1869, p. +530), has proved this to be the case; and he accounts for it by the ordinary +range of vision in sailors being “restricted to the length of the vessel +and the height of the masts.”) Short-sight and long-sight certainly tend +to be inherited. (30. ‘The Variation of Animals under +Domestication,’ vol. i. p. 8.) The inferiority of Europeans, in +comparison with savages, in eyesight and in the other senses, is no doubt the +accumulated and transmitted effect of lessened use during many generations; for +Rengger (31. ‘Säugethiere von Paraguay,’ s. 8, 10. I have had good +opportunities for observing the extraordinary power of eyesight in the +Fuegians. See also Lawrence (‘Lectures on Physiology,’ etc., 1822, +p. 404) on this same subject. M. Giraud-Teulon has recently collected +(‘Revue des Cours Scientifiques,’ 1870, p. 625) a large and +valuable body of evidence proving that the cause of short-sight, +“C’est le travail assidu, de près.”) states that he has +repeatedly observed Europeans, who had been brought up and spent their whole +lives with the wild Indians, who nevertheless did not equal them in the +sharpness of their senses. The same naturalist observes that the cavities in +the skull for the reception of the several sense-organs are larger in the +American aborigines than in Europeans; and this probably indicates a +corresponding difference in the dimensions of the organs themselves. Blumenbach +has also remarked on the large size of the nasal cavities in the skulls of the +American aborigines, and connects this fact with their remarkably acute power +of smell. The Mongolians of the plains of northern Asia, according to Pallas, +have wonderfully perfect senses; and Prichard believes that the great breadth +of their skulls across the zygomas follows from their highly-developed sense +organs. (32. Prichard, ‘Physical History of Mankind,’ on the +authority of Blumenbach, vol. i. 1851, p. 311; for the statement by Pallas, +vol. iv. 1844, p. 407.) +</p> + +<p> +The Quechua Indians inhabit the lofty plateaux of Peru; and Alcide +d’Orbigny states (33. Quoted by Prichard, ‘Researches into the +Physical History of Mankind,’ vol. v. p. 463.) that, from continually +breathing a highly rarefied atmosphere, they have acquired chests and lungs of +extraordinary dimensions. The cells, also, of the lungs are larger and more +numerous than in Europeans. These observations have been doubted, but Mr. D. +Forbes carefully measured many Aymaras, an allied race, living at the height of +between 10,000 and 15,000 feet; and he informs me (34. Mr. Forbes’ +valuable paper is now published in the ‘Journal of the Ethnological +Society of London,’ new series, vol. ii. 1870, p.193.) that they differ +conspicuously from the men of all other races seen by him in the circumference +and length of their bodies. In his table of measurements, the stature of each +man is taken at 1000, and the other measurements are reduced to this standard. +It is here seen that the extended arms of the Aymaras are shorter than those of +Europeans, and much shorter than those of Negroes. The legs are likewise +shorter; and they present this remarkable peculiarity, that in every Aymara +measured, the femur is actually shorter than the tibia. On an average, the +length of the femur to that of the tibia is as 211 to 252; whilst in two +Europeans, measured at the same time, the femora to the tibiae were as 244 to +230; and in three Negroes as 258 to 241. The humerus is likewise shorter +relatively to the forearm. This shortening of that part of the limb which is +nearest to the body, appears to be, as suggested to me by Mr. Forbes, a case of +compensation in relation with the greatly increased length of the trunk. The +Aymaras present some other singular points of structure, for instance, the very +small projection of the heel. +</p> + +<p> +These men are so thoroughly acclimatised to their cold and lofty abode, that +when formerly carried down by the Spaniards to the low eastern plains, and when +now tempted down by high wages to the gold-washings, they suffer a frightful +rate of mortality. Nevertheless Mr. Forbes found a few pure families which had +survived during two generations: and he observed that they still inherited +their characteristic peculiarities. But it was manifest, even without +measurement, that these peculiarities had all decreased; and on measurement, +their bodies were found not to be so much elongated as those of the men on the +high plateau; whilst their femora had become somewhat lengthened, as had their +tibiae, although in a less degree. The actual measurements may be seen by +consulting Mr. Forbes’s memoir. From these observations, there can, I +think, be no doubt that residence during many generations at a great elevation +tends, both directly and indirectly, to induce inherited modifications in the +proportions of the body. (35. Dr. Wilckens (‘Landwirthschaft. +Wochenblatt,’ No. 10, 1869) has lately published an interesting essay +shewing how domestic animals, which live in mountainous regions, have their +frames modified.) +</p> + +<p> +Although man may not have been much modified during the latter stages of his +existence through the increased or decreased use of parts, the facts now given +shew that his liability in this respect has not been lost; and we positively +know that the same law holds good with the lower animals. Consequently we may +infer that when at a remote epoch the progenitors of man were in a transitional +state, and were changing from quadrupeds into bipeds, natural selection would +probably have been greatly aided by the inherited effects of the increased or +diminished use of the different parts of the body. +</p> + +<h3>ARRESTS OF DEVELOPMENT.</h3> + +<p> +There is a difference between arrested development and arrested growth, for +parts in the former state continue to grow whilst still retaining their early +condition. Various monstrosities come under this head; and some, as a cleft +palate, are known to be occasionally inherited. It will suffice for our purpose +to refer to the arrested brain-development of microcephalous idiots, as +described in Vogt’s memoir. (36. ‘Mémoire sur les +Microcephales,’ 1867, pp. 50, 125, 169, 171, 184-198.) Their skulls are +smaller, and the convolutions of the brain are less complex than in normal men. +The frontal sinus, or the projection over the eye-brows, is largely developed, +and the jaws are prognathous to an “effrayant” degree; so that +these idiots somewhat resemble the lower types of mankind. Their intelligence, +and most of their mental faculties, are extremely feeble. They cannot acquire +the power of speech, and are wholly incapable of prolonged attention, but are +much given to imitation. They are strong and remarkably active, continually +gambolling and jumping about, and making grimaces. They often ascend stairs on +all-fours; and are curiously fond of climbing up furniture or trees. We are +thus reminded of the delight shewn by almost all boys in climbing trees; and +this again reminds us how lambs and kids, originally alpine animals, delight to +frisk on any hillock, however small. Idiots also resemble the lower animals in +some other respects; thus several cases are recorded of their carefully +smelling every mouthful of food before eating it. One idiot is described as +often using his mouth in aid of his hands, whilst hunting for lice. They are +often filthy in their habits, and have no sense of decency; and several cases +have been published of their bodies being remarkably hairy. (37. Prof. Laycock +sums up the character of brute-like idiots by calling them +“theroid;” ‘Journal of Mental Science,’ July 1863. Dr. +Scott (‘The Deaf and Dumb,’ 2nd ed. 1870, p. 10) has often observed +the imbecile smelling their food. See, on this same subject, and on the +hairiness of idiots, Dr. Maudsley, ‘Body and Mind,’ 1870, pp. +46-51. Pinel has also given a striking case of hairiness in an idiot.) +</p> + +<h3>REVERSION.</h3> + +<p> +Many of the cases to be here given, might have been introduced under the last +heading. When a structure is arrested in its development, but still continues +growing, until it closely resembles a corresponding structure in some lower and +adult member of the same group, it may in one sense be considered as a case of +reversion. The lower members in a group give us some idea how the common +progenitor was probably constructed; and it is hardly credible that a complex +part, arrested at an early phase of embryonic development, should go on growing +so as ultimately to perform its proper function, unless it had acquired such +power during some earlier state of existence, when the present exceptional or +arrested structure was normal. The simple brain of a microcephalous idiot, in +as far as it resembles that of an ape, may in this sense be said to offer a +case of reversion. (38. In my ‘Variation of Animals under +Domestication’ (vol. ii. p. 57), I attributed the not very rare cases of +supernumerary mammae in women to reversion. I was led to this as a probable +conclusion, by the additional mammae being generally placed symmetrically on +the breast; and more especially from one case, in which a single efficient +mamma occurred in the inguinal region of a woman, the daughter of another woman +with supernumerary mammae. But I now find (see, for instance, Prof. Preyer, +‘Der Kampf um das Dasein,’ 1869, s. 45) that mammae erraticae, +occur in other situations, as on the back, in the armpit, and on the thigh; the +mammae in this latter instance having given so much milk that the child was +thus nourished. The probability that the additional mammae are due to reversion +is thus much weakened; nevertheless, it still seems to me probable, because two +pairs are often found symmetrically on the breast; and of this I myself have +received information in several cases. It is well known that some Lemurs +normally have two pairs of mammae on the breast. Five cases have been recorded +of the presence of more than a pair of mammae (of course rudimentary) in the +male sex of mankind; see ‘Journal of Anat. and Physiology,’ 1872, +p. 56, for a case given by Dr. Handyside, in which two brothers exhibited this +peculiarity; see also a paper by Dr. Bartels, in ‘Reichert’s and du +Bois-Reymond’s Archiv.,’ 1872, p. 304. In one of the cases alluded +to by Dr. Bartels, a man bore five mammae, one being medial and placed above +the navel; Meckel von Hemsbach thinks that this latter case is illustrated by a +medial mamma occurring in certain Cheiroptera. On the whole, we may well doubt +if additional mammae would ever have been developed in both sexes of mankind, +had not his early progenitors been provided with more than a single pair. +</p> + +<p> +In the above work (vol. ii. p. 12), I also attributed, though with much +hesitation, the frequent cases of polydactylism in men and various animals to +reversion. I was partly led to this through Prof. Owen’s statement, that +some of the Ichthyopterygia possess more than five digits, and therefore, as I +supposed, had retained a primordial condition; but Prof. Gegenbaur +(‘Jenaischen Zeitschrift,’ B. v. Heft 3, s. 341), disputes +Owen’s conclusion. On the other hand, according to the opinion lately +advanced by Dr. Gunther, on the paddle of Ceratodus, which is provided with +articulated bony rays on both sides of a central chain of bones, there seems no +great difficulty in admitting that six or more digits on one side, or on both +sides, might reappear through reversion. I am informed by Dr. Zouteveen that +there is a case on record of a man having twenty-four fingers and twenty-four +toes! I was chiefly led to the conclusion that the presence of supernumerary +digits might be due to reversion from the fact that such digits, not only are +strongly inherited, but, as I then believed, had the power of regrowth after +amputation, like the normal digits of the lower vertebrata. But I have +explained in the second edition of my Variation under Domestication why I now +place little reliance on the recorded cases of such regrowth. Nevertheless it +deserves notice, inasmuch as arrested development and reversion are intimately +related processes; that various structures in an embryonic or arrested +condition, such as a cleft palate, bifid uterus, etc., are frequently +accompanied by polydactylism. This has been strongly insisted on by Meckel and +Isidore Geoffroy St.-Hilaire. But at present it is the safest course to give up +altogether the idea that there is any relation between the development of +supernumerary digits and reversion to some lowly organised progenitor of man.) +There are other cases which come more strictly under our present head of +reversion. Certain structures, regularly occurring in the lower members of the +group to which man belongs, occasionally make their appearance in him, though +not found in the normal human embryo; or, if normally present in the human +embryo, they become abnormally developed, although in a manner which is normal +in the lower members of the group. These remarks will be rendered clearer by +the following illustrations. +</p> + +<p> +In various mammals the uterus graduates from a double organ with two distinct +orifices and two passages, as in the marsupials, into a single organ, which is +in no way double except from having a slight internal fold, as in the higher +apes and man. The rodents exhibit a perfect series of gradations between these +two extreme states. In all mammals the uterus is developed from two simple +primitive tubes, the inferior portions of which form the cornua; and it is in +the words of Dr. Farre, “by the coalescence of the two cornua at their +lower extremities that the body of the uterus is formed in man; while in those +animals in which no middle portion or body exists, the cornua remain ununited. +As the development of the uterus proceeds, the two cornua become gradually +shorter, until at length they are lost, or, as it were, absorbed into the body +of the uterus.” The angles of the uterus are still produced into cornua, +even in animals as high up in the scale as the lower apes and lemurs. +</p> + +<p> +Now in women, anomalous cases are not very infrequent, in which the mature +uterus is furnished with cornua, or is partially divided into two organs; and +such cases, according to Owen, repeat “the grade of concentrative +development,” attained by certain rodents. Here perhaps we have an +instance of a simple arrest of embryonic development, with subsequent growth +and perfect functional development; for either side of the partially double +uterus is capable of performing the proper office of gestation. In other and +rarer cases, two distinct uterine cavities are formed, each having its proper +orifice and passage. (39. See Dr. A. Farre’s well-known article in the +‘Cyclopaedia of Anatomy and Physiology,’ vol. v. 1859, p. 642. +Owen, ‘Anatomy of Vertebrates,’ vol. iii. 1868, p. 687. Professor +Turner, in ‘Edinburgh Medical Journal,’ February, 1865.) No such +stage is passed through during the ordinary development of the embryo; and it +is difficult to believe, though perhaps not impossible, that the two simple, +minute, primitive tubes should know how (if such an expression may be used) to +grow into two distinct uteri, each with a well-constructed orifice and passage, +and each furnished with numerous muscles, nerves, glands and vessels, if they +had not formerly passed through a similar course of development, as in the case +of existing marsupials. No one will pretend that so perfect a structure as the +abnormal double uterus in woman could be the result of mere chance. But the +principle of reversion, by which a long-lost structure is called back into +existence, might serve as the guide for its full development, even after the +lapse of an enormous interval of time. +</p> + +<p> +Professor Canestrini, after discussing the foregoing and various analogous +cases, arrives at the same conclusion as that just given. He adduces another +instance, in the case of the malar bone (40. ‘Annuario della Soc. dei +Naturalisti,’ Modena, 1867, p. 83. Prof. Canestrini gives extracts on +this subject from various authorities. Laurillard remarks, that as he has found +a complete similarity in the form, proportions, and connection of the two malar +bones in several human subjects and in certain apes, he cannot consider this +disposition of the parts as simply accidental. Another paper on this same +anomaly has been published by Dr. Saviotti in the ‘Gazzetta delle +Cliniche,’ Turin, 1871, where he says that traces of the division may be +detected in about two per cent. of adult skulls; he also remarks that it more +frequently occurs in prognathous skulls, not of the Aryan race, than in others. +See also G. Delorenzi on the same subject; ‘Tre nuovi casi +d’anomalia dell’ osso malare,’ Torino, 1872. Also, E. +Morselli, ‘Sopra una rara anomalia dell’ osso malare,’ +Modena, 1872. Still more recently Gruber has written a pamphlet on the division +of this bone. I give these references because a reviewer, without any grounds +or scruples, has thrown doubts on my statements.), which, in some of the +Quadrumana and other mammals, normally consists of two portions. This is its +condition in the human foetus when two months old; and through arrested +development, it sometimes remains thus in man when adult, more especially in +the lower prognathous races. Hence Canestrini concludes that some ancient +progenitor of man must have had this bone normally divided into two portions, +which afterwards became fused together. In man the frontal bone consists of a +single piece, but in the embryo, and in children, and in almost all the lower +mammals, it consists of two pieces separated by a distinct suture. This suture +occasionally persists more or less distinctly in man after maturity; and more +frequently in ancient than in recent crania, especially, as Canestrini has +observed, in those exhumed from the Drift, and belonging to the brachycephalic +type. Here again he comes to the same conclusion as in the analogous case of +the malar bones. In this, and other instances presently to be given, the cause +of ancient races approaching the lower animals in certain characters more +frequently than do the modern races, appears to be, that the latter stand at a +somewhat greater distance in the long line of descent from their early +semi-human progenitors. +</p> + +<p> +Various other anomalies in man, more or less analogous to the foregoing, have +been advanced by different authors, as cases of reversion; but these seem not a +little doubtful, for we have to descend extremely low in the mammalian series, +before we find such structures normally present. (41. A whole series of cases +is given by Isidore Geoffroy St.-Hilaire, ‘Hist. des Anomalies,’ +tom, iii, p. 437. A reviewer (‘Journal of Anatomy and Physiology,’ +1871, p. 366) blames me much for not having discussed the numerous cases, which +have been recorded, of various parts arrested in their development. He says +that, according to my theory, “every transient condition of an organ, +during its development, is not only a means to an end, but once was an end in +itself.” This does not seem to me necessarily to hold good. Why should +not variations occur during an early period of development, having no relation +to reversion; yet such variations might be preserved and accumulated, if in any +way serviceable, for instance, in shortening and simplifying the course of +development? And again, why should not injurious abnormalities, such as +atrophied or hypertrophied parts, which have no relation to a former state of +existence, occur at an early period, as well as during maturity?) +</p> + +<p> +In man, the canine teeth are perfectly efficient instruments for mastication. +But their true canine character, as Owen (42. ‘Anatomy of +Vertebrates,’ vol. iii. 1868, p. 323.) remarks, “is indicated by +the conical form of the crown, which terminates in an obtuse point, is convex +outward and flat or sub-concave within, at the base of which surface there is a +feeble prominence. The conical form is best expressed in the Melanian races, +especially the Australian. The canine is more deeply implanted, and by a +stronger fang than the incisors.” Nevertheless, this tooth no longer +serves man as a special weapon for tearing his enemies or prey; it may, +therefore, as far as its proper function is concerned, be considered as +rudimentary. In every large collection of human skulls some may be found, as +Haeckel (43. ‘Generelle Morphologie,’ 1866, B. ii. s. clv.) +observes, with the canine teeth projecting considerably beyond the others in +the same manner as in the anthropomorphous apes, but in a less degree. In these +cases, open spaces between the teeth in the one jaw are left for the reception +of the canines of the opposite jaw. An inter-space of this kind in a Kaffir +skull, figured by Wagner, is surprisingly wide. (44. Carl Vogt’s +‘Lectures on Man,’ Eng. translat., 1864, p. 151.) Considering how +few are the ancient skulls which have been examined, compared to recent skulls, +it is an interesting fact that in at least three cases the canines project +largely; and in the Naulette jaw they are spoken of as enormous. (45. C. Carter +Blake, on a jaw from La Naulette, ‘Anthropological Review,’ 1867, +p. 295. Schaaffhausen, ibid. 1868, p. 426.) +</p> + +<p> +Of the anthropomorphous apes the males alone have their canines fully +developed; but in the female gorilla, and in a less degree in the female orang, +these teeth project considerably beyond the others; therefore the fact, of +which I have been assured, that women sometimes have considerably projecting +canines, is no serious objection to the belief that their occasional great +development in man is a case of reversion to an ape-like progenitor. He who +rejects with scorn the belief that the shape of his own canines, and their +occasional great development in other men, are due to our early forefathers +having been provided with these formidable weapons, will probably reveal, by +sneering, the line of his descent. For though he no longer intends, nor has the +power, to use these teeth as weapons, he will unconsciously retract his +“snarling muscles” (thus named by Sir C. Bell) (46. The Anatomy of +Expression, 1844, pp. 110, 131.), so as to expose them ready for action, like a +dog prepared to fight. +</p> + +<p> +Many muscles are occasionally developed in man, which are proper to the +Quadrumana or other mammals. Professor Vlacovich (47. Quoted by Prof. +Canestrini in the ‘Annuario della Soc. dei Naturalisti,’ 1867, p. +90.) examined forty male subjects, and found a muscle, called by him the +ischio-pubic, in nineteen of them; in three others there was a ligament which +represented this muscle; and in the remaining eighteen no trace of it. In only +two out of thirty female subjects was this muscle developed on both sides, but +in three others the rudimentary ligament was present. This muscle, therefore, +appears to be much more common in the male than in the female sex; and on the +belief in the descent of man from some lower form, the fact is intelligible; +for it has been detected in several of the lower animals, and in all of these +it serves exclusively to aid the male in the act of reproduction. +</p> + +<p> +Mr. J. Wood, in his valuable series of papers (48. These papers deserve careful +study by any one who desires to learn how frequently our muscles vary, and in +varying come to resemble those of the Quadrumana. The following references +relate to the few points touched on in my text: ‘Proc. Royal Soc.’ +vol. xiv. 1865, pp. 379-384; vol. xv. 1866, pp. 241, 242; vol. xv. 1867, p. +544; vol. xvi. 1868, p. 524. I may here add that Dr. Murie and Mr. St. George +Mivart have shewn in their Memoir on the Lemuroidea (‘Transactions, +Zoological Society,’ vol. vii. 1869, p. 96), how extraordinarily variable +some of the muscles are in these animals, the lowest members of the Primates. +Gradations, also, in the muscles leading to structures found in animals still +lower in the scale, are numerous in the Lemuroidea.), has minutely described a +vast number of muscular variations in man, which resemble normal structures in +the lower animals. The muscles which closely resemble those regularly present +in our nearest allies, the Quadrumana, are too numerous to be here even +specified. In a single male subject, having a strong bodily frame, and +well-formed skull, no less than seven muscular variations were observed, all of +which plainly represented muscles proper to various kinds of apes. This man, +for instance, had on both sides of his neck a true and powerful “levator +claviculae,” such as is found in all kinds of apes, and which is said to +occur in about one out of sixty human subjects. (49. See also Prof. Macalister +in ‘Proceedings, Royal Irish Academy,’ vol. x. 1868, p. 124.) +Again, this man had “a special abductor of the metatarsal bone of the +fifth digit, such as Professor Huxley and Mr. Flower have shewn to exist +uniformly in the higher and lower apes.” I will give only two additional +cases; the acromio-basilar muscle is found in all mammals below man, and seems +to be correlated with a quadrupedal gait, (50. Mr. Champneys in ‘Journal +of Anatomy and Physiology,’ Nov. 1871, p. 178.) and it occurs in about +one out of sixty human subjects. In the lower extremities Mr. Bradley (51. +Ibid. May 1872, p. 421.) found an abductor ossis metatarsi quinti in both feet +of man; this muscle had not up to that time been recorded in mankind, but is +always present in the anthropomorphous apes. The muscles of the hands and +arms—parts which are so eminently characteristic of man—are +extremely liable to vary, so as to resemble the corresponding muscles in the +lower animals. (52. Prof. Macalister (ibid. p. 121) has tabulated his +observations, and finds that muscular abnormalities are most frequent in the +fore-arms, secondly, in the face, thirdly, in the foot, etc.) Such resemblances +are either perfect or imperfect; yet in the latter case they are manifestly of +a transitional nature. Certain variations are more common in man, and others in +woman, without our being able to assign any reason. Mr. Wood, after describing +numerous variations, makes the following pregnant remark. “Notable +departures from the ordinary type of the muscular structures run in grooves or +directions, which must be taken to indicate some unknown factor, of much +importance to a comprehensive knowledge of general and scientific +anatomy.” (53. The Rev. Dr. Haughton, after giving (‘Proc. R. Irish +Academy,’ June 27, 1864, p. 715) a remarkable case of variation in the +human flexor pollicis longus, adds, “This remarkable example shews that +man may sometimes possess the arrangement of tendons of thumb and fingers +characteristic of the macaque; but whether such a case should be regarded as a +macaque passing upwards into a man, or a man passing downwards into a macaque, +or as a congenital freak of nature, I cannot undertake to say.” It is +satisfactory to hear so capable an anatomist, and so embittered an opponent of +evolutionism, admitting even the possibility of either of his first +propositions. Prof. Macalister has also described (‘Proceedings Royal +Irish Academy,’ vol. x. 1864, p. 138) variations in the flexor pollicis +longus, remarkable from their relations to the same muscle in the Quadrumana.) +</p> + +<p> +That this unknown factor is reversion to a former state of existence may be +admitted as in the highest degree probable. (54. Since the first edition of +this book appeared, Mr. Wood has published another memoir in the Philosophical +Transactions, 1870, p. 83, on the varieties of the muscles of the human neck, +shoulder, and chest. He here shews how extremely variable these muscles are, +and how often and how closely the variations resemble the normal muscles of the +lower animals. He sums up by remarking, “It will be enough for my purpose +if I have succeeded in shewing the more important forms which, when occurring +as varieties in the human subject, tend to exhibit in a sufficiently marked +manner what may be considered as proofs and examples of the Darwinian principle +of reversion, or law of inheritance, in this department of anatomical +science.”) It is quite incredible that a man should through mere accident +abnormally resemble certain apes in no less than seven of his muscles, if there +had been no genetic connection between them. On the other hand, if man is +descended from some ape-like creature, no valid reason can be assigned why +certain muscles should not suddenly reappear after an interval of many thousand +generations, in the same manner as with horses, asses, and mules, dark-coloured +stripes suddenly reappear on the legs, and shoulders, after an interval of +hundreds, or more probably of thousands of generations. +</p> + +<p> +These various cases of reversion are so closely related to those of rudimentary +organs given in the first chapter, that many of them might have been +indifferently introduced either there or here. Thus a human uterus furnished +with cornua may be said to represent, in a rudimentary condition, the same +organ in its normal state in certain mammals. Some parts which are rudimentary +in man, as the os coccyx in both sexes, and the mammae in the male sex, are +always present; whilst others, such as the supracondyloid foramen, only +occasionally appear, and therefore might have been introduced under the head of +reversion. These several reversionary structures, as well as the strictly +rudimentary ones, reveal the descent of man from some lower form in an +unmistakable manner. +</p> + +<h3>CORRELATED VARIATION.</h3> + +<p> +In man, as in the lower animals, many structures are so intimately related, +that when one part varies so does another, without our being able, in most +cases, to assign any reason. We cannot say whether the one part governs the +other, or whether both are governed by some earlier developed part. Various +monstrosities, as I. Geoffroy repeatedly insists, are thus intimately +connected. Homologous structures are particularly liable to change together, as +we see on the opposite sides of the body, and in the upper and lower +extremities. Meckel long ago remarked, that when the muscles of the arm depart +from their proper type, they almost always imitate those of the leg; and so, +conversely, with the muscles of the legs. The organs of sight and hearing, the +teeth and hair, the colour of the skin and of the hair, colour and +constitution, are more or less correlated. (55. The authorities for these +several statements are given in my ‘Variation of Animals under +Domestication,’ vol. ii. pp. 320-335.) Professor Schaaffhausen first drew +attention to the relation apparently existing between a muscular frame and the +strongly-pronounced supra-orbital ridges, which are so characteristic of the +lower races of man. +</p> + +<p> +Besides the variations which can be grouped with more or less probability under +the foregoing heads, there is a large class of variations which may be +provisionally called spontaneous, for to our ignorance they appear to arise +without any exciting cause. It can, however, be shewn that such variations, +whether consisting of slight individual differences, or of strongly-marked and +abrupt deviations of structure, depend much more on the constitution of the +organism than on the nature of the conditions to which it has been subjected. +(56. This whole subject has been discussed in chap. xxiii. vol. ii. of my +‘Variation of Animals and Plants under Domestication.’) +</p> + +<h3>RATE OF INCREASE.</h3> + +<p> +Civilised populations have been known under favourable conditions, as in the +United States, to double their numbers in twenty-five years; and, according to +a calculation, by Euler, this might occur in a little over twelve years. (57. +See the ever memorable ‘Essay on the Principle of Population,’ by +the Rev. T. Malthus, vol. i. 1826. pp. 6, 517.) At the former rate, the present +population of the United States (thirty millions), would in 657 years cover the +whole terraqueous globe so thickly, that four men would have to stand on each +square yard of surface. The primary or fundamental check to the continued +increase of man is the difficulty of gaining subsistence, and of living in +comfort. We may infer that this is the case from what we see, for instance, in +the United States, where subsistence is easy, and there is plenty of room. If +such means were suddenly doubled in Great Britain, our number would be quickly +doubled. With civilised nations this primary check acts chiefly by restraining +marriages. The greater death-rate of infants in the poorest classes is also +very important; as well as the greater mortality, from various diseases, of the +inhabitants of crowded and miserable houses, at all ages. The effects of severe +epidemics and wars are soon counterbalanced, and more than counterbalanced, in +nations placed under favourable conditions. Emigration also comes in aid as a +temporary check, but, with the extremely poor classes, not to any great extent. +</p> + +<p> +There is reason to suspect, as Malthus has remarked, that the reproductive +power is actually less in barbarous, than in civilised races. We know nothing +positively on this head, for with savages no census has been taken; but from +the concurrent testimony of missionaries, and of others who have long resided +with such people, it appears that their families are usually small, and large +ones rare. This may be partly accounted for, as it is believed, by the women +suckling their infants during a long time; but it is highly probable that +savages, who often suffer much hardship, and who do not obtain so much +nutritious food as civilised men, would be actually less prolific. I have shewn +in a former work (58. ‘Variation of Animals and Plants under +Domestication,’ vol ii. pp. 111-113, 163.), that all our domesticated +quadrupeds and birds, and all our cultivated plants, are more fertile than the +corresponding species in a state of nature. It is no valid objection to this +conclusion that animals suddenly supplied with an excess of food, or when grown +very fat; and that most plants on sudden removal from very poor to very rich +soil, are rendered more or less sterile. We might, therefore, expect that +civilised men, who in one sense are highly domesticated, would be more prolific +than wild men. It is also probable that the increased fertility of civilised +nations would become, as with our domestic animals, an inherited character: it +is at least known that with mankind a tendency to produce twins runs in +families. (59. Mr. Sedgwick, ‘British and Foreign Medico-Chirurgical +Review,’ July 1863, p. 170.) +</p> + +<p> +Notwithstanding that savages appear to be less prolific than civilised people, +they would no doubt rapidly increase if their numbers were not by some means +rigidly kept down. The Santali, or hill-tribes of India, have recently afforded +a good illustration of this fact; for, as shewn by Mr. Hunter (60. ‘The +Annals of Rural Bengal,’ by W.W. Hunter, 1868, p. 259.), they have +increased at an extraordinary rate since vaccination has been introduced, other +pestilences mitigated, and war sternly repressed. This increase, however, would +not have been possible had not these rude people spread into the adjoining +districts, and worked for hire. Savages almost always marry; yet there is some +prudential restraint, for they do not commonly marry at the earliest possible +age. The young men are often required to shew that they can support a wife; and +they generally have first to earn the price with which to purchase her from her +parents. With savages the difficulty of obtaining subsistence occasionally +limits their number in a much more direct manner than with civilised people, +for all tribes periodically suffer from severe famines. At such times savages +are forced to devour much bad food, and their health can hardly fail to be +injured. Many accounts have been published of their protruding stomachs and +emaciated limbs after and during famines. They are then, also, compelled to +wander much, and, as I was assured in Australia, their infants perish in large +numbers. As famines are periodical, depending chiefly on extreme seasons, all +tribes must fluctuate in number. They cannot steadily and regularly increase, +as there is no artificial increase in the supply of food. Savages, when hard +pressed, encroach on each other’s territories, and war is the result; but +they are indeed almost always at war with their neighbours. They are liable to +many accidents on land and water in their search for food; and in some +countries they suffer much from the larger beasts of prey. Even in India, +districts have been depopulated by the ravages of tigers. +</p> + +<p> +Malthus has discussed these several checks, but he does not lay stress enough +on what is probably the most important of all, namely infanticide, especially +of female infants, and the habit of procuring abortion. These practices now +prevail in many quarters of the world; and infanticide seems formerly to have +prevailed, as Mr. M’Lennan (61. ‘Primitive Marriage,’ 1865.) +has shewn, on a still more extensive scale. These practices appear to have +originated in savages recognising the difficulty, or rather the impossibility +of supporting all the infants that are born. Licentiousness may also be added +to the foregoing checks; but this does not follow from failing means of +subsistence; though there is reason to believe that in some cases (as in Japan) +it has been intentionally encouraged as a means of keeping down the population. +</p> + +<p> +If we look back to an extremely remote epoch, before man had arrived at the +dignity of manhood, he would have been guided more by instinct and less by +reason than are the lowest savages at the present time. Our early semi-human +progenitors would not have practised infanticide or polyandry; for the +instincts of the lower animals are never so perverted (62. A writer in the +‘Spectator’ (March 12, 1871, p. 320) comments as follows on this +passage:—“Mr. Darwin finds himself compelled to reintroduce a new +doctrine of the fall of man. He shews that the instincts of the higher animals +are far nobler than the habits of savage races of men, and he finds himself, +therefore, compelled to re-introduce,—in a form of the substantial +orthodoxy of which he appears to be quite unconscious,—and to introduce +as a scientific hypothesis the doctrine that man’s gain of KNOWLEDGE was +the cause of a temporary but long-enduring moral deterioration as indicated by +the many foul customs, especially as to marriage, of savage tribes. What does +the Jewish tradition of the moral degeneration of man through his snatching at +a knowledge forbidden him by his highest instinct assert beyond this?”) +as to lead them regularly to destroy their own offspring, or to be quite devoid +of jealousy. There would have been no prudential restraint from marriage, and +the sexes would have freely united at an early age. Hence the progenitors of +man would have tended to increase rapidly; but checks of some kind, either +periodical or constant, must have kept down their numbers, even more severely +than with existing savages. What the precise nature of these checks were, we +cannot say, any more than with most other animals. We know that horses and +cattle, which are not extremely prolific animals, when first turned loose in +South America, increased at an enormous rate. The elephant, the slowest breeder +of all known animals, would in a few thousand years stock the whole world. The +increase of every species of monkey must be checked by some means; but not, as +Brehm remarks, by the attacks of beasts of prey. No one will assume that the +actual power of reproduction in the wild horses and cattle of America, was at +first in any sensible degree increased; or that, as each district became fully +stocked, this same power was diminished. No doubt, in this case, and in all +others, many checks concur, and different checks under different circumstances; +periodical dearths, depending on unfavourable seasons, being probably the most +important of all. So it will have been with the early progenitors of man. +</p> + +<h3>NATURAL SELECTION.</h3> + +<p> +We have now seen that man is variable in body and mind; and that the variations +are induced, either directly or indirectly, by the same general causes, and +obey the same general laws, as with the lower animals. Man has spread widely +over the face of the earth, and must have been exposed, during his incessant +migrations (63. See some good remarks to this effect by W. Stanley Jevons, +“A Deduction from Darwin’s Theory,” ‘Nature,’ +1869, p. 231.), to the most diversified conditions. The inhabitants of Tierra +del Fuego, the Cape of Good Hope, and Tasmania in the one hemisphere, and of +the arctic regions in the other, must have passed through many climates, and +changed their habits many times, before they reached their present homes. (64. +Latham, ‘Man and his Migrations,’ 1851, p. 135.) The early +progenitors of man must also have tended, like all other animals, to have +increased beyond their means of subsistence; they must, therefore, occasionally +have been exposed to a struggle for existence, and consequently to the rigid +law of natural selection. Beneficial variations of all kinds will thus, either +occasionally or habitually, have been preserved and injurious ones eliminated. +I do not refer to strongly-marked deviations of structure, which occur only at +long intervals of time, but to mere individual differences. We know, for +instance, that the muscles of our hands and feet, which determine our powers of +movement, are liable, like those of the lower animals, (65. Messrs. Murie and +Mivart in their ‘Anatomy of the Lemuroidea’ (‘Transact. +Zoolog. Soc.’ vol. vii. 1869, pp. 96-98) say, “some muscles are so +irregular in their distribution that they cannot be well classed in any of the +above groups.” These muscles differ even on the opposite sides of the +same individual.) to incessant variability. If then the progenitors of man +inhabiting any district, especially one undergoing some change in its +conditions, were divided into two equal bodies, the one half which included all +the individuals best adapted by their powers of movement for gaining +subsistence, or for defending themselves, would on an average survive in +greater numbers, and procreate more offspring than the other and less well +endowed half. +</p> + +<p> +Man in the rudest state in which he now exists is the most dominant animal that +has ever appeared on this earth. He has spread more widely than any other +highly organised form: and all others have yielded before him. He manifestly +owes this immense superiority to his intellectual faculties, to his social +habits, which lead him to aid and defend his fellows, and to his corporeal +structure. The supreme importance of these characters has been proved by the +final arbitrament of the battle for life. Through his powers of intellect, +articulate language has been evolved; and on this his wonderful advancement has +mainly depended. As Mr. Chauncey Wright remarks (66. Limits of Natural +Selection, ‘North American Review,’ Oct. 1870, p. 295.): “a +psychological analysis of the faculty of language shews, that even the smallest +proficiency in it might require more brain power than the greatest proficiency +in any other direction.” He has invented and is able to use various +weapons, tools, traps, etc., with which he defends himself, kills or catches +prey, and otherwise obtains food. He has made rafts or canoes for fishing or +crossing over to neighbouring fertile islands. He has discovered the art of +making fire, by which hard and stringy roots can be rendered digestible, and +poisonous roots or herbs innocuous. This discovery of fire, probably the +greatest ever made by man, excepting language, dates from before the dawn of +history. These several inventions, by which man in the rudest state has become +so pre-eminent, are the direct results of the development of his powers of +observation, memory, curiosity, imagination, and reason. I cannot, therefore, +understand how it is that Mr. Wallace (67. ‘Quarterly Review,’ +April 1869, p. 392. This subject is more fully discussed in Mr. Wallace’s +‘Contributions to the Theory of Natural Selection,’ 1870, in which +all the essays referred to in this work are re-published. The ‘Essay on +Man,’ has been ably criticised by Prof. Claparede, one of the most +distinguished zoologists in Europe, in an article published in the +‘Bibliotheque Universelle,’ June 1870. The remark quoted in my text +will surprise every one who has read Mr. Wallace’s celebrated paper on +‘The Origin of Human Races Deduced from the Theory of Natural +Selection,’ originally published in the ‘Anthropological +Review,’ May 1864, p. clviii. I cannot here resist quoting a most just +remark by Sir J. Lubbock (‘Prehistoric Times,’ 1865, p. 479) in +reference to this paper, namely, that Mr. Wallace, “with characteristic +unselfishness, ascribes it (i.e. the idea of natural selection) unreservedly to +Mr. Darwin, although, as is well known, he struck out the idea independently, +and published it, though not with the same elaboration, at the same +time.”) maintains, that “natural selection could only have endowed +the savage with a brain a little superior to that of an ape.” +</p> + +<p> +Although the intellectual powers and social habits of man are of paramount +importance to him, we must not underrate the importance of his bodily +structure, to which subject the remainder of this chapter will be devoted; the +development of the intellectual and social or moral faculties being discussed +in a later chapter. +</p> + +<p> +Even to hammer with precision is no easy matter, as every one who has tried to +learn carpentry will admit. To throw a stone with as true an aim as a Fuegian +in defending himself, or in killing birds, requires the most consummate +perfection in the correlated action of the muscles of the hand, arm, and +shoulder, and, further, a fine sense of touch. In throwing a stone or spear, +and in many other actions, a man must stand firmly on his feet; and this again +demands the perfect co-adaptation of numerous muscles. To chip a flint into the +rudest tool, or to form a barbed spear or hook from a bone, demands the use of +a perfect hand; for, as a most capable judge, Mr. Schoolcraft (68. Quoted by +Mr. Lawson Tait in his ‘Law of Natural Selection,’ ‘Dublin +Quarterly Journal of Medical Science,’ Feb. 1869. Dr. Keller is likewise +quoted to the same effect.), remarks, the shaping fragments of stone into +knives, lances, or arrow-heads, shews “extraordinary ability and long +practice.” This is to a great extent proved by the fact that primeval men +practised a division of labour; each man did not manufacture his own flint +tools or rude pottery, but certain individuals appear to have devoted +themselves to such work, no doubt receiving in exchange the produce of the +chase. Archaeologists are convinced that an enormous interval of time elapsed +before our ancestors thought of grinding chipped flints into smooth tools. One +can hardly doubt, that a man-like animal who possessed a hand and arm +sufficiently perfect to throw a stone with precision, or to form a flint into a +rude tool, could, with sufficient practice, as far as mechanical skill alone is +concerned, make almost anything which a civilised man can make. The structure +of the hand in this respect may be compared with that of the vocal organs, +which in the apes are used for uttering various signal-cries, or, as in one +genus, musical cadences; but in man the closely similar vocal organs have +become adapted through the inherited effects of use for the utterance of +articulate language. +</p> + +<p> +Turning now to the nearest allies of men, and therefore to the best +representatives of our early progenitors, we find that the hands of the +Quadrumana are constructed on the same general pattern as our own, but are far +less perfectly adapted for diversified uses. Their hands do not serve for +locomotion so well as the feet of a dog; as may be seen in such monkeys as the +chimpanzee and orang, which walk on the outer margins of the palms, or on the +knuckles. (69. Owen, ‘Anatomy of Vertebrates,’ vol. iii. p. 71.) +Their hands, however, are admirably adapted for climbing trees. Monkeys seize +thin branches or ropes, with the thumb on one side and the fingers and palm on +the other, in the same manner as we do. They can thus also lift rather large +objects, such as the neck of a bottle, to their mouths. Baboons turn over +stones, and scratch up roots with their hands. They seize nuts, insects, or +other small objects with the thumb in opposition to the fingers, and no doubt +they thus extract eggs and young from the nests of birds. American monkeys beat +the wild oranges on the branches until the rind is cracked, and then tear it +off with the fingers of the two hands. In a wild state they break open hard +fruits with stones. Other monkeys open mussel-shells with the two thumbs. With +their fingers they pull out thorns and burs, and hunt for each other’s +parasites. They roll down stones, or throw them at their enemies: nevertheless, +they are clumsy in these various actions, and, as I have myself seen, are quite +unable to throw a stone with precision. +</p> + +<p> +It seems to me far from true that because “objects are grasped +clumsily” by monkeys, “a much less specialised organ of +prehension” would have served them (70. ‘Quarterly Review,’ +April 1869, p. 392.) equally well with their present hands. On the contrary, I +see no reason to doubt that more perfectly constructed hands would have been an +advantage to them, provided that they were not thus rendered less fitted for +climbing trees. We may suspect that a hand as perfect as that of man would have +been disadvantageous for climbing; for the most arboreal monkeys in the world, +namely, Ateles in America, Colobus in Africa, and Hylobates in Asia, are either +thumbless, or their toes partially cohere, so that their limbs are converted +into mere grasping hooks. (71. In Hylobates syndactylus, as the name expresses, +two of the toes regularly cohere; and this, as Mr. Blyth informs me, is +occasionally the case with the toes of H. agilis, lar, and leuciscus. Colobus +is strictly arboreal and extraordinarily active (Brehm, +‘Thierleben,’ B. i. s. 50), but whether a better climber than the +species of the allied genera, I do not know. It deserves notice that the feet +of the sloths, the most arboreal animals in the world, are wonderfully +hook-like. +</p> + +<p> +As soon as some ancient member in the great series of the Primates came to be +less arboreal, owing to a change in its manner of procuring subsistence, or to +some change in the surrounding conditions, its habitual manner of progression +would have been modified: and thus it would have been rendered more strictly +quadrupedal or bipedal. Baboons frequent hilly and rocky districts, and only +from necessity climb high trees (72. Brehm, ‘Thierleben,’ B. i. s. +80.); and they have acquired almost the gait of a dog. Man alone has become a +biped; and we can, I think, partly see how he has come to assume his erect +attitude, which forms one of his most conspicuous characters. Man could not +have attained his present dominant position in the world without the use of his +hands, which are so admirably adapted to act in obedience to his will. Sir C. +Bell (73. ‘The Hand,’ etc., ‘Bridgewater Treatise,’ +1833, p. 38.) insists that “the hand supplies all instruments, and by its +correspondence with the intellect gives him universal dominion.” But the +hands and arms could hardly have become perfect enough to have manufactured +weapons, or to have hurled stones and spears with a true aim, as long as they +were habitually used for locomotion and for supporting the whole weight of the +body, or, as before remarked, so long as they were especially fitted for +climbing trees. Such rough treatment would also have blunted the sense of +touch, on which their delicate use largely depends. From these causes alone it +would have been an advantage to man to become a biped; but for many actions it +is indispensable that the arms and whole upper part of the body should be free; +and he must for this end stand firmly on his feet. To gain this great +advantage, the feet have been rendered flat; and the great toe has been +peculiarly modified, though this has entailed the almost complete loss of its +power of prehension. It accords with the principle of the division of +physiological labour, prevailing throughout the animal kingdom, that as the +hands became perfected for prehension, the feet should have become perfected +for support and locomotion. With some savages, however, the foot has not +altogether lost its prehensile power, as shewn by their manner of climbing +trees, and of using them in other ways. (74. Haeckel has an excellent +discussion on the steps by which man became a biped: ‘Natürliche +Schöpfungsgeschichte,’ 1868, s. 507. Dr. Buchner (‘Conférences sur +la Théorie Darwinienne,’ 1869, p. 135) has given good cases of the use of +the foot as a prehensile organ by man; and has also written on the manner of +progression of the higher apes, to which I allude in the following paragraph: +see also Owen (‘Anatomy of Vertebrates,’ vol. iii. p. 71) on this +latter subject.) +</p> + +<p> +If it be an advantage to man to stand firmly on his feet and to have his hands +and arms free, of which, from his pre-eminent success in the battle of life +there can be no doubt, then I can see no reason why it should not have been +advantageous to the progenitors of man to have become more and more erect or +bipedal. They would thus have been better able to defend themselves with stones +or clubs, to attack their prey, or otherwise to obtain food. The best built +individuals would in the long run have succeeded best, and have survived in +larger numbers. If the gorilla and a few allied forms had become extinct, it +might have been argued, with great force and apparent truth, that an animal +could not have been gradually converted from a quadruped into a biped, as all +the individuals in an intermediate condition would have been miserably +ill-fitted for progression. But we know (and this is well worthy of reflection) +that the anthropomorphous apes are now actually in an intermediate condition; +and no one doubts that they are on the whole well adapted for their conditions +of life. Thus the gorilla runs with a sidelong shambling gait, but more +commonly progresses by resting on its bent hands. The long-armed apes +occasionally use their arms like crutches, swinging their bodies forward +between them, and some kinds of Hylobates, without having been taught, can walk +or run upright with tolerable quickness; yet they move awkwardly, and much less +securely than man. We see, in short, in existing monkeys a manner of +progression intermediate between that of a quadruped and a biped; but, as an +unprejudiced judge (75. Prof. Broca, La Constitution des Vertèbres caudales; +‘La Revue d’Anthropologie,’ 1872, p. 26, (separate copy).) +insists, the anthropomorphous apes approach in structure more nearly to the +bipedal than to the quadrupedal type. +</p> + +<p> +As the progenitors of man became more and more erect, with their hands and arms +more and more modified for prehension and other purposes, with their feet and +legs at the same time transformed for firm support and progression, endless +other changes of structure would have become necessary. The pelvis would have +to be broadened, the spine peculiarly curved, and the head fixed in an altered +position, all which changes have been attained by man. Prof. Schaaffhausen (76. +‘On the Primitive Form of the Skull,’ translated in +‘Anthropological Review,’ Oct. 1868, p. 428. Owen (‘Anatomy +of Vertebrates,’ vol. ii. 1866, p. 551) on the mastoid processes in the +higher apes.) maintains that “the powerful mastoid processes of the human +skull are the result of his erect position;” and these processes are +absent in the orang, chimpanzee, etc., and are smaller in the gorilla than in +man. Various other structures, which appear connected with man’s erect +position, might here have been added. It is very difficult to decide how far +these correlated modifications are the result of natural selection, and how far +of the inherited effects of the increased use of certain parts, or of the +action of one part on another. No doubt these means of change often co-operate: +thus when certain muscles, and the crests of bone to which they are attached, +become enlarged by habitual use, this shews that certain actions are habitually +performed and must be serviceable. Hence the individuals which performed them +best, would tend to survive in greater numbers. +</p> + +<p> +The free use of the arms and hands, partly the cause and partly the result of +man’s erect position, appears to have led in an indirect manner to other +modifications of structure. The early male forefathers of man were, as +previously stated, probably furnished with great canine teeth; but as they +gradually acquired the habit of using stones, clubs, or other weapons, for +fighting with their enemies or rivals, they would use their jaws and teeth less +and less. In this case, the jaws, together with the teeth, would become reduced +in size, as we may feel almost sure from innumerable analogous cases. In a +future chapter we shall meet with a closely parallel case, in the reduction or +complete disappearance of the canine teeth in male ruminants, apparently in +relation with the development of their horns; and in horses, in relation to +their habit of fighting with their incisor teeth and hoofs. +</p> + +<p> +In the adult male anthropomorphous apes, as Rutimeyer (77. ‘Die Grenzen +der Thierwelt, eine Betrachtung zu Darwin’s Lehre,’ 1868, s. 51.), +and others, have insisted, it is the effect on the skull of the great +development of the jaw-muscles that causes it to differ so greatly in many +respects from that of man, and has given to these animals “a truly +frightful physiognomy.” Therefore, as the jaws and teeth in man’s +progenitors gradually become reduced in size, the adult skull would have come +to resemble more and more that of existing man. As we shall hereafter see, a +great reduction of the canine teeth in the males would almost certainly affect +the teeth of the females through inheritance. +</p> + +<p> +As the various mental faculties gradually developed themselves the brain would +almost certainly become larger. No one, I presume, doubts that the large +proportion which the size of man’s brain bears to his body, compared to +the same proportion in the gorilla or orang, is closely connected with his +higher mental powers. We meet with closely analogous facts with insects, for in +ants the cerebral ganglia are of extraordinary dimensions, and in all the +Hymenoptera these ganglia are many times larger than in the less intelligent +orders, such as beetles. (78. Dujardin, ‘Annales des Sciences Nat.’ +3rd series, Zoolog., tom. xiv. 1850, p. 203. See also Mr. Lowne, ‘Anatomy +and Phys. of the Musca vomitoria,’ 1870, p. 14. My son, Mr. F. Darwin, +dissected for me the cerebral ganglia of the Formica rufa.) On the other hand, +no one supposes that the intellect of any two animals or of any two men can be +accurately gauged by the cubic contents of their skulls. It is certain that +there may be extraordinary mental activity with an extremely small absolute +mass of nervous matter: thus the wonderfully diversified instincts, mental +powers, and affections of ants are notorious, yet their cerebral ganglia are +not so large as the quarter of a small pin’s head. Under this point of +view, the brain of an ant is one of the most marvellous atoms of matter in the +world, perhaps more so than the brain of a man. +</p> + +<p> +The belief that there exists in man some close relation between the size of the +brain and the development of the intellectual faculties is supported by the +comparison of the skulls of savage and civilised races, of ancient and modern +people, and by the analogy of the whole vertebrate series. Dr. J. Barnard Davis +has proved (79. ‘Philosophical Transactions,’ 1869, p. 513.), by +many careful measurements, that the mean internal capacity of the skull in +Europeans is 92.3 cubic inches; in Americans 87.5; in Asiatics 87.1; and in +Australians only 81.9 cubic inches. Professor Broca (80. ‘Les +Selections,’ M. P. Broca, ‘Revue d’Anthropologies,’ +1873; see also, as quoted in C. Vogt’s ‘Lectures on Man,’ +Engl. translat., 1864, pp. 88, 90. Prichard, ‘Physical History of +Mankind,’ vol. i. 1838, p. 305.) found that the nineteenth century skulls +from graves in Paris were larger than those from vaults of the twelfth century, +in the proportion of 1484 to 1426; and that the increased size, as ascertained +by measurements, was exclusively in the frontal part of the skull—the +seat of the intellectual faculties. Prichard is persuaded that the present +inhabitants of Britain have “much more capacious brain-cases” than +the ancient inhabitants. Nevertheless, it must be admitted that some skulls of +very high antiquity, such as the famous one of Neanderthal, are well developed +and capacious. (81. In the interesting article just referred to, Prof. Broca +has well remarked, that in civilised nations, the average capacity of the skull +must be lowered by the preservation of a considerable number of individuals, +weak in mind and body, who would have been promptly eliminated in the savage +state. On the other hand, with savages, the average includes only the more +capable individuals, who have been able to survive under extremely hard +conditions of life. Broca thus explains the otherwise inexplicable fact, that +the mean capacity of the skull of the ancient Troglodytes of Lozere is greater +than that of modern Frenchmen.) With respect to the lower animals, M.E. Lartet +(82. ‘Comptes-rendus des Sciences,’ etc., June 1, 1868.), by +comparing the crania of tertiary and recent mammals belonging to the same +groups, has come to the remarkable conclusion that the brain is generally +larger and the convolutions are more complex in the more recent forms. On the +other hand, I have shewn (83. The ‘Variation of Animals and Plants under +Domestication,’ vol. i. pp. 124-129.) that the brains of domestic rabbits +are considerably reduced in bulk, in comparison with those of the wild rabbit +or hare; and this may be attributed to their having been closely confined +during many generations, so that they have exerted their intellect, instincts, +senses and voluntary movements but little. +</p> + +<p> +The gradually increasing weight of the brain and skull in man must have +influenced the development of the supporting spinal column, more especially +whilst he was becoming erect. As this change of position was being brought +about, the internal pressure of the brain will also have influenced the form of +the skull; for many facts shew how easily the skull is thus affected. +Ethnologists believe that it is modified by the kind of cradle in which infants +sleep. Habitual spasms of the muscles, and a cicatrix from a severe burn, have +permanently modified the facial bones. In young persons whose heads have become +fixed either sideways or backwards, owing to disease, one of the two eyes has +changed its position, and the shape of the skull has been altered apparently by +the pressure of the brain in a new direction. (84. Schaaffhausen gives from +Blumenbach and Busch, the cases of the spasms and cicatrix, in +‘Anthropological Review,’ Oct. 1868, p. 420. Dr. Jarrold +(‘Anthropologia,’ 1808, pp. 115, 116) adduces from Camper and from +his own observations, cases of the modification of the skull from the head +being fixed in an unnatural position. He believes that in certain trades, such +as that of a shoemaker, where the head is habitually held forward, the forehead +becomes more rounded and prominent.) I have shewn that with long-eared rabbits +even so trifling a cause as the lopping forward of one ear drags forward almost +every bone of the skull on that side; so that the bones on the opposite side no +longer strictly correspond. Lastly, if any animal were to increase or diminish +much in general size, without any change in its mental powers, or if the mental +powers were to be much increased or diminished, without any great change in the +size of the body, the shape of the skull would almost certainly be altered. I +infer this from my observations on domestic rabbits, some kinds of which have +become very much larger than the wild animal, whilst others have retained +nearly the same size, but in both cases the brain has been much reduced +relatively to the size of the body. Now I was at first much surprised on +finding that in all these rabbits the skull had become elongated or +dolichocephalic; for instance, of two skulls of nearly equal breadth, the one +from a wild rabbit and the other from a large domestic kind, the former was +3.15 and the latter 4.3 inches in length. (85. ‘Variation of Animals and +Plants under Domestication,’ vol. i. p. 117, on the elongation of the +skull; p. 119, on the effect of the lopping of one ear.) One of the most marked +distinctions in different races of men is that the skull in some is elongated, +and in others rounded; and here the explanation suggested by the case of the +rabbits may hold good; for Welcker finds that short “men incline more to +brachycephaly, and tall men to dolichocephaly” (86. Quoted by +Schaaffhausen, in ‘Anthropological Review,’ Oct. 1868, p. 419.); +and tall men may be compared with the larger and longer-bodied rabbits, all of +which have elongated skulls or are dolichocephalic. +</p> + +<p> +From these several facts we can understand, to a certain extent, the means by +which the great size and more or less rounded form of the skull have been +acquired by man; and these are characters eminently distinctive of him in +comparison with the lower animals. +</p> + +<p> +Another most conspicuous difference between man and the lower animals is the +nakedness of his skin. Whales and porpoises (Cetacea), dugongs (Sirenia) and +the hippopotamus are naked; and this may be advantageous to them for gliding +through the water; nor would it be injurious to them from the loss of warmth, +as the species, which inhabit the colder regions, are protected by a thick +layer of blubber, serving the same purpose as the fur of seals and otters. +Elephants and rhinoceroses are almost hairless; and as certain extinct species, +which formerly lived under an Arctic climate, were covered with long wool or +hair, it would almost appear as if the existing species of both genera had lost +their hairy covering from exposure to heat. This appears the more probable, as +the elephants in India which live on elevated and cool districts are more hairy +(87. Owen, ‘Anatomy of Vertebrates,’ vol. iii. p. 619.) than those +on the lowlands. May we then infer that man became divested of hair from having +aboriginally inhabited some tropical land? That the hair is chiefly retained in +the male sex on the chest and face, and in both sexes at the junction of all +four limbs with the trunk, favours this inference—on the assumption that +the hair was lost before man became erect; for the parts which now retain most +hair would then have been most protected from the heat of the sun. The crown of +the head, however, offers a curious exception, for at all times it must have +been one of the most exposed parts, yet it is thickly clothed with hair. The +fact, however, that the other members of the order of Primates, to which man +belongs, although inhabiting various hot regions, are well clothed with hair, +generally thickest on the upper surface (88. Isidore Geoffroy St.-Hilaire +remarks (‘Histoire Nat. Generale,’ tom. ii. 1859, pp. 215-217) on +the head of man being covered with long hair; also on the upper surfaces of +monkeys and of other mammals being more thickly clothed than the lower +surfaces. This has likewise been observed by various authors. Prof. P. Gervais +(‘Histoire Nat. des Mammifères,’ tom. i. 1854, p. 28), however, +states that in the Gorilla the hair is thinner on the back, where it is partly +rubbed off, than on the lower surface.), is opposed to the supposition that man +became naked through the action of the sun. Mr. Belt believes (89. The +‘Naturalist in Nicaragua,’ 1874, p. 209. As some confirmation of +Mr. Belt’s view, I may quote the following passage from Sir W. Denison +(‘Varieties of Vice-Regal Life,’ vol. i. 1870, p. 440): “It +is said to be a practice with the Australians, when the vermin get troublesome, +to singe themselves.”) that within the tropics it is an advantage to man +to be destitute of hair, as he is thus enabled to free himself of the multitude +of ticks (acari) and other parasites, with which he is often infested, and +which sometimes cause ulceration. But whether this evil is of sufficient +magnitude to have led to the denudation of his body through natural selection, +may be doubted, since none of the many quadrupeds inhabiting the tropics have, +as far as I know, acquired any specialised means of relief. The view which +seems to me the most probable is that man, or rather primarily woman, became +divested of hair for ornamental purposes, as we shall see under Sexual +Selection; and, according to this belief, it is not surprising that man should +differ so greatly in hairiness from all other Primates, for characters, gained +through sexual selection, often differ to an extraordinary degree in closely +related forms. +</p> + +<p> +According to a popular impression, the absence of a tail is eminently +distinctive of man; but as those apes which come nearest to him are destitute +of this organ, its disappearance does not relate exclusively to man. The tail +often differs remarkably in length within the same genus: thus in some species +of Macacus it is longer than the whole body, and is formed of twenty-four +vertebrae; in others it consists of a scarcely visible stump, containing only +three or four vertebrae. In some kinds of baboons there are twenty-five, whilst +in the mandrill there are ten very small stunted caudal vertebrae, or, +according to Cuvier (90. Mr. St. George Mivart, ‘Proc. Zoolog. +Soc.’ 1865, pp. 562, 583. Dr. J.E. Gray, ‘Cat. Brit. Mus.: +‘Skeletons.’ Owen, ‘Anatomy of Vertebrates,’ vol. ii. +p. 517. Isidore Geoffroy, ‘Hist. Nat. Gen.’ tom. ii. p. 244.), +sometimes only five. The tail, whether it be long or short, almost always +tapers towards the end; and this, I presume, results from the atrophy of the +terminal muscles, together with their arteries and nerves, through disuse, +leading to the atrophy of the terminal bones. But no explanation can at present +be given of the great diversity which often occurs in its length. Here, +however, we are more specially concerned with the complete external +disappearance of the tail. Professor Broca has recently shewn (91. ‘Revue +d’Anthropologie,’ 1872; ‘La Constitution des vertèbres +caudales.’) that the tail in all quadrupeds consists of two portions, +generally separated abruptly from each other; the basal portion consists of +vertebrae, more or less perfectly channelled and furnished with apophyses like +ordinary vertebrae; whereas those of the terminal portion are not channelled, +are almost smooth, and scarcely resemble true vertebrae. A tail, though not +externally visible, is really present in man and the anthropomorphous apes, and +is constructed on exactly the same pattern in both. In the terminal portion the +vertebrae, constituting the os coccyx, are quite rudimentary, being much +reduced in size and number. In the basal portion, the vertebrae are likewise +few, are united firmly together, and are arrested in development; but they have +been rendered much broader and flatter than the corresponding vertebrae in the +tails of other animals: they constitute what Broca calls the accessory sacral +vertebrae. These are of functional importance by supporting certain internal +parts and in other ways; and their modification is directly connected with the +erect or semi-erect attitude of man and the anthropomorphous apes. This +conclusion is the more trustworthy, as Broca formerly held a different view, +which he has now abandoned. The modification, therefore, of the basal caudal +vertebrae in man and the higher apes may have been effected, directly or +indirectly, through natural selection. +</p> + +<p> +But what are we to say about the rudimentary and variable vertebrae of the +terminal portion of the tail, forming the os coccyx? A notion which has often +been, and will no doubt again be ridiculed, namely, that friction has had +something to do with the disappearance of the external portion of the tail, is +not so ridiculous as it at first appears. Dr. Anderson (92. ‘Proceedings +Zoological Society,’ 1872, p. 210.) states that the extremely short tail +of Macacus brunneus is formed of eleven vertebrae, including the imbedded basal +ones. The extremity is tendinous and contains no vertebrae; this is succeeded +by five rudimentary ones, so minute that together they are only one line and a +half in length, and these are permanently bent to one side in the shape of a +hook. The free part of the tail, only a little above an inch in length, +includes only four more small vertebrae. This short tail is carried erect; but +about a quarter of its total length is doubled on to itself to the left; and +this terminal part, which includes the hook-like portion, serves “to fill +up the interspace between the upper divergent portion of the +callosities;” so that the animal sits on it, and thus renders it rough +and callous. Dr. Anderson thus sums up his observations: “These facts +seem to me to have only one explanation; this tail, from its short size, is in +the monkey’s way when it sits down, and frequently becomes placed under +the animal while it is in this attitude; and from the circumstance that it does +not extend beyond the extremity of the ischial tuberosities, it seems as if the +tail originally had been bent round by the will of the animal, into the +interspace between the callosities, to escape being pressed between them and +the ground, and that in time the curvature became permanent, fitting in of +itself when the organ happens to be sat upon.” Under these circumstances +it is not surprising that the surface of the tail should have been roughened +and rendered callous, and Dr. Murie (93. ‘Proceedings Zoological +Society,’ 1872, p. 786.), who carefully observed this species in the +Zoological Gardens, as well as three other closely allied forms with slightly +longer tails, says that when the animal sits down, the tail “is +necessarily thrust to one side of the buttocks; and whether long or short its +root is consequently liable to be rubbed or chafed.” As we now have +evidence that mutilations occasionally produce an inherited effect (94. I +allude to Dr. Brown-Sequard’s observations on the transmitted effect of +an operation causing epilepsy in guinea-pigs, and likewise more recently on the +analogous effects of cutting the sympathetic nerve in the neck. I shall +hereafter have occasion to refer to Mr. Salvin’s interesting case of the +apparently inherited effects of mot-mots biting off the barbs of their own +tail-feathers. See also on the general subject ‘Variation of Animals and +Plants under Domestication,’ vol. ii. pp. 22-24.), it is not very +improbable that in short-tailed monkeys, the projecting part of the tail, being +functionally useless, should after many generations have become rudimentary and +distorted, from being continually rubbed and chafed. We see the projecting part +in this condition in the Macacus brunneus, and absolutely aborted in the M. +ecaudatus and in several of the higher apes. Finally, then, as far as we can +judge, the tail has disappeared in man and the anthropomorphous apes, owing to +the terminal portion having been injured by friction during a long lapse of +time; the basal and embedded portion having been reduced and modified, so as to +become suitable to the erect or semi-erect position. +</p> + +<p> +I have now endeavoured to shew that some of the most distinctive characters of +man have in all probability been acquired, either directly, or more commonly +indirectly, through natural selection. We should bear in mind that +modifications in structure or constitution which do not serve to adapt an +organism to its habits of life, to the food which it consumes, or passively to +the surrounding conditions, cannot have been thus acquired. We must not, +however, be too confident in deciding what modifications are of service to each +being: we should remember how little we know about the use of many parts, or +what changes in the blood or tissues may serve to fit an organism for a new +climate or new kinds of food. Nor must we forget the principle of correlation, +by which, as Isidore Geoffroy has shewn in the case of man, many strange +deviations of structure are tied together. Independently of correlation, a +change in one part often leads, through the increased or decreased use of other +parts, to other changes of a quite unexpected nature. It is also well to +reflect on such facts, as the wonderful growth of galls on plants caused by the +poison of an insect, and on the remarkable changes of colour in the plumage of +parrots when fed on certain fishes, or inoculated with the poison of toads (95. +The ‘Variation of Animals and Plants under Domestication,’ vol. ii. +pp. 280, 282.); for we can thus see that the fluids of the system, if altered +for some special purpose, might induce other changes. We should especially bear +in mind that modifications acquired and continually used during past ages for +some useful purpose, would probably become firmly fixed, and might be long +inherited. +</p> + +<p> +Thus a large yet undefined extension may safely be given to the direct and +indirect results of natural selection; but I now admit, after reading the essay +by Nageli on plants, and the remarks by various authors with respect to +animals, more especially those recently made by Professor Broca, that in the +earlier editions of my ‘Origin of Species’ I perhaps attributed too +much to the action of natural selection or the survival of the fittest. I have +altered the fifth edition of the ‘Origin’ so as to confine my +remarks to adaptive changes of structure; but I am convinced, from the light +gained during even the last few years, that very many structures which now +appear to us useless, will hereafter be proved to be useful, and will therefore +come within the range of natural selection. Nevertheless, I did not formerly +consider sufficiently the existence of structures, which, as far as we can at +present judge, are neither beneficial nor injurious; and this I believe to be +one of the greatest oversights as yet detected in my work. I may be permitted +to say, as some excuse, that I had two distinct objects in view; firstly, to +shew that species had not been separately created, and secondly, that natural +selection had been the chief agent of change, though largely aided by the +inherited effects of habit, and slightly by the direct action of the +surrounding conditions. I was not, however, able to annul the influence of my +former belief, then almost universal, that each species had been purposely +created; and this led to my tacit assumption that every detail of structure, +excepting rudiments, was of some special, though unrecognised, service. Any one +with this assumption in his mind would naturally extend too far the action of +natural selection, either during past or present times. Some of those who admit +the principle of evolution, but reject natural selection, seem to forget, when +criticising my book, that I had the above two objects in view; hence if I have +erred in giving to natural selection great power, which I am very far from +admitting, or in having exaggerated its power, which is in itself probable, I +have at least, as I hope, done good service in aiding to overthrow the dogma of +separate creations. +</p> + +<p> +It is, as I can now see, probable that all organic beings, including man, +possess peculiarities of structure, which neither are now, nor were formerly of +any service to them, and which, therefore, are of no physiological importance. +We know not what produces the numberless slight differences between the +individuals of each species, for reversion only carries the problem a few steps +backwards, but each peculiarity must have had its efficient cause. If these +causes, whatever they may be, were to act more uniformly and energetically +during a lengthened period (and against this no reason can be assigned), the +result would probably be not a mere slight individual difference, but a +well-marked and constant modification, though one of no physiological +importance. Changed structures, which are in no way beneficial, cannot be kept +uniform through natural selection, though the injurious will be thus +eliminated. Uniformity of character would, however, naturally follow from the +assumed uniformity of the exciting causes, and likewise from the free +intercrossing of many individuals. During successive periods, the same organism +might in this manner acquire successive modifications, which would be +transmitted in a nearly uniform state as long as the exciting causes remained +the same and there was free intercrossing. With respect to the exciting causes +we can only say, as when speaking of so-called spontaneous variations, that +they relate much more closely to the constitution of the varying organism, than +to the nature of the conditions to which it has been subjected. +</p> + +<h3>—CONCLUSION—</h3> + +<p> +In this chapter we have seen that as man at the present day is liable, like +every other animal, to multiform individual differences or slight variations, +so no doubt were the early progenitors of man; the variations being formerly +induced by the same general causes, and governed by the same general and +complex laws as at present. As all animals tend to multiply beyond their means +of subsistence, so it must have been with the progenitors of man; and this +would inevitably lead to a struggle for existence and to natural selection. The +latter process would be greatly aided by the inherited effects of the increased +use of parts, and these two processes would incessantly react on each other. It +appears, also, as we shall hereafter see, that various unimportant characters +have been acquired by man through sexual selection. An unexplained residuum of +change must be left to the assumed uniform action of those unknown agencies, +which occasionally induce strongly marked and abrupt deviations of structure in +our domestic productions. +</p> + +<p> +Judging from the habits of savages and of the greater number of the Quadrumana, +primeval men, and even their ape-like progenitors, probably lived in society. +With strictly social animals, natural selection sometimes acts on the +individual, through the preservation of variations which are beneficial to the +community. A community which includes a large number of well-endowed +individuals increases in number, and is victorious over other less favoured +ones; even although each separate member gains no advantage over the others of +the same community. Associated insects have thus acquired many remarkable +structures, which are of little or no service to the individual, such as the +pollen-collecting apparatus, or the sting of the worker-bee, or the great jaws +of soldier-ants. With the higher social animals, I am not aware that any +structure has been modified solely for the good of the community, though some +are of secondary service to it. For instance, the horns of ruminants and the +great canine teeth of baboons appear to have been acquired by the males as +weapons for sexual strife, but they are used in defence of the herd or troop. +In regard to certain mental powers the case, as we shall see in the fifth +chapter, is wholly different; for these faculties have been chiefly, or even +exclusively, gained for the benefit of the community, and the individuals +thereof have at the same time gained an advantage indirectly. +</p> + +<p> +It has often been objected to such views as the foregoing, that man is one of +the most helpless and defenceless creatures in the world; and that during his +early and less well-developed condition, he would have been still more +helpless. The Duke of Argyll, for instance, insists (96. ‘Primeval +Man,’ 1869, p. 66.) that “the human frame has diverged from the +structure of brutes, in the direction of greater physical helplessness and +weakness. That is to say, it is a divergence which of all others it is most +impossible to ascribe to mere natural selection.” He adduces the naked +and unprotected state of the body, the absence of great teeth or claws for +defence, the small strength and speed of man, and his slight power of +discovering food or of avoiding danger by smell. To these deficiencies there +might be added one still more serious, namely, that he cannot climb quickly, +and so escape from enemies. The loss of hair would not have been a great injury +to the inhabitants of a warm country. For we know that the unclothed Fuegians +can exist under a wretched climate. When we compare the defenceless state of +man with that of apes, we must remember that the great canine teeth with which +the latter are provided, are possessed in their full development by the males +alone, and are chiefly used by them for fighting with their rivals; yet the +females, which are not thus provided, manage to survive. +</p> + +<p> +In regard to bodily size or strength, we do not know whether man is descended +from some small species, like the chimpanzee, or from one as powerful as the +gorilla; and, therefore, we cannot say whether man has become larger and +stronger, or smaller and weaker, than his ancestors. We should, however, bear +in mind that an animal possessing great size, strength, and ferocity, and +which, like the gorilla, could defend itself from all enemies, would not +perhaps have become social: and this would most effectually have checked the +acquirement of the higher mental qualities, such as sympathy and the love of +his fellows. Hence it might have been an immense advantage to man to have +sprung from some comparatively weak creature. +</p> + +<p> +The small strength and speed of man, his want of natural weapons, etc., are +more than counterbalanced, firstly, by his intellectual powers, through which +he has formed for himself weapons, tools, etc., though still remaining in a +barbarous state, and, secondly, by his social qualities which lead him to give +and receive aid from his fellow-men. No country in the world abounds in a +greater degree with dangerous beasts than Southern Africa; no country presents +more fearful physical hardships than the Arctic regions; yet one of the puniest +of races, that of the Bushmen, maintains itself in Southern Africa, as do the +dwarfed Esquimaux in the Arctic regions. The ancestors of man were, no doubt, +inferior in intellect, and probably in social disposition, to the lowest +existing savages; but it is quite conceivable that they might have existed, or +even flourished, if they had advanced in intellect, whilst gradually losing +their brute-like powers, such as that of climbing trees, etc. But these +ancestors would not have been exposed to any special danger, even if far more +helpless and defenceless than any existing savages, had they inhabited some +warm continent or large island, such as Australia, New Guinea, or Borneo, which +is now the home of the orang. And natural selection arising from the +competition of tribe with tribe, in some such large area as one of these, +together with the inherited effects of habit, would, under favourable +conditions, have sufficed to raise man to his present high position in the +organic scale. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0003" id="link2HCH0003"></a> +CHAPTER III.<br /> +COMPARISON OF THE MENTAL POWERS OF MAN AND THE LOWER ANIMALS.</h2> + +<p class="letter"> +The difference in mental power between the highest ape and the lowest savage, +immense—Certain instincts in common—The +emotions—Curiosity—Imitation—Attention—Memory— +Imagination—Reason—Progressive improvement —Tools and weapons +used by animals—Abstraction, +Self-consciousness—Language—Sense of beauty—Belief in God, +spiritual agencies, superstitions. +</p> + +<p> +We have seen in the last two chapters that man bears in his bodily structure +clear traces of his descent from some lower form; but it may be urged that, as +man differs so greatly in his mental power from all other animals, there must +be some error in this conclusion. No doubt the difference in this respect is +enormous, even if we compare the mind of one of the lowest savages, who has no +words to express any number higher than four, and who uses hardly any abstract +terms for common objects or for the affections (1. See the evidence on those +points, as given by Lubbock, ‘Prehistoric Times,’ p. 354, etc.), +with that of the most highly organised ape. The difference would, no doubt, +still remain immense, even if one of the higher apes had been improved or +civilised as much as a dog has been in comparison with its parent-form, the +wolf or jackal. The Fuegians rank amongst the lowest barbarians; but I was +continually struck with surprise how closely the three natives on board H.M.S. +“Beagle,” who had lived some years in England, and could talk a +little English, resembled us in disposition and in most of our mental +faculties. If no organic being excepting man had possessed any mental power, or +if his powers had been of a wholly different nature from those of the lower +animals, then we should never have been able to convince ourselves that our +high faculties had been gradually developed. But it can be shewn that there is +no fundamental difference of this kind. We must also admit that there is a much +wider interval in mental power between one of the lowest fishes, as a lamprey +or lancelet, and one of the higher apes, than between an ape and man; yet this +interval is filled up by numberless gradations. +</p> + +<p> +Nor is the difference slight in moral disposition between a barbarian, such as +the man described by the old navigator Byron, who dashed his child on the rocks +for dropping a basket of sea-urchins, and a Howard or Clarkson; and in +intellect, between a savage who uses hardly any abstract terms, and a Newton or +Shakspeare. Differences of this kind between the highest men of the highest +races and the lowest savages, are connected by the finest gradations. Therefore +it is possible that they might pass and be developed into each other. +</p> + +<p> +My object in this chapter is to shew that there is no fundamental difference +between man and the higher mammals in their mental faculties. Each division of +the subject might have been extended into a separate essay, but must here be +treated briefly. As no classification of the mental powers has been universally +accepted, I shall arrange my remarks in the order most convenient for my +purpose; and will select those facts which have struck me most, with the hope +that they may produce some effect on the reader. +</p> + +<p> +With respect to animals very low in the scale, I shall give some additional +facts under Sexual Selection, shewing that their mental powers are much higher +than might have been expected. The variability of the faculties in the +individuals of the same species is an important point for us, and some few +illustrations will here be given. But it would be superfluous to enter into +many details on this head, for I have found on frequent enquiry, that it is the +unanimous opinion of all those who have long attended to animals of many kinds, +including birds, that the individuals differ greatly in every mental +characteristic. In what manner the mental powers were first developed in the +lowest organisms, is as hopeless an enquiry as how life itself first +originated. These are problems for the distant future, if they are ever to be +solved by man. +</p> + +<p> +As man possesses the same senses as the lower animals, his fundamental +intuitions must be the same. Man has also some few instincts in common, as that +of self-preservation, sexual love, the love of the mother for her new-born +offspring, the desire possessed by the latter to suck, and so forth. But man, +perhaps, has somewhat fewer instincts than those possessed by the animals which +come next to him in the series. The orang in the Eastern islands, and the +chimpanzee in Africa, build platforms on which they sleep; and, as both species +follow the same habit, it might be argued that this was due to instinct, but we +cannot feel sure that it is not the result of both animals having similar +wants, and possessing similar powers of reasoning. These apes, as we may +assume, avoid the many poisonous fruits of the tropics, and man has no such +knowledge: but as our domestic animals, when taken to foreign lands, and when +first turned out in the spring, often eat poisonous herbs, which they +afterwards avoid, we cannot feel sure that the apes do not learn from their own +experience or from that of their parents what fruits to select. It is, however, +certain, as we shall presently see, that apes have an instinctive dread of +serpents, and probably of other dangerous animals. +</p> + +<p> +The fewness and the comparative simplicity of the instincts in the higher +animals are remarkable in contrast with those of the lower animals. Cuvier +maintained that instinct and intelligence stand in an inverse ratio to each +other; and some have thought that the intellectual faculties of the higher +animals have been gradually developed from their instincts. But Pouchet, in an +interesting essay (2. ‘L’Instinct chez les Insectes,’ +‘Revue des Deux Mondes,’ Feb. 1870, p. 690.), has shewn that no +such inverse ratio really exists. Those insects which possess the most +wonderful instincts are certainly the most intelligent. In the vertebrate +series, the least intelligent members, namely fishes and amphibians, do not +possess complex instincts; and amongst mammals the animal most remarkable for +its instincts, namely the beaver, is highly intelligent, as will be admitted by +every one who has read Mr. Morgan’s excellent work. (3. ‘The +American Beaver and His Works,’ 1868.) +</p> + +<p> +Although the first dawnings of intelligence, according to Mr. Herbert Spencer +(4. ‘The Principles of Psychology,’ 2nd edit., 1870, pp. 418-443.), +have been developed through the multiplication and co-ordination of reflex +actions, and although many of the simpler instincts graduate into reflex +actions, and can hardly be distinguished from them, as in the case of young +animals sucking, yet the more complex instincts seem to have originated +independently of intelligence. I am, however, very far from wishing to deny +that instinctive actions may lose their fixed and untaught character, and be +replaced by others performed by the aid of the free will. On the other hand, +some intelligent actions, after being performed during several generations, +become converted into instincts and are inherited, as when birds on oceanic +islands learn to avoid man. These actions may then be said to be degraded in +character, for they are no longer performed through reason or from experience. +But the greater number of the more complex instincts appear to have been gained +in a wholly different manner, through the natural selection of variations of +simpler instinctive actions. Such variations appear to arise from the same +unknown causes acting on the cerebral organisation, which induce slight +variations or individual differences in other parts of the body; and these +variations, owing to our ignorance, are often said to arise spontaneously. We +can, I think, come to no other conclusion with respect to the origin of the +more complex instincts, when we reflect on the marvellous instincts of sterile +worker-ants and bees, which leave no offspring to inherit the effects of +experience and of modified habits. +</p> + +<p> +Although, as we learn from the above-mentioned insects and the beaver, a high +degree of intelligence is certainly compatible with complex instincts, and +although actions, at first learnt voluntarily can soon through habit be +performed with the quickness and certainty of a reflex action, yet it is not +improbable that there is a certain amount of interference between the +development of free intelligence and of instinct,—which latter implies +some inherited modification of the brain. Little is known about the functions +of the brain, but we can perceive that as the intellectual powers become highly +developed, the various parts of the brain must be connected by very intricate +channels of the freest intercommunication; and as a consequence each separate +part would perhaps tend to be less well fitted to answer to particular +sensations or associations in a definite and inherited—that is +instinctive—manner. There seems even to exist some relation between a low +degree of intelligence and a strong tendency to the formation of fixed, though +not inherited habits; for as a sagacious physician remarked to me, persons who +are slightly imbecile tend to act in everything by routine or habit; and they +are rendered much happier if this is encouraged. +</p> + +<p> +I have thought this digression worth giving, because we may easily underrate +the mental powers of the higher animals, and especially of man, when we compare +their actions founded on the memory of past events, on foresight, reason, and +imagination, with exactly similar actions instinctively performed by the lower +animals; in this latter case the capacity of performing such actions has been +gained, step by step, through the variability of the mental organs and natural +selection, without any conscious intelligence on the part of the animal during +each successive generation. No doubt, as Mr. Wallace has argued (5. +‘Contributions to the Theory of Natural Selection,’ 1870, p. 212.), +much of the intelligent work done by man is due to imitation and not to reason; +but there is this great difference between his actions and many of those +performed by the lower animals, namely, that man cannot, on his first trial, +make, for instance, a stone hatchet or a canoe, through his power of imitation. +He has to learn his work by practice; a beaver, on the other hand, can make its +dam or canal, and a bird its nest, as well, or nearly as well, and a spider its +wonderful web, quite as well (6. For the evidence on this head, see Mr. J. +Traherne Moggridge’s most interesting work, ‘Harvesting Ants and +Trap-Door Spiders,’ 1873, pp. 126, 128.), the first time it tries as when +old and experienced. +</p> + +<p> +To return to our immediate subject: the lower animals, like man, manifestly +feel pleasure and pain, happiness and misery. Happiness is never better +exhibited than by young animals, such as puppies, kittens, lambs, etc., when +playing together, like our own children. Even insects play together, as has +been described by that excellent observer, P. Huber (7. ‘Recherches sur +les Moeurs des Fourmis,’ 1810, p. 173.), who saw ants chasing and +pretending to bite each other, like so many puppies. +</p> + +<p> +The fact that the lower animals are excited by the same emotions as ourselves +is so well established, that it will not be necessary to weary the reader by +many details. Terror acts in the same manner on them as on us, causing the +muscles to tremble, the heart to palpitate, the sphincters to be relaxed, and +the hair to stand on end. Suspicion, the offspring of fear, is eminently +characteristic of most wild animals. It is, I think, impossible to read the +account given by Sir E. Tennent, of the behaviour of the female elephants, used +as decoys, without admitting that they intentionally practise deceit, and well +know what they are about. Courage and timidity are extremely variable qualities +in the individuals of the same species, as is plainly seen in our dogs. Some +dogs and horses are ill-tempered, and easily turn sulky; others are +good-tempered; and these qualities are certainly inherited. Every one knows how +liable animals are to furious rage, and how plainly they shew it. Many, and +probably true, anecdotes have been published on the long-delayed and artful +revenge of various animals. The accurate Rengger, and Brehm (8. All the +following statements, given on the authority of these two naturalists, are +taken from Rengger’s ‘Naturgesch. der Säugethiere von +Paraguay,’ 1830, s. 41-57, and from Brehm’s +‘Thierleben,’ B. i. s. 10-87.) state that the American and African +monkeys which they kept tame, certainly revenged themselves. Sir Andrew Smith, +a zoologist whose scrupulous accuracy was known to many persons, told me the +following story of which he was himself an eye-witness; at the Cape of Good +Hope an officer had often plagued a certain baboon, and the animal, seeing him +approaching one Sunday for parade, poured water into a hole and hastily made +some thick mud, which he skilfully dashed over the officer as he passed by, to +the amusement of many bystanders. For long afterwards the baboon rejoiced and +triumphed whenever he saw his victim. +</p> + +<p> +The love of a dog for his master is notorious; as an old writer quaintly says +(9. Quoted by Dr. Lauder Lindsay, in his ‘Physiology of Mind in the Lower +Animals,’ ‘Journal of Mental Science,’ April 1871, p. 38.), +“A dog is the only thing on this earth that luvs you more than he luvs +himself.” +</p> + +<p> +In the agony of death a dog has been known to caress his master, and every one +has heard of the dog suffering under vivisection, who licked the hand of the +operator; this man, unless the operation was fully justified by an increase of +our knowledge, or unless he had a heart of stone, must have felt remorse to the +last hour of his life. +</p> + +<p> +As Whewell (10. ‘Bridgewater Treatise,’ p. 263.) has well asked, +“who that reads the touching instances of maternal affection, related so +often of the women of all nations, and of the females of all animals, can doubt +that the principle of action is the same in the two cases?” We see +maternal affection exhibited in the most trifling details; thus Rengger +observed an American monkey (a Cebus) carefully driving away the flies which +plagued her infant; and Duvaucel saw a Hylobates washing the faces of her young +ones in a stream. So intense is the grief of female monkeys for the loss of +their young, that it invariably caused the death of certain kinds kept under +confinement by Brehm in N. Africa. Orphan monkeys were always adopted and +carefully guarded by the other monkeys, both males and females. One female +baboon had so capacious a heart that she not only adopted young monkeys of +other species, but stole young dogs and cats, which she continually carried +about. Her kindness, however, did not go so far as to share her food with her +adopted offspring, at which Brehm was surprised, as his monkeys always divided +everything quite fairly with their own young ones. An adopted kitten scratched +this affectionate baboon, who certainly had a fine intellect, for she was much +astonished at being scratched, and immediately examined the kitten’s +feet, and without more ado bit off the claws. (11. A critic, without any +grounds (‘Quarterly Review,’ July 1871, p. 72), disputes the +possibility of this act as described by Brehm, for the sake of discrediting my +work. Therefore I tried, and found that I could readily seize with my own teeth +the sharp little claws of a kitten nearly five weeks old.) In the Zoological +Gardens, I heard from the keeper that an old baboon (C. chacma) had adopted a +Rhesus monkey; but when a young drill and mandrill were placed in the cage, she +seemed to perceive that these monkeys, though distinct species, were her nearer +relatives, for she at once rejected the Rhesus and adopted both of them. The +young Rhesus, as I saw, was greatly discontented at being thus rejected, and it +would, like a naughty child, annoy and attack the young drill and mandrill +whenever it could do so with safety; this conduct exciting great indignation in +the old baboon. Monkeys will also, according to Brehm, defend their master when +attacked by any one, as well as dogs to whom they are attached, from the +attacks of other dogs. But we here trench on the subjects of sympathy and +fidelity, to which I shall recur. Some of Brehm’s monkeys took much +delight in teasing a certain old dog whom they disliked, as well as other +animals, in various ingenious ways. +</p> + +<p> +Most of the more complex emotions are common to the higher animals and +ourselves. Every one has seen how jealous a dog is of his master’s +affection, if lavished on any other creature; and I have observed the same fact +with monkeys. This shews that animals not only love, but have desire to be +loved. Animals manifestly feel emulation. They love approbation or praise; and +a dog carrying a basket for his master exhibits in a high degree +self-complacency or pride. There can, I think, be no doubt that a dog feels +shame, as distinct from fear, and something very like modesty when begging too +often for food. A great dog scorns the snarling of a little dog, and this may +be called magnanimity. Several observers have stated that monkeys certainly +dislike being laughed at; and they sometimes invent imaginary offences. In the +Zoological Gardens I saw a baboon who always got into a furious rage when his +keeper took out a letter or book and read it aloud to him; and his rage was so +violent that, as I witnessed on one occasion, he bit his own leg till the blood +flowed. Dogs shew what may be fairly called a sense of humour, as distinct from +mere play; if a bit of stick or other such object be thrown to one, he will +often carry it away for a short distance; and then squatting down with it on +the ground close before him, will wait until his master comes quite close to +take it away. The dog will then seize it and rush away in triumph, repeating +the same manoeuvre, and evidently enjoying the practical joke. +</p> + +<p> +We will now turn to the more intellectual emotions and faculties, which are +very important, as forming the basis for the development of the higher mental +powers. Animals manifestly enjoy excitement, and suffer from ennui, as may be +seen with dogs, and, according to Rengger, with monkeys. All animals feel +WONDER, and many exhibit CURIOSITY. They sometimes suffer from this latter +quality, as when the hunter plays antics and thus attracts them; I have +witnessed this with deer, and so it is with the wary chamois, and with some +kinds of wild-ducks. Brehm gives a curious account of the instinctive dread, +which his monkeys exhibited, for snakes; but their curiosity was so great that +they could not desist from occasionally satiating their horror in a most human +fashion, by lifting up the lid of the box in which the snakes were kept. I was +so much surprised at his account, that I took a stuffed and coiled-up snake +into the monkey-house at the Zoological Gardens, and the excitement thus caused +was one of the most curious spectacles which I ever beheld. Three species of +Cercopithecus were the most alarmed; they dashed about their cages, and uttered +sharp signal cries of danger, which were understood by the other monkeys. A few +young monkeys and one old Anubis baboon alone took no notice of the snake. I +then placed the stuffed specimen on the ground in one of the larger +compartments. After a time all the monkeys collected round it in a large +circle, and staring intently, presented a most ludicrous appearance. They +became extremely nervous; so that when a wooden ball, with which they were +familiar as a plaything, was accidentally moved in the straw, under which it +was partly hidden, they all instantly started away. These monkeys behaved very +differently when a dead fish, a mouse (12. I have given a short account of +their behaviour on this occasion in my ‘Expression of the Emotions in Man +and Animals,’ p. 43.), a living turtle, and other new objects were placed +in their cages; for though at first frightened, they soon approached, handled +and examined them. I then placed a live snake in a paper bag, with the mouth +loosely closed, in one of the larger compartments. One of the monkeys +immediately approached, cautiously opened the bag a little, peeped in, and +instantly dashed away. Then I witnessed what Brehm has described, for monkey +after monkey, with head raised high and turned on one side, could not resist +taking a momentary peep into the upright bag, at the dreadful object lying +quietly at the bottom. It would almost appear as if monkeys had some notion of +zoological affinities, for those kept by Brehm exhibited a strange, though +mistaken, instinctive dread of innocent lizards and frogs. An orang, also, has +been known to be much alarmed at the first sight of a turtle. (13. W.C.L. +Martin, ‘Natural History of Mammalia,’ 1841, p. 405.) +</p> + +<p> +The principle of IMITATION is strong in man, and especially, as I have myself +observed, with savages. In certain morbid states of the brain this tendency is +exaggerated to an extraordinary degree: some hemiplegic patients and others, at +the commencement of inflammatory softening of the brain, unconsciously imitate +every word which is uttered, whether in their own or in a foreign language, and +every gesture or action which is performed near them. (14. Dr. Bateman, +‘On Aphasia,’ 1870, p. 110.) Desor (15. Quoted by Vogt, +‘Mémoire sur les Microcephales,’ 1867, p. 168.) has remarked that +no animal voluntarily imitates an action performed by man, until in the +ascending scale we come to monkeys, which are well known to be ridiculous +mockers. Animals, however, sometimes imitate each other’s actions: thus +two species of wolves, which had been reared by dogs, learned to bark, as does +sometimes the jackal (16. The ‘Variation of Animals and Plants under +Domestication,’ vol. i. p. 27.), but whether this can be called voluntary +imitation is another question. Birds imitate the songs of their parents, and +sometimes of other birds; and parrots are notorious imitators of any sound +which they often hear. Dureau de la Malle gives an account (17. ‘Annales +des Sciences Nat.’ (1st Series), tom. xxii. p. 397.) of a dog reared by a +cat, who learnt to imitate the well-known action of a cat licking her paws, and +thus washing her ears and face; this was also witnessed by the celebrated +naturalist Audouin. I have received several confirmatory accounts; in one of +these, a dog had not been suckled by a cat, but had been brought up with one, +together with kittens, and had thus acquired the above habit, which he ever +afterwards practised during his life of thirteen years. Dureau de la +Malle’s dog likewise learnt from the kittens to play with a ball by +rolling it about with his fore paws, and springing on it. A correspondent +assures me that a cat in his house used to put her paws into jugs of milk +having too narrow a mouth for her head. A kitten of this cat soon learned the +same trick, and practised it ever afterwards, whenever there was an +opportunity. +</p> + +<p> +The parents of many animals, trusting to the principle of imitation in their +young, and more especially to their instinctive or inherited tendencies, may be +said to educate them. We see this when a cat brings a live mouse to her +kittens; and Dureau de la Malle has given a curious account (in the paper above +quoted) of his observations on hawks which taught their young dexterity, as +well as judgment of distances, by first dropping through the air dead mice and +sparrows, which the young generally failed to catch, and then bringing them +live birds and letting them loose. +</p> + +<p> +Hardly any faculty is more important for the intellectual progress of man than +ATTENTION. Animals clearly manifest this power, as when a cat watches by a hole +and prepares to spring on its prey. Wild animals sometimes become so absorbed +when thus engaged, that they may be easily approached. Mr. Bartlett has given +me a curious proof how variable this faculty is in monkeys. A man who trains +monkeys to act in plays, used to purchase common kinds from the Zoological +Society at the price of five pounds for each; but he offered to give double the +price, if he might keep three or four of them for a few days, in order to +select one. When asked how he could possibly learn so soon, whether a +particular monkey would turn out a good actor, he answered that it all depended +on their power of attention. If when he was talking and explaining anything to +a monkey, its attention was easily distracted, as by a fly on the wall or other +trifling object, the case was hopeless. If he tried by punishment to make an +inattentive monkey act, it turned sulky. On the other hand, a monkey which +carefully attended to him could always be trained. +</p> + +<p> +It is almost superfluous to state that animals have excellent MEMORIES for +persons and places. A baboon at the Cape of Good Hope, as I have been informed +by Sir Andrew Smith, recognised him with joy after an absence of nine months. I +had a dog who was savage and averse to all strangers, and I purposely tried his +memory after an absence of five years and two days. I went near the stable +where he lived, and shouted to him in my old manner; he shewed no joy, but +instantly followed me out walking, and obeyed me, exactly as if I had parted +with him only half an hour before. A train of old associations, dormant during +five years, had thus been instantaneously awakened in his mind. Even ants, as +P. Huber (18. ‘Les Moeurs des Fourmis,’ 1810, p. 150.) has clearly +shewn, recognised their fellow-ants belonging to the same community after a +separation of four months. Animals can certainly by some means judge of the +intervals of time between recurrent events. +</p> + +<p> +The IMAGINATION is one of the highest prerogatives of man. By this faculty he +unites former images and ideas, independently of the will, and thus creates +brilliant and novel results. A poet, as Jean Paul Richter remarks (19. Quoted +in Dr. Maudsley’s ‘Physiology and Pathology of Mind,’ 1868, +pp. 19, 220.), “who must reflect whether he shall make a character say +yes or no—to the devil with him; he is only a stupid corpse.” +Dreaming gives us the best notion of this power; as Jean Paul again says, +“The dream is an involuntary art of poetry.” The value of the +products of our imagination depends of course on the number, accuracy, and +clearness of our impressions, on our judgment and taste in selecting or +rejecting the involuntary combinations, and to a certain extent on our power of +voluntarily combining them. As dogs, cats, horses, and probably all the higher +animals, even birds (20. Dr. Jerdon, ‘Birds of India,’ vol. i. +1862, p. xxi. Houzeau says that his parokeets and canary-birds dreamt: +‘Etudes sur les Facultes Mentales des Animaux,’ tom. ii. p. 136.) +have vivid dreams, and this is shewn by their movements and the sounds uttered, +we must admit that they possess some power of imagination. There must be +something special, which causes dogs to howl in the night, and especially +during moonlight, in that remarkable and melancholy manner called baying. All +dogs do not do so; and, according to Houzeau (21. ibid. 1872, tom. ii. p. +181.), they do not then look at the moon, but at some fixed point near the +horizon. Houzeau thinks that their imaginations are disturbed by the vague +outlines of the surrounding objects, and conjure up before them fantastic +images: if this be so, their feelings may almost be called superstitious. +</p> + +<p> +Of all the faculties of the human mind, it will, I presume, be admitted that +REASON stands at the summit. Only a few persons now dispute that animals +possess some power of reasoning. Animals may constantly be seen to pause, +deliberate, and resolve. It is a significant fact, that the more the habits of +any particular animal are studied by a naturalist, the more he attributes to +reason and the less to unlearnt instincts. (22. Mr. L.H. Morgan’s work on +‘The American Beaver,’ 1868, offers a good illustration of this +remark. I cannot help thinking, however, that he goes too far in underrating +the power of instinct.) In future chapters we shall see that some animals +extremely low in the scale apparently display a certain amount of reason. No +doubt it is often difficult to distinguish between the power of reason and that +of instinct. For instance, Dr. Hayes, in his work on ‘The Open Polar +Sea,’ repeatedly remarks that his dogs, instead of continuing to draw the +sledges in a compact body, diverged and separated when they came to thin ice, +so that their weight might be more evenly distributed. This was often the first +warning which the travellers received that the ice was becoming thin and +dangerous. Now, did the dogs act thus from the experience of each individual, +or from the example of the older and wiser dogs, or from an inherited habit, +that is from instinct? This instinct, may possibly have arisen since the time, +long ago, when dogs were first employed by the natives in drawing their +sledges; or the Arctic wolves, the parent-stock of the Esquimaux dog, may have +acquired an instinct impelling them not to attack their prey in a close pack, +when on thin ice. +</p> + +<p> +We can only judge by the circumstances under which actions are performed, +whether they are due to instinct, or to reason, or to the mere association of +ideas: this latter principle, however, is intimately connected with reason. A +curious case has been given by Prof. Mobius (23. ‘Die Bewegungen der +Thiere,’ etc., 1873, p. 11.), of a pike, separated by a plate of glass +from an adjoining aquarium stocked with fish, and who often dashed himself with +such violence against the glass in trying to catch the other fishes, that he +was sometimes completely stunned. The pike went on thus for three months, but +at last learnt caution, and ceased to do so. The plate of glass was then +removed, but the pike would not attack these particular fishes, though he would +devour others which were afterwards introduced; so strongly was the idea of a +violent shock associated in his feeble mind with the attempt on his former +neighbours. If a savage, who had never seen a large plate-glass window, were to +dash himself even once against it, he would for a long time afterwards +associate a shock with a window-frame; but very differently from the pike, he +would probably reflect on the nature of the impediment, and be cautious under +analogous circumstances. Now with monkeys, as we shall presently see, a painful +or merely a disagreeable impression, from an action once performed, is +sometimes sufficient to prevent the animal from repeating it. If we attribute +this difference between the monkey and the pike solely to the association of +ideas being so much stronger and more persistent in the one than the other, +though the pike often received much the more severe injury, can we maintain in +the case of man that a similar difference implies the possession of a +fundamentally different mind? +</p> + +<p> +Houzeau relates (24. ‘Études sur les Facultés Mentales des +Animaux,’ 1872, tom. ii. p. 265.) that, whilst crossing a wide and arid +plain in Texas, his two dogs suffered greatly from thirst, and that between +thirty and forty times they rushed down the hollows to search for water. These +hollows were not valleys, and there were no trees in them, or any other +difference in the vegetation, and as they were absolutely dry there could have +been no smell of damp earth. The dogs behaved as if they knew that a dip in the +ground offered them the best chance of finding water, and Houzeau has often +witnessed the same behaviour in other animals. +</p> + +<p> +I have seen, as I daresay have others, that when a small object is thrown on +the ground beyond the reach of one of the elephants in the Zoological Gardens, +he blows through his trunk on the ground beyond the object, so that the current +reflected on all sides may drive the object within his reach. Again a +well-known ethnologist, Mr. Westropp, informs me that he observed in Vienna a +bear deliberately making with his paw a current in some water, which was close +to the bars of his cage, so as to draw a piece of floating bread within his +reach. These actions of the elephant and bear can hardly be attributed to +instinct or inherited habit, as they would be of little use to an animal in a +state of nature. Now, what is the difference between such actions, when +performed by an uncultivated man, and by one of the higher animals? +</p> + +<p> +The savage and the dog have often found water at a low level, and the +coincidence under such circumstances has become associated in their minds. A +cultivated man would perhaps make some general proposition on the subject; but +from all that we know of savages it is extremely doubtful whether they would do +so, and a dog certainly would not. But a savage, as well as a dog, would search +in the same way, though frequently disappointed; and in both it seems to be +equally an act of reason, whether or not any general proposition on the subject +is consciously placed before the mind. (25. Prof. Huxley has analysed with +admirable clearness the mental steps by which a man, as well as a dog, arrives +at a conclusion in a case analogous to that given in my text. See his article, +‘Mr. Darwin’s Critics,’ in the ‘Contemporary +Review,’ Nov. 1871, p. 462, and in his ‘Critiques and +Essays,’ 1873, p. 279.) The same would apply to the elephant and the bear +making currents in the air or water. The savage would certainly neither know +nor care by what law the desired movements were effected; yet his act would be +guided by a rude process of reasoning, as surely as would a philosopher in his +longest chain of deductions. There would no doubt be this difference between +him and one of the higher animals, that he would take notice of much slighter +circumstances and conditions, and would observe any connection between them +after much less experience, and this would be of paramount importance. I kept a +daily record of the actions of one of my infants, and when he was about eleven +months old, and before he could speak a single word, I was continually struck +with the greater quickness, with which all sorts of objects and sounds were +associated together in his mind, compared with that of the most intelligent +dogs I ever knew. But the higher animals differ in exactly the same way in this +power of association from those low in the scale, such as the pike, as well as +in that of drawing inferences and of observation. +</p> + +<p> +The promptings of reason, after very short experience, are well shewn by the +following actions of American monkeys, which stand low in their order. Rengger, +a most careful observer, states that when he first gave eggs to his monkeys in +Paraguay, they smashed them, and thus lost much of their contents; afterwards +they gently hit one end against some hard body, and picked off the bits of +shell with their fingers. After cutting themselves only ONCE with any sharp +tool, they would not touch it again, or would handle it with the greatest +caution. Lumps of sugar were often given them wrapped up in paper; and Rengger +sometimes put a live wasp in the paper, so that in hastily unfolding it they +got stung; after this had ONCE happened, they always first held the packet to +their ears to detect any movement within. (26. Mr. Belt, in his most +interesting work, ‘The Naturalist in Nicaragua,’ 1874, (p. 119), +likewise describes various actions of a tamed Cebus, which, I think, clearly +shew that this animal possessed some reasoning power.) +</p> + +<p> +The following cases relate to dogs. Mr. Colquhoun (27. ‘The Moor and the +Loch,’ p. 45. Col. Hutchinson on ‘Dog Breaking,’ 1850, p. +46.) winged two wild-ducks, which fell on the further side of a stream; his +retriever tried to bring over both at once, but could not succeed; she then, +though never before known to ruffle a feather, deliberately killed one, brought +over the other, and returned for the dead bird. Col. Hutchinson relates that +two partridges were shot at once, one being killed, the other wounded; the +latter ran away, and was caught by the retriever, who on her return came across +the dead bird; “she stopped, evidently greatly puzzled, and after one or +two trials, finding she could not take it up without permitting the escape of +the winged bird, she considered a moment, then deliberately murdered it by +giving it a severe crunch, and afterwards brought away both together. This was +the only known instance of her ever having wilfully injured any game.” +Here we have reason though not quite perfect, for the retriever might have +brought the wounded bird first and then returned for the dead one, as in the +case of the two wild-ducks. I give the above cases, as resting on the evidence +of two independent witnesses, and because in both instances the retrievers, +after deliberation, broke through a habit which is inherited by them (that of +not killing the game retrieved), and because they shew how strong their +reasoning faculty must have been to overcome a fixed habit. +</p> + +<p> +I will conclude by quoting a remark by the illustrious Humboldt. (28. +‘Personal Narrative,’ Eng. translat., vol. iii. p. 106.) “The +muleteers in S. America say, ‘I will not give you the mule whose step is +easiest, but la mas racional,—the one that reasons best’”; +and; as, he adds, “this popular expression, dictated by long experience, +combats the system of animated machines, better perhaps than all the arguments +of speculative philosophy.” Nevertheless some writers even yet deny that +the higher animals possess a trace of reason; and they endeavour to explain +away, by what appears to be mere verbiage, (29. I am glad to find that so acute +a reasoner as Mr. Leslie Stephen (‘Darwinism and Divinity, Essays on Free +Thinking,’ 1873, p. 80), in speaking of the supposed impassable barrier +between the minds of man and the lower animals, says, “The distinctions, +indeed, which have been drawn, seem to us to rest upon no better foundation +than a great many other metaphysical distinctions; that is, the assumption that +because you can give two things different names, they must therefore have +different natures. It is difficult to understand how anybody who has ever kept +a dog, or seen an elephant, can have any doubt as to an animal’s power of +performing the essential processes of reasoning.”) all such facts as +those above given. +</p> + +<p> +It has, I think, now been shewn that man and the higher animals, especially the +Primates, have some few instincts in common. All have the same senses, +intuitions, and sensations,—similar passions, affections, and emotions, +even the more complex ones, such as jealousy, suspicion, emulation, gratitude, +and magnanimity; they practise deceit and are revengeful; they are sometimes +susceptible to ridicule, and even have a sense of humour; they feel wonder and +curiosity; they possess the same faculties of imitation, attention, +deliberation, choice, memory, imagination, the association of ideas, and +reason, though in very different degrees. The individuals of the same species +graduate in intellect from absolute imbecility to high excellence. They are +also liable to insanity, though far less often than in the case of man. (30. +See ‘Madness in Animals,’ by Dr. W. Lauder Lindsay, in +‘Journal of Mental Science,’ July 1871.) Nevertheless, many authors +have insisted that man is divided by an insuperable barrier from all the lower +animals in his mental faculties. I formerly made a collection of above a score +of such aphorisms, but they are almost worthless, as their wide difference and +number prove the difficulty, if not the impossibility, of the attempt. It has +been asserted that man alone is capable of progressive improvement; that he +alone makes use of tools or fire, domesticates other animals, or possesses +property; that no animal has the power of abstraction, or of forming general +concepts, is self-conscious and comprehends itself; that no animal employs +language; that man alone has a sense of beauty, is liable to caprice, has the +feeling of gratitude, mystery, etc.; believes in God, or is endowed with a +conscience. I will hazard a few remarks on the more important and interesting +of these points. +</p> + +<p> +Archbishop Sumner formerly maintained (31. Quoted by Sir C. Lyell, +‘Antiquity of Man,’ p. 497.) that man alone is capable of +progressive improvement. That he is capable of incomparably greater and more +rapid improvement than is any other animal, admits of no dispute; and this is +mainly due to his power of speaking and handing down his acquired knowledge. +With animals, looking first to the individual, every one who has had any +experience in setting traps, knows that young animals can be caught much more +easily than old ones; and they can be much more easily approached by an enemy. +Even with respect to old animals, it is impossible to catch many in the same +place and in the same kind of trap, or to destroy them by the same kind of +poison; yet it is improbable that all should have partaken of the poison, and +impossible that all should have been caught in a trap. They must learn caution +by seeing their brethren caught or poisoned. In North America, where the +fur-bearing animals have long been pursued, they exhibit, according to the +unanimous testimony of all observers, an almost incredible amount of sagacity, +caution and cunning; but trapping has been there so long carried on, that +inheritance may possibly have come into play. I have received several accounts +that when telegraphs are first set up in any district, many birds kill +themselves by flying against the wires, but that in the course of a very few +years they learn to avoid this danger, by seeing, as it would appear, their +comrades killed. (32. For additional evidence, with details, see M. Houzeau, +‘Études sur les Facultés Mentales des Animaux,’ tom. ii. 1872, p. +147.) +</p> + +<p> +If we look to successive generations, or to the race, there is no doubt that +birds and other animals gradually both acquire and lose caution in relation to +man or other enemies (33. See, with respect to birds on oceanic islands, my +‘Journal of Researches during the Voyage of the +“Beagle,”’ 1845, p. 398. ‘Origin of Species,’ 5th +ed. p. 260.); and this caution is certainly in chief part an inherited habit or +instinct, but in part the result of individual experience. A good observer, +Leroy (34. ‘Lettres Phil. sur l’Intelligence des Animaux,’ +nouvelle edit., 1802, p. 86.), states, that in districts where foxes are much +hunted, the young, on first leaving their burrows, are incontestably much more +wary than the old ones in districts where they are not much disturbed. +</p> + +<p> +Our domestic dogs are descended from wolves and jackals (35. See the evidence +on this head in chap. i. vol. i., ‘On the Variation of Animals and Plants +under Domestication.’), and though they may not have gained in cunning, +and may have lost in wariness and suspicion, yet they have progressed in +certain moral qualities, such as in affection, trust-worthiness, temper, and +probably in general intelligence. The common rat has conquered and beaten +several other species throughout Europe, in parts of North America, New +Zealand, and recently in Formosa, as well as on the mainland of China. Mr. +Swinhoe (36. ‘Proceedings Zoological Society,’ 1864, p. 186.), who +describes these two latter cases, attributes the victory of the common rat over +the large Mus coninga to its superior cunning; and this latter quality may +probably be attributed to the habitual exercise of all its faculties in +avoiding extirpation by man, as well as to nearly all the less cunning or +weak-minded rats having been continuously destroyed by him. It is, however, +possible that the success of the common rat may be due to its having possessed +greater cunning than its fellow-species, before it became associated with man. +To maintain, independently of any direct evidence, that no animal during the +course of ages has progressed in intellect or other mental faculties, is to beg +the question of the evolution of species. We have seen that, according to +Lartet, existing mammals belonging to several orders have larger brains than +their ancient tertiary prototypes. +</p> + +<p> +It has often been said that no animal uses any tool; but the chimpanzee in a +state of nature cracks a native fruit, somewhat like a walnut, with a stone. +(37. Savage and Wyman in ‘Boston Journal of Natural History,’ vol. +iv. 1843-44, p. 383.) Rengger (38. ‘Säugethiere von Paraguay,’ +1830, s. 51-56.) easily taught an American monkey thus to break open hard +palm-nuts; and afterwards of its own accord, it used stones to open other kinds +of nuts, as well as boxes. It thus also removed the soft rind of fruit that had +a disagreeable flavour. Another monkey was taught to open the lid of a large +box with a stick, and afterwards it used the stick as a lever to move heavy +bodies; and I have myself seen a young orang put a stick into a crevice, slip +his hand to the other end, and use it in the proper manner as a lever. The +tamed elephants in India are well known to break off branches of trees and use +them to drive away the flies; and this same act has been observed in an +elephant in a state of nature. (39. The Indian Field, March 4, 1871.) I have +seen a young orang, when she thought she was going to be whipped, cover and +protect herself with a blanket or straw. In these several cases stones and +sticks were employed as implements; but they are likewise used as weapons. +Brehm (40. ‘Thierleben,’ B. i. s. 79, 82.) states, on the authority +of the well-known traveller Schimper, that in Abyssinia when the baboons +belonging to one species (C. gelada) descend in troops from the mountains to +plunder the fields, they sometimes encounter troops of another species (C. +hamadryas), and then a fight ensues. The Geladas roll down great stones, which +the Hamadryas try to avoid, and then both species, making a great uproar, rush +furiously against each other. Brehm, when accompanying the Duke of +Coburg-Gotha, aided in an attack with fire-arms on a troop of baboons in the +pass of Mensa in Abyssinia. The baboons in return rolled so many stones down +the mountain, some as large as a man’s head, that the attackers had to +beat a hasty retreat; and the pass was actually closed for a time against the +caravan. It deserves notice that these baboons thus acted in concert. Mr. +Wallace (41. ‘The Malay Archipelago,’ vol. i. 1869, p. 87.) on +three occasions saw female orangs, accompanied by their young, “breaking +off branches and the great spiny fruit of the Durian tree, with every +appearance of rage; causing such a shower of missiles as effectually kept us +from approaching too near the tree.” As I have repeatedly seen, a +chimpanzee will throw any object at hand at a person who offends him; and the +before-mentioned baboon at the Cape of Good Hope prepared mud for the purpose. +</p> + +<p> +In the Zoological Gardens, a monkey, which had weak teeth, used to break open +nuts with a stone; and I was assured by the keepers that after using the stone, +he hid it in the straw, and would not let any other monkey touch it. Here, +then, we have the idea of property; but this idea is common to every dog with a +bone, and to most or all birds with their nests. +</p> + +<p> +The Duke of Argyll (42. ‘Primeval Man,’ 1869, pp. 145, 147.) +remarks, that the fashioning of an implement for a special purpose is +absolutely peculiar to man; and he considers that this forms an immeasurable +gulf between him and the brutes. This is no doubt a very important distinction; +but there appears to me much truth in Sir J. Lubbock’s suggestion (43. +‘Prehistoric Times,’ 1865, p. 473, etc.), that when primeval man +first used flint-stones for any purpose, he would have accidentally splintered +them, and would then have used the sharp fragments. From this step it would be +a small one to break the flints on purpose, and not a very wide step to fashion +them rudely. This latter advance, however, may have taken long ages, if we may +judge by the immense interval of time which elapsed before the men of the +neolithic period took to grinding and polishing their stone tools. In breaking +the flints, as Sir J. Lubbock likewise remarks, sparks would have been emitted, +and in grinding them heat would have been evolved: thus the two usual methods +of “obtaining fire may have originated.” The nature of fire would +have been known in the many volcanic regions where lava occasionally flows +through forests. The anthropomorphous apes, guided probably by instinct, build +for themselves temporary platforms; but as many instincts are largely +controlled by reason, the simpler ones, such as this of building a platform, +might readily pass into a voluntary and conscious act. The orang is known to +cover itself at night with the leaves of the Pandanus; and Brehm states that +one of his baboons used to protect itself from the heat of the sun by throwing +a straw-mat over its head. In these several habits, we probably see the first +steps towards some of the simpler arts, such as rude architecture and dress, as +they arose amongst the early progenitors of man. +</p> + +<p> +ABSTRACTION, GENERAL CONCEPTIONS, SELF-CONSCIOUSNESS, MENTAL INDIVIDUALITY. +</p> + +<p> +It would be very difficult for any one with even much more knowledge than I +possess, to determine how far animals exhibit any traces of these high mental +powers. This difficulty arises from the impossibility of judging what passes +through the mind of an animal; and again, the fact that writers differ to a +great extent in the meaning which they attribute to the above terms, causes a +further difficulty. If one may judge from various articles which have been +published lately, the greatest stress seems to be laid on the supposed entire +absence in animals of the power of abstraction, or of forming general concepts. +But when a dog sees another dog at a distance, it is often clear that he +perceives that it is a dog in the abstract; for when he gets nearer his whole +manner suddenly changes, if the other dog be a friend. A recent writer remarks, +that in all such cases it is a pure assumption to assert that the mental act is +not essentially of the same nature in the animal as in man. If either refers +what he perceives with his senses to a mental concept, then so do both. (44. +Mr. Hookham, in a letter to Prof. Max Muller, in the ‘Birmingham +News,’ May 1873.) When I say to my terrier, in an eager voice (and I have +made the trial many times), “Hi, hi, where is it?” she at once +takes it as a sign that something is to be hunted, and generally first looks +quickly all around, and then rushes into the nearest thicket, to scent for any +game, but finding nothing, she looks up into any neighbouring tree for a +squirrel. Now do not these actions clearly shew that she had in her mind a +general idea or concept that some animal is to be discovered and hunted? +</p> + +<p> +It may be freely admitted that no animal is self-conscious, if by this term it +is implied, that he reflects on such points, as whence he comes or whither he +will go, or what is life and death, and so forth. But how can we feel sure that +an old dog with an excellent memory and some power of imagination, as shewn by +his dreams, never reflects on his past pleasures or pains in the chase? And +this would be a form of self-consciousness. On the other hand, as Buchner (45. +‘Conférences sur la Théorie Darwinienne,’ French translat. 1869, p. +132.) has remarked, how little can the hard-worked wife of a degraded +Australian savage, who uses very few abstract words, and cannot count above +four, exert her self-consciousness, or reflect on the nature of her own +existence. It is generally admitted, that the higher animals possess memory, +attention, association, and even some imagination and reason. If these powers, +which differ much in different animals, are capable of improvement, there seems +no great improbability in more complex faculties, such as the higher forms of +abstraction, and self-consciousness, etc., having been evolved through the +development and combination of the simpler ones. It has been urged against the +views here maintained that it is impossible to say at what point in the +ascending scale animals become capable of abstraction, etc.; but who can say at +what age this occurs in our young children? We see at least that such powers +are developed in children by imperceptible degrees. +</p> + +<p> +That animals retain their mental individuality is unquestionable. When my voice +awakened a train of old associations in the mind of the before-mentioned dog, +he must have retained his mental individuality, although every atom of his +brain had probably undergone change more than once during the interval of five +years. This dog might have brought forward the argument lately advanced to +crush all evolutionists, and said, “I abide amid all mental moods and all +material changes...The teaching that atoms leave their impressions as legacies +to other atoms falling into the places they have vacated is contradictory of +the utterance of consciousness, and is therefore false; but it is the teaching +necessitated by evolutionism, consequently the hypothesis is a false +one.” (46. The Rev. Dr. J. M’Cann, ‘Anti-Darwinism,’ +1869, p. 13.) +</p> + +<h3>LANGUAGE.</h3> + +<p> +This faculty has justly been considered as one of the chief distinctions +between man and the lower animals. But man, as a highly competent judge, +Archbishop Whately remarks, “is not the only animal that can make use of +language to express what is passing in his mind, and can understand, more or +less, what is so expressed by another.” (47. Quoted in +‘Anthropological Review,’ 1864, p. 158.) In Paraguay the Cebus +azarae when excited utters at least six distinct sounds, which excite in other +monkeys similar emotions. (48. Rengger, ibid. s. 45.) The movements of the +features and gestures of monkeys are understood by us, and they partly +understand ours, as Rengger and others declare. It is a more remarkable fact +that the dog, since being domesticated, has learnt to bark (49. See my +‘Variation of Animals and Plants under Domestication,’ vol. i. p. +27.) in at least four or five distinct tones. Although barking is a new art, no +doubt the wild parent-species of the dog expressed their feelings by cries of +various kinds. With the domesticated dog we have the bark of eagerness, as in +the chase; that of anger, as well as growling; the yelp or howl of despair, as +when shut up; the baying at night; the bark of joy, as when starting on a walk +with his master; and the very distinct one of demand or supplication, as when +wishing for a door or window to be opened. According to Houzeau, who paid +particular attention to the subject, the domestic fowl utters at least a dozen +significant sounds. (50. ‘Facultés Mentales des Animaux,’ tom. ii. +1872, p. 346-349.) +</p> + +<p> +The habitual use of articulate language is, however, peculiar to man; but he +uses, in common with the lower animals, inarticulate cries to express his +meaning, aided by gestures and the movements of the muscles of the face. (51. +See a discussion on this subject in Mr. E.B. Tylor’s very interesting +work, ‘Researches into the Early History of Mankind,’ 1865, chaps. +ii. to iv.) This especially holds good with the more simple and vivid feelings, +which are but little connected with our higher intelligence. Our cries of pain, +fear, surprise, anger, together with their appropriate actions, and the murmur +of a mother to her beloved child are more expressive than any words. That which +distinguishes man from the lower animals is not the understanding of articulate +sounds, for, as every one knows, dogs understand many words and sentences. In +this respect they are at the same stage of development as infants, between the +ages of ten and twelve months, who understand many words and short sentences, +but cannot yet utter a single word. It is not the mere articulation which is +our distinguishing character, for parrots and other birds possess this power. +Nor is it the mere capacity of connecting definite sounds with definite ideas; +for it is certain that some parrots, which have been taught to speak, connect +unerringly words with things, and persons with events. (52. I have received +several detailed accounts to this effect. Admiral Sir B.J. Sulivan, whom I know +to be a careful observer, assures me that an African parrot, long kept in his +father’s house, invariably called certain persons of the household, as +well as visitors, by their names. He said “good morning” to every +one at breakfast, and “good night” to each as they left the room at +night, and never reversed these salutations. To Sir B.J. Sulivan’s +father, he used to add to the “ good morning” a short sentence, +which was never once repeated after his father’s death. He scolded +violently a strange dog which came into the room through the open window; and +he scolded another parrot (saying “you naughty polly”) which had +got out of its cage, and was eating apples on the kitchen table. See also, to +the same effect, Houzeau on parrots, ‘Facultés Mentales,’ tom. ii. +p. 309. Dr. A. Moschkau informs me that he knew a starling which never made a +mistake in saying in German “good morning” to persons arriving, and +“good bye, old fellow,” to those departing. I could add several +other such cases.) The lower animals differ from man solely in his almost +infinitely larger power of associating together the most diversified sounds and +ideas; and this obviously depends on the high development of his mental powers. +</p> + +<p> +As Horne Tooke, one of the founders of the noble science of philology, +observes, language is an art, like brewing or baking; but writing would have +been a better simile. It certainly is not a true instinct, for every language +has to be learnt. It differs, however, widely from all ordinary arts, for man +has an instinctive tendency to speak, as we see in the babble of our young +children; whilst no child has an instinctive tendency to brew, bake, or write. +Moreover, no philologist now supposes that any language has been deliberately +invented; it has been slowly and unconsciously developed by many steps. (53. +See some good remarks on this head by Prof. Whitney, in his ‘Oriental and +Linguistic Studies,’ 1873, p. 354. He observes that the desire of +communication between man is the living force, which, in the development of +language, “works both consciously and unconsciously; consciously as +regards the immediate end to be attained; unconsciously as regards the further +consequences of the act.”) The sounds uttered by birds offer in several +respects the nearest analogy to language, for all the members of the same +species utter the same instinctive cries expressive of their emotions; and all +the kinds which sing, exert their power instinctively; but the actual song, and +even the call-notes, are learnt from their parents or foster-parents. These +sounds, as Daines Barrington (54. Hon. Daines Barrington in ‘Philosoph. +Transactions,’ 1773, p. 262. See also Dureau de la Malle, in ‘Ann. +des. Sc. Nat.’ 3rd series, Zoolog., tom. x. p. 119.) has proved, +“are no more innate than language is in man.” The first attempts to +sing “may be compared to the imperfect endeavour in a child to +babble.” The young males continue practising, or as the bird-catchers +say, “recording,” for ten or eleven months. Their first essays shew +hardly a rudiment of the future song; but as they grow older we can perceive +what they are aiming at; and at last they are said “to sing their song +round.” Nestlings which have learnt the song of a distinct species, as +with the canary-birds educated in the Tyrol, teach and transmit their new song +to their offspring. The slight natural differences of song in the same species +inhabiting different districts may be appositely compared, as Barrington +remarks, “to provincial dialects”; and the songs of allied, though +distinct species may be compared with the languages of distinct races of man. I +have given the foregoing details to shew that an instinctive tendency to +acquire an art is not peculiar to man. +</p> + +<p> +With respect to the origin of articulate language, after having read on the one +side the highly interesting works of Mr. Hensleigh Wedgwood, the Rev. F. +Farrar, and Prof. Schleicher (55. ‘On the Origin of Language,’ by +H. Wedgwood, 1866. ‘Chapters on Language,’ by the Rev. F.W. Farrar, +1865. These works are most interesting. See also ‘De la Phys. et de +Parole,’ par Albert Lemoine, 1865, p. 190. The work on this subject, by +the late Prof. Aug. Schleicher, has been translated by Dr. Bikkers into +English, under the title of ‘Darwinism tested by the Science of +Language,’ 1869.), and the celebrated lectures of Prof. Max Muller on the +other side, I cannot doubt that language owes its origin to the imitation and +modification of various natural sounds, the voices of other animals, and +man’s own instinctive cries, aided by signs and gestures. When we treat +of sexual selection we shall see that primeval man, or rather some early +progenitor of man, probably first used his voice in producing true musical +cadences, that is in singing, as do some of the gibbon-apes at the present day; +and we may conclude from a widely-spread analogy, that this power would have +been especially exerted during the courtship of the sexes,—would have +expressed various emotions, such as love, jealousy, triumph,—and would +have served as a challenge to rivals. It is, therefore, probable that the +imitation of musical cries by articulate sounds may have given rise to words +expressive of various complex emotions. The strong tendency in our nearest +allies, the monkeys, in microcephalous idiots (56. Vogt, ‘Mémoire sur les +Microcephales,’ 1867, p. 169. With respect to savages, I have given some +facts in my ‘Journal of Researches,’ etc., 1845, p. 206.), and in +the barbarous races of mankind, to imitate whatever they hear deserves notice, +as bearing on the subject of imitation. Since monkeys certainly understand much +that is said to them by man, and when wild, utter signal-cries of danger to +their fellows (57. See clear evidence on this head in the two works so often +quoted, by Brehm and Rengger.); and since fowls give distinct warnings for +danger on the ground, or in the sky from hawks (both, as well as a third cry, +intelligible to dogs) (58. Houzeau gives a very curious account of his +observations on this subject in his ‘Facultés Mentales des +Animaux,’ tom. ii. p. 348.), may not some unusually wise ape-like animal +have imitated the growl of a beast of prey, and thus told his fellow-monkeys +the nature of the expected danger? This would have been a first step in the +formation of a language. +</p> + +<p> +As the voice was used more and more, the vocal organs would have been +strengthened and perfected through the principle of the inherited effects of +use; and this would have reacted on the power of speech. But the relation +between the continued use of language and the development of the brain, has no +doubt been far more important. The mental powers in some early progenitor of +man must have been more highly developed than in any existing ape, before even +the most imperfect form of speech could have come into use; but we may +confidently believe that the continued use and advancement of this power would +have reacted on the mind itself, by enabling and encouraging it to carry on +long trains of thought. A complex train of thought can no more be carried on +without the aid of words, whether spoken or silent, than a long calculation +without the use of figures or algebra. It appears, also, that even an ordinary +train of thought almost requires, or is greatly facilitated by some form of +language, for the dumb, deaf, and blind girl, Laura Bridgman, was observed to +use her fingers whilst dreaming. (59. See remarks on this head by Dr. Maudsley, +‘The Physiology and Pathology of Mind,’ 2nd ed., 1868, p. 199.) +Nevertheless, a long succession of vivid and connected ideas may pass through +the mind without the aid of any form of language, as we may infer from the +movements of dogs during their dreams. We have, also, seen that animals are +able to reason to a certain extent, manifestly without the aid of language. The +intimate connection between the brain, as it is now developed in us, and the +faculty of speech, is well shewn by those curious cases of brain-disease in +which speech is specially affected, as when the power to remember substantives +is lost, whilst other words can be correctly used, or where substantives of a +certain class, or all except the initial letters of substantives and proper +names are forgotten. (60. Many curious cases have been recorded. See, for +instance, Dr. Bateman ‘On Aphasia,’ 1870, pp. 27, 31, 53, 100, etc. +Also, ‘Inquiries Concerning the Intellectual Powers,’ by Dr. +Abercrombie, 1838, p. 150.) There is no more improbability in the continued use +of the mental and vocal organs leading to inherited changes in their structure +and functions, than in the case of hand-writing, which depends partly on the +form of the hand and partly on the disposition of the mind; and handwriting is +certainly inherited. (61. ‘The Variation of Animals and Plants under +Domestication,’ vol. ii. p. 6.’) +</p> + +<p> +Several writers, more especially Prof. Max Muller (62. Lectures on ‘Mr. +Darwin’s Philosophy of Language,’ 1873.), have lately insisted that +the use of language implies the power of forming general concepts; and that as +no animals are supposed to possess this power, an impassable barrier is formed +between them and man. (63. The judgment of a distinguished philologist, such as +Prof. Whitney, will have far more weight on this point than anything that I can +say. He remarks (‘Oriental and Linguistic Studies,’ 1873, p. 297), +in speaking of Bleek’s views: “Because on the grand scale language +is the necessary auxiliary of thought, indispensable to the development of the +power of thinking, to the distinctness and variety and complexity of cognitions +to the full mastery of consciousness; therefore he would fain make thought +absolutely impossible without speech, identifying the faculty with its +instrument. He might just as reasonably assert that the human hand cannot act +without a tool. With such a doctrine to start from, he cannot stop short of Max +Muller’s worst paradoxes, that an infant (in fans, not speaking) is not a +human being, and that deaf-mutes do not become possessed of reason until they +learn to twist their fingers into imitation of spoken words.” Max Muller +gives in italics (‘Lectures on Mr. Darwin’s Philosophy of +Language,’ 1873, third lecture) this aphorism: “There is no thought +without words, as little as there are words without thought.” What a +strange definition must here be given to the word thought!) With respect to +animals, I have already endeavoured to shew that they have this power, at least +in a rude and incipient degree. As far as concerns infants of from ten to +eleven months old, and deaf-mutes, it seems to me incredible, that they should +be able to connect certain sounds with certain general ideas as quickly as they +do, unless such ideas were already formed in their minds. The same remark may +be extended to the more intelligent animals; as Mr. Leslie Stephen observes +(64. ‘Essays on Free Thinking,’ etc., 1873, p. 82.), “A dog +frames a general concept of cats or sheep, and knows the corresponding words as +well as a philosopher. And the capacity to understand is as good a proof of +vocal intelligence, though in an inferior degree, as the capacity to +speak.” +</p> + +<p> +Why the organs now used for speech should have been originally perfected for +this purpose, rather than any other organs, it is not difficult to see. Ants +have considerable powers of intercommunication by means of their antennae, as +shewn by Huber, who devotes a whole chapter to their language. We might have +used our fingers as efficient instruments, for a person with practice can +report to a deaf man every word of a speech rapidly delivered at a public +meeting; but the loss of our hands, whilst thus employed, would have been a +serious inconvenience. As all the higher mammals possess vocal organs, +constructed on the same general plan as ours, and used as a means of +communication, it was obviously probable that these same organs would be still +further developed if the power of communication had to be improved; and this +has been effected by the aid of adjoining and well adapted parts, namely the +tongue and lips. (65. See some good remarks to this effect by Dr. Maudsley, +‘The Physiology and Pathology of Mind,’ 1868, p. 199.) The fact of +the higher apes not using their vocal organs for speech, no doubt depends on +their intelligence not having been sufficiently advanced. The possession by +them of organs, which with long-continued practice might have been used for +speech, although not thus used, is paralleled by the case of many birds which +possess organs fitted for singing, though they never sing. Thus, the +nightingale and crow have vocal organs similarly constructed, these being used +by the former for diversified song, and by the latter only for croaking. (66. +Macgillivray, ‘Hist. of British Birds,’ vol. ii. 1839, p. 29. An +excellent observer, Mr. Blackwall, remarks that the magpie learns to pronounce +single words, and even short sentences, more readily than almost any other +British bird; yet, as he adds, after long and closely investigating its habits, +he has never known it, in a state of nature, display any unusual capacity for +imitation. ‘Researches in Zoology,’ 1834, p. 158.) If it be asked +why apes have not had their intellects developed to the same degree as that of +man, general causes only can be assigned in answer, and it is unreasonable to +expect any thing more definite, considering our ignorance with respect to the +successive stages of development through which each creature has passed. +</p> + +<p> +The formation of different languages and of distinct species, and the proofs +that both have been developed through a gradual process, are curiously +parallel. (67. See the very interesting parallelism between the development of +species and languages, given by Sir C. Lyell in ‘The Geological Evidences +of the Antiquity of Man,’ 1863, chap. xxiii.) But we can trace the +formation of many words further back than that of species, for we can perceive +how they actually arose from the imitation of various sounds. We find in +distinct languages striking homologies due to community of descent, and +analogies due to a similar process of formation. The manner in which certain +letters or sounds change when others change is very like correlated growth. We +have in both cases the reduplication of parts, the effects of long-continued +use, and so forth. The frequent presence of rudiments, both in languages and in +species, is still more remarkable. The letter m in the word am, means I; so +that in the expression I am, a superfluous and useless rudiment has been +retained. In the spelling also of words, letters often remain as the rudiments +of ancient forms of pronunciation. Languages, like organic beings, can be +classed in groups under groups; and they can be classed either naturally +according to descent, or artificially by other characters. Dominant languages +and dialects spread widely, and lead to the gradual extinction of other +tongues. A language, like a species, when once extinct, never, as Sir C. Lyell +remarks, reappears. The same language never has two birth-places. Distinct +languages may be crossed or blended together. (68. See remarks to this effect +by the Rev. F.W. Farrar, in an interesting article, entitled ‘Philology +and Darwinism,’ in ‘Nature,’ March 24th, 1870, p. 528.) We +see variability in every tongue, and new words are continually cropping up; but +as there is a limit to the powers of the memory, single words, like whole +languages, gradually become extinct. As Max Muller (69. ‘Nature,’ +January 6th, 1870, p. 257.) has well remarked:—“A struggle for life +is constantly going on amongst the words and grammatical forms in each +language. The better, the shorter, the easier forms are constantly gaining the +upper hand, and they owe their success to their own inherent virtue.” To +these more important causes of the survival of certain words, mere novelty and +fashion may be added; for there is in the mind of man a strong love for slight +changes in all things. The survival or preservation of certain favoured words +in the struggle for existence is natural selection. +</p> + +<p> +The perfectly regular and wonderfully complex construction of the languages of +many barbarous nations has often been advanced as a proof, either of the divine +origin of these languages, or of the high art and former civilisation of their +founders. Thus F. von Schlegel writes: “In those languages which appear +to be at the lowest grade of intellectual culture, we frequently observe a very +high and elaborate degree of art in their grammatical structure. This is +especially the case with the Basque and the Lapponian, and many of the American +languages.” (70. Quoted by C.S. Wake, ‘Chapters on Man,’ +1868, p. 101.) But it is assuredly an error to speak of any language as an art, +in the sense of its having been elaborately and methodically formed. +Philologists now admit that conjugations, declensions, etc., originally existed +as distinct words, since joined together; and as such words express the most +obvious relations between objects and persons, it is not surprising that they +should have been used by the men of most races during the earliest ages. With +respect to perfection, the following illustration will best shew how easily we +may err: a Crinoid sometimes consists of no less than 150,000 pieces of shell +(71. Buckland, ‘Bridgewater Treatise,’ p. 411.), all arranged with +perfect symmetry in radiating lines; but a naturalist does not consider an +animal of this kind as more perfect than a bilateral one with comparatively few +parts, and with none of these parts alike, excepting on the opposite sides of +the body. He justly considers the differentiation and specialisation of organs +as the test of perfection. So with languages: the most symmetrical and complex +ought not to be ranked above irregular, abbreviated, and bastardised languages, +which have borrowed expressive words and useful forms of construction from +various conquering, conquered, or immigrant races. +</p> + +<p> +From these few and imperfect remarks I conclude that the extremely complex and +regular construction of many barbarous languages, is no proof that they owe +their origin to a special act of creation. (72. See some good remarks on the +simplification of languages, by Sir J. Lubbock, ‘Origin of +Civilisation,’ 1870, p. 278.) Nor, as we have seen, does the faculty of +articulate speech in itself offer any insuperable objection to the belief that +man has been developed from some lower form. +</p> + +<h3>SENSE OF BEAUTY.</h3> + +<p> +This sense has been declared to be peculiar to man. I refer here only to the +pleasure given by certain colours, forms, and sounds, and which may fairly be +called a sense of the beautiful; with cultivated men such sensations are, +however, intimately associated with complex ideas and trains of thought. When +we behold a male bird elaborately displaying his graceful plumes or splendid +colours before the female, whilst other birds, not thus decorated, make no such +display, it is impossible to doubt that she admires the beauty of her male +partner. As women everywhere deck themselves with these plumes, the beauty of +such ornaments cannot be disputed. As we shall see later, the nests of +humming-birds, and the playing passages of bower-birds are tastefully +ornamented with gaily-coloured objects; and this shews that they must receive +some kind of pleasure from the sight of such things. With the great majority of +animals, however, the taste for the beautiful is confined, as far as we can +judge, to the attractions of the opposite sex. The sweet strains poured forth +by many male birds during the season of love, are certainly admired by the +females, of which fact evidence will hereafter be given. If female birds had +been incapable of appreciating the beautiful colours, the ornaments, and voices +of their male partners, all the labour and anxiety exhibited by the latter in +displaying their charms before the females would have been thrown away; and +this it is impossible to admit. Why certain bright colours should excite +pleasure cannot, I presume, be explained, any more than why certain flavours +and scents are agreeable; but habit has something to do with the result, for +that which is at first unpleasant to our senses, ultimately becomes pleasant, +and habits are inherited. With respect to sounds, Helmholtz has explained to a +certain extent on physiological principles, why harmonies and certain cadences +are agreeable. But besides this, sounds frequently recurring at irregular +intervals are highly disagreeable, as every one will admit who has listened at +night to the irregular flapping of a rope on board ship. The same principle +seems to come into play with vision, as the eye prefers symmetry or figures +with some regular recurrence. Patterns of this kind are employed by even the +lowest savages as ornaments; and they have been developed through sexual +selection for the adornment of some male animals. Whether we can or not give +any reason for the pleasure thus derived from vision and hearing, yet man and +many of the lower animals are alike pleased by the same colours, graceful +shading and forms, and the same sounds. +</p> + +<p> +The taste for the beautiful, at least as far as female beauty is concerned, is +not of a special nature in the human mind; for it differs widely in the +different races of man, and is not quite the same even in the different nations +of the same race. Judging from the hideous ornaments, and the equally hideous +music admired by most savages, it might be urged that their aesthetic faculty +was not so highly developed as in certain animals, for instance, as in birds. +Obviously no animal would be capable of admiring such scenes as the heavens at +night, a beautiful landscape, or refined music; but such high tastes are +acquired through culture, and depend on complex associations; they are not +enjoyed by barbarians or by uneducated persons. +</p> + +<p> +Many of the faculties, which have been of inestimable service to man for his +progressive advancement, such as the powers of the imagination, wonder, +curiosity, an undefined sense of beauty, a tendency to imitation, and the love +of excitement or novelty, could hardly fail to lead to capricious changes of +customs and fashions. I have alluded to this point, because a recent writer +(73. ‘The Spectator,’ Dec. 4th, 1869, p. 1430.) has oddly fixed on +Caprice “as one of the most remarkable and typical differences between +savages and brutes.” But not only can we partially understand how it is +that man is from various conflicting influences rendered capricious, but that +the lower animals are, as we shall hereafter see, likewise capricious in their +affections, aversions, and sense of beauty. There is also reason to suspect +that they love novelty, for its own sake. +</p> + +<h3>BELIEF IN GOD—RELIGION.</h3> + +<p> +There is no evidence that man was aboriginally endowed with the ennobling +belief in the existence of an Omnipotent God. On the contrary there is ample +evidence, derived not from hasty travellers, but from men who have long resided +with savages, that numerous races have existed, and still exist, who have no +idea of one or more gods, and who have no words in their languages to express +such an idea. (74. See an excellent article on this subject by the Rev. F.W. +Farrar, in the ‘Anthropological Review,’ Aug. 1864, p. ccxvii. For +further facts see Sir J. Lubbock, ‘Prehistoric Times,’ 2nd edit., +1869, p. 564; and especially the chapters on Religion in his ‘Origin of +Civilisation,’ 1870.) The question is of course wholly distinct from that +higher one, whether there exists a Creator and Ruler of the universe; and this +has been answered in the affirmative by some of the highest intellects that +have ever existed. +</p> + +<p> +If, however, we include under the term “religion” the belief in +unseen or spiritual agencies, the case is wholly different; for this belief +seems to be universal with the less civilised races. Nor is it difficult to +comprehend how it arose. As soon as the important faculties of the imagination, +wonder, and curiosity, together with some power of reasoning, had become +partially developed, man would naturally crave to understand what was passing +around him, and would have vaguely speculated on his own existence. As Mr. +M’Lennan (75. ‘The Worship of Animals and Plants,’ in the +‘Fortnightly Review,’ Oct. 1, 1869, p. 422.) has remarked, +“Some explanation of the phenomena of life, a man must feign for himself, +and to judge from the universality of it, the simplest hypothesis, and the +first to occur to men, seems to have been that natural phenomena are ascribable +to the presence in animals, plants, and things, and in the forces of nature, of +such spirits prompting to action as men are conscious they themselves +possess.” It is also probable, as Mr. Tylor has shewn, that dreams may +have first given rise to the notion of spirits; for savages do not readily +distinguish between subjective and objective impressions. When a savage dreams, +the figures which appear before him are believed to have come from a distance, +and to stand over him; or “the soul of the dreamer goes out on its +travels, and comes home with a remembrance of what it has seen.” (76. +Tylor, ‘Early History of Mankind,’ 1865, p. 6. See also the three +striking chapters on the ‘Development of Religion,’ in +Lubbock’s ‘Origin of Civilisation,’ 1870. In a like manner +Mr. Herbert Spencer, in his ingenious essay in the ‘Fortnightly +Review’ (May 1st, 1870, p. 535), accounts for the earliest forms of +religious belief throughout the world, by man being led through dreams, +shadows, and other causes, to look at himself as a double essence, corporeal +and spiritual. As the spiritual being is supposed to exist after death and to +be powerful, it is propitiated by various gifts and ceremonies, and its aid +invoked. He then further shews that names or nicknames given from some animal +or other object, to the early progenitors or founders of a tribe, are supposed +after a long interval to represent the real progenitor of the tribe; and such +animal or object is then naturally believed still to exist as a spirit, is held +sacred, and worshipped as a god. Nevertheless I cannot but suspect that there +is a still earlier and ruder stage, when anything which manifests power or +movement is thought to be endowed with some form of life, and with mental +faculties analogous to our own.) But until the faculties of imagination, +curiosity, reason, etc., had been fairly well developed in the mind of man, his +dreams would not have led him to believe in spirits, any more than in the case +of a dog. +</p> + +<p> +The tendency in savages to imagine that natural objects and agencies are +animated by spiritual or living essences, is perhaps illustrated by a little +fact which I once noticed: my dog, a full-grown and very sensible animal, was +lying on the lawn during a hot and still day; but at a little distance a slight +breeze occasionally moved an open parasol, which would have been wholly +disregarded by the dog, had any one stood near it. As it was, every time that +the parasol slightly moved, the dog growled fiercely and barked. He must, I +think, have reasoned to himself in a rapid and unconscious manner, that +movement without any apparent cause indicated the presence of some strange +living agent, and that no stranger had a right to be on his territory. +</p> + +<p> +The belief in spiritual agencies would easily pass into the belief in the +existence of one or more gods. For savages would naturally attribute to spirits +the same passions, the same love of vengeance or simplest form of justice, and +the same affections which they themselves feel. The Fuegians appear to be in +this respect in an intermediate condition, for when the surgeon on board the +“Beagle” shot some young ducklings as specimens, York Minster +declared in the most solemn manner, “Oh, Mr. Bynoe, much rain, much snow, +blow much”; and this was evidently a retributive punishment for wasting +human food. So again he related how, when his brother killed a “wild +man,” storms long raged, much rain and snow fell. Yet we could never +discover that the Fuegians believed in what we should call a God, or practised +any religious rites; and Jemmy Button, with justifiable pride, stoutly +maintained that there was no devil in his land. This latter assertion is the +more remarkable, as with savages the belief in bad spirits is far more common +than that in good ones. +</p> + +<p> +The feeling of religious devotion is a highly complex one, consisting of love, +complete submission to an exalted and mysterious superior, a strong sense of +dependence (77. See an able article on the ‘Physical Elements of +Religion,’ by Mr. L. Owen Pike, in ‘Anthropological Review,’ +April 1870, p. lxiii.), fear, reverence, gratitude, hope for the future, and +perhaps other elements. No being could experience so complex an emotion until +advanced in his intellectual and moral faculties to at least a moderately high +level. Nevertheless, we see some distant approach to this state of mind in the +deep love of a dog for his master, associated with complete submission, some +fear, and perhaps other feelings. The behaviour of a dog when returning to his +master after an absence, and, as I may add, of a monkey to his beloved keeper, +is widely different from that towards their fellows. In the latter case the +transports of joy appear to be somewhat less, and the sense of equality is +shewn in every action. Professor Braubach goes so far as to maintain that a dog +looks on his master as on a god. (78. ‘Religion, Moral, etc., der +Darwin’schen Art-Lehre,’ 1869, s. 53. It is said (Dr. W. Lauder +Lindsay, ‘Journal of Mental Science,’ 1871, p. 43), that Bacon long +ago, and the poet Burns, held the same notion.) +</p> + +<p> +The same high mental faculties which first led man to believe in unseen +spiritual agencies, then in fetishism, polytheism, and ultimately in +monotheism, would infallibly lead him, as long as his reasoning powers remained +poorly developed, to various strange superstitions and customs. Many of these +are terrible to think of—such as the sacrifice of human beings to a +blood-loving god; the trial of innocent persons by the ordeal of poison or +fire; witchcraft, etc.—yet it is well occasionally to reflect on these +superstitions, for they shew us what an infinite debt of gratitude we owe to +the improvement of our reason, to science, and to our accumulated knowledge. As +Sir J. Lubbock (79. ‘Prehistoric Times,’ 2nd edit., p. 571. In this +work (p. 571) there will be found an excellent account of the many strange and +capricious customs of savages.) has well observed, “it is not too much to +say that the horrible dread of unknown evil hangs like a thick cloud over +savage life, and embitters every pleasure.” These miserable and indirect +consequences of our highest faculties may be compared with the incidental and +occasional mistakes of the instincts of the lower animals. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0004" id="link2HCH0004"></a> +CHAPTER IV.<br /> +COMPARISON OF THE MENTAL POWERS OF MAN AND THE LOWER ANIMALS—continued.</h2> + +<p class="letter"> +The moral sense—Fundamental proposition—The qualities of social +animals—Origin of sociability—Struggle between opposed +instincts—Man a social animal—The more enduring social instincts +conquer other less persistent instincts—The social virtues alone regarded +by savages—The self-regarding virtues acquired at a later stage of +development—The importance of the judgment of the members of the same +community on conduct—Transmission of moral tendencies—Summary. +</p> + +<p> +I fully subscribe to the judgment of those writers (1. See, for instance, on +this subject, Quatrefages, ‘Unité de l’Espèce Humaine,’ 1861, +p. 21, etc.) who maintain that of all the differences between man and the lower +animals, the moral sense or conscience is by far the most important. This +sense, as Mackintosh (2. ‘Dissertation on Ethical Philosophy,’ +1837, p. 231, etc.) remarks, “has a rightful supremacy over every other +principle of human action”; it is summed up in that short but imperious +word “ought,” so full of high significance. It is the most noble of +all the attributes of man, leading him without a moment’s hesitation to +risk his life for that of a fellow-creature; or after due deliberation, +impelled simply by the deep feeling of right or duty, to sacrifice it in some +great cause. Immanuel Kant exclaims, “Duty! Wondrous thought, that +workest neither by fond insinuation, flattery, nor by any threat, but merely by +holding up thy naked law in the soul, and so extorting for thyself always +reverence, if not always obedience; before whom all appetites are dumb, however +secretly they rebel; whence thy original?” (3. ‘Metaphysics of +Ethics,’ translated by J.W. Semple, Edinburgh, 1836, p. 136.) +</p> + +<p> +This great question has been discussed by many writers (4. Mr. Bain gives a +list (‘Mental and Moral Science,’ 1868, pp. 543-725) of twenty-six +British authors who have written on this subject, and whose names are familiar +to every reader; to these, Mr. Bain’s own name, and those of Mr. Lecky, +Mr. Shadworth Hodgson, Sir J. Lubbock, and others, might be added.) of +consummate ability; and my sole excuse for touching on it, is the impossibility +of here passing it over; and because, as far as I know, no one has approached +it exclusively from the side of natural history. The investigation possesses, +also, some independent interest, as an attempt to see how far the study of the +lower animals throws light on one of the highest psychical faculties of man. +</p> + +<p> +The following proposition seems to me in a high degree probable—namely, +that any animal whatever, endowed with well-marked social instincts (5. Sir B. +Brodie, after observing that man is a social animal (‘Psychological +Enquiries,’ 1854, p. 192), asks the pregnant question, “ought not +this to settle the disputed question as to the existence of a moral +sense?” Similar ideas have probably occurred to many persons, as they did +long ago to Marcus Aurelius. Mr. J.S. Mill speaks, in his celebrated work, +‘Utilitarianism,’ (1864, pp. 45, 46), of the social feelings as a +“powerful natural sentiment,” and as “the natural basis of +sentiment for utilitarian morality.” Again he says, “Like the other +acquired capacities above referred to, the moral faculty, if not a part of our +nature, is a natural out-growth from it; capable, like them, in a certain small +degree of springing up spontaneously.” But in opposition to all this, he +also remarks, “if, as in my own belief, the moral feelings are not +innate, but acquired, they are not for that reason less natural.” It is +with hesitation that I venture to differ at all from so profound a thinker, but +it can hardly be disputed that the social feelings are instinctive or innate in +the lower animals; and why should they not be so in man? Mr. Bain (see, for +instance, ‘The Emotions and the Will,’ 1865, p. 481) and others +believe that the moral sense is acquired by each individual during his +lifetime. On the general theory of evolution this is at least extremely +improbable. The ignoring of all transmitted mental qualities will, as it seems +to me, be hereafter judged as a most serious blemish in the works of Mr. +Mill.), the parental and filial affections being here included, would +inevitably acquire a moral sense or conscience, as soon as its intellectual +powers had become as well, or nearly as well developed, as in man. For, +FIRSTLY, the social instincts lead an animal to take pleasure in the society of +its fellows, to feel a certain amount of sympathy with them, and to perform +various services for them. The services may be of a definite and evidently +instinctive nature; or there may be only a wish and readiness, as with most of +the higher social animals, to aid their fellows in certain general ways. But +these feelings and services are by no means extended to all the individuals of +the same species, only to those of the same association. SECONDLY, as soon as +the mental faculties had become highly developed, images of all past actions +and motives would be incessantly passing through the brain of each individual: +and that feeling of dissatisfaction, or even misery, which invariably results, +as we shall hereafter see, from any unsatisfied instinct, would arise, as often +as it was perceived that the enduring and always present social instinct had +yielded to some other instinct, at the time stronger, but neither enduring in +its nature, nor leaving behind it a very vivid impression. It is clear that +many instinctive desires, such as that of hunger, are in their nature of short +duration; and after being satisfied, are not readily or vividly recalled. +THIRDLY, after the power of language had been acquired, and the wishes of the +community could be expressed, the common opinion how each member ought to act +for the public good, would naturally become in a paramount degree the guide to +action. But it should be borne in mind that however great weight we may +attribute to public opinion, our regard for the approbation and disapprobation +of our fellows depends on sympathy, which, as we shall see, forms an essential +part of the social instinct, and is indeed its foundation-stone. LASTLY, habit +in the individual would ultimately play a very important part in guiding the +conduct of each member; for the social instinct, together with sympathy, is, +like any other instinct, greatly strengthened by habit, and so consequently +would be obedience to the wishes and judgment of the community. These several +subordinate propositions must now be discussed, and some of them at +considerable length. +</p> + +<p> +It may be well first to premise that I do not wish to maintain that any +strictly social animal, if its intellectual faculties were to become as active +and as highly developed as in man, would acquire exactly the same moral sense +as ours. In the same manner as various animals have some sense of beauty, +though they admire widely-different objects, so they might have a sense of +right and wrong, though led by it to follow widely different lines of conduct. +If, for instance, to take an extreme case, men were reared under precisely the +same conditions as hive-bees, there can hardly be a doubt that our unmarried +females would, like the worker-bees, think it a sacred duty to kill their +brothers, and mothers would strive to kill their fertile daughters; and no one +would think of interfering. (6. Mr. H. Sidgwick remarks, in an able discussion +on this subject (the ‘Academy,’ June 15, 1872, p. 231), “a +superior bee, we may feel sure, would aspire to a milder solution of the +population question.” Judging, however, from the habits of many or most +savages, man solves the problem by female infanticide, polyandry and +promiscuous intercourse; therefore it may well be doubted whether it would be +by a milder method. Miss Cobbe, in commenting (‘Darwinism in +Morals,’ ‘Theological Review,’ April 1872, pp. 188-191) on +the same illustration, says, the PRINCIPLES of social duty would be thus +reversed; and by this, I presume, she means that the fulfilment of a social +duty would tend to the injury of individuals; but she overlooks the fact, which +she would doubtless admit, that the instincts of the bee have been acquired for +the good of the community. She goes so far as to say that if the theory of +ethics advocated in this chapter were ever generally accepted, “I cannot +but believe that in the hour of their triumph would be sounded the knell of the +virtue of mankind!” It is to be hoped that the belief in the permanence +of virtue on this earth is not held by many persons on so weak a tenure.) +Nevertheless, the bee, or any other social animal, would gain in our supposed +case, as it appears to me, some feeling of right or wrong, or a conscience. For +each individual would have an inward sense of possessing certain stronger or +more enduring instincts, and others less strong or enduring; so that there +would often be a struggle as to which impulse should be followed; and +satisfaction, dissatisfaction, or even misery would be felt, as past +impressions were compared during their incessant passage through the mind. In +this case an inward monitor would tell the animal that it would have been +better to have followed the one impulse rather than the other. The one course +ought to have been followed, and the other ought not; the one would have been +right and the other wrong; but to these terms I shall recur. +</p> + +<h3>SOCIABILITY.</h3> + +<p> +Animals of many kinds are social; we find even distinct species living +together; for example, some American monkeys; and united flocks of rooks, +jackdaws, and starlings. Man shews the same feeling in his strong love for the +dog, which the dog returns with interest. Every one must have noticed how +miserable horses, dogs, sheep, etc., are when separated from their companions, +and what strong mutual affection the two former kinds, at least, shew on their +reunion. It is curious to speculate on the feelings of a dog, who will rest +peacefully for hours in a room with his master or any of the family, without +the least notice being taken of him; but if left for a short time by himself, +barks or howls dismally. We will confine our attention to the higher social +animals; and pass over insects, although some of these are social, and aid one +another in many important ways. The most common mutual service in the higher +animals is to warn one another of danger by means of the united senses of all. +Every sportsman knows, as Dr. Jaeger remarks (7. ‘Die Darwin’sche +Theorie,’ s. 101.), how difficult it is to approach animals in a herd or +troop. Wild horses and cattle do not, I believe, make any danger-signal; but +the attitude of any one of them who first discovers an enemy, warns the others. +Rabbits stamp loudly on the ground with their hind-feet as a signal: sheep and +chamois do the same with their forefeet, uttering likewise a whistle. Many +birds, and some mammals, post sentinels, which in the case of seals are said +(8. Mr. R. Brown in ‘Proc. Zoolog. Soc.’ 1868, p. 409.) generally +to be the females. The leader of a troop of monkeys acts as the sentinel, and +utters cries expressive both of danger and of safety. (9. Brehm, +‘Thierleben,’ B. i. 1864, s. 52, 79. For the case of the monkeys +extracting thorns from each other, see s. 54. With respect to the Hamadryas +turning over stones, the fact is given (s. 76), on the evidence of Alvarez, +whose observations Brehm thinks quite trustworthy. For the cases of the old +male baboons attacking the dogs, see s. 79; and with respect to the eagle, s. +56.) Social animals perform many little services for each other: horses nibble, +and cows lick each other, on any spot which itches: monkeys search each other +for external parasites; and Brehm states that after a troop of the +Cercopithecus griseo-viridis has rushed through a thorny brake, each monkey +stretches itself on a branch, and another monkey sitting by, +“conscientiously” examines its fur, and extracts every thorn or +burr. +</p> + +<p> +Animals also render more important services to one another: thus wolves and +some other beasts of prey hunt in packs, and aid one another in attacking their +victims. Pelicans fish in concert. The Hamadryas baboons turn over stones to +find insects, etc.; and when they come to a large one, as many as can stand +round, turn it over together and share the booty. Social animals mutually +defend each other. Bull bisons in N. America, when there is danger, drive the +cows and calves into the middle of the herd, whilst they defend the outside. I +shall also in a future chapter give an account of two young wild bulls at +Chillingham attacking an old one in concert, and of two stallions together +trying to drive away a third stallion from a troop of mares. In Abyssinia, +Brehm encountered a great troop of baboons who were crossing a valley: some had +already ascended the opposite mountain, and some were still in the valley; the +latter were attacked by the dogs, but the old males immediately hurried down +from the rocks, and with mouths widely opened, roared so fearfully, that the +dogs quickly drew back. They were again encouraged to the attack; but by this +time all the baboons had reascended the heights, excepting a young one, about +six months old, who, loudly calling for aid, climbed on a block of rock, and +was surrounded. Now one of the largest males, a true hero, came down again from +the mountain, slowly went to the young one, coaxed him, and triumphantly led +him away—the dogs being too much astonished to make an attack. I cannot +resist giving another scene which was witnessed by this same naturalist; an +eagle seized a young Cercopithecus, which, by clinging to a branch, was not at +once carried off; it cried loudly for assistance, upon which the other members +of the troop, with much uproar, rushed to the rescue, surrounded the eagle, and +pulled out so many feathers, that he no longer thought of his prey, but only +how to escape. This eagle, as Brehm remarks, assuredly would never again attack +a single monkey of a troop. (10. Mr. Belt gives the case of a spider-monkey +(Ateles) in Nicaragua, which was heard screaming for nearly two hours in the +forest, and was found with an eagle perched close by it. The bird apparently +feared to attack as long as it remained face to face; and Mr. Belt believes, +from what he has seen of the habits of these monkeys, that they protect +themselves from eagles by keeping two or three together. ‘The Naturalist +in Nicaragua,’ 1874, p. 118.) +</p> + +<p> +It is certain that associated animals have a feeling of love for each other, +which is not felt by non-social adult animals. How far in most cases they +actually sympathise in the pains and pleasures of others, is more doubtful, +especially with respect to pleasures. Mr. Buxton, however, who had excellent +means of observation (11. ‘Annals and Magazine of Natural History,’ +November 1868, p. 382.), states that his macaws, which lived free in Norfolk, +took “an extravagant interest” in a pair with a nest; and whenever +the female left it, she was surrounded by a troop “screaming horrible +acclamations in her honour.” It is often difficult to judge whether +animals have any feeling for the sufferings of others of their kind. Who can +say what cows feel, when they surround and stare intently on a dying or dead +companion; apparently, however, as Houzeau remarks, they feel no pity. That +animals sometimes are far from feeling any sympathy is too certain; for they +will expel a wounded animal from the herd, or gore or worry it to death. This +is almost the blackest fact in natural history, unless, indeed, the explanation +which has been suggested is true, that their instinct or reason leads them to +expel an injured companion, lest beasts of prey, including man, should be +tempted to follow the troop. In this case their conduct is not much worse than +that of the North American Indians, who leave their feeble comrades to perish +on the plains; or the Fijians, who, when their parents get old, or fall ill, +bury them alive. (12. Sir J. Lubbock, ‘Prehistoric Times,’ 2nd ed., +p. 446.) +</p> + +<p> +Many animals, however, certainly sympathise with each other’s distress or +danger. This is the case even with birds. Captain Stansbury (13. As quoted by +Mr. L.H. Morgan, ‘The American Beaver,’ 1868, p. 272. Capt. +Stansbury also gives an interesting account of the manner in which a very young +pelican, carried away by a strong stream, was guided and encouraged in its +attempts to reach the shore by half a dozen old birds.) found on a salt lake in +Utah an old and completely blind pelican, which was very fat, and must have +been well fed for a long time by his companions. Mr. Blyth, as he informs me, +saw Indian crows feeding two or three of their companions which were blind; and +I have heard of an analogous case with the domestic cock. We may, if we choose, +call these actions instinctive; but such cases are much too rare for the +development of any special instinct. (14. As Mr. Bain states, “effective +aid to a sufferer springs from sympathy proper:” ‘Mental and Moral +Science,’ 1868, p. 245.) I have myself seen a dog, who never passed a cat +who lay sick in a basket, and was a great friend of his, without giving her a +few licks with his tongue, the surest sign of kind feeling in a dog. +</p> + +<p> +It must be called sympathy that leads a courageous dog to fly at any one who +strikes his master, as he certainly will. I saw a person pretending to beat a +lady, who had a very timid little dog on her lap, and the trial had never been +made before; the little creature instantly jumped away, but after the pretended +beating was over, it was really pathetic to see how perseveringly he tried to +lick his mistress’s face, and comfort her. Brehm (15. +‘Thierleben,’ B. i. s. 85.) states that when a baboon in +confinement was pursued to be punished, the others tried to protect him. It +must have been sympathy in the cases above given which led the baboons and +Cercopitheci to defend their young comrades from the dogs and the eagle. I will +give only one other instance of sympathetic and heroic conduct, in the case of +a little American monkey. Several years ago a keeper at the Zoological Gardens +shewed me some deep and scarcely healed wounds on the nape of his own neck, +inflicted on him, whilst kneeling on the floor, by a fierce baboon. The little +American monkey, who was a warm friend of this keeper, lived in the same large +compartment, and was dreadfully afraid of the great baboon. Nevertheless, as +soon as he saw his friend in peril, he rushed to the rescue, and by screams and +bites so distracted the baboon that the man was able to escape, after, as the +surgeon thought, running great risk of his life. +</p> + +<p> +Besides love and sympathy, animals exhibit other qualities connected with the +social instincts, which in us would be called moral; and I agree with Agassiz +(16. ‘De l’Espèce et de la Classe,’ 1869, p. 97.) that dogs +possess something very like a conscience. +</p> + +<p> +Dogs possess some power of self-command, and this does not appear to be wholly +the result of fear. As Braubach (17. ‘Die Darwin’sche +Art-Lehre,’ 1869, s. 54.) remarks, they will refrain from stealing food +in the absence of their master. They have long been accepted as the very type +of fidelity and obedience. But the elephant is likewise very faithful to his +driver or keeper, and probably considers him as the leader of the herd. Dr. +Hooker informs me that an elephant, which he was riding in India, became so +deeply bogged that he remained stuck fast until the next day, when he was +extricated by men with ropes. Under such circumstances elephants will seize +with their trunks any object, dead or alive, to place under their knees, to +prevent their sinking deeper in the mud; and the driver was dreadfully afraid +lest the animal should have seized Dr. Hooker and crushed him to death. But the +driver himself, as Dr. Hooker was assured, ran no risk. This forbearance under +an emergency so dreadful for a heavy animal, is a wonderful proof of noble +fidelity. (18. See also Hooker’s ‘Himalayan Journals,’ vol. +ii. 1854, p. 333.) +</p> + +<p> +All animals living in a body, which defend themselves or attack their enemies +in concert, must indeed be in some degree faithful to one another; and those +that follow a leader must be in some degree obedient. When the baboons in +Abyssinia (19. Brehm, ‘Thierleben,’ B. i. s. 76.) plunder a garden, +they silently follow their leader; and if an imprudent young animal makes a +noise, he receives a slap from the others to teach him silence and obedience. +Mr. Galton, who has had excellent opportunities for observing the half-wild +cattle in S. Africa, says (20. See his extremely interesting paper on +‘Gregariousness in Cattle, and in Man,’ ‘Macmillan’s +Magazine,’ Feb. 1871, p. 353.), that they cannot endure even a momentary +separation from the herd. They are essentially slavish, and accept the common +determination, seeking no better lot than to be led by any one ox who has +enough self-reliance to accept the position. The men who break in these animals +for harness, watch assiduously for those who, by grazing apart, shew a +self-reliant disposition, and these they train as fore-oxen. Mr. Galton adds +that such animals are rare and valuable; and if many were born they would soon +be eliminated, as lions are always on the look-out for the individuals which +wander from the herd. +</p> + +<p> +With respect to the impulse which leads certain animals to associate together, +and to aid one another in many ways, we may infer that in most cases they are +impelled by the same sense of satisfaction or pleasure which they experience in +performing other instinctive actions; or by the same sense of dissatisfaction +as when other instinctive actions are checked. We see this in innumerable +instances, and it is illustrated in a striking manner by the acquired instincts +of our domesticated animals; thus a young shepherd-dog delights in driving and +running round a flock of sheep, but not in worrying them; a young fox-hound +delights in hunting a fox, whilst some other kinds of dogs, as I have +witnessed, utterly disregard foxes. What a strong feeling of inward +satisfaction must impel a bird, so full of activity, to brood day after day +over her eggs. Migratory birds are quite miserable if stopped from migrating; +perhaps they enjoy starting on their long flight; but it is hard to believe +that the poor pinioned goose, described by Audubon, which started on foot at +the proper time for its journey of probably more than a thousand miles, could +have felt any joy in doing so. Some instincts are determined solely by painful +feelings, as by fear, which leads to self-preservation, and is in some cases +directed towards special enemies. No one, I presume, can analyse the sensations +of pleasure or pain. In many instances, however, it is probable that instincts +are persistently followed from the mere force of inheritance, without the +stimulus of either pleasure or pain. A young pointer, when it first scents +game, apparently cannot help pointing. A squirrel in a cage who pats the nuts +which it cannot eat, as if to bury them in the ground, can hardly be thought to +act thus, either from pleasure or pain. Hence the common assumption that men +must be impelled to every action by experiencing some pleasure or pain may be +erroneous. Although a habit may be blindly and implicitly followed, +independently of any pleasure or pain felt at the moment, yet if it be forcibly +and abruptly checked, a vague sense of dissatisfaction is generally +experienced. +</p> + +<p> +It has often been assumed that animals were in the first place rendered social, +and that they feel as a consequence uncomfortable when separated from each +other, and comfortable whilst together; but it is a more probable view that +these sensations were first developed, in order that those animals which would +profit by living in society, should be induced to live together, in the same +manner as the sense of hunger and the pleasure of eating were, no doubt, first +acquired in order to induce animals to eat. The feeling of pleasure from +society is probably an extension of the parental or filial affections, since +the social instinct seems to be developed by the young remaining for a long +time with their parents; and this extension may be attributed in part to habit, +but chiefly to natural selection. With those animals which were benefited by +living in close association, the individuals which took the greatest pleasure +in society would best escape various dangers, whilst those that cared least for +their comrades, and lived solitary, would perish in greater numbers. With +respect to the origin of the parental and filial affections, which apparently +lie at the base of the social instincts, we know not the steps by which they +have been gained; but we may infer that it has been to a large extent through +natural selection. So it has almost certainly been with the unusual and +opposite feeling of hatred between the nearest relations, as with the +worker-bees which kill their brother drones, and with the queen-bees which kill +their daughter-queens; the desire to destroy their nearest relations having +been in this case of service to the community. Parental affection, or some +feeling which replaces it, has been developed in certain animals extremely low +in the scale, for example, in star-fishes and spiders. It is also occasionally +present in a few members alone in a whole group of animals, as in the genus +Forficula, or earwigs. +</p> + +<p> +The all-important emotion of sympathy is distinct from that of love. A mother +may passionately love her sleeping and passive infant, but she can hardly at +such times be said to feel sympathy for it. The love of a man for his dog is +distinct from sympathy, and so is that of a dog for his master. Adam Smith +formerly argued, as has Mr. Bain recently, that the basis of sympathy lies in +our strong retentiveness of former states of pain or pleasure. Hence, +“the sight of another person enduring hunger, cold, fatigue, revives in +us some recollection of these states, which are painful even in idea.” We +are thus impelled to relieve the sufferings of another, in order that our own +painful feelings may be at the same time relieved. In like manner we are led to +participate in the pleasures of others. (21. See the first and striking chapter +in Adam Smith’s ‘Theory of Moral Sentiments.’ Also ‘Mr. +Bain’s Mental and Moral Science,’ 1868, pp. 244, and 275-282. Mr. +Bain states, that, “sympathy is, indirectly, a source of pleasure to the +sympathiser”; and he accounts for this through reciprocity. He remarks +that “the person benefited, or others in his stead, may make up, by +sympathy and good offices returned, for all the sacrifice.” But if, as +appears to be the case, sympathy is strictly an instinct, its exercise would +give direct pleasure, in the same manner as the exercise, as before remarked, +of almost every other instinct.) But I cannot see how this view explains the +fact that sympathy is excited, in an immeasurably stronger degree, by a +beloved, than by an indifferent person. The mere sight of suffering, +independently of love, would suffice to call up in us vivid recollections and +associations. The explanation may lie in the fact that, with all animals, +sympathy is directed solely towards the members of the same community, and +therefore towards known, and more or less beloved members, but not to all the +individuals of the same species. This fact is not more surprising than that the +fears of many animals should be directed against special enemies. Species which +are not social, such as lions and tigers, no doubt feel sympathy for the +suffering of their own young, but not for that of any other animal. With +mankind, selfishness, experience, and imitation, probably add, as Mr. Bain has +shewn, to the power of sympathy; for we are led by the hope of receiving good +in return to perform acts of sympathetic kindness to others; and sympathy is +much strengthened by habit. In however complex a manner this feeling may have +originated, as it is one of high importance to all those animals which aid and +defend one another, it will have been increased through natural selection; for +those communities, which included the greatest number of the most sympathetic +members, would flourish best, and rear the greatest number of offspring. +</p> + +<p> +It is, however, impossible to decide in many cases whether certain social +instincts have been acquired through natural selection, or are the indirect +result of other instincts and faculties, such as sympathy, reason, experience, +and a tendency to imitation; or again, whether they are simply the result of +long-continued habit. So remarkable an instinct as the placing sentinels to +warn the community of danger, can hardly have been the indirect result of any +of these faculties; it must, therefore, have been directly acquired. On the +other hand, the habit followed by the males of some social animals of defending +the community, and of attacking their enemies or their prey in concert, may +perhaps have originated from mutual sympathy; but courage, and in most cases +strength, must have been previously acquired, probably through natural +selection. +</p> + +<p> +Of the various instincts and habits, some are much stronger than others; that +is, some either give more pleasure in their performance, and more distress in +their prevention, than others; or, which is probably quite as important, they +are, through inheritance, more persistently followed, without exciting any +special feeling of pleasure or pain. We are ourselves conscious that some +habits are much more difficult to cure or change than others. Hence a struggle +may often be observed in animals between different instincts, or between an +instinct and some habitual disposition; as when a dog rushes after a hare, is +rebuked, pauses, hesitates, pursues again, or returns ashamed to his master; or +as between the love of a female dog for her young puppies and for her +master,—for she may be seen to slink away to them, as if half ashamed of +not accompanying her master. But the most curious instance known to me of one +instinct getting the better of another, is the migratory instinct conquering +the maternal instinct. The former is wonderfully strong; a confined bird will +at the proper season beat her breast against the wires of her cage, until it is +bare and bloody. It causes young salmon to leap out of the fresh water, in +which they could continue to exist, and thus unintentionally to commit suicide. +Every one knows how strong the maternal instinct is, leading even timid birds +to face great danger, though with hesitation, and in opposition to the instinct +of self-preservation. Nevertheless, the migratory instinct is so powerful, that +late in the autumn swallows, house-martins, and swifts frequently desert their +tender young, leaving them to perish miserably in their nests. (22. This fact, +the Rev. L. Jenyns states (see his edition of ‘White’s Nat. Hist. +of Selborne,’ 1853, p. 204) was first recorded by the illustrious Jenner, +in ‘Phil. Transact.’ 1824, and has since been confirmed by several +observers, especially by Mr. Blackwall. This latter careful observer examined, +late in the autumn, during two years, thirty-six nests; he found that twelve +contained young dead birds, five contained eggs on the point of being hatched, +and three, eggs not nearly hatched. Many birds, not yet old enough for a +prolonged flight, are likewise deserted and left behind. See Blackwall, +‘Researches in Zoology,’ 1834, pp. 108, 118. For some additional +evidence, although this is not wanted, see Leroy, ‘Lettres Phil.’ +1802, p. 217. For Swifts, Gould’s ‘Introduction to the Birds of +Great Britain,’ 1823, p. 5. Similar cases have been observed in Canada by +Mr. Adams; ‘Pop. Science Review,’ July 1873, p. 283.) +</p> + +<p> +We can perceive that an instinctive impulse, if it be in any way more +beneficial to a species than some other or opposed instinct, would be rendered +the more potent of the two through natural selection; for the individuals which +had it most strongly developed would survive in larger numbers. Whether this is +the case with the migratory in comparison with the maternal instinct, may be +doubted. The great persistence, or steady action of the former at certain +seasons of the year during the whole day, may give it for a time paramount +force. +</p> + +<h3>MAN A SOCIAL ANIMAL.</h3> + +<p> +Every one will admit that man is a social being. We see this in his dislike of +solitude, and in his wish for society beyond that of his own family. Solitary +confinement is one of the severest punishments which can be inflicted. Some +authors suppose that man primevally lived in single families; but at the +present day, though single families, or only two or three together, roam the +solitudes of some savage lands, they always, as far as I can discover, hold +friendly relations with other families inhabiting the same district. Such +families occasionally meet in council, and unite for their common defence. It +is no argument against savage man being a social animal, that the tribes +inhabiting adjacent districts are almost always at war with each other; for the +social instincts never extend to all the individuals of the same species. +Judging from the analogy of the majority of the Quadrumana, it is probable that +the early ape-like progenitors of man were likewise social; but this is not of +much importance for us. Although man, as he now exists, has few special +instincts, having lost any which his early progenitors may have possessed, this +is no reason why he should not have retained from an extremely remote period +some degree of instinctive love and sympathy for his fellows. We are indeed all +conscious that we do possess such sympathetic feelings (23. Hume remarks +(‘An Enquiry Concerning the Principles of Morals,’ edit. of 1751, +p. 132), “There seems a necessity for confessing that the happiness and +misery of others are not spectacles altogether indifferent to us, but that the +view of the former...communicates a secret joy; the appearance of the latter... +throws a melancholy damp over the imagination.”); but our consciousness +does not tell us whether they are instinctive, having originated long ago in +the same manner as with the lower animals, or whether they have been acquired +by each of us during our early years. As man is a social animal, it is almost +certain that he would inherit a tendency to be faithful to his comrades, and +obedient to the leader of his tribe; for these qualities are common to most +social animals. He would consequently possess some capacity for self-command. +He would from an inherited tendency be willing to defend, in concert with +others, his fellow-men; and would be ready to aid them in any way, which did +not too greatly interfere with his own welfare or his own strong desires. +</p> + +<p> +The social animals which stand at the bottom of the scale are guided almost +exclusively, and those which stand higher in the scale are largely guided, by +special instincts in the aid which they give to the members of the same +community; but they are likewise in part impelled by mutual love and sympathy, +assisted apparently by some amount of reason. Although man, as just remarked, +has no special instincts to tell him how to aid his fellow-men, he still has +the impulse, and with his improved intellectual faculties would naturally be +much guided in this respect by reason and experience. Instinctive sympathy +would also cause him to value highly the approbation of his fellows; for, as +Mr. Bain has clearly shewn (24. ‘Mental and Moral Science,’ 1868, +p. 254.), the love of praise and the strong feeling of glory, and the still +stronger horror of scorn and infamy, “are due to the workings of +sympathy.” Consequently man would be influenced in the highest degree by +the wishes, approbation, and blame of his fellow-men, as expressed by their +gestures and language. Thus the social instincts, which must have been acquired +by man in a very rude state, and probably even by his early ape-like +progenitors, still give the impulse to some of his best actions; but his +actions are in a higher degree determined by the expressed wishes and judgment +of his fellow-men, and unfortunately very often by his own strong selfish +desires. But as love, sympathy and self-command become strengthened by habit, +and as the power of reasoning becomes clearer, so that man can value justly the +judgments of his fellows, he will feel himself impelled, apart from any +transitory pleasure or pain, to certain lines of conduct. He might then +declare—not that any barbarian or uncultivated man could thus +think—I am the supreme judge of my own conduct, and in the words of Kant, +I will not in my own person violate the dignity of humanity. +</p> + +<p> +THE MORE ENDURING SOCIAL INSTINCTS CONQUER THE LESS PERSISTENT INSTINCTS. +</p> + +<p> +We have not, however, as yet considered the main point, on which, from our +present point of view, the whole question of the moral sense turns. Why should +a man feel that he ought to obey one instinctive desire rather than another? +Why is he bitterly regretful, if he has yielded to a strong sense of +self-preservation, and has not risked his life to save that of a +fellow-creature? or why does he regret having stolen food from hunger? +</p> + +<p> +It is evident in the first place, that with mankind the instinctive impulses +have different degrees of strength; a savage will risk his own life to save +that of a member of the same community, but will be wholly indifferent about a +stranger: a young and timid mother urged by the maternal instinct will, without +a moment’s hesitation, run the greatest danger for her own infant, but +not for a mere fellow-creature. Nevertheless many a civilised man, or even boy, +who never before risked his life for another, but full of courage and sympathy, +has disregarded the instinct of self-preservation, and plunged at once into a +torrent to save a drowning man, though a stranger. In this case man is impelled +by the same instinctive motive, which made the heroic little American monkey, +formerly described, save his keeper, by attacking the great and dreaded baboon. +Such actions as the above appear to be the simple result of the greater +strength of the social or maternal instincts rather than that of any other +instinct or motive; for they are performed too instantaneously for reflection, +or for pleasure or pain to be felt at the time; though, if prevented by any +cause, distress or even misery might be felt. In a timid man, on the other +hand, the instinct of self-preservation might be so strong, that he would be +unable to force himself to run any such risk, perhaps not even for his own +child. +</p> + +<p> +I am aware that some persons maintain that actions performed impulsively, as in +the above cases, do not come under the dominion of the moral sense, and cannot +be called moral. They confine this term to actions done deliberately, after a +victory over opposing desires, or when prompted by some exalted motive. But it +appears scarcely possible to draw any clear line of distinction of this kind. +(25. I refer here to the distinction between what has been called MATERIAL and +FORMAL morality. I am glad to find that Professor Huxley (‘Critiques and +Addresses,’ 1873, p. 287) takes the same view on this subject as I do. +Mr. Leslie Stephen remarks (‘Essays on Freethinking and Plain +Speaking,’ 1873, p. 83), “the metaphysical distinction, between +material and formal morality is as irrelevant as other such +distinctions.”) As far as exalted motives are concerned, many instances +have been recorded of savages, destitute of any feeling of general benevolence +towards mankind, and not guided by any religious motive, who have deliberately +sacrificed their lives as prisoners(26. I have given one such case, namely of +three Patagonian Indians who preferred being shot, one after the other, to +betraying the plans of their companions in war (‘Journal of +Researches,’ 1845, p. 103).), rather than betray their comrades; and +surely their conduct ought to be considered as moral. As far as deliberation, +and the victory over opposing motives are concerned, animals may be seen +doubting between opposed instincts, in rescuing their offspring or comrades +from danger; yet their actions, though done for the good of others, are not +called moral. Moreover, anything performed very often by us, will at last be +done without deliberation or hesitation, and can then hardly be distinguished +from an instinct; yet surely no one will pretend that such an action ceases to +be moral. On the contrary, we all feel that an act cannot be considered as +perfect, or as performed in the most noble manner, unless it be done +impulsively, without deliberation or effort, in the same manner as by a man in +whom the requisite qualities are innate. He who is forced to overcome his fear +or want of sympathy before he acts, deserves, however, in one way higher credit +than the man whose innate disposition leads him to a good act without effort. +As we cannot distinguish between motives, we rank all actions of a certain +class as moral, if performed by a moral being. A moral being is one who is +capable of comparing his past and future actions or motives, and of approving +or disapproving of them. We have no reason to suppose that any of the lower +animals have this capacity; therefore, when a Newfoundland dog drags a child +out of the water, or a monkey faces danger to rescue its comrade, or takes +charge of an orphan monkey, we do not call its conduct moral. But in the case +of man, who alone can with certainty be ranked as a moral being, actions of a +certain class are called moral, whether performed deliberately, after a +struggle with opposing motives, or impulsively through instinct, or from the +effects of slowly-gained habit. +</p> + +<p> +But to return to our more immediate subject. Although some instincts are more +powerful than others, and thus lead to corresponding actions, yet it is +untenable, that in man the social instincts (including the love of praise and +fear of blame) possess greater strength, or have, through long habit, acquired +greater strength than the instincts of self-preservation, hunger, lust, +vengeance, etc. Why then does man regret, even though trying to banish such +regret, that he has followed the one natural impulse rather than the other; and +why does he further feel that he ought to regret his conduct? Man in this +respect differs profoundly from the lower animals. Nevertheless we can, I +think, see with some degree of clearness the reason of this difference. +</p> + +<p> +Man, from the activity of his mental faculties, cannot avoid reflection: past +impressions and images are incessantly and clearly passing through his mind. +Now with those animals which live permanently in a body, the social instincts +are ever present and persistent. Such animals are always ready to utter the +danger-signal, to defend the community, and to give aid to their fellows in +accordance with their habits; they feel at all times, without the stimulus of +any special passion or desire, some degree of love and sympathy for them; they +are unhappy if long separated from them, and always happy to be again in their +company. So it is with ourselves. Even when we are quite alone, how often do we +think with pleasure or pain of what others think of us,—of their imagined +approbation or disapprobation; and this all follows from sympathy, a +fundamental element of the social instincts. A man who possessed no trace of +such instincts would be an unnatural monster. On the other hand, the desire to +satisfy hunger, or any passion such as vengeance, is in its nature temporary, +and can for a time be fully satisfied. Nor is it easy, perhaps hardly possible, +to call up with complete vividness the feeling, for instance, of hunger; nor +indeed, as has often been remarked, of any suffering. The instinct of +self-preservation is not felt except in the presence of danger; and many a +coward has thought himself brave until he has met his enemy face to face. The +wish for another man’s property is perhaps as persistent a desire as any +that can be named; but even in this case the satisfaction of actual possession +is generally a weaker feeling than the desire: many a thief, if not a habitual +one, after success has wondered why he stole some article. (27. Enmity or +hatred seems also to be a highly persistent feeling, perhaps more so than any +other that can be named. Envy is defined as hatred of another for some +excellence or success; and Bacon insists (Essay ix.), “Of all other +affections envy is the most importune and continual.” Dogs are very apt +to hate both strange men and strange dogs, especially if they live near at +hand, but do not belong to the same family, tribe, or clan; this feeling would +thus seem to be innate, and is certainly a most persistent one. It seems to be +the complement and converse of the true social instinct. From what we hear of +savages, it would appear that something of the same kind holds good with them. +If this be so, it would be a small step in any one to transfer such feelings to +any member of the same tribe if he had done him an injury and had become his +enemy. Nor is it probable that the primitive conscience would reproach a man +for injuring his enemy; rather it would reproach him, if he had not revenged +himself. To do good in return for evil, to love your enemy, is a height of +morality to which it may be doubted whether the social instincts would, by +themselves, have ever led us. It is necessary that these instincts, together +with sympathy, should have been highly cultivated and extended by the aid of +reason, instruction, and the love or fear of God, before any such golden rule +would ever be thought of and obeyed.) +</p> + +<p> +A man cannot prevent past impressions often repassing through his mind; he will +thus be driven to make a comparison between the impressions of past hunger, +vengeance satisfied, or danger shunned at other men’s cost, with the +almost ever-present instinct of sympathy, and with his early knowledge of what +others consider as praiseworthy or blameable. This knowledge cannot be banished +from his mind, and from instinctive sympathy is esteemed of great moment. He +will then feel as if he had been baulked in following a present instinct or +habit, and this with all animals causes dissatisfaction, or even misery. +</p> + +<p> +The above case of the swallow affords an illustration, though of a reversed +nature, of a temporary though for the time strongly persistent instinct +conquering another instinct, which is usually dominant over all others. At the +proper season these birds seem all day long to be impressed with the desire to +migrate; their habits change; they become restless, are noisy and congregate in +flocks. Whilst the mother-bird is feeding, or brooding over her nestlings, the +maternal instinct is probably stronger than the migratory; but the instinct +which is the more persistent gains the victory, and at last, at a moment when +her young ones are not in sight, she takes flight and deserts them. When +arrived at the end of her long journey, and the migratory instinct has ceased +to act, what an agony of remorse the bird would feel, if, from being endowed +with great mental activity, she could not prevent the image constantly passing +through her mind, of her young ones perishing in the bleak north from cold and +hunger. +</p> + +<p> +At the moment of action, man will no doubt be apt to follow the stronger +impulse; and though this may occasionally prompt him to the noblest deeds, it +will more commonly lead him to gratify his own desires at the expense of other +men. But after their gratification when past and weaker impressions are judged +by the ever-enduring social instinct, and by his deep regard for the good +opinion of his fellows, retribution will surely come. He will then feel +remorse, repentance, regret, or shame; this latter feeling, however, relates +almost exclusively to the judgment of others. He will consequently resolve more +or less firmly to act differently for the future; and this is conscience; for +conscience looks backwards, and serves as a guide for the future. +</p> + +<p> +The nature and strength of the feelings which we call regret, shame, repentance +or remorse, depend apparently not only on the strength of the violated +instinct, but partly on the strength of the temptation, and often still more on +the judgment of our fellows. How far each man values the appreciation of +others, depends on the strength of his innate or acquired feeling of sympathy; +and on his own capacity for reasoning out the remote consequences of his acts. +Another element is most important, although not necessary, the reverence or +fear of the Gods, or Spirits believed in by each man: and this applies +especially in cases of remorse. Several critics have objected that though some +slight regret or repentance may be explained by the view advocated in this +chapter, it is impossible thus to account for the soul-shaking feeling of +remorse. But I can see little force in this objection. My critics do not define +what they mean by remorse, and I can find no definition implying more than an +overwhelming sense of repentance. Remorse seems to bear the same relation to +repentance, as rage does to anger, or agony to pain. It is far from strange +that an instinct so strong and so generally admired, as maternal love, should, +if disobeyed, lead to the deepest misery, as soon as the impression of the past +cause of disobedience is weakened. Even when an action is opposed to no special +instinct, merely to know that our friends and equals despise us for it is +enough to cause great misery. Who can doubt that the refusal to fight a duel +through fear has caused many men an agony of shame? Many a Hindoo, it is said, +has been stirred to the bottom of his soul by having partaken of unclean food. +Here is another case of what must, I think, be called remorse. Dr. Landor acted +as a magistrate in West Australia, and relates (28. ‘Insanity in Relation +to Law,’ Ontario, United States, 1871, p. 1.), that a native on his farm, +after losing one of his wives from disease, came and said that, “he was +going to a distant tribe to spear a woman, to satisfy his sense of duty to his +wife. I told him that if he did so, I would send him to prison for life. He +remained about the farm for some months, but got exceedingly thin, and +complained that he could not rest or eat, that his wife’s spirit was +haunting him, because he had not taken a life for hers. I was inexorable, and +assured him that nothing should save him if he did.” Nevertheless the man +disappeared for more than a year, and then returned in high condition; and his +other wife told Dr. Landor that her husband had taken the life of a woman +belonging to a distant tribe; but it was impossible to obtain legal evidence of +the act. The breach of a rule held sacred by the tribe, will thus, as it seems, +give rise to the deepest feelings,—and this quite apart from the social +instincts, excepting in so far as the rule is grounded on the judgment of the +community. How so many strange superstitions have arisen throughout the world +we know not; nor can we tell how some real and great crimes, such as incest, +have come to be held in an abhorrence (which is not however quite universal) by +the lowest savages. It is even doubtful whether in some tribes incest would be +looked on with greater horror, than would the marriage of a man with a woman +bearing the same name, though not a relation. “To violate this law is a +crime which the Australians hold in the greatest abhorrence, in this agreeing +exactly with certain tribes of North America. When the question is put in +either district, is it worse to kill a girl of a foreign tribe, or to marry a +girl of one’s own, an answer just opposite to ours would be given without +hesitation.” (29. E.B. Tylor, in ‘Contemporary Review,’ April +1873, p. 707.) We may, therefore, reject the belief, lately insisted on by some +writers, that the abhorrence of incest is due to our possessing a special +God-implanted conscience. On the whole it is intelligible, that a man urged by +so powerful a sentiment as remorse, though arising as above explained, should +be led to act in a manner, which he has been taught to believe serves as an +expiation, such as delivering himself up to justice. +</p> + +<p> +Man prompted by his conscience, will through long habit acquire such perfect +self-command, that his desires and passions will at last yield instantly and +without a struggle to his social sympathies and instincts, including his +feeling for the judgment of his fellows. The still hungry, or the still +revengeful man will not think of stealing food, or of wreaking his vengeance. +It is possible, or as we shall hereafter see, even probable, that the habit of +self-command may, like other habits, be inherited. Thus at last man comes to +feel, through acquired and perhaps inherited habit, that it is best for him to +obey his more persistent impulses. The imperious word “ought” seems +merely to imply the consciousness of the existence of a rule of conduct, +however it may have originated. Formerly it must have been often vehemently +urged that an insulted gentleman OUGHT to fight a duel. We even say that a +pointer OUGHT to point, and a retriever to retrieve game. If they fail to do +so, they fail in their duty and act wrongly. +</p> + +<p> +If any desire or instinct leading to an action opposed to the good of others +still appears, when recalled to mind, as strong as, or stronger than, the +social instinct, a man will feel no keen regret at having followed it; but he +will be conscious that if his conduct were known to his fellows, it would meet +with their disapprobation; and few are so destitute of sympathy as not to feel +discomfort when this is realised. If he has no such sympathy, and if his +desires leading to bad actions are at the time strong, and when recalled are +not over-mastered by the persistent social instincts, and the judgment of +others, then he is essentially a bad man (30. Dr. Prosper Despine, in his +Psychologie Naturelle, 1868 (tom. i. p. 243; tom. ii. p. 169) gives many +curious cases of the worst criminals, who apparently have been entirely +destitute of conscience.); and the sole restraining motive left is the fear of +punishment, and the conviction that in the long run it would be best for his +own selfish interests to regard the good of others rather than his own. +</p> + +<p> +It is obvious that every one may with an easy conscience gratify his own +desires, if they do not interfere with his social instincts, that is with the +good of others; but in order to be quite free from self-reproach, or at least +of anxiety, it is almost necessary for him to avoid the disapprobation, whether +reasonable or not, of his fellow-men. Nor must he break through the fixed +habits of his life, especially if these are supported by reason; for if he +does, he will assuredly feel dissatisfaction. He must likewise avoid the +reprobation of the one God or gods in whom, according to his knowledge or +superstition, he may believe; but in this case the additional fear of divine +punishment often supervenes. +</p> + +<h3>THE STRICTLY SOCIAL VIRTUES AT FIRST ALONE REGARDED.</h3> + +<p> +The above view of the origin and nature of the moral sense, which tells us what +we ought to do, and of the conscience which reproves us if we disobey it, +accords well with what we see of the early and undeveloped condition of this +faculty in mankind. The virtues which must be practised, at least generally, by +rude men, so that they may associate in a body, are those which are still +recognised as the most important. But they are practised almost exclusively in +relation to the men of the same tribe; and their opposites are not regarded as +crimes in relation to the men of other tribes. No tribe could hold together if +murder, robbery, treachery, etc., were common; consequently such crimes within +the limits of the same tribe “are branded with everlasting infamy” +(31. See an able article in the ‘North British Review,’ 1867, p. +395. See also Mr. W. Bagehot’s articles on the Importance of Obedience +and Coherence to Primitive Man, in the ‘Fortnightly Review,’ 1867, +p. 529, and 1868, p. 457, etc.); but excite no such sentiment beyond these +limits. A North-American Indian is well pleased with himself, and is honoured +by others, when he scalps a man of another tribe; and a Dyak cuts off the head +of an unoffending person, and dries it as a trophy. The murder of infants has +prevailed on the largest scale throughout the world (32. The fullest account +which I have met with is by Dr. Gerland, in his ‘Ueber den Aussterben der +Naturvölker,’ 1868; but I shall have to recur to the subject of +infanticide in a future chapter.), and has met with no reproach; but +infanticide, especially of females, has been thought to be good for the tribe, +or at least not injurious. Suicide during former times was not generally +considered as a crime (33. See the very interesting discussion on suicide in +Lecky’s ‘History of European Morals,’ vol. i. 1869, p. 223. +With respect to savages, Mr. Winwood Reade informs me that the negroes of West +Africa often commit suicide. It is well known how common it was amongst the +miserable aborigines of South America after the Spanish conquest. For New +Zealand, see the voyage of the Novara, and for the Aleutian Islands, Müller, as +quoted by Houzeau, ‘Les Facultés Mentales,’ etc., tom. ii. p. +136.), but rather, from the courage displayed, as an honourable act; and it is +still practised by some semi-civilised and savage nations without reproach, for +it does not obviously concern others of the tribe. It has been recorded that an +Indian Thug conscientiously regretted that he had not robbed and strangled as +many travellers as did his father before him. In a rude state of civilisation +the robbery of strangers is, indeed, generally considered as honourable. +</p> + +<p> +Slavery, although in some ways beneficial during ancient times (34. See Mr. +Bagehot, ‘Physics and Politics,’ 1872, p. 72.), is a great crime; +yet it was not so regarded until quite recently, even by the most civilised +nations. And this was especially the case, because the slaves belonged in +general to a race different from that of their masters. As barbarians do not +regard the opinion of their women, wives are commonly treated like slaves. Most +savages are utterly indifferent to the sufferings of strangers, or even delight +in witnessing them. It is well known that the women and children of the +North-American Indians aided in torturing their enemies. Some savages take a +horrid pleasure in cruelty to animals (35. See, for instance, Mr. +Hamilton’s account of the Kaffirs, ‘Anthropological Review,’ +1870, p. xv.), and humanity is an unknown virtue. Nevertheless, besides the +family affections, kindness is common, especially during sickness, between the +members of the same tribe, and is sometimes extended beyond these limits. Mungo +Park’s touching account of the kindness of the negro women of the +interior to him is well known. Many instances could be given of the noble +fidelity of savages towards each other, but not to strangers; common experience +justifies the maxim of the Spaniard, “Never, never trust an +Indian.” There cannot be fidelity without truth; and this fundamental +virtue is not rare between the members of the same tribe: thus Mungo Park heard +the negro women teaching their young children to love the truth. This, again, +is one of the virtues which becomes so deeply rooted in the mind, that it is +sometimes practised by savages, even at a high cost, towards strangers; but to +lie to your enemy has rarely been thought a sin, as the history of modern +diplomacy too plainly shews. As soon as a tribe has a recognised leader, +disobedience becomes a crime, and even abject submission is looked at as a +sacred virtue. +</p> + +<p> +As during rude times no man can be useful or faithful to his tribe without +courage, this quality has universally been placed in the highest rank; and +although in civilised countries a good yet timid man may be far more useful to +the community than a brave one, we cannot help instinctively honouring the +latter above a coward, however benevolent. Prudence, on the other hand, which +does not concern the welfare of others, though a very useful virtue, has never +been highly esteemed. As no man can practise the virtues necessary for the +welfare of his tribe without self-sacrifice, self-command, and the power of +endurance, these qualities have been at all times highly and most justly +valued. The American savage voluntarily submits to the most horrid tortures +without a groan, to prove and strengthen his fortitude and courage; and we +cannot help admiring him, or even an Indian Fakir, who, from a foolish +religious motive, swings suspended by a hook buried in his flesh. +</p> + +<p> +The other so-called self-regarding virtues, which do not obviously, though they +may really, affect the welfare of the tribe, have never been esteemed by +savages, though now highly appreciated by civilised nations. The greatest +intemperance is no reproach with savages. Utter licentiousness, and unnatural +crimes, prevail to an astounding extent. (36. Mr. M’Lennan has given +(‘Primitive Marriage,’ 1865, p. 176) a good collection of facts on +this head.) As soon, however, as marriage, whether polygamous, or monogamous, +becomes common, jealousy will lead to the inculcation of female virtue; and +this, being honoured, will tend to spread to the unmarried females. How slowly +it spreads to the male sex, we see at the present day. Chastity eminently +requires self-command; therefore it has been honoured from a very early period +in the moral history of civilised man. As a consequence of this, the senseless +practice of celibacy has been ranked from a remote period as a virtue. (38. +Lecky, ‘History of European Morals,’ vol. i. 1869, p. 109.) The +hatred of indecency, which appears to us so natural as to be thought innate, +and which is so valuable an aid to chastity, is a modern virtue, appertaining +exclusively, as Sir G. Staunton remarks (38. ‘Embassy to China,’ +vol. ii. p. 348.), to civilised life. This is shewn by the ancient religious +rites of various nations, by the drawings on the walls of Pompeii, and by the +practices of many savages. +</p> + +<p> +We have now seen that actions are regarded by savages, and were probably so +regarded by primeval man, as good or bad, solely as they obviously affect the +welfare of the tribe,—not that of the species, nor that of an individual +member of the tribe. This conclusion agrees well with the belief that the +so-called moral sense is aboriginally derived from the social instincts, for +both relate at first exclusively to the community. +</p> + +<p> +The chief causes of the low morality of savages, as judged by our standard, +are, firstly, the confinement of sympathy to the same tribe. Secondly, powers +of reasoning insufficient to recognise the bearing of many virtues, especially +of the self-regarding virtues, on the general welfare of the tribe. Savages, +for instance, fail to trace the multiplied evils consequent on a want of +temperance, chastity, etc. And, thirdly, weak power of self-command; for this +power has not been strengthened through long-continued, perhaps inherited, +habit, instruction and religion. +</p> + +<p> +I have entered into the above details on the immorality of savages (39. See on +this subject copious evidence in Chap. vii. of Sir J. Lubbock, ‘Origin of +Civilisation,’ 1870.), because some authors have recently taken a high +view of their moral nature, or have attributed most of their crimes to mistaken +benevolence. (40. For instance Lecky, ‘History of European Morals,’ +vol. i. p. 124.) These authors appear to rest their conclusion on savages +possessing those virtues which are serviceable, or even necessary, for the +existence of the family and of the tribe,—qualities which they +undoubtedly do possess, and often in a high degree. +</p> + +<h3>CONCLUDING REMARKS.</h3> + +<p> +It was assumed formerly by philosophers of the derivative (41. This term is +used in an able article in the ‘Westminster Review,’ Oct. 1869, p. +498. For the “Greatest happiness principle,” see J.S. Mill, +‘Utilitarianism,’ p. 17.) school of morals that the foundation of +morality lay in a form of Selfishness; but more recently the “Greatest +happiness principle” has been brought prominently forward. It is, +however, more correct to speak of the latter principle as the standard, and not +as the motive of conduct. Nevertheless, all the authors whose works I have +consulted, with a few exceptions (42. Mill recognises (‘System of +Logic,’ vol. ii. p. 422) in the clearest manner, that actions may be +performed through habit without the anticipation of pleasure. Mr. H. Sidgwick +also, in his Essay on Pleasure and Desire (‘The Contemporary +Review,’ April 1872, p. 671), remarks: “To sum up, in contravention +of the doctrine that our conscious active impulses are always directed towards +the production of agreeable sensations in ourselves, I would maintain that we +find everywhere in consciousness extra-regarding impulse, directed towards +something that is not pleasure; that in many cases the impulse is so far +incompatible with the self-regarding that the two do not easily co-exist in the +same moment of consciousness.” A dim feeling that our impulses do not by +any means always arise from any contemporaneous or anticipated pleasure, has, I +cannot but think, been one chief cause of the acceptance of the intuitive +theory of morality, and of the rejection of the utilitarian or “Greatest +happiness” theory. With respect to the latter theory the standard and the +motive of conduct have no doubt often been confused, but they are really in +some degree blended.), write as if there must be a distinct motive for every +action, and that this must be associated with some pleasure or displeasure. But +man seems often to act impulsively, that is from instinct or long habit, +without any consciousness of pleasure, in the same manner as does probably a +bee or ant, when it blindly follows its instincts. Under circumstances of +extreme peril, as during a fire, when a man endeavours to save a +fellow-creature without a moment’s hesitation, he can hardly feel +pleasure; and still less has he time to reflect on the dissatisfaction which he +might subsequently experience if he did not make the attempt. Should he +afterwards reflect over his own conduct, he would feel that there lies within +him an impulsive power widely different from a search after pleasure or +happiness; and this seems to be the deeply planted social instinct. +</p> + +<p> +In the case of the lower animals it seems much more appropriate to speak of +their social instincts, as having been developed for the general good rather +than for the general happiness of the species. The term, general good, may be +defined as the rearing of the greatest number of individuals in full vigour and +health, with all their faculties perfect, under the conditions to which they +are subjected. As the social instincts both of man and the lower animals have +no doubt been developed by nearly the same steps, it would be advisable, if +found practicable, to use the same definition in both cases, and to take as the +standard of morality, the general good or welfare of the community, rather than +the general happiness; but this definition would perhaps require some +limitation on account of political ethics. +</p> + +<p> +When a man risks his life to save that of a fellow-creature, it seems also more +correct to say that he acts for the general good, rather than for the general +happiness of mankind. No doubt the welfare and the happiness of the individual +usually coincide; and a contented, happy tribe will flourish better than one +that is discontented and unhappy. We have seen that even at an early period in +the history of man, the expressed wishes of the community will have naturally +influenced to a large extent the conduct of each member; and as all wish for +happiness, the “greatest happiness principle” will have become a +most important secondary guide and object; the social instinct, however, +together with sympathy (which leads to our regarding the approbation and +disapprobation of others), having served as the primary impulse and guide. Thus +the reproach is removed of laying the foundation of the noblest part of our +nature in the base principle of selfishness; unless, indeed, the satisfaction +which every animal feels, when it follows its proper instincts, and the +dissatisfaction felt when prevented, be called selfish. +</p> + +<p> +The wishes and opinions of the members of the same community, expressed at +first orally, but later by writing also, either form the sole guides of our +conduct, or greatly reinforce the social instincts; such opinions, however, +have sometimes a tendency directly opposed to these instincts. This latter fact +is well exemplified by the LAW OF HONOUR, that is, the law of the opinion of +our equals, and not of all our countrymen. The breach of this law, even when +the breach is known to be strictly accordant with true morality, has caused +many a man more agony than a real crime. We recognise the same influence in the +burning sense of shame which most of us have felt, even after the interval of +years, when calling to mind some accidental breach of a trifling, though fixed, +rule of etiquette. The judgment of the community will generally be guided by +some rude experience of what is best in the long run for all the members; but +this judgment will not rarely err from ignorance and weak powers of reasoning. +Hence the strangest customs and superstitions, in complete opposition to the +true welfare and happiness of mankind, have become all-powerful throughout the +world. We see this in the horror felt by a Hindoo who breaks his caste, and in +many other such cases. It would be difficult to distinguish between the remorse +felt by a Hindoo who has yielded to the temptation of eating unclean food, from +that felt after committing a theft; but the former would probably be the more +severe. +</p> + +<p> +How so many absurd rules of conduct, as well as so many absurd religious +beliefs, have originated, we do not know; nor how it is that they have become, +in all quarters of the world, so deeply impressed on the mind of men; but it is +worthy of remark that a belief constantly inculcated during the early years of +life, whilst the brain is impressible, appears to acquire almost the nature of +an instinct; and the very essence of an instinct is that it is followed +independently of reason. Neither can we say why certain admirable virtues, such +as the love of truth, are much more highly appreciated by some savage tribes +than by others (43. Good instances are given by Mr. Wallace in +‘Scientific Opinion,’ Sept. 15, 1869; and more fully in his +‘Contributions to the Theory of Natural Selection,’ 1870, p. 353.); +nor, again, why similar differences prevail even amongst highly civilised +nations. Knowing how firmly fixed many strange customs and superstitions have +become, we need feel no surprise that the self-regarding virtues, supported as +they are by reason, should now appear to us so natural as to be thought innate, +although they were not valued by man in his early condition. +</p> + +<p> +Not withstanding many sources of doubt, man can generally and readily +distinguish between the higher and lower moral rules. The higher are founded on +the social instincts, and relate to the welfare of others. They are supported +by the approbation of our fellow-men and by reason. The lower rules, though +some of them when implying self-sacrifice hardly deserve to be called lower, +relate chiefly to self, and arise from public opinion, matured by experience +and cultivation; for they are not practised by rude tribes. +</p> + +<p> +As man advances in civilisation, and small tribes are united into larger +communities, the simplest reason would tell each individual that he ought to +extend his social instincts and sympathies to all the members of the same +nation, though personally unknown to him. This point being once reached, there +is only an artificial barrier to prevent his sympathies extending to the men of +all nations and races. If, indeed, such men are separated from him by great +differences in appearance or habits, experience unfortunately shews us how long +it is, before we look at them as our fellow-creatures. Sympathy beyond the +confines of man, that is, humanity to the lower animals, seems to be one of the +latest moral acquisitions. It is apparently unfelt by savages, except towards +their pets. How little the old Romans knew of it is shewn by their abhorrent +gladiatorial exhibitions. The very idea of humanity, as far as I could observe, +was new to most of the Gauchos of the Pampas. This virtue, one of the noblest +with which man is endowed, seems to arise incidentally from our sympathies +becoming more tender and more widely diffused, until they are extended to all +sentient beings. As soon as this virtue is honoured and practised by some few +men, it spreads through instruction and example to the young, and eventually +becomes incorporated in public opinion. +</p> + +<p> +The highest possible stage in moral culture is when we recognise that we ought +to control our thoughts, and “not even in inmost thought to think again +the sins that made the past so pleasant to us.” (44. Tennyson, Idylls of +the King, p. 244.) Whatever makes any bad action familiar to the mind, renders +its performance by so much the easier. As Marcus Aurelius long ago said, +“Such as are thy habitual thoughts, such also will be the character of +thy mind; for the soul is dyed by the thoughts.” (45. ‘The Thoughts +of the Emperor M. Aurelius Antoninus,’ English translation, 2nd edit., +1869. p. 112. Marcus Aurelius was born A.D. 121.) +</p> + +<p> +Our great philosopher, Herbert Spencer, has recently explained his views on the +moral sense. He says (46. Letter to Mr. Mill in Bain’s ‘Mental and +Moral Science,’ 1868, p. 722.), “I believe that the experiences of +utility organised and consolidated through all past generations of the human +race, have been producing corresponding modifications, which, by continued +transmission and accumulation, have become in us certain faculties of moral +intuition—certain emotions responding to right and wrong conduct, which +have no apparent basis in the individual experiences of utility.” There +is not the least inherent improbability, as it seems to me, in virtuous +tendencies being more or less strongly inherited; for, not to mention the +various dispositions and habits transmitted by many of our domestic animals to +their offspring, I have heard of authentic cases in which a desire to steal and +a tendency to lie appeared to run in families of the upper ranks; and as +stealing is a rare crime in the wealthy classes, we can hardly account by +accidental coincidence for the tendency occurring in two or three members of +the same family. If bad tendencies are transmitted, it is probable that good +ones are likewise transmitted. That the state of the body by affecting the +brain, has great influence on the moral tendencies is known to most of those +who have suffered from chronic derangements of the digestion or liver. The same +fact is likewise shewn by the “perversion or destruction of the moral +sense being often one of the earliest symptoms of mental derangement” +(47. Maudsley, ‘Body and Mind,’ 1870, p. 60.); and insanity is +notoriously often inherited. Except through the principle of the transmission +of moral tendencies, we cannot understand the differences believed to exist in +this respect between the various races of mankind. +</p> + +<p> +Even the partial transmission of virtuous tendencies would be an immense +assistance to the primary impulse derived directly and indirectly from the +social instincts. Admitting for a moment that virtuous tendencies are +inherited, it appears probable, at least in such cases as chastity, temperance, +humanity to animals, etc., that they become first impressed on the mental +organization through habit, instruction and example, continued during several +generations in the same family, and in a quite subordinate degree, or not at +all, by the individuals possessing such virtues having succeeded best in the +struggle for life. My chief source of doubt with respect to any such +inheritance, is that senseless customs, superstitions, and tastes, such as the +horror of a Hindoo for unclean food, ought on the same principle to be +transmitted. I have not met with any evidence in support of the transmission of +superstitious customs or senseless habits, although in itself it is perhaps not +less probable than that animals should acquire inherited tastes for certain +kinds of food or fear of certain foes. +</p> + +<p> +Finally the social instincts, which no doubt were acquired by man as by the +lower animals for the good of the community, will from the first have given to +him some wish to aid his fellows, some feeling of sympathy, and have compelled +him to regard their approbation and disapprobation. Such impulses will have +served him at a very early period as a rude rule of right and wrong. But as man +gradually advanced in intellectual power, and was enabled to trace the more +remote consequences of his actions; as he acquired sufficient knowledge to +reject baneful customs and superstitions; as he regarded more and more, not +only the welfare, but the happiness of his fellow-men; as from habit, following +on beneficial experience, instruction and example, his sympathies became more +tender and widely diffused, extending to men of all races, to the imbecile, +maimed, and other useless members of society, and finally to the lower +animals,—so would the standard of his morality rise higher and higher. +And it is admitted by moralists of the derivative school and by some +intuitionists, that the standard of morality has risen since an early period in +the history of man. (48. A writer in the ‘North British Review’ +(July 1869, p. 531), well capable of forming a sound judgment, expresses +himself strongly in favour of this conclusion. Mr. Lecky (‘History of +Morals,’ vol. i. p. 143) seems to a certain extent to coincide therein.) +</p> + +<p> +As a struggle may sometimes be seen going on between the various instincts of +the lower animals, it is not surprising that there should be a struggle in man +between his social instincts, with their derived virtues, and his lower, though +momentarily stronger impulses or desires. This, as Mr. Galton (49. See his +remarkable work on ‘Hereditary Genius,’ 1869, p. 349. The Duke of +Argyll (‘Primeval Man,’ 1869, p. 188) has some good remarks on the +contest in man’s nature between right and wrong.) has remarked, is all +the less surprising, as man has emerged from a state of barbarism within a +comparatively recent period. After having yielded to some temptation we feel a +sense of dissatisfaction, shame, repentance, or remorse, analogous to the +feelings caused by other powerful instincts or desires, when left unsatisfied +or baulked. We compare the weakened impression of a past temptation with the +ever present social instincts, or with habits, gained in early youth and +strengthened during our whole lives, until they have become almost as strong as +instincts. If with the temptation still before us we do not yield, it is +because either the social instinct or some custom is at the moment predominant, +or because we have learnt that it will appear to us hereafter the stronger, +when compared with the weakened impression of the temptation, and we realise +that its violation would cause us suffering. Looking to future generations, +there is no cause to fear that the social instincts will grow weaker, and we +may expect that virtuous habits will grow stronger, becoming perhaps fixed by +inheritance. In this case the struggle between our higher and lower impulses +will be less severe, and virtue will be triumphant. +</p> + +<h3>A SUMMARY OF THE LAST TWO CHAPTERS.</h3> + +<p> +There can be no doubt that the difference between the mind of the lowest man +and that of the highest animal is immense. An anthropomorphous ape, if he could +take a dispassionate view of his own case, would admit that though he could +form an artful plan to plunder a garden—though he could use stones for +fighting or for breaking open nuts, yet that the thought of fashioning a stone +into a tool was quite beyond his scope. Still less, as he would admit, could he +follow out a train of metaphysical reasoning, or solve a mathematical problem, +or reflect on God, or admire a grand natural scene. Some apes, however, would +probably declare that they could and did admire the beauty of the coloured skin +and fur of their partners in marriage. They would admit, that though they could +make other apes understand by cries some of their perceptions and simpler +wants, the notion of expressing definite ideas by definite sounds had never +crossed their minds. They might insist that they were ready to aid their +fellow-apes of the same troop in many ways, to risk their lives for them, and +to take charge of their orphans; but they would be forced to acknowledge that +disinterested love for all living creatures, the most noble attribute of man, +was quite beyond their comprehension. +</p> + +<p> +Nevertheless the difference in mind between man and the higher animals, great +as it is, certainly is one of degree and not of kind. We have seen that the +senses and intuitions, the various emotions and faculties, such as love, +memory, attention, curiosity, imitation, reason, etc., of which man boasts, may +be found in an incipient, or even sometimes in a well-developed condition, in +the lower animals. They are also capable of some inherited improvement, as we +see in the domestic dog compared with the wolf or jackal. If it could be proved +that certain high mental powers, such as the formation of general concepts, +self-consciousness, etc., were absolutely peculiar to man, which seems +extremely doubtful, it is not improbable that these qualities are merely the +incidental results of other highly-advanced intellectual faculties; and these +again mainly the result of the continued use of a perfect language. At what age +does the new-born infant possess the power of abstraction, or become +self-conscious, and reflect on its own existence? We cannot answer; nor can we +answer in regard to the ascending organic scale. The half-art, half-instinct of +language still bears the stamp of its gradual evolution. The ennobling belief +in God is not universal with man; and the belief in spiritual agencies +naturally follows from other mental powers. The moral sense perhaps affords the +best and highest distinction between man and the lower animals; but I need say +nothing on this head, as I have so lately endeavoured to shew that the social +instincts,—the prime principle of man’s moral constitution (50. +‘The Thoughts of Marcus Aurelius,’ etc., p. 139.)—with the +aid of active intellectual powers and the effects of habit, naturally lead to +the golden rule, “As ye would that men should do to you, do ye to them +likewise;” and this lies at the foundation of morality. +</p> + +<p> +In the next chapter I shall make some few remarks on the probable steps and +means by which the several mental and moral faculties of man have been +gradually evolved. That such evolution is at least possible, ought not to be +denied, for we daily see these faculties developing in every infant; and we may +trace a perfect gradation from the mind of an utter idiot, lower than that of +an animal low in the scale, to the mind of a Newton. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0005" id="link2HCH0005"></a> +CHAPTER V.<br /> +ON THE DEVELOPMENT OF THE INTELLECTUAL AND MORAL FACULTIES DURING PRIMEVAL AND CIVILISED TIMES.</h2> + +<p class="letter"> +Advancement of the intellectual powers through natural +selection—Importance of imitation—Social and moral +faculties—Their development within the limits of the same +tribe—Natural selection as affecting civilised nations—Evidence +that civilised nations were once barbarous. +</p> + +<p> +The subjects to be discussed in this chapter are of the highest interest, but +are treated by me in an imperfect and fragmentary manner. Mr. Wallace, in an +admirable paper before referred to (1. Anthropological Review, May 1864, p. +clviii.), argues that man, after he had partially acquired those intellectual +and moral faculties which distinguish him from the lower animals, would have +been but little liable to bodily modifications through natural selection or any +other means. For man is enabled through his mental faculties “to keep +with an unchanged body in harmony with the changing universe.” He has +great power of adapting his habits to new conditions of life. He invents +weapons, tools, and various stratagems to procure food and to defend himself. +When he migrates into a colder climate he uses clothes, builds sheds, and makes +fires; and by the aid of fire cooks food otherwise indigestible. He aids his +fellow-men in many ways, and anticipates future events. Even at a remote period +he practised some division of labour. +</p> + +<p> +The lower animals, on the other hand, must have their bodily structure modified +in order to survive under greatly changed conditions. They must be rendered +stronger, or acquire more effective teeth or claws, for defence against new +enemies; or they must be reduced in size, so as to escape detection and danger. +When they migrate into a colder climate, they must become clothed with thicker +fur, or have their constitutions altered. If they fail to be thus modified, +they will cease to exist. +</p> + +<p> +The case, however, is widely different, as Mr. Wallace has with justice +insisted, in relation to the intellectual and moral faculties of man. These +faculties are variable; and we have every reason to believe that the variations +tend to be inherited. Therefore, if they were formerly of high importance to +primeval man and to his ape-like progenitors, they would have been perfected or +advanced through natural selection. Of the high importance of the intellectual +faculties there can be no doubt, for man mainly owes to them his predominant +position in the world. We can see, that in the rudest state of society, the +individuals who were the most sagacious, who invented and used the best weapons +or traps, and who were best able to defend themselves, would rear the greatest +number of offspring. The tribes, which included the largest number of men thus +endowed, would increase in number and supplant other tribes. Numbers depend +primarily on the means of subsistence, and this depends partly on the physical +nature of the country, but in a much higher degree on the arts which are there +practised. As a tribe increases and is victorious, it is often still further +increased by the absorption of other tribes. (2. After a time the members or +tribes which are absorbed into another tribe assume, as Sir Henry Maine remarks +(‘Ancient Law,’ 1861, p. 131), that they are the co-descendants of +the same ancestors.) The stature and strength of the men of a tribe are +likewise of some importance for its success, and these depend in part on the +nature and amount of the food which can be obtained. In Europe the men of the +Bronze period were supplanted by a race more powerful, and, judging from their +sword-handles, with larger hands (3. Morlot, ‘Soc. Vaud. Sc. Nat.’ +1860, p. 294.); but their success was probably still more due to their +superiority in the arts. +</p> + +<p> +All that we know about savages, or may infer from their traditions and from old +monuments, the history of which is quite forgotten by the present inhabitants, +shew that from the remotest times successful tribes have supplanted other +tribes. Relics of extinct or forgotten tribes have been discovered throughout +the civilised regions of the earth, on the wild plains of America, and on the +isolated islands in the Pacific Ocean. At the present day civilised nations are +everywhere supplanting barbarous nations, excepting where the climate opposes a +deadly barrier; and they succeed mainly, though not exclusively, through their +arts, which are the products of the intellect. It is, therefore, highly +probable that with mankind the intellectual faculties have been mainly and +gradually perfected through natural selection; and this conclusion is +sufficient for our purpose. Undoubtedly it would be interesting to trace the +development of each separate faculty from the state in which it exists in the +lower animals to that in which it exists in man; but neither my ability nor +knowledge permits the attempt. +</p> + +<p> +It deserves notice that, as soon as the progenitors of man became social (and +this probably occurred at a very early period), the principle of imitation, and +reason, and experience would have increased, and much modified the intellectual +powers in a way, of which we see only traces in the lower animals. Apes are +much given to imitation, as are the lowest savages; and the simple fact +previously referred to, that after a time no animal can be caught in the same +place by the same sort of trap, shews that animals learn by experience, and +imitate the caution of others. Now, if some one man in a tribe, more sagacious +than the others, invented a new snare or weapon, or other means of attack or +defence, the plainest self-interest, without the assistance of much reasoning +power, would prompt the other members to imitate him; and all would thus +profit. The habitual practice of each new art must likewise in some slight +degree strengthen the intellect. If the new invention were an important one, +the tribe would increase in number, spread, and supplant other tribes. In a +tribe thus rendered more numerous there would always be a rather greater chance +of the birth of other superior and inventive members. If such men left children +to inherit their mental superiority, the chance of the birth of still more +ingenious members would be somewhat better, and in a very small tribe decidedly +better. Even if they left no children, the tribe would still include their +blood-relations; and it has been ascertained by agriculturists (4. I have given +instances in my Variation of Animals under Domestication, vol. ii. p. 196.) +that by preserving and breeding from the family of an animal, which when +slaughtered was found to be valuable, the desired character has been obtained. +</p> + +<p> +Turning now to the social and moral faculties. In order that primeval men, or +the ape-like progenitors of man, should become social, they must have acquired +the same instinctive feelings, which impel other animals to live in a body; and +they no doubt exhibited the same general disposition. They would have felt +uneasy when separated from their comrades, for whom they would have felt some +degree of love; they would have warned each other of danger, and have given +mutual aid in attack or defence. All this implies some degree of sympathy, +fidelity, and courage. Such social qualities, the paramount importance of which +to the lower animals is disputed by no one, were no doubt acquired by the +progenitors of man in a similar manner, namely, through natural selection, +aided by inherited habit. When two tribes of primeval man, living in the same +country, came into competition, if (other circumstances being equal) the one +tribe included a great number of courageous, sympathetic and faithful members, +who were always ready to warn each other of danger, to aid and defend each +other, this tribe would succeed better and conquer the other. Let it be borne +in mind how all-important in the never-ceasing wars of savages, fidelity and +courage must be. The advantage which disciplined soldiers have over +undisciplined hordes follows chiefly from the confidence which each man feels +in his comrades. Obedience, as Mr. Bagehot has well shewn (5. See a remarkable +series of articles on ‘Physics and Politics,’ in the +‘Fortnightly Review,’ Nov. 1867; April 1, 1868; July 1, 1869, since +separately published.), is of the highest value, for any form of government is +better than none. Selfish and contentious people will not cohere, and without +coherence nothing can be effected. A tribe rich in the above qualities would +spread and be victorious over other tribes: but in the course of time it would, +judging from all past history, be in its turn overcome by some other tribe +still more highly endowed. Thus the social and moral qualities would tend +slowly to advance and be diffused throughout the world. +</p> + +<p> +But it may be asked, how within the limits of the same tribe did a large number +of members first become endowed with these social and moral qualities, and how +was the standard of excellence raised? It is extremely doubtful whether the +offspring of the more sympathetic and benevolent parents, or of those who were +the most faithful to their comrades, would be reared in greater numbers than +the children of selfish and treacherous parents belonging to the same tribe. He +who was ready to sacrifice his life, as many a savage has been, rather than +betray his comrades, would often leave no offspring to inherit his noble +nature. The bravest men, who were always willing to come to the front in war, +and who freely risked their lives for others, would on an average perish in +larger numbers than other men. Therefore, it hardly seems probable, that the +number of men gifted with such virtues, or that the standard of their +excellence, could be increased through natural selection, that is, by the +survival of the fittest; for we are not here speaking of one tribe being +victorious over another. +</p> + +<p> +Although the circumstances, leading to an increase in the number of those thus +endowed within the same tribe, are too complex to be clearly followed out, we +can trace some of the probable steps. In the first place, as the reasoning +powers and foresight of the members became improved, each man would soon learn +that if he aided his fellow-men, he would commonly receive aid in return. From +this low motive he might acquire the habit of aiding his fellows; and the habit +of performing benevolent actions certainly strengthens the feeling of sympathy +which gives the first impulse to benevolent actions. Habits, moreover, followed +during many generations probably tend to be inherited. +</p> + +<p> +But another and much more powerful stimulus to the development of the social +virtues, is afforded by the praise and the blame of our fellow-men. To the +instinct of sympathy, as we have already seen, it is primarily due, that we +habitually bestow both praise and blame on others, whilst we love the former +and dread the latter when applied to ourselves; and this instinct no doubt was +originally acquired, like all the other social instincts, through natural +selection. At how early a period the progenitors of man in the course of their +development, became capable of feeling and being impelled by, the praise or +blame of their fellow-creatures, we cannot of course say. But it appears that +even dogs appreciate encouragement, praise, and blame. The rudest savages feel +the sentiment of glory, as they clearly shew by preserving the trophies of +their prowess, by their habit of excessive boasting, and even by the extreme +care which they take of their personal appearance and decorations; for unless +they regarded the opinion of their comrades, such habits would be senseless. +</p> + +<p> +They certainly feel shame at the breach of some of their lesser rules, and +apparently remorse, as shewn by the case of the Australian who grew thin and +could not rest from having delayed to murder some other woman, so as to +propitiate his dead wife’s spirit. Though I have not met with any other +recorded case, it is scarcely credible that a savage, who will sacrifice his +life rather than betray his tribe, or one who will deliver himself up as a +prisoner rather than break his parole (6. Mr. Wallace gives cases in his +‘Contributions to the Theory of Natural Selection,’ 1870, p. 354.), +would not feel remorse in his inmost soul, if he had failed in a duty, which he +held sacred. +</p> + +<p> +We may therefore conclude that primeval man, at a very remote period, was +influenced by the praise and blame of his fellows. It is obvious, that the +members of the same tribe would approve of conduct which appeared to them to be +for the general good, and would reprobate that which appeared evil. To do good +unto others—to do unto others as ye would they should do unto +you—is the foundation-stone of morality. It is, therefore, hardly +possible to exaggerate the importance during rude times of the love of praise +and the dread of blame. A man who was not impelled by any deep, instinctive +feeling, to sacrifice his life for the good of others, yet was roused to such +actions by a sense of glory, would by his example excite the same wish for +glory in other men, and would strengthen by exercise the noble feeling of +admiration. He might thus do far more good to his tribe than by begetting +offspring with a tendency to inherit his own high character. +</p> + +<p> +With increased experience and reason, man perceives the more remote +consequences of his actions, and the self-regarding virtues, such as +temperance, chastity, etc., which during early times are, as we have before +seen, utterly disregarded, come to be highly esteemed or even held sacred. I +need not, however, repeat what I have said on this head in the fourth chapter. +Ultimately our moral sense or conscience becomes a highly complex +sentiment—originating in the social instincts, largely guided by the +approbation of our fellow-men, ruled by reason, self-interest, and in later +times by deep religious feelings, and confirmed by instruction and habit. +</p> + +<p> +It must not be forgotten that although a high standard of morality gives but a +slight or no advantage to each individual man and his children over the other +men of the same tribe, yet that an increase in the number of well-endowed men +and an advancement in the standard of morality will certainly give an immense +advantage to one tribe over another. A tribe including many members who, from +possessing in a high degree the spirit of patriotism, fidelity, obedience, +courage, and sympathy, were always ready to aid one another, and to sacrifice +themselves for the common good, would be victorious over most other tribes; and +this would be natural selection. At all times throughout the world tribes have +supplanted other tribes; and as morality is one important element in their +success, the standard of morality and the number of well-endowed men will thus +everywhere tend to rise and increase. +</p> + +<p> +It is, however, very difficult to form any judgment why one particular tribe +and not another has been successful and has risen in the scale of civilisation. +Many savages are in the same condition as when first discovered several +centuries ago. As Mr. Bagehot has remarked, we are apt to look at progress as +normal in human society; but history refutes this. The ancients did not even +entertain the idea, nor do the Oriental nations at the present day. According +to another high authority, Sir Henry Maine (7. ‘Ancient Law,’ 1861, +p. 22. For Mr. Bagehot’s remarks, ‘Fortnightly Review,’ April +1, 1868, p. 452.), “the greatest part of mankind has never shewn a +particle of desire that its civil institutions should be improved.” +Progress seems to depend on many concurrent favourable conditions, far too +complex to be followed out. But it has often been remarked, that a cool +climate, from leading to industry and to the various arts, has been highly +favourable thereto. The Esquimaux, pressed by hard necessity, have succeeded in +many ingenious inventions, but their climate has been too severe for continued +progress. Nomadic habits, whether over wide plains, or through the dense +forests of the tropics, or along the shores of the sea, have in every case been +highly detrimental. Whilst observing the barbarous inhabitants of Tierra del +Fuego, it struck me that the possession of some property, a fixed abode, and +the union of many families under a chief, were the indispensable requisites for +civilisation. Such habits almost necessitate the cultivation of the ground; and +the first steps in cultivation would probably result, as I have elsewhere shewn +(8. ‘The Variation of Animals and Plants under Domestication,’ vol. +i. p. 309.), from some such accident as the seeds of a fruit-tree falling on a +heap of refuse, and producing an unusually fine variety. The problem, however, +of the first advance of savages towards civilisation is at present much too +difficult to be solved. +</p> + +<h3>NATURAL SELECTION AS AFFECTING CIVILISED NATIONS.</h3> + +<p> +I have hitherto only considered the advancement of man from a semi-human +condition to that of the modern savage. But some remarks on the action of +natural selection on civilised nations may be worth adding. This subject has +been ably discussed by Mr. W.R. Greg (9. ‘Fraser’s Magazine,’ +Sept. 1868, p. 353. This article seems to have struck many persons, and has +given rise to two remarkable essays and a rejoinder in the +‘Spectator,’ Oct. 3rd and 17th, 1868. It has also been discussed in +the ‘Quarterly Journal of Science,’ 1869, p. 152, and by Mr. Lawson +Tait in the ‘Dublin Quarterly Journal of Medical Science,’ Feb. +1869, and by Mr. E. Ray Lankester in his ‘Comparative Longevity,’ +1870, p. 128. Similar views appeared previously in the +‘Australasian,’ July 13, 1867. I have borrowed ideas from several +of these writers.), and previously by Mr. Wallace and Mr. Galton. (10. For Mr. +Wallace, see ‘Anthropological Review,’ as before cited. Mr. Galton +in ‘Macmillan’s Magazine,’ Aug. 1865, p. 318; also his great +work, ‘Hereditary Genius,’ 1870.) Most of my remarks are taken from +these three authors. With savages, the weak in body or mind are soon +eliminated; and those that survive commonly exhibit a vigorous state of health. +We civilised men, on the other hand, do our utmost to check the process of +elimination; we build asylums for the imbecile, the maimed, and the sick; we +institute poor-laws; and our medical men exert their utmost skill to save the +life of every one to the last moment. There is reason to believe that +vaccination has preserved thousands, who from a weak constitution would +formerly have succumbed to small-pox. Thus the weak members of civilised +societies propagate their kind. No one who has attended to the breeding of +domestic animals will doubt that this must be highly injurious to the race of +man. It is surprising how soon a want of care, or care wrongly directed, leads +to the degeneration of a domestic race; but excepting in the case of man +himself, hardly any one is so ignorant as to allow his worst animals to breed. +</p> + +<p> +The aid which we feel impelled to give to the helpless is mainly an incidental +result of the instinct of sympathy, which was originally acquired as part of +the social instincts, but subsequently rendered, in the manner previously +indicated, more tender and more widely diffused. Nor could we check our +sympathy, even at the urging of hard reason, without deterioration in the +noblest part of our nature. The surgeon may harden himself whilst performing an +operation, for he knows that he is acting for the good of his patient; but if +we were intentionally to neglect the weak and helpless, it could only be for a +contingent benefit, with an overwhelming present evil. We must therefore bear +the undoubtedly bad effects of the weak surviving and propagating their kind; +but there appears to be at least one check in steady action, namely that the +weaker and inferior members of society do not marry so freely as the sound; and +this check might be indefinitely increased by the weak in body or mind +refraining from marriage, though this is more to be hoped for than expected. +</p> + +<p> +In every country in which a large standing army is kept up, the finest young +men are taken by the conscription or are enlisted. They are thus exposed to +early death during war, are often tempted into vice, and are prevented from +marrying during the prime of life. On the other hand the shorter and feebler +men, with poor constitutions, are left at home, and consequently have a much +better chance of marrying and propagating their kind. (11. Prof. H. Fick +(‘Einfluss der Naturwissenschaft auf das Recht,’ June 1872) has +some good remarks on this head, and on other such points.) +</p> + +<p> +Man accumulates property and bequeaths it to his children, so that the children +of the rich have an advantage over the poor in the race for success, +independently of bodily or mental superiority. On the other hand, the children +of parents who are short-lived, and are therefore on an average deficient in +health and vigour, come into their property sooner than other children, and +will be likely to marry earlier, and leave a larger number of offspring to +inherit their inferior constitutions. But the inheritance of property by itself +is very far from an evil; for without the accumulation of capital the arts +could not progress; and it is chiefly through their power that the civilised +races have extended, and are now everywhere extending their range, so as to +take the place of the lower races. Nor does the moderate accumulation of wealth +interfere with the process of selection. When a poor man becomes moderately +rich, his children enter trades or professions in which there is struggle +enough, so that the able in body and mind succeed best. The presence of a body +of well-instructed men, who have not to labour for their daily bread, is +important to a degree which cannot be over-estimated; as all high intellectual +work is carried on by them, and on such work, material progress of all kinds +mainly depends, not to mention other and higher advantages. No doubt wealth +when very great tends to convert men into useless drones, but their number is +never large; and some degree of elimination here occurs, for we daily see rich +men, who happen to be fools or profligate, squandering away their wealth. +</p> + +<p> +Primogeniture with entailed estates is a more direct evil, though it may +formerly have been a great advantage by the creation of a dominant class, and +any government is better than none. Most eldest sons, though they may be weak +in body or mind, marry, whilst the younger sons, however superior in these +respects, do not so generally marry. Nor can worthless eldest sons with +entailed estates squander their wealth. But here, as elsewhere, the relations +of civilised life are so complex that some compensatory checks intervene. The +men who are rich through primogeniture are able to select generation after +generation the more beautiful and charming women; and these must generally be +healthy in body and active in mind. The evil consequences, such as they may be, +of the continued preservation of the same line of descent, without any +selection, are checked by men of rank always wishing to increase their wealth +and power; and this they effect by marrying heiresses. But the daughters of +parents who have produced single children, are themselves, as Mr. Galton (12. +‘Hereditary Genius,’ 1870, pp. 132-140.) has shewn, apt to be +sterile; and thus noble families are continually cut off in the direct line, +and their wealth flows into some side channel; but unfortunately this channel +is not determined by superiority of any kind. +</p> + +<p> +Although civilisation thus checks in many ways the action of natural selection, +it apparently favours the better development of the body, by means of good food +and the freedom from occasional hardships. This may be inferred from civilised +men having been found, wherever compared, to be physically stronger than +savages. (13. Quatrefages, ‘Revue des Cours Scientifiques,’ +1867-68, p. 659.) They appear also to have equal powers of endurance, as has +been proved in many adventurous expeditions. Even the great luxury of the rich +can be but little detrimental; for the expectation of life of our aristocracy, +at all ages and of both sexes, is very little inferior to that of healthy +English lives in the lower classes. (14. See the fifth and sixth columns, +compiled from good authorities, in the table given in Mr. E.R. +Lankester’s ‘Comparative Longevity,’ 1870, p. 115.) +</p> + +<p> +We will now look to the intellectual faculties. If in each grade of society the +members were divided into two equal bodies, the one including the +intellectually superior and the other the inferior, there can be little doubt +that the former would succeed best in all occupations, and rear a greater +number of children. Even in the lowest walks of life, skill and ability must be +of some advantage; though in many occupations, owing to the great division of +labour, a very small one. Hence in civilised nations there will be some +tendency to an increase both in the number and in the standard of the +intellectually able. But I do not wish to assert that this tendency may not be +more than counterbalanced in other ways, as by the multiplication of the +reckless and improvident; but even to such as these, ability must be some +advantage. +</p> + +<p> +It has often been objected to views like the foregoing, that the most eminent +men who have ever lived have left no offspring to inherit their great +intellect. Mr. Galton says, “I regret I am unable to solve the simple +question whether, and how far, men and women who are prodigies of genius are +infertile. I have, however, shewn that men of eminence are by no means +so.” (15. ‘Hereditary Genius,’ 1870, p. 330.) Great +lawgivers, the founders of beneficent religions, great philosophers and +discoverers in science, aid the progress of mankind in a far higher degree by +their works than by leaving a numerous progeny. In the case of corporeal +structures, it is the selection of the slightly better-endowed and the +elimination of the slightly less well-endowed individuals, and not the +preservation of strongly-marked and rare anomalies, that leads to the +advancement of a species. (16. ‘Origin of Species’ (fifth edition, +1869), p. 104.) So it will be with the intellectual faculties, since the +somewhat abler men in each grade of society succeed rather better than the less +able, and consequently increase in number, if not otherwise prevented. When in +any nation the standard of intellect and the number of intellectual men have +increased, we may expect from the law of the deviation from an average, that +prodigies of genius will, as shewn by Mr. Galton, appear somewhat more +frequently than before. +</p> + +<p> +In regard to the moral qualities, some elimination of the worst dispositions is +always in progress even in the most civilised nations. Malefactors are +executed, or imprisoned for long periods, so that they cannot freely transmit +their bad qualities. Melancholic and insane persons are confined, or commit +suicide. Violent and quarrelsome men often come to a bloody end. The restless +who will not follow any steady occupation—and this relic of barbarism is +a great check to civilisation (17. ‘Hereditary Genius,’ 1870, p. +347.)—emigrate to newly-settled countries; where they prove useful +pioneers. Intemperance is so highly destructive, that the expectation of life +of the intemperate, at the age of thirty for instance, is only 13.8 years; +whilst for the rural labourers of England at the same age it is 40.59 years. +(18. E. Ray Lankester, ‘Comparative Longevity,’ 1870, p. 115. The +table of the intemperate is from Neison’s ‘Vital Statistics.’ +In regard to profligacy, see Dr. Farr, ‘Influence of Marriage on +Mortality,’ ‘Nat. Assoc. for the Promotion of Social +Science,’ 1858.) Profligate women bear few children, and profligate men +rarely marry; both suffer from disease. In the breeding of domestic animals, +the elimination of those individuals, though few in number, which are in any +marked manner inferior, is by no means an unimportant element towards success. +This especially holds good with injurious characters which tend to reappear +through reversion, such as blackness in sheep; and with mankind some of the +worst dispositions, which occasionally without any assignable cause make their +appearance in families, may perhaps be reversions to a savage state, from which +we are not removed by very many generations. This view seems indeed recognised +in the common expression that such men are the black sheep of the family. +</p> + +<p> +With civilised nations, as far as an advanced standard of morality, and an +increased number of fairly good men are concerned, natural selection apparently +effects but little; though the fundamental social instincts were originally +thus gained. But I have already said enough, whilst treating of the lower +races, on the causes which lead to the advance of morality, namely, the +approbation of our fellow-men—the strengthening of our sympathies by +habit—example and imitation—reason—experience, and even +self-interest—instruction during youth, and religious feelings. +</p> + +<p> +A most important obstacle in civilised countries to an increase in the number +of men of a superior class has been strongly insisted on by Mr. Greg and Mr. +Galton (19. ‘Fraser’s Magazine,’ Sept. 1868, p. 353. +‘Macmillan’s Magazine,’ Aug. 1865, p. 318. The Rev. F.W. +Farrar (‘Fraser’s Magazine,’ Aug. 1870, p. 264) takes a +different view.), namely, the fact that the very poor and reckless, who are +often degraded by vice, almost invariably marry early, whilst the careful and +frugal, who are generally otherwise virtuous, marry late in life, so that they +may be able to support themselves and their children in comfort. Those who +marry early produce within a given period not only a greater number of +generations, but, as shewn by Dr. Duncan (20. ‘On the Laws of the +Fertility of Women,’ in ‘Transactions of the Royal Society,’ +Edinburgh, vol. xxiv. p. 287; now published separately under the title of +‘Fecundity, Fertility, and Sterility,’ 1871. See, also, Mr. Galton, +‘Hereditary Genius,’ pp. 352-357, for observations to the above +effect.), they produce many more children. The children, moreover, that are +borne by mothers during the prime of life are heavier and larger, and therefore +probably more vigorous, than those born at other periods. Thus the reckless, +degraded, and often vicious members of society, tend to increase at a quicker +rate than the provident and generally virtuous members. Or as Mr. Greg puts the +case: “The careless, squalid, unaspiring Irishman multiplies like +rabbits: the frugal, foreseeing, self-respecting, ambitious Scot, stern in his +morality, spiritual in his faith, sagacious and disciplined in his +intelligence, passes his best years in struggle and in celibacy, marries late, +and leaves few behind him. Given a land originally peopled by a thousand Saxons +and a thousand Celts—and in a dozen generations five-sixths of the +population would be Celts, but five-sixths of the property, of the power, of +the intellect, would belong to the one-sixth of Saxons that remained. In the +eternal ‘struggle for existence,’ it would be the inferior and LESS +favoured race that had prevailed—and prevailed by virtue not of its good +qualities but of its faults.” +</p> + +<p> +There are, however, some checks to this downward tendency. We have seen that +the intemperate suffer from a high rate of mortality, and the extremely +profligate leave few offspring. The poorest classes crowd into towns, and it +has been proved by Dr. Stark from the statistics of ten years in Scotland (21. +‘Tenth Annual Report of Births, Deaths, etc., in Scotland,’ 1867, +p. xxix.), that at all ages the death-rate is higher in towns than in rural +districts, “and during the first five years of life the town death-rate +is almost exactly double that of the rural districts.” As these returns +include both the rich and the poor, no doubt more than twice the number of +births would be requisite to keep up the number of the very poor inhabitants in +the towns, relatively to those in the country. With women, marriage at too +early an age is highly injurious; for it has been found in France that, +“Twice as many wives under twenty die in the year, as died out of the +same number of the unmarried.” The mortality, also, of husbands under +twenty is “excessively high” (22. These quotations are taken from +our highest authority on such questions, namely, Dr. Farr, in his paper +‘On the Influence of Marriage on the Mortality of the French +People,’ read before the Nat. Assoc. for the Promotion of Social Science, +1858.), but what the cause of this may be, seems doubtful. Lastly, if the men +who prudently delay marrying until they can bring up their families in comfort, +were to select, as they often do, women in the prime of life, the rate of +increase in the better class would be only slightly lessened. +</p> + +<p> +It was established from an enormous body of statistics, taken during 1853, that +the unmarried men throughout France, between the ages of twenty and eighty, die +in a much larger proportion than the married: for instance, out of every 1000 +unmarried men, between the ages of twenty and thirty, 11.3 annually died, +whilst of the married, only 6.5 died. (23. Dr. Farr, ibid. The quotations given +below are extracted from the same striking paper.) A similar law was proved to +hold good, during the years 1863 and 1864, with the entire population above the +age of twenty in Scotland: for instance, out of every 1000 unmarried men, +between the ages of twenty and thirty, 14.97 annually died, whilst of the +married only 7.24 died, that is less than half. (24. I have taken the mean of +the quinquennial means, given in ‘The Tenth Annual Report of Births, +Deaths, etc., in Scotland,’ 1867. The quotation from Dr. Stark is copied +from an article in the ‘Daily News,’ Oct. 17, 1868, which Dr. Farr +considers very carefully written.) Dr. Stark remarks on this, +“Bachelorhood is more destructive to life than the most unwholesome +trades, or than residence in an unwholesome house or district where there has +never been the most distant attempt at sanitary improvement.” He +considers that the lessened mortality is the direct result of “marriage, +and the more regular domestic habits which attend that state.” He admits, +however, that the intemperate, profligate, and criminal classes, whose duration +of life is low, do not commonly marry; and it must likewise be admitted that +men with a weak constitution, ill health, or any great infirmity in body or +mind, will often not wish to marry, or will be rejected. Dr. Stark seems to +have come to the conclusion that marriage in itself is a main cause of +prolonged life, from finding that aged married men still have a considerable +advantage in this respect over the unmarried of the same advanced age; but +every one must have known instances of men, who with weak health during youth +did not marry, and yet have survived to old age, though remaining weak, and +therefore always with a lessened chance of life or of marrying. There is +another remarkable circumstance which seems to support Dr. Stark’s +conclusion, namely, that widows and widowers in France suffer in comparison +with the married a very heavy rate of mortality; but Dr. Farr attributes this +to the poverty and evil habits consequent on the disruption of the family, and +to grief. On the whole we may conclude with Dr. Farr that the lesser mortality +of married than of unmarried men, which seems to be a general law, “is +mainly due to the constant elimination of imperfect types, and to the skilful +selection of the finest individuals out of each successive generation;” +the selection relating only to the marriage state, and acting on all corporeal, +intellectual, and moral qualities. (25. Dr. Duncan remarks (‘Fecundity, +Fertility, etc.’ 1871, p. 334) on this subject: “At every age the +healthy and beautiful go over from the unmarried side to the married, leaving +the unmarried columns crowded with the sickly and unfortunate.”) We may, +therefore, infer that sound and good men who out of prudence remain for a time +unmarried, do not suffer a high rate of mortality. +</p> + +<p> +If the various checks specified in the two last paragraphs, and perhaps others +as yet unknown, do not prevent the reckless, the vicious and otherwise inferior +members of society from increasing at a quicker rate than the better class of +men, the nation will retrograde, as has too often occurred in the history of +the world. We must remember that progress is no invariable rule. It is very +difficult to say why one civilised nation rises, becomes more powerful, and +spreads more widely, than another; or why the same nation progresses more +quickly at one time than at another. We can only say that it depends on an +increase in the actual number of the population, on the number of men endowed +with high intellectual and moral faculties, as well as on their standard of +excellence. Corporeal structure appears to have little influence, except so far +as vigour of body leads to vigour of mind. +</p> + +<p> +It has been urged by several writers that as high intellectual powers are +advantageous to a nation, the old Greeks, who stood some grades higher in +intellect than any race that has ever existed (26. See the ingenious and +original argument on this subject by Mr. Galton, ‘Hereditary +Genius,’ pp. 340-342.), ought, if the power of natural selection were +real, to have risen still higher in the scale, increased in number, and stocked +the whole of Europe. Here we have the tacit assumption, so often made with +respect to corporeal structures, that there is some innate tendency towards +continued development in mind and body. But development of all kinds depends on +many concurrent favourable circumstances. Natural selection acts only +tentatively. Individuals and races may have acquired certain indisputable +advantages, and yet have perished from failing in other characters. The Greeks +may have retrograded from a want of coherence between the many small states, +from the small size of their whole country, from the practice of slavery, or +from extreme sensuality; for they did not succumb until “they were +enervated and corrupt to the very core.” (27. Mr. Greg, +‘Fraser’s Magazine,’ Sept. 1868, p. 357.) The western nations +of Europe, who now so immeasurably surpass their former savage progenitors, and +stand at the summit of civilisation, owe little or none of their superiority to +direct inheritance from the old Greeks, though they owe much to the written +works of that wonderful people. +</p> + +<p> +Who can positively say why the Spanish nation, so dominant at one time, has +been distanced in the race. The awakening of the nations of Europe from the +dark ages is a still more perplexing problem. At that early period, as Mr. +Galton has remarked, almost all the men of a gentle nature, those given to +meditation or culture of the mind, had no refuge except in the bosom of a +Church which demanded celibacy (28. ‘Hereditary Genius,’ 1870, pp. +357-359. The Rev. F.W. Farrar (‘Fraser’s Magazine,’ Aug. +1870, p. 257) advances arguments on the other side. Sir C. Lyell had already +(‘Principles of Geology,’ vol. ii. 1868, p. 489), in a striking +passage called attention to the evil influence of the Holy Inquisition in +having, through selection, lowered the general standard of intelligence in +Europe.); and this could hardly fail to have had a deteriorating influence on +each successive generation. During this same period the Holy Inquisition +selected with extreme care the freest and boldest men in order to burn or +imprison them. In Spain alone some of the best men—those who doubted and +questioned, and without doubting there can be no progress—were eliminated +during three centuries at the rate of a thousand a year. The evil which the +Catholic Church has thus effected is incalculable, though no doubt +counterbalanced to a certain, perhaps to a large, extent in other ways; +nevertheless, Europe has progressed at an unparalleled rate. +</p> + +<p> +The remarkable success of the English as colonists, compared to other European +nations, has been ascribed to their “daring and persistent energy”; +a result which is well illustrated by comparing the progress of the Canadians +of English and French extraction; but who can say how the English gained their +energy? There is apparently much truth in the belief that the wonderful +progress of the United States, as well as the character of the people, are the +results of natural selection; for the more energetic, restless, and courageous +men from all parts of Europe have emigrated during the last ten or twelve +generations to that great country, and have there succeeded best. (29. Mr. +Galton, ‘Macmillan’s Magazine,’ August 1865, p. 325. See +also, ‘Nature,’ ‘On Darwinism and National Life,’ Dec. +1869, p. 184.) Looking to the distant future, I do not think that the Rev. Mr. +Zincke takes an exaggerated view when he says (30. ‘Last Winter in the +United States,’ 1868, p. 29.): “All other series of events—as +that which resulted in the culture of mind in Greece, and that which resulted +in the empire of Rome—only appear to have purpose and value when viewed +in connection with, or rather as subsidiary to...the great stream of +Anglo-Saxon emigration to the west.” Obscure as is the problem of the +advance of civilisation, we can at least see that a nation which produced +during a lengthened period the greatest number of highly intellectual, +energetic, brave, patriotic, and benevolent men, would generally prevail over +less favoured nations. +</p> + +<p> +Natural selection follows from the struggle for existence; and this from a +rapid rate of increase. It is impossible not to regret bitterly, but whether +wisely is another question, the rate at which man tends to increase; for this +leads in barbarous tribes to infanticide and many other evils, and in civilised +nations to abject poverty, celibacy, and to the late marriages of the prudent. +But as man suffers from the same physical evils as the lower animals, he has no +right to expect an immunity from the evils consequent on the struggle for +existence. Had he not been subjected during primeval times to natural +selection, assuredly he would never have attained to his present rank. Since we +see in many parts of the world enormous areas of the most fertile land capable +of supporting numerous happy homes, but peopled only by a few wandering +savages, it might be argued that the struggle for existence had not been +sufficiently severe to force man upwards to his highest standard. Judging from +all that we know of man and the lower animals, there has always been sufficient +variability in their intellectual and moral faculties, for a steady advance +through natural selection. No doubt such advance demands many favourable +concurrent circumstances; but it may well be doubted whether the most +favourable would have sufficed, had not the rate of increase been rapid, and +the consequent struggle for existence extremely severe. It even appears from +what we see, for instance, in parts of S. America, that a people which may be +called civilised, such as the Spanish settlers, is liable to become indolent +and to retrograde, when the conditions of life are very easy. With highly +civilised nations continued progress depends in a subordinate degree on natural +selection; for such nations do not supplant and exterminate one another as do +savage tribes. Nevertheless the more intelligent members within the same +community will succeed better in the long run than the inferior, and leave a +more numerous progeny, and this is a form of natural selection. The more +efficient causes of progress seem to consist of a good education during youth +whilst the brain is impressible, and of a high standard of excellence, +inculcated by the ablest and best men, embodied in the laws, customs and +traditions of the nation, and enforced by public opinion. It should, however, +be borne in mind, that the enforcement of public opinion depends on our +appreciation of the approbation and disapprobation of others; and this +appreciation is founded on our sympathy, which it can hardly be doubted was +originally developed through natural selection as one of the most important +elements of the social instincts. (31. I am much indebted to Mr. John Morley +for some good criticisms on this subject: see, also Broca, ‘Les +Selections,’ ‘Revue d’Anthropologie,’ 1872.) +</p> + +<h3>ON THE EVIDENCE THAT ALL CIVILISED NATIONS WERE ONCE BARBAROUS.</h3> + +<p> +The present subject has been treated in so full and admirable a manner by Sir +J. Lubbock (32. ‘On the Origin of Civilisation,’ ‘Proceedings +of the Ethnological Society,’ Nov. 26, 1867.), Mr. Tylor, Mr. +M’Lennan, and others, that I need here give only the briefest summary of +their results. The arguments recently advanced by the Duke of Argyll (33. +‘Primeval Man,’ 1869.) and formerly by Archbishop Whately, in +favour of the belief that man came into the world as a civilised being, and +that all savages have since undergone degradation, seem to me weak in +comparison with those advanced on the other side. Many nations, no doubt, have +fallen away in civilisation, and some may have lapsed into utter barbarism, +though on this latter head I have met with no evidence. The Fuegians were +probably compelled by other conquering hordes to settle in their inhospitable +country, and they may have become in consequence somewhat more degraded; but it +would be difficult to prove that they have fallen much below the Botocudos, who +inhabit the finest parts of Brazil. +</p> + +<p> +The evidence that all civilised nations are the descendants of barbarians, +consists, on the one side, of clear traces of their former low condition in +still-existing customs, beliefs, language, etc.; and on the other side, of +proofs that savages are independently able to raise themselves a few steps in +the scale of civilisation, and have actually thus risen. The evidence on the +first head is extremely curious, but cannot be here given: I refer to such +cases as that of the art of enumeration, which, as Mr. Tylor clearly shews by +reference to the words still used in some places, originated in counting the +fingers, first of one hand and then of the other, and lastly of the toes. We +have traces of this in our own decimal system, and in the Roman numerals, +where, after the V, which is supposed to be an abbreviated picture of a human +hand, we pass on to VI, etc., when the other hand no doubt was used. So again, +“when we speak of three-score and ten, we are counting by the vigesimal +system, each score thus ideally made, standing for 20—for ‘one +man’ as a Mexican or Carib would put it.” (34. ‘Royal +Institution of Great Britain,’ March 15, 1867. Also, ‘Researches +into the Early History of Mankind,’ 1865.) According to a large and +increasing school of philologists, every language bears the marks of its slow +and gradual evolution. So it is with the art of writing, for letters are +rudiments of pictorial representations. It is hardly possible to read Mr. +M’Lennan’s work (35. ‘Primitive Marriage,’ 1865. See, +likewise, an excellent article, evidently by the same author, in the +‘North British Review,’ July 1869. Also, Mr. L.H. Morgan, ‘A +Conjectural Solution of the Origin of the Class. System of Relationship,’ +in ‘Proc. American Acad. of Sciences,’ vol. vii. Feb. 1868. Prof. +Schaaffhausen (‘Anthropolog. Review,’ Oct. 1869, p. 373) remarks on +“the vestiges of human sacrifices found both in Homer and the Old +Testament.”) and not admit that almost all civilised nations still retain +traces of such rude habits as the forcible capture of wives. What ancient +nation, as the same author asks, can be named that was originally monogamous? +The primitive idea of justice, as shewn by the law of battle and other customs +of which vestiges still remain, was likewise most rude. Many existing +superstitions are the remnants of former false religious beliefs. The highest +form of religion—the grand idea of God hating sin and loving +righteousness—was unknown during primeval times. +</p> + +<p> +Turning to the other kind of evidence: Sir J. Lubbock has shewn that some +savages have recently improved a little in some of their simpler arts. From the +extremely curious account which he gives of the weapons, tools, and arts, in +use amongst savages in various parts of the world, it cannot be doubted that +these have nearly all been independent discoveries, excepting perhaps the art +of making fire. (36. Sir J. Lubbock, ‘Prehistoric Times,’ 2nd edit. +1869, chaps. xv. and xvi. et passim. See also the excellent 9th Chapter in +Tylor’s ‘Early History of Mankind,’ 2nd edit., 1870.) The +Australian boomerang is a good instance of one such independent discovery. The +Tahitians when first visited had advanced in many respects beyond the +inhabitants of most of the other Polynesian islands. There are no just grounds +for the belief that the high culture of the native Peruvians and Mexicans was +derived from abroad (37. Dr. F. Müller has made some good remarks to this +effect in the ‘Reise der Novara: Anthropolog. Theil,’ Abtheil. iii. +1868, s. 127.); many native plants were there cultivated, and a few native +animals domesticated. We should bear in mind that, judging from the small +influence of most missionaries, a wandering crew from some semi-civilised land, +if washed to the shores of America, would not have produced any marked effect +on the natives, unless they had already become somewhat advanced. Looking to a +very remote period in the history of the world, we find, to use Sir J. +Lubbock’s well-known terms, a paleolithic and neolithic period; and no +one will pretend that the art of grinding rough flint tools was a borrowed one. +In all parts of Europe, as far east as Greece, in Palestine, India, Japan, New +Zealand, and Africa, including Egypt, flint tools have been discovered in +abundance; and of their use the existing inhabitants retain no tradition. There +is also indirect evidence of their former use by the Chinese and ancient Jews. +Hence there can hardly be a doubt that the inhabitants of these countries, +which include nearly the whole civilised world, were once in a barbarous +condition. To believe that man was aboriginally civilised and then suffered +utter degradation in so many regions, is to take a pitiably low view of human +nature. It is apparently a truer and more cheerful view that progress has been +much more general than retrogression; that man has risen, though by slow and +interrupted steps, from a lowly condition to the highest standard as yet +attained by him in knowledge, morals and religion. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0006" id="link2HCH0006"></a> +CHAPTER VI.<br /> +ON THE AFFINITIES AND GENEALOGY OF MAN.</h2> + +<p class="letter"> +Position of man in the animal series—The natural system +genealogical—Adaptive characters of slight value—Various small +points of resemblance between man and the Quadrumana—Rank of man in the +natural system—Birthplace and antiquity of man—Absence of fossil +connecting links—Lower stages in the genealogy of man, as inferred, +firstly from his affinities and secondly from his structure—Early +androgynous condition of the Vertebrata—Conclusion. +</p> + +<p> +Even if it be granted that the difference between man and his nearest allies is +as great in corporeal structure as some naturalists maintain, and although we +must grant that the difference between them is immense in mental power, yet the +facts given in the earlier chapters appear to declare, in the plainest manner, +that man is descended from some lower form, notwithstanding that +connecting-links have not hitherto been discovered. +</p> + +<p> +Man is liable to numerous, slight, and diversified variations, which are +induced by the same general causes, are governed and transmitted in accordance +with the same general laws, as in the lower animals. Man has multiplied so +rapidly, that he has necessarily been exposed to struggle for existence, and +consequently to natural selection. He has given rise to many races, some of +which differ so much from each other, that they have often been ranked by +naturalists as distinct species. His body is constructed on the same +homological plan as that of other mammals. He passes through the same phases of +embryological development. He retains many rudimentary and useless structures, +which no doubt were once serviceable. Characters occasionally make their +re-appearance in him, which we have reason to believe were possessed by his +early progenitors. If the origin of man had been wholly different from that of +all other animals, these various appearances would be mere empty deceptions; +but such an admission is incredible. These appearances, on the other hand, are +intelligible, at least to a large extent, if man is the co-descendant with +other mammals of some unknown and lower form. +</p> + +<p> +Some naturalists, from being deeply impressed with the mental and spiritual +powers of man, have divided the whole organic world into three kingdoms, the +Human, the Animal, and the Vegetable, thus giving to man a separate kingdom. +(1. Isidore Geoffroy St.-Hilaire gives a detailed account of the position +assigned to man by various naturalists in their classifications: ‘Hist. +Nat. Gen.’ tom. ii. 1859, pp. 170-189.) Spiritual powers cannot be +compared or classed by the naturalist: but he may endeavour to shew, as I have +done, that the mental faculties of man and the lower animals do not differ in +kind, although immensely in degree. A difference in degree, however great, does +not justify us in placing man in a distinct kingdom, as will perhaps be best +illustrated by comparing the mental powers of two insects, namely, a coccus or +scale-insect and an ant, which undoubtedly belong to the same class. The +difference is here greater than, though of a somewhat different kind from, that +between man and the highest mammal. The female coccus, whilst young, attaches +itself by its proboscis to a plant; sucks the sap, but never moves again; is +fertilised and lays eggs; and this is its whole history. On the other hand, to +describe the habits and mental powers of worker-ants, would require, as Pierre +Huber has shewn, a large volume; I may, however, briefly specify a few points. +Ants certainly communicate information to each other, and several unite for the +same work, or for games of play. They recognise their fellow-ants after months +of absence, and feel sympathy for each other. They build great edifices, keep +them clean, close the doors in the evening, and post sentries. They make roads +as well as tunnels under rivers, and temporary bridges over them, by clinging +together. They collect food for the community, and when an object, too large +for entrance, is brought to the nest, they enlarge the door, and afterwards +build it up again. They store up seeds, of which they prevent the germination, +and which, if damp, are brought up to the surface to dry. They keep aphides and +other insects as milch-cows. They go out to battle in regular bands, and freely +sacrifice their lives for the common weal. They emigrate according to a +preconcerted plan. They capture slaves. They move the eggs of their aphides, as +well as their own eggs and cocoons, into warm parts of the nest, in order that +they may be quickly hatched; and endless similar facts could be given. (2. Some +of the most interesting facts ever published on the habits of ants are given by +Mr. Belt, in his ‘Naturalist in Nicaragua,’ 1874. See also Mr. +Moggridge’s admirable work, ‘Harvesting Ants,’ etc., 1873, +also ‘L’Instinct chez les Insectes,’ by M. George Pouchet, +‘Revue des Deux Mondes,’ Feb. 1870, p. 682.) On the whole, the +difference in mental power between an ant and a coccus is immense; yet no one +has ever dreamed of placing these insects in distinct classes, much less in +distinct kingdoms. No doubt the difference is bridged over by other insects; +and this is not the case with man and the higher apes. But we have every reason +to believe that the breaks in the series are simply the results of many forms +having become extinct. +</p> + +<p> +Professor Owen, relying chiefly on the structure of the brain, has divided the +mammalian series into four sub-classes. One of these he devotes to man; in +another he places both the marsupials and the Monotremata; so that he makes man +as distinct from all other mammals as are these two latter groups conjoined. +This view has not been accepted, as far as I am aware, by any naturalist +capable of forming an independent judgment, and therefore need not here be +further considered. +</p> + +<p> +We can understand why a classification founded on any single character or +organ—even an organ so wonderfully complex and important as the +brain—or on the high development of the mental faculties, is almost sure +to prove unsatisfactory. This principle has indeed been tried with +hymenopterous insects; but when thus classed by their habits or instincts, the +arrangement proved thoroughly artificial. (3. Westwood, ‘Modern +Classification of Insects,’ vol. ii. 1840, p. 87.) Classifications may, +of course, be based on any character whatever, as on size, colour, or the +element inhabited; but naturalists have long felt a profound conviction that +there is a natural system. This system, it is now generally admitted, must be, +as far as possible, genealogical in arrangement,—that is, the +co-descendants of the same form must be kept together in one group, apart from +the co-descendants of any other form; but if the parent-forms are related, so +will be their descendants, and the two groups together will form a larger +group. The amount of difference between the several groups—that is the +amount of modification which each has undergone—is expressed by such +terms as genera, families, orders, and classes. As we have no record of the +lines of descent, the pedigree can be discovered only by observing the degrees +of resemblance between the beings which are to be classed. For this object +numerous points of resemblance are of much more importance than the amount of +similarity or dissimilarity in a few points. If two languages were found to +resemble each other in a multitude of words and points of construction, they +would be universally recognised as having sprung from a common source, +notwithstanding that they differed greatly in some few words or points of +construction. But with organic beings the points of resemblance must not +consist of adaptations to similar habits of life: two animals may, for +instance, have had their whole frames modified for living in the water, and yet +they will not be brought any nearer to each other in the natural system. Hence +we can see how it is that resemblances in several unimportant structures, in +useless and rudimentary organs, or not now functionally active, or in an +embryological condition, are by far the most serviceable for classification; +for they can hardly be due to adaptations within a late period; and thus they +reveal the old lines of descent or of true affinity. +</p> + +<p> +We can further see why a great amount of modification in some one character +ought not to lead us to separate widely any two organisms. A part which already +differs much from the same part in other allied forms has already, according to +the theory of evolution, varied much; consequently it would (as long as the +organism remained exposed to the same exciting conditions) be liable to further +variations of the same kind; and these, if beneficial, would be preserved, and +thus be continually augmented. In many cases the continued development of a +part, for instance, of the beak of a bird, or of the teeth of a mammal, would +not aid the species in gaining its food, or for any other object; but with man +we can see no definite limit to the continued development of the brain and +mental faculties, as far as advantage is concerned. Therefore in determining +the position of man in the natural or genealogical system, the extreme +development of his brain ought not to outweigh a multitude of resemblances in +other less important or quite unimportant points. +</p> + +<p> +The greater number of naturalists who have taken into consideration the whole +structure of man, including his mental faculties, have followed Blumenbach and +Cuvier, and have placed man in a separate Order, under the title of the Bimana, +and therefore on an equality with the orders of the Quadrumana, Carnivora, etc. +Recently many of our best naturalists have recurred to the view first +propounded by Linnaeus, so remarkable for his sagacity, and have placed man in +the same Order with the Quadrumana, under the title of the Primates. The +justice of this conclusion will be admitted: for in the first place, we must +bear in mind the comparative insignificance for classification of the great +development of the brain in man, and that the strongly-marked differences +between the skulls of man and the Quadrumana (lately insisted upon by Bischoff, +Aeby, and others) apparently follow from their differently developed brains. In +the second place, we must remember that nearly all the other and more important +differences between man and the Quadrumana are manifestly adaptive in their +nature, and relate chiefly to the erect position of man; such as the structure +of his hand, foot, and pelvis, the curvature of his spine, and the position of +his head. The family of Seals offers a good illustration of the small +importance of adaptive characters for classification. These animals differ from +all other Carnivora in the form of their bodies and in the structure of their +limbs, far more than does man from the higher apes; yet in most systems, from +that of Cuvier to the most recent one by Mr. Flower (4. ‘Proceedings +Zoological Society,’ 1863, p. 4.), seals are ranked as a mere family in +the Order of the Carnivora. If man had not been his own classifier, he would +never have thought of founding a separate order for his own reception. +</p> + +<p> +It would be beyond my limits, and quite beyond my knowledge, even to name the +innumerable points of structure in which man agrees with the other Primates. +Our great anatomist and philosopher, Prof. Huxley, has fully discussed this +subject (5. ‘Evidence as to Man’s Place in Nature,’ 1863, p. +70, et passim.), and concludes that man in all parts of his organization +differs less from the higher apes, than these do from the lower members of the +same group. Consequently there “is no justification for placing man in a +distinct order.” +</p> + +<p> +In an early part of this work I brought forward various facts, shewing how +closely man agrees in constitution with the higher mammals; and this agreement +must depend on our close similarity in minute structure and chemical +composition. I gave, as instances, our liability to the same diseases, and to +the attacks of allied parasites; our tastes in common for the same stimulants, +and the similar effects produced by them, as well as by various drugs, and +other such facts. +</p> + +<p> +As small unimportant points of resemblance between man and the Quadrumana are +not commonly noticed in systematic works, and as, when numerous, they clearly +reveal our relationship, I will specify a few such points. The relative +position of our features is manifestly the same; and the various emotions are +displayed by nearly similar movements of the muscles and skin, chiefly above +the eyebrows and round the mouth. Some few expressions are, indeed, almost the +same, as in the weeping of certain kinds of monkeys and in the laughing noise +made by others, during which the corners of the mouth are drawn backwards, and +the lower eyelids wrinkled. The external ears are curiously alike. In man the +nose is much more prominent than in most monkeys; but we may trace the +commencement of an aquiline curvature in the nose of the Hoolock Gibbon; and +this in the Semnopithecus nasica is carried to a ridiculous extreme. +</p> + +<p> +The faces of many monkeys are ornamented with beards, whiskers, or moustaches. +The hair on the head grows to a great length in some species of Semnopithecus +(6. Isidore Geoffroy St.-Hilaire, ‘Hist. Nat. Gen.’ tom. ii. 1859, +p. 217.); and in the Bonnet monkey (Macacus radiatus) it radiates from a point +on the crown, with a parting down the middle. It is commonly said that the +forehead gives to man his noble and intellectual appearance; but the thick hair +on the head of the Bonnet monkey terminates downwards abruptly, and is +succeeded by hair so short and fine that at a little distance the forehead, +with the exception of the eyebrows, appears quite naked. It has been +erroneously asserted that eyebrows are not present in any monkey. In the +species just named the degree of nakedness of the forehead differs in different +individuals; and Eschricht states (7. ‘Über die Richtung der +Haare,’ etc., Müller’s ‘Archiv fur Anat. und Phys.’ +1837, s. 51.) that in our children the limit between the hairy scalp and the +naked forehead is sometimes not well defined; so that here we seem to have a +trifling case of reversion to a progenitor, in whom the forehead had not as yet +become quite naked. +</p> + +<p> +It is well known that the hair on our arms tends to converge from above and +below to a point at the elbow. This curious arrangement, so unlike that in most +of the lower mammals, is common to the gorilla, chimpanzee, orang, some species +of Hylobates, and even to some few American monkeys. But in Hylobates agilis +the hair on the fore-arm is directed downwards or towards the wrist in the +ordinary manner; and in H. lar it is nearly erect, with only a very slight +forward inclination; so that in this latter species it is in a transitional +state. It can hardly be doubted that with most mammals the thickness of the +hair on the back and its direction, is adapted to throw off the rain; even the +transverse hairs on the fore-legs of a dog may serve for this end when he is +coiled up asleep. Mr. Wallace, who has carefully studied the habits of the +orang, remarks that the convergence of the hair towards the elbow on the arms +of the orang may be explained as serving to throw off the rain, for this animal +during rainy weather sits with its arms bent, and with the hands clasped round +a branch or over its head. According to Livingstone, the gorilla also +“sits in pelting rain with his hands over his head.” (8. Quoted by +Reade, ‘The African Sketch Book,’ vol i. 1873, p. 152.) If the +above explanation is correct, as seems probable, the direction of the hair on +our own arms offers a curious record of our former state; for no one supposes +that it is now of any use in throwing off the rain; nor, in our present erect +condition, is it properly directed for this purpose. +</p> + +<p> +It would, however, be rash to trust too much to the principle of adaptation in +regard to the direction of the hair in man or his early progenitors; for it is +impossible to study the figures given by Eschricht of the arrangement of the +hair on the human foetus (this being the same as in the adult) and not agree +with this excellent observer that other and more complex causes have +intervened. The points of convergence seem to stand in some relation to those +points in the embryo which are last closed in during development. There +appears, also, to exist some relation between the arrangement of the hair on +the limbs, and the course of the medullary arteries. (9. On the hair in +Hylobates, see ‘Natural History of Mammals,’ by C.L. Martin, 1841, +p. 415. Also, Isidore Geoffroy on the American monkeys and other kinds, +‘Hist. Nat. Gen.’ vol. ii. 1859, pp. 216, 243. Eschricht, ibid. s. +46, 55, 61. Owen, ‘Anatomy of Vertebrates,’ vol. iii. p. 619. +Wallace, ‘Contributions to the Theory of Natural Selection,’ 1870, +p. 344.) +</p> + +<p> +It must not be supposed that the resemblances between man and certain apes in +the above and in many other points—such as in having a naked forehead, +long tresses on the head, etc.,—are all necessarily the result of +unbroken inheritance from a common progenitor, or of subsequent reversion. Many +of these resemblances are more probably due to analogous variation, which +follows, as I have elsewhere attempted to shew (10. ‘Origin of +Species,’ 5th edit. 1869, p.194. ‘The Variation of Animals and +Plants under Domestication,’ vol. ii. 1868, p. 348.), from co-descended +organisms having a similar constitution, and having been acted on by like +causes inducing similar modifications. With respect to the similar direction of +the hair on the fore-arms of man and certain monkeys, as this character is +common to almost all the anthropomorphous apes, it may probably be attributed +to inheritance; but this is not certain, as some very distinct American monkeys +are thus characterised. +</p> + +<p> +Although, as we have now seen, man has no just right to form a separate Order +for his own reception, he may perhaps claim a distinct Sub-order or Family. +Prof. Huxley, in his last work (11. ‘An Introduction to the +Classification of Animals,’ 1869, p. 99.), divides the primates into +three Sub-orders; namely, the Anthropidae with man alone, the Simiadae +including monkeys of all kinds, and the Lemuridae with the diversified genera +of lemurs. As far as differences in certain important points of structure are +concerned, man may no doubt rightly claim the rank of a Sub-order; and this +rank is too low, if we look chiefly to his mental faculties. Nevertheless, from +a genealogical point of view it appears that this rank is too high, and that +man ought to form merely a Family, or possibly even only a Sub-family. If we +imagine three lines of descent proceeding from a common stock, it is quite +conceivable that two of them might after the lapse of ages be so slightly +changed as still to remain as species of the same genus, whilst the third line +might become so greatly modified as to deserve to rank as a distinct +Sub-family, Family, or even Order. But in this case it is almost certain that +the third line would still retain through inheritance numerous small points of +resemblance with the other two. Here, then, would occur the difficulty, at +present insoluble, how much weight we ought to assign in our classifications to +strongly-marked differences in some few points,—that is, to the amount of +modification undergone; and how much to close resemblance in numerous +unimportant points, as indicating the lines of descent or genealogy. To attach +much weight to the few but strong differences is the most obvious and perhaps +the safest course, though it appears more correct to pay great attention to the +many small resemblances, as giving a truly natural classification. +</p> + +<p> +In forming a judgment on this head with reference to man, we must glance at the +classification of the Simiadae. This family is divided by almost all +naturalists into the Catarrhine group, or Old World monkeys, all of which are +characterised (as their name expresses) by the peculiar structure of their +nostrils, and by having four premolars in each jaw; and into the Platyrrhine +group or New World monkeys (including two very distinct sub-groups), all of +which are characterised by differently constructed nostrils, and by having six +premolars in each jaw. Some other small differences might be mentioned. Now man +unquestionably belongs in his dentition, in the structure of his nostrils, and +some other respects, to the Catarrhine or Old World division; nor does he +resemble the Platyrrhines more closely than the Catarrhines in any characters, +excepting in a few of not much importance and apparently of an adaptive nature. +It is therefore against all probability that some New World species should have +formerly varied and produced a man-like creature, with all the distinctive +characters proper to the Old World division; losing at the same time all its +own distinctive characters. There can, consequently, hardly be a doubt that man +is an off-shoot from the Old World Simian stem; and that under a genealogical +point of view he must be classed with the Catarrhine division. (12. This is +nearly the same classification as that provisionally adopted by Mr. St. George +Mivart, (‘Transactions, Philosophical Society,” 1867, p. 300), who, +after separating the Lemuridae, divides the remainder of the Primates into the +Hominidae, the Simiadae which answer to the Catarrhines, the Cebidae, and the +Hapalidae,—these two latter groups answering to the Platyrrhines. Mr. +Mivart still abides by the same view; see ‘Nature,’ 1871, p. 481.) +</p> + +<p> +The anthropomorphous apes, namely the gorilla, chimpanzee, orang, and +hylobates, are by most naturalists separated from the other Old World monkeys, +as a distinct sub-group. I am aware that Gratiolet, relying on the structure of +the brain, does not admit the existence of this sub-group, and no doubt it is a +broken one. Thus the orang, as Mr. St. G. Mivart remarks, “is one of the +most peculiar and aberrant forms to be found in the Order.” (13. +‘Transactions, Zoolog. Soc.’ vol. vi. 1867, p. 214.) The remaining +non-anthropomorphous Old World monkeys, are again divided by some naturalists +into two or three smaller sub-groups; the genus Semnopithecus, with its +peculiar sacculated stomach, being the type of one sub-group. But it appears +from M. Gaudry’s wonderful discoveries in Attica, that during the Miocene +period a form existed there, which connected Semnopithecus and Macacus; and +this probably illustrates the manner in which the other and higher groups were +once blended together. +</p> + +<p> +If the anthropomorphous apes be admitted to form a natural sub-group, then as +man agrees with them, not only in all those characters which he possesses in +common with the whole Catarrhine group, but in other peculiar characters, such +as the absence of a tail and of callosities, and in general appearance, we may +infer that some ancient member of the anthropomorphous sub-group gave birth to +man. It is not probable that, through the law of analogous variation, a member +of one of the other lower sub-groups should have given rise to a man-like +creature, resembling the higher anthropomorphous apes in so many respects. No +doubt man, in comparison with most of his allies, has undergone an +extraordinary amount of modification, chiefly in consequence of the great +development of his brain and his erect position; nevertheless, we should bear +in mind that he “is but one of several exceptional forms of +Primates.” (14. Mr. St. G. Mivart, ‘Transactions of the +Philosophical Society,’ 1867, p. 410.) +</p> + +<p> +Every naturalist, who believes in the principle of evolution, will grant that +the two main divisions of the Simiadae, namely the Catarrhine and Platyrrhine +monkeys, with their sub-groups, have all proceeded from some one extremely +ancient progenitor. The early descendants of this progenitor, before they had +diverged to any considerable extent from each other, would still have formed a +single natural group; but some of the species or incipient genera would have +already begun to indicate by their diverging characters the future distinctive +marks of the Catarrhine and Platyrrhine divisions. Hence the members of this +supposed ancient group would not have been so uniform in their dentition, or in +the structure of their nostrils, as are the existing Catarrhine monkeys in one +way and the Platyrrhines in another way, but would have resembled in this +respect the allied Lemuridae, which differ greatly from each other in the form +of their muzzles (15. Messrs. Murie and Mivart on the Lemuroidea, +‘Transactions, Zoological Society,’ vol. vii, 1869, p. 5.), and to +an extraordinary degree in their dentition. +</p> + +<p> +The Catarrhine and Platyrrhine monkeys agree in a multitude of characters, as +is shewn by their unquestionably belonging to one and the same Order. The many +characters which they possess in common can hardly have been independently +acquired by so many distinct species; so that these characters must have been +inherited. But a naturalist would undoubtedly have ranked as an ape or a +monkey, an ancient form which possessed many characters common to the +Catarrhine and Platyrrhine monkeys, other characters in an intermediate +condition, and some few, perhaps, distinct from those now found in either +group. And as man from a genealogical point of view belongs to the Catarrhine +or Old World stock, we must conclude, however much the conclusion may revolt +our pride, that our early progenitors would have been properly thus designated. +(16. Haeckel has come to this same conclusion. See ‘Über die Entstehung +des Menschengeschlechts,’ in Virchow’s ‘Sammlung. gemein. +wissen. Vorträge,’ 1868, s. 61. Also his ‘Natürliche +Schöpfungsgeschichte,’ 1868, in which he gives in detail his views on the +genealogy of man.) But we must not fall into the error of supposing that the +early progenitor of the whole Simian stock, including man, was identical with, +or even closely resembled, any existing ape or monkey. +</p> + +<h3>ON THE BIRTHPLACE AND ANTIQUITY OF MAN.</h3> + +<p> +We are naturally led to enquire, where was the birthplace of man at that stage +of descent when our progenitors diverged from the Catarrhine stock? The fact +that they belonged to this stock clearly shews that they inhabited the Old +World; but not Australia nor any oceanic island, as we may infer from the laws +of geographical distribution. In each great region of the world the living +mammals are closely related to the extinct species of the same region. It is +therefore probable that Africa was formerly inhabited by extinct apes closely +allied to the gorilla and chimpanzee; and as these two species are now +man’s nearest allies, it is somewhat more probable that our early +progenitors lived on the African continent than elsewhere. But it is useless to +speculate on this subject; for two or three anthropomorphous apes, one the +Dryopithecus (17. Dr. C. Forsyth Major, ‘Sur les Singes fossiles trouvés +en Italie:’ ‘Soc. Ital. des Sc. Nat.’ tom. xv. 1872.) of +Lartet, nearly as large as a man, and closely allied to Hylobates, existed in +Europe during the Miocene age; and since so remote a period the earth has +certainly undergone many great revolutions, and there has been ample time for +migration on the largest scale. +</p> + +<p> +At the period and place, whenever and wherever it was, when man first lost his +hairy covering, he probably inhabited a hot country; a circumstance favourable +for the frugiferous diet on which, judging from analogy, he subsisted. We are +far from knowing how long ago it was when man first diverged from the +Catarrhine stock; but it may have occurred at an epoch as remote as the Eocene +period; for that the higher apes had diverged from the lower apes as early as +the Upper Miocene period is shewn by the existence of the Dryopithecus. We are +also quite ignorant at how rapid a rate organisms, whether high or low in the +scale, may be modified under favourable circumstances; we know, however, that +some have retained the same form during an enormous lapse of time. From what we +see going on under domestication, we learn that some of the co-descendants of +the same species may be not at all, some a little, and some greatly changed, +all within the same period. Thus it may have been with man, who has undergone a +great amount of modification in certain characters in comparison with the +higher apes. +</p> + +<p> +The great break in the organic chain between man and his nearest allies, which +cannot be bridged over by any extinct or living species, has often been +advanced as a grave objection to the belief that man is descended from some +lower form; but this objection will not appear of much weight to those who, +from general reasons, believe in the general principle of evolution. Breaks +often occur in all parts of the series, some being wide, sharp and defined, +others less so in various degrees; as between the orang and its nearest +allies—between the Tarsius and the other Lemuridae—between the +elephant, and in a more striking manner between the Ornithorhynchus or Echidna, +and all other mammals. But these breaks depend merely on the number of related +forms which have become extinct. At some future period, not very distant as +measured by centuries, the civilised races of man will almost certainly +exterminate, and replace, the savage races throughout the world. At the same +time the anthropomorphous apes, as Professor Schaaffhausen has remarked (18. +‘Anthropological Review,’ April 1867, p. 236.), will no doubt be +exterminated. The break between man and his nearest allies will then be wider, +for it will intervene between man in a more civilised state, as we may hope, +even than the Caucasian, and some ape as low as a baboon, instead of as now +between the negro or Australian and the gorilla. +</p> + +<p> +With respect to the absence of fossil remains, serving to connect man with his +ape-like progenitors, no one will lay much stress on this fact who reads Sir C. +Lyell’s discussion (19. ‘Elements of Geology,’ 1865, pp. +583-585. ‘Antiquity of Man,’ 1863, p. 145.), where he shews that in +all the vertebrate classes the discovery of fossil remains has been a very slow +and fortuitous process. Nor should it be forgotten that those regions which are +the most likely to afford remains connecting man with some extinct ape-like +creature, have not as yet been searched by geologists. +</p> + +<h3>LOWER STAGES IN THE GENEALOGY OF MAN.</h3> + +<p> +We have seen that man appears to have diverged from the Catarrhine or Old World +division of the Simiadae, after these had diverged from the New World division. +We will now endeavour to follow the remote traces of his genealogy, trusting +principally to the mutual affinities between the various classes and orders, +with some slight reference to the periods, as far as ascertained, of their +successive appearance on the earth. The Lemuridae stand below and near to the +Simiadae, and constitute a very distinct family of the primates, or, according +to Haeckel and others, a distinct Order. This group is diversified and broken +to an extraordinary degree, and includes many aberrant forms. It has, +therefore, probably suffered much extinction. Most of the remnants survive on +islands, such as Madagascar and the Malayan archipelago, where they have not +been exposed to so severe a competition as they would have been on well-stocked +continents. This group likewise presents many gradations, leading, as Huxley +remarks (20. ‘Man’s Place in Nature,’ p. 105.), +“insensibly from the crown and summit of the animal creation down to +creatures from which there is but a step, as it seems, to the lowest, smallest, +and least intelligent of the placental mammalia.” From these various +considerations it is probable that the Simiadae were originally developed from +the progenitors of the existing Lemuridae; and these in their turn from forms +standing very low in the mammalian series. +</p> + +<p> +The Marsupials stand in many important characters below the placental mammals. +They appeared at an earlier geological period, and their range was formerly +much more extensive than at present. Hence the Placentata are generally +supposed to have been derived from the Implacentata or Marsupials; not, +however, from forms closely resembling the existing Marsupials, but from their +early progenitors. The Monotremata are plainly allied to the Marsupials, +forming a third and still lower division in the great mammalian series. They +are represented at the present day solely by the Ornithorhynchus and Echidna; +and these two forms may be safely considered as relics of a much larger group, +representatives of which have been preserved in Australia through some +favourable concurrence of circumstances. The Monotremata are eminently +interesting, as leading in several important points of structure towards the +class of reptiles. +</p> + +<p> +In attempting to trace the genealogy of the Mammalia, and therefore of man, +lower down in the series, we become involved in greater and greater obscurity; +but as a most capable judge, Mr. Parker, has remarked, we have good reason to +believe, that no true bird or reptile intervenes in the direct line of descent. +He who wishes to see what ingenuity and knowledge can effect, may consult Prof. +Haeckel’s works. (21. Elaborate tables are given in his ‘Generelle +Morphologie’ (B. ii. s. cliii. and s. 425); and with more especial +reference to man in his ‘Natürliche Schöpfungsgeschichte,’ 1868. +Prof. Huxley, in reviewing this latter work (‘The Academy,’ 1869, +p. 42) says, that he considers the phylum or lines of descent of the Vertebrata +to be admirably discussed by Haeckel, although he differs on some points. He +expresses, also, his high estimate of the general tenor and spirit of the whole +work.) I will content myself with a few general remarks. Every evolutionist +will admit that the five great vertebrate classes, namely, mammals, birds, +reptiles, amphibians, and fishes, are descended from some one prototype; for +they have much in common, especially during their embryonic state. As the class +of fishes is the most lowly organised, and appeared before the others, we may +conclude that all the members of the vertebrate kingdom are derived from some +fishlike animal. The belief that animals so distinct as a monkey, an elephant, +a humming-bird, a snake, a frog, and a fish, etc., could all have sprung from +the same parents, will appear monstrous to those who have not attended to the +recent progress of natural history. For this belief implies the former +existence of links binding closely together all these forms, now so utterly +unlike. +</p> + +<p> +Nevertheless, it is certain that groups of animals have existed, or do now +exist, which serve to connect several of the great vertebrate classes more or +less closely. We have seen that the Ornithorhynchus graduates towards reptiles; +and Prof. Huxley has discovered, and is confirmed by Mr. Cope and others, that +the Dinosaurians are in many important characters intermediate between certain +reptiles and certain birds—the birds referred to being the ostrich-tribe +(itself evidently a widely-diffused remnant of a larger group) and the +Archeopteryx, that strange Secondary bird, with a long lizard-like tail. Again, +according to Prof. Owen (22. ‘Palaeontology’ 1860, p. 199.), the +Ichthyosaurians—great sea-lizards furnished with paddles—present +many affinities with fishes, or rather, according to Huxley, with amphibians; a +class which, including in its highest division frogs and toads, is plainly +allied to the Ganoid fishes. These latter fishes swarmed during the earlier +geological periods, and were constructed on what is called a generalised type, +that is, they presented diversified affinities with other groups of organisms. +The Lepidosiren is also so closely allied to amphibians and fishes, that +naturalists long disputed in which of these two classes to rank it; it, and +also some few Ganoid fishes, have been preserved from utter extinction by +inhabiting rivers, which are harbours of refuge, and are related to the great +waters of the ocean in the same way that islands are to continents. +</p> + +<p> +Lastly, one single member of the immense and diversified class of fishes, +namely, the lancelet or amphioxus, is so different from all other fishes, that +Haeckel maintains that it ought to form a distinct class in the vertebrate +kingdom. This fish is remarkable for its negative characters; it can hardly be +said to possess a brain, vertebral column, or heart, etc.; so that it was +classed by the older naturalists amongst the worms. Many years ago Prof. +Goodsir perceived that the lancelet presented some affinities with the +Ascidians, which are invertebrate, hermaphrodite, marine creatures permanently +attached to a support. They hardly appear like animals, and consist of a +simple, tough, leathery sack, with two small projecting orifices. They belong +to the Mulluscoida of Huxley—a lower division of the great kingdom of the +Mollusca; but they have recently been placed by some naturalists amongst the +Vermes or worms. Their larvae somewhat resemble tadpoles in shape (23. At the +Falkland Islands I had the satisfaction of seeing, in April, 1833, and +therefore some years before any other naturalist, the locomotive larvae of a +compound Ascidian, closely allied to Synoicum, but apparently generically +distinct from it. The tail was about five times as long as the oblong head, and +terminated in a very fine filament. It was, as sketched by me under a simple +microscope, plainly divided by transverse opaque partitions, which I presume +represent the great cells figured by Kovalevsky. At an early stage of +development the tail was closely coiled round the head of the larva.), and have +the power of swimming freely about. Mr. Kovalevsky (24. ‘Memoires de +l’Acad. des Sciences de St. Petersbourg,’ tom. x. No. 15, 1866.) +has lately observed that the larvae of Ascidians are related to the Vertebrata, +in their manner of development, in the relative position of the nervous system, +and in possessing a structure closely like the chorda dorsalis of vertebrate +animals; and in this he has been since confirmed by Prof. Kupffer. M. +Kovalevsky writes to me from Naples, that he has now carried these observations +yet further, and should his results be well established, the whole will form a +discovery of the very greatest value. Thus, if we may rely on embryology, ever +the safest guide in classification, it seems that we have at last gained a clue +to the source whence the Vertebrata were derived. (25. But I am bound to add +that some competent judges dispute this conclusion; for instance, M. Giard, in +a series of papers in the ‘Archives de Zoologie Experimentale,’ for +1872. Nevertheless, this naturalist remarks, p. 281, +“L’organisation de la larve ascidienne en dehors de toute hypothèse +et de toute théorie, nous montre comment la nature peut produire la disposition +fondamentale du type vertébré (l’existence d’une corde dorsale) +chez un invertébré par la seule condition vitale de l’adaptation, et +cette simple possibilité du passage supprime l’abîme entre les deux +sous-règnes, encore bien qu’en ignore par où le passage s’est fait +en realité.”) We should then be justified in believing that at an +extremely remote period a group of animals existed, resembling in many respects +the larvae of our present Ascidians, which diverged into two great +branches—the one retrograding in development and producing the present +class of Ascidians, the other rising to the crown and summit of the animal +kingdom by giving birth to the Vertebrata. +</p> + +<p> +We have thus far endeavoured rudely to trace the genealogy of the Vertebrata by +the aid of their mutual affinities. We will now look to man as he exists; and +we shall, I think, be able partially to restore the structure of our early +progenitors, during successive periods, but not in due order of time. This can +be effected by means of the rudiments which man still retains, by the +characters which occasionally make their appearance in him through reversion, +and by the aid of the principles of morphology and embryology. The various +facts, to which I shall here allude, have been given in the previous chapters. +</p> + +<p> +The early progenitors of man must have been once covered with hair, both sexes +having beards; their ears were probably pointed, and capable of movement; and +their bodies were provided with a tail, having the proper muscles. Their limbs +and bodies were also acted on by many muscles which now only occasionally +reappear, but are normally present in the Quadrumana. At this or some earlier +period, the great artery and nerve of the humerus ran through a supra-condyloid +foramen. The intestine gave forth a much larger diverticulum or caecum than +that now existing. The foot was then prehensile, judging from the condition of +the great toe in the foetus; and our progenitors, no doubt, were arboreal in +their habits, and frequented some warm, forest-clad land. The males had great +canine teeth, which served them as formidable weapons. At a much earlier period +the uterus was double; the excreta were voided through a cloaca; and the eye +was protected by a third eyelid or nictitating membrane. At a still earlier +period the progenitors of man must have been aquatic in their habits; for +morphology plainly tells us that our lungs consist of a modified swim-bladder, +which once served as a float. The clefts on the neck in the embryo of man shew +where the branchiae once existed. In the lunar or weekly recurrent periods of +some of our functions we apparently still retain traces of our primordial +birthplace, a shore washed by the tides. At about this same early period the +true kidneys were replaced by the corpora wolffiana. The heart existed as a +simple pulsating vessel; and the chorda dorsalis took the place of a vertebral +column. These early ancestors of man, thus seen in the dim recesses of time, +must have been as simply, or even still more simply organised than the lancelet +or amphioxus. +</p> + +<p> +There is one other point deserving a fuller notice. It has long been known that +in the vertebrate kingdom one sex bears rudiments of various accessory parts, +appertaining to the reproductive system, which properly belong to the opposite +sex; and it has now been ascertained that at a very early embryonic period both +sexes possess true male and female glands. Hence some remote progenitor of the +whole vertebrate kingdom appears to have been hermaphrodite or androgynous. +(26. This is the conclusion of Prof. Gegenbaur, one of the highest authorities +in comparative anatomy: see ‘Grundzüge der vergleich. Anat.’ 1870, +s. 876. The result has been arrived at chiefly from the study of the Amphibia; +but it appears from the researches of Waldeyer (as quoted in ‘Journal of +Anat. and Phys.’ 1869, p. 161), that the sexual organs of even “the +higher vertebrata are, in their early condition, hermaphrodite.” Similar +views have long been held by some authors, though until recently without a firm +basis.) But here we encounter a singular difficulty. In the mammalian class the +males possess rudiments of a uterus with the adjacent passage, in their +vesiculae prostaticae; they bear also rudiments of mammae, and some male +Marsupials have traces of a marsupial sack. (27. The male Thylacinus offers the +best instance. Owen, ‘Anatomy of Vertebrates,’ vol. iii. p. 771.) +Other analogous facts could be added. Are we, then, to suppose that some +extremely ancient mammal continued androgynous, after it had acquired the chief +distinctions of its class, and therefore after it had diverged from the lower +classes of the vertebrate kingdom? This seems very improbable, for we have to +look to fishes, the lowest of all the classes, to find any still existent +androgynous forms. (28. Hermaphroditism has been observed in several species of +Serranus, as well as in some other fishes, where it is either normal and +symmetrical, or abnormal and unilateral. Dr. Zouteveen has given me references +on this subject, more especially to a paper by Prof. Halbertsma, in the +‘Transact. of the Dutch Acad. of Sciences,’ vol. xvi. Dr. Gunther +doubts the fact, but it has now been recorded by too many good observers to be +any longer disputed. Dr. M. Lessona writes to me, that he has verified the +observations made by Cavolini on Serranus. Prof. Ercolani has recently shewn +(‘Accad. delle Scienze,’ Bologna, Dec. 28, 1871) that eels are +androgynous.) That various accessory parts, proper to each sex, are found in a +rudimentary condition in the opposite sex, may be explained by such organs +having been gradually acquired by the one sex, and then transmitted in a more +or less imperfect state to the other. When we treat of sexual selection, we +shall meet with innumerable instances of this form of transmission,—as in +the case of the spurs, plumes, and brilliant colours, acquired for battle or +ornament by male birds, and inherited by the females in an imperfect or +rudimentary condition. +</p> + +<p> +The possession by male mammals of functionally imperfect mammary organs is, in +some respects, especially curious. The Monotremata have the proper +milk-secreting glands with orifices, but no nipples; and as these animals stand +at the very base of the mammalian series, it is probable that the progenitors +of the class also had milk-secreting glands, but no nipples. This conclusion is +supported by what is known of their manner of development; for Professor Turner +informs me, on the authority of Kolliker and Langer, that in the embryo the +mammary glands can be distinctly traced before the nipples are in the least +visible; and the development of successive parts in the individual generally +represents and accords with the development of successive beings in the same +line of descent. The Marsupials differ from the Monotremata by possessing +nipples; so that probably these organs were first acquired by the Marsupials, +after they had diverged from, and risen above, the Monotremata, and were then +transmitted to the placental mammals. (29. Prof. Gegenbaur has shewn +(‘Jenäische Zeitschrift,’ Bd. vii. p. 212) that two distinct types +of nipples prevail throughout the several mammalian orders, but that it is +quite intelligible how both could have been derived from the nipples of the +Marsupials, and the latter from those of the Monotremata. See, also, a memoir +by Dr. Max Huss, on the mammary glands, ibid. B. viii. p. 176.) No one will +suppose that the marsupials still remained androgynous, after they had +approximately acquired their present structure. How then are we to account for +male mammals possessing mammae? It is possible that they were first developed +in the females and then transferred to the males, but from what follows this is +hardly probable. +</p> + +<p> +It may be suggested, as another view, that long after the progenitors of the +whole mammalian class had ceased to be androgynous, both sexes yielded milk, +and thus nourished their young; and in the case of the Marsupials, that both +sexes carried their young in marsupial sacks. This will not appear altogether +improbable, if we reflect that the males of existing syngnathous fishes receive +the eggs of the females in their abdominal pouches, hatch them, and afterwards, +as some believe, nourish the young (30. Mr. Lockwood believes (as quoted in +‘Quart. Journal of Science,’ April 1868, p. 269), from what he has +observed of the development of Hippocampus, that the walls of the abdominal +pouch of the male in some way afford nourishment. On male fishes hatching the +ova in their mouths, see a very interesting paper by 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 similar cases.);—that certain +other male fishes hatch the eggs within their mouths or branchial +cavities;—that certain male toads take the chaplets of eggs from the +females, and wind them round their own thighs, keeping them there until the +tadpoles are born;—that certain male birds undertake the whole duty of +incubation, and that male pigeons, as well as the females, feed their nestlings +with a secretion from their crops. But the above suggestion first occurred to +me from mammary glands of male mammals being so much more perfectly developed +than the rudiments of the other accessory reproductive parts, which are found +in the one sex though proper to the other. The mammary glands and nipples, as +they exist in male mammals, can indeed hardly be called rudimentary; they are +merely not fully developed, and not functionally active. They are +sympathetically affected under the influence of certain diseases, like the same +organs in the female. They often secrete a few drops of milk at birth and at +puberty: this latter fact occurred in the curious case, before referred to, +where a young man possessed two pairs of mammae. In man and some other male +mammals these organs have been known occasionally to become so well developed +during maturity as to yield a fair supply of milk. Now if we suppose that +during a former prolonged period male mammals aided the females in nursing +their offspring (31. Mlle. C. Royer has suggested a similar view in her +‘Origine de l’homme,’ etc., 1870.), and that afterwards from +some cause (as from the production of a smaller number of young) the males +ceased to give this aid, disuse of the organs during maturity would lead to +their becoming inactive; and from two well-known principles of inheritance, +this state of inactivity would probably be transmitted to the males at the +corresponding age of maturity. But at an earlier age these organs would be left +unaffected, so that they would be almost equally well developed in the young of +both sexes. +</p> + +<h3>—CONCLUSION—</h3> + +<p> +Von Baer has defined advancement or progress in the organic scale better than +any one else, as resting on the amount of differentiation and specialisation of +the several parts of a being,—when arrived at maturity, as I should be +inclined to add. Now as organisms have become slowly adapted to diversified +lines of life by means of natural selection, their parts will have become more +and more differentiated and specialised for various functions from the +advantage gained by the division of physiological labour. The same part appears +often to have been modified first for one purpose, and then long afterwards for +some other and quite distinct purpose; and thus all the parts are rendered more +and more complex. But each organism still retains the general type of structure +of the progenitor from which it was aboriginally derived. In accordance with +this view it seems, if we turn to geological evidence, that organisation on the +whole has advanced throughout the world by slow and interrupted steps. In the +great kingdom of the Vertebrata it has culminated in man. It must not, however, +be supposed that groups of organic beings are always supplanted, and disappear +as soon as they have given birth to other and more perfect groups. The latter, +though victorious over their predecessors, may not have become better adapted +for all places in the economy of nature. Some old forms appear to have survived +from inhabiting protected sites, where they have not been exposed to very +severe competition; and these often aid us in constructing our genealogies, by +giving us a fair idea of former and lost populations. But we must not fall into +the error of looking at the existing members of any lowly-organised group as +perfect representatives of their ancient predecessors. +</p> + +<p> +The most ancient progenitors in the kingdom of the Vertebrata, at which we are +able to obtain an obscure glance, apparently consisted of a group of marine +animals (32. The inhabitants of the seashore must be greatly affected by the +tides; animals living either about the MEAN high-water mark, or about the MEAN +low-water mark, pass through a complete cycle of tidal changes in a fortnight. +Consequently, their food supply will undergo marked changes week by week. The +vital functions of such animals, living under these conditions for many +generations, can hardly fail to run their course in regular weekly periods. Now +it is a mysterious fact that in the higher and now terrestrial Vertebrata, as +well as in other classes, many normal and abnormal processes have one or more +whole weeks as their periods; this would be rendered intelligible if the +Vertebrata are descended from an animal allied to the existing tidal Ascidians. +Many instances of such periodic processes might be given, as the gestation of +mammals, the duration of fevers, etc. The hatching of eggs affords also a good +example, for, according to Mr. Bartlett (‘Land and Water,’ Jan. 7, +1871), the eggs of the pigeon are hatched in two weeks; those of the fowl in +three; those of the duck in four; those of the goose in five; and those of the +ostrich in seven weeks. As far as we can judge, a recurrent period, if +approximately of the right duration for any process or function, would not, +when once gained, be liable to change; consequently it might be thus +transmitted through almost any number of generations. But if the function +changed, the period would have to change, and would be apt to change almost +abruptly by a whole week. This conclusion, if sound, is highly remarkable; for +the period of gestation in each mammal, and the hatching of each bird’s +eggs, and many other vital processes, thus betray to us the primordial +birthplace of these animals.), resembling the larvae of existing Ascidians. +These animals probably gave rise to a group of fishes, as lowly organised as +the lancelet; and from these the Ganoids, and other fishes like the +Lepidosiren, must have been developed. From such fish a very small advance +would carry us on to the Amphibians. We have seen that birds and reptiles were +once intimately connected together; and the Monotremata now connect mammals +with reptiles in a slight degree. But no one can at present say by what line of +descent the three higher and related classes, namely, mammals, birds, and +reptiles, were derived from the two lower vertebrate classes, namely, +amphibians and fishes. In the class of mammals the steps are not difficult to +conceive which led from the ancient Monotremata to the ancient Marsupials; and +from these to the early progenitors of the placental mammals. We may thus +ascend to the Lemuridae; and the interval is not very wide from these to the +Simiadae. The Simiadae then branched off into two great stems, the New World +and Old World monkeys; and from the latter, at a remote period, Man, the wonder +and glory of the Universe, proceeded. +</p> + +<p> +Thus we have given to man a pedigree of prodigious length, but not, it may be +said, of noble quality. The world, it has often been remarked, appears as if it +had long been preparing for the advent of man: and this, in one sense is +strictly true, for he owes his birth to a long line of progenitors. If any +single link in this chain had never existed, man would not have been exactly +what he now is. Unless we wilfully close our eyes, we may, with our present +knowledge, approximately recognise our parentage; nor need we feel ashamed of +it. The most humble organism is something much higher than the inorganic dust +under our feet; and no one with an unbiassed mind can study any living +creature, however humble, without being struck with enthusiasm at its +marvellous structure and properties. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0007" id="link2HCH0007"></a> +CHAPTER VII.<br /> +ON THE RACES OF MAN.</h2> + +<p class="letter"> +The nature and value of specific characters—Application to the races of +man—Arguments in favour of, and opposed to, ranking the so-called races +of man as distinct species—Sub-species—Monogenists and +polygenists—Convergence of character—Numerous points of resemblance +in body and mind between the most distinct races of man—The state of man +when he first spread over the earth—Each race not descended from a single +pair—The extinction of races—The formation of races—The +effects of crossing—Slight influence of the direct action of the +conditions of life—Slight or no influence of natural +selection—Sexual selection. +</p> + +<p> +It is not my intention here to describe the several so-called races of men; but +I am about to enquire what is the value of the differences between them under a +classificatory point of view, and how they have originated. In determining +whether two or more allied forms ought to be ranked as species or varieties, +naturalists are practically guided by the following considerations; namely, the +amount of difference between them, and whether such differences relate to few +or many points of structure, and whether they are of physiological importance; +but more especially whether they are constant. Constancy of character is what +is chiefly valued and sought for by naturalists. Whenever it can be shewn, or +rendered probable, that the forms in question have remained distinct for a long +period, this becomes an argument of much weight in favour of treating them as +species. Even a slight degree of sterility between any two forms when first +crossed, or in their offspring, is generally considered as a decisive test of +their specific distinctness; and their continued persistence without blending +within the same area, is usually accepted as sufficient evidence, either of +some degree of mutual sterility, or in the case of animals of some mutual +repugnance to pairing. +</p> + +<p> +Independently of fusion from intercrossing, the complete absence, in a +well-investigated region, of varieties linking together any two closely-allied +forms, is probably the most important of all the criterions of their specific +distinctness; and this is a somewhat different consideration from mere +constancy of character, for two forms may be highly variable and yet not yield +intermediate varieties. Geographical distribution is often brought into play +unconsciously and sometimes consciously; so that forms living in two widely +separated areas, in which most of the other inhabitants are specifically +distinct, are themselves usually looked at as distinct; but in truth this +affords no aid in distinguishing geographical races from so-called good or true +species. +</p> + +<p> +Now let us apply these generally-admitted principles to the races of man, +viewing him in the same spirit as a naturalist would any other animal. In +regard to the amount of difference between the races, we must make some +allowance for our nice powers of discrimination gained by the long habit of +observing ourselves. In India, as Elphinstone remarks, although a newly-arrived +European cannot at first distinguish the various native races, yet they soon +appear to him extremely dissimilar (1. ‘History of India,’ 1841, +vol. i. p. 323. Father Ripa makes exactly the same remark with respect to the +Chinese.); and the Hindoo cannot at first perceive any difference between the +several European nations. Even the most distinct races of man are much more +like each other in form than would at first be supposed; certain negro tribes +must be excepted, whilst others, as Dr. Rohlfs writes to me, and as I have +myself seen, have Caucasian features. This general similarity is well shewn by +the French photographs in the Collection Anthropologique du Museum de Paris of +the men belonging to various races, the greater number of which might pass for +Europeans, as many persons to whom I have shewn them have remarked. +Nevertheless, these men, if seen alive, would undoubtedly appear very distinct, +so that we are clearly much influenced in our judgment by the mere colour of +the skin and hair, by slight differences in the features, and by expression. +</p> + +<p> +There is, however, no doubt that the various races, when carefully compared and +measured, differ much from each other,—as in the texture of the hair, the +relative proportions of all parts of the body (2. A vast number of measurements +of Whites, Blacks, and Indians, are given in the ‘Investigations in the +Military and Anthropolog. Statistics of American Soldiers,’ by B.A. +Gould, 1869, pp. 298-358; ‘On the capacity of the lungs,’ p. 471. +See also the numerous and valuable tables, by Dr. Weisbach, from the +observations of Dr. Scherzer and Dr. Schwarz, in the ‘Reise der Novara: +Anthropolog. Theil,’ 1867.), the capacity of the lungs, the form and +capacity of the skull, and even in the convolutions of the brain. (3. See, for +instance, Mr. Marshall’s account of the brain of a Bushwoman, in +‘Philosophical Transactions,’ 1864, p. 519.) But it would be an +endless task to specify the numerous points of difference. The races differ +also in constitution, in acclimatisation and in liability to certain diseases. +Their mental characteristics are likewise very distinct; chiefly as it would +appear in their emotional, but partly in their intellectual faculties. Every +one who has had the opportunity of comparison, must have been struck with the +contrast between the taciturn, even morose, aborigines of S. America and the +light-hearted, talkative negroes. There is a nearly similar contrast between +the Malays and the Papuans (4. Wallace, ‘The Malay Archipelago,’ +vol. ii. 1869, p. 178.), who live under the same physical conditions, and are +separated from each other only by a narrow space of sea. +</p> + +<p> +We will first consider the arguments which may be advanced in favour of +classing the races of man as distinct species, and then the arguments on the +other side. If a naturalist, who had never before seen a Negro, Hottentot, +Australian, or Mongolian, were to compare them, he would at once perceive that +they differed in a multitude of characters, some of slight and some of +considerable importance. On enquiry he would find that they were adapted to +live under widely different climates, and that they differed somewhat in bodily +constitution and mental disposition. If he were then told that hundreds of +similar specimens could be brought from the same countries, he would assuredly +declare that they were as good species as many to which he had been in the +habit of affixing specific names. This conclusion would be greatly strengthened +as soon as he had ascertained that these forms had all retained the same +character for many centuries; and that negroes, apparently identical with +existing negroes, had lived at least 4000 years ago. (5. With respect to the +figures in the famous Egyptian caves of Abou-Simbel, M. Pouchet says +(‘The Plurality of the Human Races,’ Eng. translat., 1864, p. 50), +that he was far from finding recognisable representations of the dozen or more +nations which some authors believe that they can recognise. Even some of the +most strongly-marked races cannot be identified with that degree of unanimity +which might have been expected from what has been written on the subject. Thus +Messrs. Nott and Gliddon (‘Types of Mankind,’ p. 148), state that +Rameses II., or the Great, has features superbly European; whereas Knox, +another firm believer in the specific distinctness of the races of man +(‘Races of Man,’ 1850, p. 201), speaking of young Memnon (the same +as Rameses II., as I am informed by Mr. Birch), insists in the strongest manner +that he is identical in character with the Jews of Antwerp. Again, when I +looked at the statue of Amunoph III., I agreed with two officers of the +establishment, both competent judges, that he had a strongly-marked negro type +of features; but Messrs. Nott and Gliddon (ibid. p. 146, fig. 53), describe him +as a hybrid, but not of “negro intermixture.”) He would also hear, +on the authority of an excellent observer, Dr. Lund (6. As quoted by Nott and +Gliddon, ‘Types of Mankind,’ 1854, p. 439. They give also +corroborative evidence; but C. Vogt thinks that the subject requires further +investigation.), that the human skulls found in the caves of Brazil, entombed +with many extinct mammals, belonged to the same type as that now prevailing +throughout the American Continent. +</p> + +<p> +Our naturalist would then perhaps turn to geographical distribution, and he +would probably declare that those forms must be distinct species, which differ +not only in appearance, but are fitted for hot, as well as damp or dry +countries, and for the Arctic regions. He might appeal to the fact that no +species in the group next to man—namely, the Quadrumana, can resist a low +temperature, or any considerable change of climate; and that the species which +come nearest to man have never been reared to maturity, even under the +temperate climate of Europe. He would be deeply impressed with the fact, first +noticed by Agassiz (7. ‘Diversity of Origin of the Human Races,’ in +the ‘Christian Examiner,’ July 1850.), that the different races of +man are distributed over the world in the same zoological provinces, as those +inhabited by undoubtedly distinct species and genera of mammals. This is +manifestly the case with the Australian, Mongolian, and Negro races of man; in +a less well-marked manner with the Hottentots; but plainly with the Papuans and +Malays, who are separated, as Mr. Wallace has shewn, by nearly the same line +which divides the great Malayan and Australian zoological provinces. The +Aborigines of America range throughout the Continent; and this at first appears +opposed to the above rule, for most of the productions of the Southern and +Northern halves differ widely: yet some few living forms, as the opossum, range +from the one into the other, as did formerly some of the gigantic Edentata. The +Esquimaux, like other Arctic animals, extend round the whole polar regions. It +should be observed that the amount of difference between the mammals of the +several zoological provinces does not correspond with the degree of separation +between the latter; so that it can hardly be considered as an anomaly that the +Negro differs more, and the American much less from the other races of man, +than do the mammals of the African and American continents from the mammals of +the other provinces. Man, it may be added, does not appear to have aboriginally +inhabited any oceanic island; and in this respect, he resembles the other +members of his class. +</p> + +<p> +In determining whether the supposed varieties of the same kind of domestic +animal should be ranked as such, or as specifically distinct, that is, whether +any of them are descended from distinct wild species, every naturalist would +lay much stress on the fact of their external parasites being specifically +distinct. All the more stress would be laid on this fact, as it would be an +exceptional one; for I am informed by Mr. Denny that the most different kinds +of dogs, fowls, and pigeons, in England, are infested by the same species of +Pediculi or lice. Now Mr. A. Murray has carefully examined the Pediculi +collected in different countries from the different races of man (8. +‘Transactions of the Royal Society of Edinburgh,’ vol. xxii, 1861, +p. 567.); and he finds that they differ, not only in colour, but in the +structure of their claws and limbs. In every case in which many specimens were +obtained the differences were constant. The surgeon of a whaling ship in the +Pacific assured me that when the Pediculi, with which some Sandwich Islanders +on board swarmed, strayed on to the bodies of the English sailors, they died in +the course of three or four days. These Pediculi were darker coloured, and +appeared different from those proper to the natives of Chiloe in South America, +of which he gave me specimens. These, again, appeared larger and much softer +than European lice. Mr. Murray procured four kinds from Africa, namely, from +the Negroes of the Eastern and Western coasts, from the Hottentots and Kaffirs; +two kinds from the natives of Australia; two from North and two from South +America. In these latter cases it may be presumed that the Pediculi came from +natives inhabiting different districts. With insects slight structural +differences, if constant, are generally esteemed of specific value: and the +fact of the races of man being infested by parasites, which appear to be +specifically distinct, might fairly be urged as an argument that the races +themselves ought to be classed as distinct species. +</p> + +<p> +Our supposed naturalist having proceeded thus far in his investigation, would +next enquire whether the races of men, when crossed, were in any degree +sterile. He might consult the work (9. ‘On the Phenomena of Hybridity in +the Genus Homo,’ Eng. translat., 1864.) of Professor Broca, a cautious +and philosophical observer, and in this he would find good evidence that some +races were quite fertile together, but evidence of an opposite nature in regard +to other races. Thus it has been asserted that the native women of Australia +and Tasmania rarely produce children to European men; the evidence, however, on +this head has now been shewn to be almost valueless. The half-castes are killed +by the pure blacks: and an account has lately been published of eleven +half-caste youths murdered and burnt at the same time, whose remains were found +by the police. (10. See the interesting letter by Mr. T.A. Murray, in the +‘Anthropological Review,’ April 1868, p. liii. In this letter Count +Strzelecki’s statement that Australian women who have borne children to a +white man, are afterwards sterile with their own race, is disproved. M. A. de +Quatrefages has also collected (Revue des Cours Scientifiques, March, 1869, p. +239), much evidence that Australians and Europeans are not sterile when +crossed.) Again, it has often been said that when mulattoes intermarry, they +produce few children; on the other hand, Dr. Bachman, of Charleston (11. +‘An Examination of Prof. Agassiz’s Sketch of the Nat. Provinces of +the Animal World,’ Charleston, 1855, p. 44.), positively asserts that he +has known mulatto families which have intermarried for several generations, and +have continued on an average as fertile as either pure whites or pure blacks. +Enquiries formerly made by Sir C. Lyell on this subject led him, as he informs +me, to the same conclusion. (12. Dr. Rohlfs writes to me that he found the +mixed races in the Great Sahara, derived from Arabs, Berbers, and Negroes of +three tribes, extraordinarily fertile. On the other hand, Mr. Winwood Reade +informs me that the Negroes on the Gold Coast, though admiring white men and +mulattoes, have a maxim that mulattoes should not intermarry, as the children +are few and sickly. This belief, as Mr. Reade remarks, deserves attention, as +white men have visited and resided on the Gold Coast for four hundred years, so +that the natives have had ample time to gain knowledge through experience.) In +the United States the census for the year 1854 included, according to Dr. +Bachman, 405,751 mulattoes; and this number, considering all the circumstances +of the case, seems small; but it may partly be accounted for by the degraded +and anomalous position of the class, and by the profligacy of the women. A +certain amount of absorption of mulattoes into negroes must always be in +progress; and this would lead to an apparent diminution of the former. The +inferior vitality of mulattoes is spoken of in a trustworthy work (13. +‘Military and Anthropological Statistics of American Soldiers,’ by +B.A. Gould, 1869, p. 319.) as a well-known phenomenon; and this, although a +different consideration from their lessened fertility, may perhaps be advanced +as a proof of the specific distinctness of the parent races. No doubt both +animal and vegetable hybrids, when produced from extremely distinct species, +are liable to premature death; but the parents of mulattoes cannot be put under +the category of extremely distinct species. The common Mule, so notorious for +long life and vigour, and yet so sterile, shews how little necessary connection +there is in hybrids between lessened fertility and vitality; other analogous +cases could be cited. +</p> + +<p> +Even if it should hereafter be proved that all the races of men were perfectly +fertile together, he who was inclined from other reasons to rank them as +distinct species, might with justice argue that fertility and sterility are not +safe criterions of specific distinctness. We know that these qualities are +easily affected by changed conditions of life, or by close inter-breeding, and +that they are governed by highly complex laws, for instance, that of the +unequal fertility of converse crosses between the same two species. With forms +which must be ranked as undoubted species, a perfect series exists from those +which are absolutely sterile when crossed, to those which are almost or +completely fertile. The degrees of sterility do not coincide strictly with the +degrees of difference between the parents in external structure or habits of +life. Man in many respects may be compared with those animals which have long +been domesticated, and a large body of evidence can be advanced in favour of +the Pallasian doctrine (14. The ‘Variation of Animals and Plants under +Domestication,’ vol. ii. p. 109. I may here remind the reader that the +sterility of species when crossed is not a specially-acquired quality, but, +like the incapacity of certain trees to be grafted together, is incidental on +other acquired differences. The nature of these differences is unknown, but +they relate more especially to the reproductive system, and much less so to +external structure or to ordinary differences in constitution. One important +element in the sterility of crossed species apparently lies in one or both +having been long habituated to fixed conditions; for we know that changed +conditions have a special influence on the reproductive system, and we have +good reason to believe (as before remarked) that the fluctuating conditions of +domestication tend to eliminate that sterility which is so general with +species, in a natural state, when crossed. It has elsewhere been shewn by me +(ibid. vol. ii. p. 185, and ‘Origin of Species,’ 5th edit. p. 317), +that the sterility of crossed species has not been acquired through natural +selection: we can see that when two forms have already been rendered very +sterile, it is scarcely possible that their sterility should be augmented by +the preservation or survival of the more and more sterile individuals; for, as +the sterility increases, fewer and fewer offspring will be produced from which +to breed, and at last only single individuals will be produced at the rarest +intervals. But there is even a higher grade of sterility than this. Both +Gartner and Kolreuter have proved that in genera of plants, including many +species, a series can be formed from species which, when crossed, yield fewer +and fewer seeds, to species which never produce a single seed, but yet are +affected by the pollen of the other species, as shewn by the swelling of the +germen. It is here manifestly impossible to select the more sterile +individuals, which have already ceased to yield seeds; so that the acme of +sterility, when the germen alone is affected, cannot have been gained through +selection. This acme, and no doubt the other grades of sterility, are the +incidental results of certain unknown differences in the constitution of the +reproductive system of the species which are crossed.), that domestication +tends to eliminate the sterility which is so general a result of the crossing +of species in a state of nature. From these several considerations, it may be +justly urged that the perfect fertility of the intercrossed races of man, if +established, would not absolutely preclude us from ranking them as distinct +species. +</p> + +<p> +Independently of fertility, the characters presented by the offspring from a +cross have been thought to indicate whether or not the parent-forms ought to be +ranked as species or varieties; but after carefully studying the evidence, I +have come to the conclusion that no general rules of this kind can be trusted. +The ordinary result of a cross is the production of a blended or intermediate +form; but in certain cases some of the offspring take closely after one +parent-form, and some after the other. This is especially apt to occur when the +parents differ in characters which first appeared as sudden variations or +monstrosities. (15. ‘The Variation of Animals,’ etc., vol. ii. p. +92.) I refer to this point, because Dr. Rohlfs informs me that he has +frequently seen in Africa the offspring of negroes crossed with members of +other races, either completely black or completely white, or rarely piebald. On +the other hand, it is notorious that in America mulattoes commonly present an +intermediate appearance. +</p> + +<p> +We have now seen that a naturalist might feel himself fully justified in +ranking the races of man as distinct species; for he has found that they are +distinguished by many differences in structure and constitution, some being of +importance. These differences have, also, remained nearly constant for very +long periods of time. Our naturalist will have been in some degree influenced +by the enormous range of man, which is a great anomaly in the class of mammals, +if mankind be viewed as a single species. He will have been struck with the +distribution of the several so-called races, which accords with that of other +undoubtedly distinct species of mammals. Finally, he might urge that the mutual +fertility of all the races has not as yet been fully proved, and even if proved +would not be an absolute proof of their specific identity. +</p> + +<p> +On the other side of the question, if our supposed naturalist were to enquire +whether the forms of man keep distinct like ordinary species, when mingled +together in large numbers in the same country, he would immediately discover +that this was by no means the case. In Brazil he would behold an immense +mongrel population of Negroes and Portuguese; in Chiloe, and other parts of +South America, he would behold the whole population consisting of Indians and +Spaniards blended in various degrees. (16. M. de Quatrefages has given +(‘Anthropological Review,’ Jan. 1869, p. 22), an interesting +account of the success and energy of the Paulistas in Brazil, who are a much +crossed race of Portuguese and Indians, with a mixture of the blood of other +races.) In many parts of the same continent he would meet with the most complex +crosses between Negroes, Indians, and Europeans; and judging from the vegetable +kingdom, such triple crosses afford the severest test of the mutual fertility +of the parent forms. In one island of the Pacific he would find a small +population of mingled Polynesian and English blood; and in the Fiji Archipelago +a population of Polynesian and Negritos crossed in all degrees. Many analogous +cases could be added; for instance, in Africa. Hence the races of man are not +sufficiently distinct to inhabit the same country without fusion; and the +absence of fusion affords the usual and best test of specific distinctness. +</p> + +<p> +Our naturalist would likewise be much disturbed as soon as he perceived that +the distinctive characters of all the races were highly variable. This fact +strikes every one on first beholding the negro slaves in Brazil, who have been +imported from all parts of Africa. The same remark holds good with the +Polynesians, and with many other races. It may be doubted whether any character +can be named which is distinctive of a race and is constant. Savages, even +within the limits of the same tribe, are not nearly so uniform in character, as +has been often asserted. Hottentot women offer certain peculiarities, more +strongly marked than those occurring in any other race, but these are known not +to be of constant occurrence. In the several American tribes, colour and +hairiness differ considerably; as does colour to a certain degree, and the +shape of the features greatly, in the Negroes of Africa. The shape of the skull +varies much in some races (17. For instance, with the aborigines of America and +Australia, Prof. Huxley says (‘Transact. Internat. Congress of Prehist. +Arch.’ 1868, p. 105), that the skulls of many South Germans and Swiss are +“as short and as broad as those of the Tartars,” etc.); and so it +is with every other character. Now all naturalists have learnt by dearly bought +experience, how rash it is to attempt to define species by the aid of +inconstant characters. +</p> + +<p> +But the most weighty of all the arguments against treating the races of man as +distinct species, is that they graduate into each other, independently in many +cases, as far as we can judge, of their having intercrossed. Man has been +studied more carefully than any other animal, and yet there is the greatest +possible diversity amongst capable judges whether he should be classed as a +single species or race, or as two (Virey), as three (Jacquinot), as four +(Kant), five (Blumenbach), six (Buffon), seven (Hunter), eight (Agassiz), +eleven (Pickering), fifteen (Bory St. Vincent), sixteen (Desmoulins), +twenty-two (Morton), sixty (Crawfurd), or as sixty-three, according to Burke. +(18. See a good discussion on this subject in Waitz, ‘Introduction to +Anthropology,’ Eng. translat., 1863, pp. 198-208, 227. I have taken some +of the above statements from H. Tuttle’s ‘Origin and Antiquity of +Physical Man,’ Boston, 1866, p. 35.) This diversity of judgment does not +prove that the races ought not to be ranked as species, but it shews that they +graduate into each other, and that it is hardly possible to discover clear +distinctive characters between them. +</p> + +<p> +Every naturalist who has had the misfortune to undertake the description of a +group of highly varying organisms, has encountered cases (I speak after +experience) precisely like that of man; and if of a cautious disposition, he +will end by uniting all the forms which graduate into each other, under a +single species; for he will say to himself that he has no right to give names +to objects which he cannot define. Cases of this kind occur in the Order which +includes man, namely in certain genera of monkeys; whilst in other genera, as +in Cercopithecus, most of the species can be determined with certainty. In the +American genus Cebus, the various forms are ranked by some naturalists as +species, by others as mere geographical races. Now if numerous specimens of +Cebus were collected from all parts of South America, and those forms which at +present appear to be specifically distinct, were found to graduate into each +other by close steps, they would usually be ranked as mere varieties or races; +and this course has been followed by most naturalists with respect to the races +of man. Nevertheless, it must be confessed that there are forms, at least in +the vegetable kingdom (19. Prof. Nageli has carefully described several +striking cases in his ‘Botanische Mittheilungen,’ B. ii. 1866, ss. +294-369. Prof. Asa Gray has made analogous remarks on some intermediate forms +in the Compositae of N. America.), which we cannot avoid naming as species, but +which are connected together by numberless gradations, independently of +intercrossing. +</p> + +<p> +Some naturalists have lately employed the term “sub-species” to +designate forms which possess many of the characteristics of true species, but +which hardly deserve so high a rank. Now if we reflect on the weighty arguments +above given, for raising the races of man to the dignity of species, and the +insuperable difficulties on the other side in defining them, it seems that the +term “sub-species” might here be used with propriety. But from long +habit the term “race” will perhaps always be employed. The choice +of terms is only so far important in that it is desirable to use, as far as +possible, the same terms for the same degrees of difference. Unfortunately this +can rarely be done: for the larger genera generally include closely-allied +forms, which can be distinguished only with much difficulty, whilst the smaller +genera within the same family include forms that are perfectly distinct; yet +all must be ranked equally as species. So again, species within the same large +genus by no means resemble each other to the same degree: on the contrary, some +of them can generally be arranged in little groups round other species, like +satellites round planets. (20. ‘Origin of Species,’ 5th edit. p. +68.) +</p> + +<p> +The question whether mankind consists of one or several species has of late +years been much discussed by anthropologists, who are divided into the two +schools of monogenists and polygenists. Those who do not admit the principle of +evolution, must look at species as separate creations, or in some manner as +distinct entities; and they must decide what forms of man they will consider as +species by the analogy of the method commonly pursued in ranking other organic +beings as species. But it is a hopeless endeavour to decide this point, until +some definition of the term “species” is generally accepted; and +the definition must not include an indeterminate element such as an act of +creation. We might as well attempt without any definition to decide whether a +certain number of houses should be called a village, town, or city. We have a +practical illustration of the difficulty in the never-ending doubts whether +many closely-allied mammals, birds, insects, and plants, which represent each +other respectively in North America and Europe, should be ranked as species or +geographical races; and the like holds true of the productions of many islands +situated at some little distance from the nearest continent. +</p> + +<p> +Those naturalists, on the other hand, who admit the principle of evolution, and +this is now admitted by the majority of rising men, will feel no doubt that all +the races of man are descended from a single primitive stock; whether or not +they may think fit to designate the races as distinct species, for the sake of +expressing their amount of difference. (21. See Prof. Huxley to this effect in +the ‘Fortnightly Review,’ 1865, p. 275.) With our domestic animals +the question whether the various races have arisen from one or more species is +somewhat different. Although it may be admitted that all the races, as well as +all the natural species within the same genus, have sprung from the same +primitive stock, yet it is a fit subject for discussion, whether all the +domestic races of the dog, for instance, have acquired their present amount of +difference since some one species was first domesticated by man; or whether +they owe some of their characters to inheritance from distinct species, which +had already been differentiated in a state of nature. With man no such question +can arise, for he cannot be said to have been domesticated at any particular +period. +</p> + +<p> +During an early stage in the divergence of the races of man from a common +stock, the differences between the races and their number must have been small; +consequently as far as their distinguishing characters are concerned, they then +had less claim to rank as distinct species than the existing so-called races. +Nevertheless, so arbitrary is the term of species, that such early races would +perhaps have been ranked by some naturalists as distinct species, if their +differences, although extremely slight, had been more constant than they are at +present, and had not graduated into each other. +</p> + +<p> +It is however possible, though far from probable, that the early progenitors of +man might formerly have diverged much in character, until they became more +unlike each other than any now existing races; but that subsequently, as +suggested by Vogt (22. ‘Lectures on Man,’ Eng. translat., 1864, p. +468.), they converged in character. When man selects the offspring of two +distinct species for the same object, he sometimes induces a considerable +amount of convergence, as far as general appearance is concerned. This is the +case, as shewn by von Nathusius (23. ‘Die Rassen des Schweines,’ +1860, s. 46. ‘Vorstudien für Geschichte,’ etc., Schweinesschädel, +1864, s. 104. With respect to cattle, see M. de Quatrefages, ‘Unité de +l’Espèce Humaine,’ 1861, p. 119.), with the improved breeds of the +pig, which are descended from two distinct species; and in a less marked manner +with the improved breeds of cattle. A great anatomist, Gratiolet, maintains +that the anthropomorphous apes do not form a natural sub-group; but that the +orang is a highly developed gibbon or semnopithecus, the chimpanzee a highly +developed macacus, and the gorilla a highly developed mandrill. If this +conclusion, which rests almost exclusively on brain-characters, be admitted, we +should have a case of convergence at least in external characters, for the +anthropomorphous apes are certainly more like each other in many points, than +they are to other apes. All analogical resemblances, as of a whale to a fish, +may indeed be said to be cases of convergence; but this term has never been +applied to superficial and adaptive resemblances. It would, however, be +extremely rash to attribute to convergence close similarity of character in +many points of structure amongst the modified descendants of widely distinct +beings. The form of a crystal is determined solely by the molecular forces, and +it is not surprising that dissimilar substances should sometimes assume the +same form; but with organic beings we should bear in mind that the form of each +depends on an infinity of complex relations, namely on variations, due to +causes far too intricate to be followed,—on the nature of the variations +preserved, these depending on the physical conditions, and still more on the +surrounding organisms which compete with each,—and lastly, on inheritance +(in itself a fluctuating element) from innumerable progenitors, all of which +have had their forms determined through equally complex relations. It appears +incredible that the modified descendants of two organisms, if these differed +from each other in a marked manner, should ever afterwards converge so closely +as to lead to a near approach to identity throughout their whole organisation. +In the case of the convergent races of pigs above referred to, evidence of +their descent from two primitive stocks is, according to von Nathusius, still +plainly retained, in certain bones of their skulls. If the races of man had +descended, as is supposed by some naturalists, from two or more species, which +differed from each other as much, or nearly as much, as does the orang from the +gorilla, it can hardly be doubted that marked differences in the structure of +certain bones would still be discoverable in man as he now exists. +</p> + +<p> +Although the existing races of man differ in many respects, as in colour, hair, +shape of skull, proportions of the body, etc., yet if their whole structure be +taken into consideration they are found to resemble each other closely in a +multitude of points. Many of these are of so unimportant or of so singular a +nature, that it is extremely improbable that they should have been +independently acquired by aboriginally distinct species or races. The same +remark holds good with equal or greater force with respect to the numerous +points of mental similarity between the most distinct races of man. The +American aborigines, Negroes and Europeans are as different from each other in +mind as any three races that can be named; yet I was incessantly struck, whilst +living with the Fuegians on board the “Beagle,” with the many +little traits of character, shewing how similar their minds were to ours; and +so it was with a full-blooded negro with whom I happened once to be intimate. +</p> + +<p> +He who will read Mr. Tylor’s and Sir J. Lubbock’s interesting works +(24. Tylor’s ‘Early History of Mankind,’ 1865: with respect +to gesture-language, see p. 54. Lubbock’s ‘Prehistoric +Times,’ 2nd edit. 1869.) can hardly fail to be deeply impressed with the +close similarity between the men of all races in tastes, dispositions and +habits. This is shewn by the pleasure which they all take in dancing, rude +music, acting, painting, tattooing, and otherwise decorating themselves; in +their mutual comprehension of gesture-language, by the same expression in their +features, and by the same inarticulate cries, when excited by the same +emotions. This similarity, or rather identity, is striking, when contrasted +with the different expressions and cries made by distinct species of monkeys. +There is good evidence that the art of shooting with bows and arrows has not +been handed down from any common progenitor of mankind, yet as Westropp and +Nilsson have remarked (25. ‘On Analogous Forms of Implements,’ in +‘Memoirs of Anthropological Society’ by H.M. Westropp. ‘The +Primitive Inhabitants of Scandinavia,’ Eng. translat., edited by Sir J. +Lubbock, 1868, p. 104.), the stone arrow-heads, brought from the most distant +parts of the world, and manufactured at the most remote periods, are almost +identical; and this fact can only be accounted for by the various races having +similar inventive or mental powers. The same observation has been made by +archaeologists (26. Westropp ‘On Cromlechs,’ etc., ‘Journal +of Ethnological Soc.’ as given in ‘Scientific Opinion,’ June +2nd, 1869, p. 3.) with respect to certain widely-prevalent ornaments, such as +zig-zags, etc.; and with respect to various simple beliefs and customs, such as +the burying of the dead under megalithic structures. I remember observing in +South America (27. ‘Journal of Researches: Voyage of the +“Beagle,”’ p. 46.), that there, as in so many other parts of +the world, men have generally chosen the summits of lofty hills, to throw up +piles of stones, either as a record of some remarkable event, or for burying +their dead. +</p> + +<p> +Now when naturalists observe a close agreement in numerous small details of +habits, tastes, and dispositions between two or more domestic races, or between +nearly-allied natural forms, they use this fact as an argument that they are +descended from a common progenitor who was thus endowed; and consequently that +all should be classed under the same species. The same argument may be applied +with much force to the races of man. +</p> + +<p> +As it is improbable that the numerous and unimportant points of resemblance +between the several races of man in bodily structure and mental faculties (I do +not here refer to similar customs) should all have been independently acquired, +they must have been inherited from progenitors who had these same characters. +We thus gain some insight into the early state of man, before he had spread +step by step over the face of the earth. The spreading of man to regions widely +separated by the sea, no doubt, preceded any great amount of divergence of +character in the several races; for otherwise we should sometimes meet with the +same race in distinct continents; and this is never the case. Sir J. Lubbock, +after comparing the arts now practised by savages in all parts of the world, +specifies those which man could not have known, when he first wandered from his +original birthplace; for if once learnt they would never have been forgotten. +(28. ‘Prehistoric Times,’ 1869, p. 574.) He thus shews that +“the spear, which is but a development of the knife-point, and the club, +which is but a long hammer, are the only things left.” He admits, +however, that the art of making fire probably had been already discovered, for +it is common to all the races now existing, and was known to the ancient +cave-inhabitants of Europe. Perhaps the art of making rude canoes or rafts was +likewise known; but as man existed at a remote epoch, when the land in many +places stood at a very different level to what it does now, he would have been +able, without the aid of canoes, to have spread widely. Sir J. Lubbock further +remarks how improbable it is that our earliest ancestors could have +“counted as high as ten, considering that so many races now in existence +cannot get beyond four.” Nevertheless, at this early period, the +intellectual and social faculties of man could hardly have been inferior in any +extreme degree to those possessed at present by the lowest savages; otherwise +primeval man could not have been so eminently successful in the struggle for +life, as proved by his early and wide diffusion. +</p> + +<p> +From the fundamental differences between certain languages, some philologists +have inferred that when man first became widely diffused, he was not a speaking +animal; but it may be suspected that languages, far less perfect than any now +spoken, aided by gestures, might have been used, and yet have left no traces on +subsequent and more highly-developed tongues. Without the use of some language, +however imperfect, it appears doubtful whether man’s intellect could have +risen to the standard implied by his dominant position at an early period. +</p> + +<p> +Whether primeval man, when he possessed but few arts, and those of the rudest +kind, and when his power of language was extremely imperfect, would have +deserved to be called man, must depend on the definition which we employ. In a +series of forms graduating insensibly from some ape-like creature to man as he +now exists, it would be impossible to fix on any definite point where the term +“man” ought to be used. But this is a matter of very little +importance. So again, it is almost a matter of indifference whether the +so-called races of man are thus designated, or are ranked as species or +sub-species; but the latter term appears the more appropriate. Finally, we may +conclude that when the principle of evolution is generally accepted, as it +surely will be before long, the dispute between the monogenists and the +polygenists will die a silent and unobserved death. +</p> + +<p> +One other question ought not to be passed over without notice, namely, whether, +as is sometimes assumed, each sub-species or race of man has sprung from a +single pair of progenitors. With our domestic animals a new race can readily be +formed by carefully matching the varying offspring from a single pair, or even +from a single individual possessing some new character; but most of our races +have been formed, not intentionally from a selected pair, but unconsciously by +the preservation of many individuals which have varied, however slightly, in +some useful or desired manner. If in one country stronger and heavier horses, +and in another country lighter and fleeter ones, were habitually preferred, we +may feel sure that two distinct sub-breeds would be produced in the course of +time, without any one pair having been separated and bred from, in either +country. Many races have been thus formed, and their manner of formation is +closely analogous to that of natural species. We know, also, that the horses +taken to the Falkland Islands have, during successive generations, become +smaller and weaker, whilst those which have run wild on the Pampas have +acquired larger and coarser heads; and such changes are manifestly due, not to +any one pair, but to all the individuals having been subjected to the same +conditions, aided, perhaps, by the principle of reversion. The new sub-breeds +in such cases are not descended from any single pair, but from many individuals +which have varied in different degrees, but in the same general manner; and we +may conclude that the races of man have been similarly produced, the +modifications being either the direct result of exposure to different +conditions, or the indirect result of some form of selection. But to this +latter subject we shall presently return. +</p> + +<h3>ON THE EXTINCTION OF THE RACES OF MAN.</h3> + +<p> +The partial or complete extinction of many races and sub-races of man is +historically known. Humboldt saw in South America a parrot which was the sole +living creature that could speak a word of the language of a lost tribe. +Ancient monuments and stone implements found in all parts of the world, about +which no tradition has been preserved by the present inhabitants, indicate much +extinction. Some small and broken tribes, remnants of former races, still +survive in isolated and generally mountainous districts. In Europe the ancient +races were all, according to Shaaffhausen (29. Translation in +‘Anthropological Review,’ Oct. 1868, p. 431.), “lower in the +scale than the rudest living savages”; they must therefore have differed, +to a certain extent, from any existing race. The remains described by Professor +Broca from Les Eyzies, though they unfortunately appear to have belonged to a +single family, indicate a race with a most singular combination of low or +simious, and of high characteristics. This race is “entirely different +from any other, ancient or modern, that we have heard of.” (30. +‘Transactions, International Congress of Prehistoric Archaeology’ +1868, pp. 172-175. See also Broca (tr.) in ‘Anthropological +Review,’ Oct. 1868, p. 410.) It differed, therefore, from the quaternary +race of the caverns of Belgium. +</p> + +<p> +Man can long resist conditions which appear extremely unfavourable for his +existence. (31. Dr. Gerland, ‘Ueber das Aussterben der +Naturvölker,’ 1868, s. 82.) He has long lived in the extreme regions of +the North, with no wood for his canoes or implements, and with only blubber as +fuel, and melted snow as drink. In the southern extremity of America the +Fuegians survive without the protection of clothes, or of any building worthy +to be called a hovel. In South Africa the aborigines wander over arid plains, +where dangerous beasts abound. Man can withstand the deadly influence of the +Terai at the foot of the Himalaya, and the pestilential shores of tropical +Africa. +</p> + +<p> +Extinction follows chiefly from the competition of tribe with tribe, and race +with race. Various checks are always in action, serving to keep down the +numbers of each savage tribe,—such as periodical famines, nomadic habits +and the consequent deaths of infants, prolonged suckling, wars, accidents, +sickness, licentiousness, the stealing of women, infanticide, and especially +lessened fertility. If any one of these checks increases in power, even +slightly, the tribe thus affected tends to decrease; and when of two adjoining +tribes one becomes less numerous and less powerful than the other, the contest +is soon settled by war, slaughter, cannibalism, slavery, and absorption. Even +when a weaker tribe is not thus abruptly swept away, if it once begins to +decrease, it generally goes on decreasing until it becomes extinct. (32. +Gerland (ibid. s. 12) gives facts in support of this statement.) +</p> + +<p> +When civilised nations come into contact with barbarians the struggle is short, +except where a deadly climate gives its aid to the native race. Of the causes +which lead to the victory of civilised nations, some are plain and simple, +others complex and obscure. We can see that the cultivation of the land will be +fatal in many ways to savages, for they cannot, or will not, change their +habits. New diseases and vices have in some cases proved highly destructive; +and it appears that a new disease often causes much death, until those who are +most susceptible to its destructive influence are gradually weeded out (33. See +remarks to this effect in Sir H. Holland’s ‘Medical Notes and +Reflections,’ 1839, p. 390.); and so it may be with the evil effects from +spirituous liquors, as well as with the unconquerably strong taste for them +shewn by so many savages. It further appears, mysterious as is the fact, that +the first meeting of distinct and separated people generates disease. (34. I +have collected (‘Journal of Researches: Voyage of the +“Beagle,”’ p. 435) a good many cases bearing on this subject; +see also Gerland, ibid. s. 8. Poeppig speaks of the “breath of +civilisation as poisonous to savages.”) Mr. Sproat, who in Vancouver +Island closely attended to the subject of extinction, believed that changed +habits of life, consequent on the advent of Europeans, induces much ill health. +He lays, also, great stress on the apparently trifling cause that the natives +become “bewildered and dull by the new life around them; they lose the +motives for exertion, and get no new ones in their place.” (35. Sproat, +‘Scenes and Studies of Savage Life,’ 1868, p. 284.) +</p> + +<p> +The grade of their civilisation seems to be a most important element in the +success of competing nations. A few centuries ago Europe feared the inroads of +Eastern barbarians; now any such fear would be ridiculous. It is a more curious +fact, as Mr. Bagehot has remarked, that savages did not formerly waste away +before the classical nations, as they now do before modern civilised nations; +had they done so, the old moralists would have mused over the event; but there +is no lament in any writer of that period over the perishing barbarians. (36. +Bagehot, ‘Physics and Politics,’ ‘Fortnightly Review,’ +April 1, 1868, p. 455.) The most potent of all the causes of extinction, +appears in many cases to be lessened fertility and ill-health, especially +amongst the children, arising from changed conditions of life, notwithstanding +that the new conditions may not be injurious in themselves. I am much indebted +to Mr. H.H. Howorth for having called my attention to this subject, and for +having given me information respecting it. I have collected the following +cases. +</p> + +<p> +When Tasmania was first colonised the natives were roughly estimated by some at +7000 and by others at 20,000. Their number was soon greatly reduced, chiefly by +fighting with the English and with each other. After the famous hunt by all the +colonists, when the remaining natives delivered themselves up to the +government, they consisted only of 120 individuals (37. All the statements here +given are taken from ‘The Last of the Tasmanians,’ by J. Bonwick, +1870.), who were in 1832 transported to Flinders Island. This island, situated +between Tasmania and Australia, is forty miles long, and from twelve to +eighteen miles broad: it seems healthy, and the natives were well treated. +Nevertheless, they suffered greatly in health. In 1834 they consisted (Bonwick, +p. 250) of forty-seven adult males, forty-eight adult females, and sixteen +children, or in all of 111 souls. In 1835 only one hundred were left. As they +continued rapidly to decrease, and as they themselves thought that they should +not perish so quickly elsewhere, they were removed in 1847 to Oyster Cove in +the southern part of Tasmania. They then consisted (Dec. 20th, 1847) of +fourteen men, twenty-two women and ten children. (38. This is the statement of +the Governor of Tasmania, Sir W. Denison, ‘Varieties of Vice-Regal +Life,’ 1870, vol. i. p. 67.) But the change of site did no good. Disease +and death still pursued them, and in 1864 one man (who died in 1869), and three +elderly women alone survived. The infertility of the women is even a more +remarkable fact than the liability of all to ill-health and death. At the time +when only nine women were left at Oyster Cove, they told Mr. Bonwick (p. 386), +that only two had ever borne children: and these two had together produced only +three children! +</p> + +<p> +With respect to the cause of this extraordinary state of things, Dr. Story +remarks that death followed the attempts to civilise the natives. “If +left to themselves to roam as they were wont and undisturbed, they would have +reared more children, and there would have been less mortality.” Another +careful observer of the natives, Mr. Davis, remarks, “The births have +been few and the deaths numerous. This may have been in a great measure owing +to their change of living and food; but more so to their banishment from the +mainland of Van Diemen’s Land, and consequent depression of +spirits” (Bonwick, pp. 388, 390). +</p> + +<p> +Similar facts have been observed in two widely different parts of Australia. +The celebrated explorer, Mr. Gregory, told Mr. Bonwick, that in Queensland +“the want of reproduction was being already felt with the blacks, even in +the most recently settled parts, and that decay would set in.” Of +thirteen aborigines from Shark’s Bay who visited Murchison River, twelve +died of consumption within three months. (39. For these cases, see +Bonwick’s ‘Daily Life of the Tasmanians,’ 1870, p. 90: and +the ‘Last of the Tasmanians,’ 1870, p. 386.) +</p> + +<p> +The decrease of the Maories of New Zealand has been carefully investigated by +Mr. Fenton, in an admirable Report, from which all the following statements, +with one exception, are taken. (40. ‘Observations on the Aboriginal +Inhabitants of New Zealand,’ published by the Government, 1859.) The +decrease in number since 1830 is admitted by every one, including the natives +themselves, and is still steadily progressing. Although it has hitherto been +found impossible to take an actual census of the natives, their numbers were +carefully estimated by residents in many districts. The result seems +trustworthy, and shows that during the fourteen years, previous to 1858, the +decrease was 19.42 per cent. Some of the tribes, thus carefully examined, lived +above a hundred miles apart, some on the coast, some inland; and their means of +subsistence and habits differed to a certain extent (p. 28). The total number +in 1858 was believed to be 53,700, and in 1872, after a second interval of +fourteen years, another census was taken, and the number is given as only +36,359, shewing a decrease of 32.29 per cent! (41. ‘New Zealand,’ +by Alex. Kennedy, 1873, p. 47.) Mr. Fenton, after shewing in detail the +insufficiency of the various causes, usually assigned in explanation of this +extraordinary decrease, such as new diseases, the profligacy of the women, +drunkenness, wars, etc., concludes on weighty grounds that it depends chiefly +on the unproductiveness of the women, and on the extraordinary mortality of the +young children (pp. 31, 34). In proof of this he shews (p. 33) that in 1844 +there was one non-adult for every 2.57 adults; whereas in 1858 there was only +one non-adult for every 3.27 adults. The mortality of the adults is also great. +He adduces as a further cause of the decrease the inequality of the sexes; for +fewer females are born than males. To this latter point, depending perhaps on a +widely distinct cause, I shall return in a future chapter. Mr. Fenton contrasts +with astonishment the decrease in New Zealand with the increase in Ireland; +countries not very dissimilar in climate, and where the inhabitants now follow +nearly similar habits. The Maories themselves (p. 35) “attribute their +decadence, in some measure, to the introduction of new food and clothing, and +the attendant change of habits”; and it will be seen, when we consider +the influence of changed conditions on fertility, that they are probably right. +The diminution began between the years 1830 and 1840; and Mr. Fenton shews (p. +40) that about 1830, the art of manufacturing putrid corn (maize), by long +steeping in water, was discovered and largely practised; and this proves that a +change of habits was beginning amongst the natives, even when New Zealand was +only thinly inhabited by Europeans. When I visited the Bay of Islands in 1835, +the dress and food of the inhabitants had already been much modified: they +raised potatoes, maize, and other agricultural produce, and exchanged them for +English manufactured goods and tobacco. +</p> + +<p> +It is evident from many statements in the life of Bishop Patteson (42. +‘Life of J.C. Patteson,’ by C.M. Younge, 1874; see more especially +vol. i. p. 530.), that the Melanesians of the New Hebrides and neighbouring +archipelagoes, suffered to an extraordinary degree in health, and perished in +large numbers, when they were removed to New Zealand, Norfolk Island, and other +salubrious places, in order to be educated as missionaries. +</p> + +<pre> +The decrease of the native population of the Sandwich Islands is as +notorious as that of New Zealand. It has been roughly estimated by those +best capable of judging, that when Cook discovered the Islands in 1779, the +population amounted to about 300,000. According to a loose census in 1823, +the numbers then were 142,050. In 1832, and at several subsequent periods, +an accurate census was officially taken, but I have been able to obtain +only the following returns: + Native Population Annual rate of decrease + per cent., assuming it to + (Except during 1832 and have been uniform between + 1836, when the few the successive censuses; + foreigners in the islands these censuses being taken + Year were included.) at irregular intervals. + + 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 +</pre> + +<p> +We here see that in the interval of forty years, between 1832 and 1872, the +population has decreased no less than sixty-eight per cent.! This has been +attributed by most writers to the profligacy of the women, to former bloody +wars, and to the severe labour imposed on conquered tribes and to newly +introduced diseases, which have been on several occasions extremely +destructive. No doubt these and other such causes have been highly efficient, +and may account for the extraordinary rate of decrease between the years 1832 +and 1836; but the most potent of all the causes seems to be lessened fertility. +According to Dr. Ruschenberger of the U.S. Navy, who visited these islands +between 1835 and 1837, in one district of Hawaii, only twenty-five men out of +1134, and in another district only ten out of 637, had a family with as many as +three children. Of eighty married women, only thirty-nine had ever borne +children; and “the official report gives an average of half a child to +each married couple in the whole island.” This is almost exactly the same +average as with the Tasmanians at Oyster Cove. Jarves, who published his +History in 1843, says that “families who have three children are freed +from all taxes; those having more, are rewarded by gifts of land and other +encouragements.” This unparalleled enactment by the government well shews +how infertile the race had become. The Rev. A. Bishop stated in the Hawaiian +‘Spectator’ in 1839, that a large proportion of the children die at +early ages, and Bishop Staley informs me that this is still the case, just as +in New Zealand. This has been attributed to the neglect of the children by the +women, but it is probably in large part due to innate weakness of constitution +in the children, in relation to the lessened fertility of their parents. There +is, moreover, a further resemblance to the case of New Zealand, in the fact +that there is a large excess of male over female births: the census of 1872 +gives 31,650 males to 25,247 females of all ages, that is 125.36 males for +every 100 females; whereas in all civilised countries the females exceed the +males. No doubt the profligacy of the women may in part account for their small +fertility; but their changed habits of life is a much more probable cause, and +which will at the same time account for the increased mortality, especially of +the children. The islands were visited by Cook in 1779, Vancouver in 1794, and +often subsequently by whalers. In 1819 missionaries arrived, and found that +idolatry had been already abolished, and other changes effected by the king. +After this period there was a rapid change in almost all the habits of life of +the natives, and they soon became “the most civilised of the Pacific +Islanders.” One of my informants, Mr. Coan, who was born on the islands, +remarks that the natives have undergone a greater change in their habits of +life in the course of fifty years than Englishmen during a thousand years. From +information received from Bishop Staley, it does not appear that the poorer +classes have ever much changed their diet, although many new kinds of fruit +have been introduced, and the sugar-cane is in universal use. Owing, however, +to their passion for imitating Europeans, they altered their manner of dressing +at an early period, and the use of alcoholic drinks became very general. +Although these changes appear inconsiderable, I can well believe, from what is +known with respect to animals, that they might suffice to lessen the fertility +of the natives. (43. The foregoing statements are taken chiefly from the +following works: Jarves’ ‘History of the Hawaiian Islands,’ +1843, pp. 400-407. Cheever, ‘Life in the Sandwich Islands,’ 1851, +p. 277. Ruschenberger is quoted by Bonwick, ‘Last of the +Tasmanians,’ 1870, p. 378. Bishop is quoted by Sir E. Belcher, +‘Voyage Round the World,’ 1843, vol. i. p. 272. I owe the census of +the several years to the kindness of Mr. Coan, at the request of Dr. Youmans of +New York; and in most cases I have compared the Youmans figures with those +given in several of the above-named works. I have omitted the census for 1850, +as I have seen two widely different numbers given.) +</p> + +<p> +Lastly, Mr. Macnamara states (44. ‘The Indian Medical Gazette,’ +Nov. 1, 1871, p. 240.) that the low and degraded inhabitants of the Andaman +Islands, on the eastern side of the Gulf of Bengal, are “eminently +susceptible to any change of climate: in fact, take them away from their island +homes, and they are almost certain to die, and that independently of diet or +extraneous influences.” He further states that the inhabitants of the +Valley of Nepal, which is extremely hot in summer, and also the various +hill-tribes of India, suffer from dysentery and fever when on the plains; and +they die if they attempt to pass the whole year there. +</p> + +<p> +We thus see that many of the wilder races of man are apt to suffer much in +health when subjected to changed conditions or habits of life, and not +exclusively from being transported to a new climate. Mere alterations in +habits, which do not appear injurious in themselves, seem to have this same +effect; and in several cases the children are particularly liable to suffer. It +has often been said, as Mr. Macnamara remarks, that man can resist with +impunity the greatest diversities of climate and other changes; but this is +true only of the civilised races. Man in his wild condition seems to be in this +respect almost as susceptible as his nearest allies, the anthropoid apes, which +have never yet survived long, when removed from their native country. +</p> + +<p> +Lessened fertility from changed conditions, as in the case of the Tasmanians, +Maories, Sandwich Islanders, and apparently the Australians, is still more +interesting than their liability to ill-health and death; for even a slight +degree of infertility, combined with those other causes which tend to check the +increase of every population, would sooner or later lead to extinction. The +diminution of fertility may be explained in some cases by the profligacy of the +women (as until lately with the Tahitians), but Mr. Fenton has shewn that this +explanation by no means suffices with the New Zealanders, nor does it with the +Tasmanians. +</p> + +<p> +In the paper above quoted, Mr. Macnamara gives reasons for believing that the +inhabitants of districts subject to malaria are apt to be sterile; but this +cannot apply in several of the above cases. Some writers have suggested that +the aborigines of islands have suffered in fertility and health from long +continued inter-breeding; but in the above cases infertility has coincided too +closely with the arrival of Europeans for us to admit this explanation. Nor +have we at present any reason to believe that man is highly sensitive to the +evil effects of inter-breeding, especially in areas so large as New Zealand, +and the Sandwich archipelago with its diversified stations. On the contrary, it +is known that the present inhabitants of Norfolk Island are nearly all cousins +or near relations, as are the Todas in India, and the inhabitants of some of +the Western Islands of Scotland; and yet they seem not to have suffered in +fertility. (45. On the close relationship of the Norfolk Islanders, Sir W. +Denison, ‘Varieties of Vice-Regal Life,’ vol. i. 1870, p. 410. For +the Todas, see Col. Marshall’s work 1873, p. 110. For the Western Islands +of Scotland, Dr. Mitchell, ‘Edinburgh Medical Journal,’ March to +June, 1865.) +</p> + +<p> +A much more probable view is suggested by the analogy of the lower animals. The +reproductive system can be shewn to be susceptible to an extraordinary degree +(though why we know not) to changed conditions of life; and this susceptibility +leads both to beneficial and to evil results. A large collection of facts on +this subject is given in chap. xviii. of vol. ii. of my ‘Variation of +Animals and Plants under Domestication.’ I can here give only the +briefest abstract; and every one interested in the subject may consult the +above work. Very slight changes increase the health, vigour, and fertility of +most or all organic beings, whilst other changes are known to render a large +number of animals sterile. One of the most familiar cases, is that of tamed +elephants not breeding in India; though they often breed in Ava, where the +females are allowed to roam about the forests to some extent, and are thus +placed under more natural conditions. The case of various American monkeys, +both sexes of which have been kept for many years together in their own +countries, and yet have very rarely or never bred, is a more apposite instance, +because of their relationship to man. It is remarkable how slight a change in +the conditions often induces sterility in a wild animal when captured; and this +is the more strange as all our domesticated animals have become more fertile +than they were in a state of nature; and some of them can resist the most +unnatural conditions with undiminished fertility. (46. For the evidence on this +head, see ‘Variation of Animals,’ etc., vol. ii. p. 111.) Certain +groups of animals are much more liable than others to be affected by captivity; +and generally all the species of the same group are affected in the same +manner. But sometimes a single species in a group is rendered sterile, whilst +the others are not so; on the other hand, a single species may retain its +fertility whilst most of the others fail to breed. The males and females of +some species when confined, or when allowed to live almost, but not quite free, +in their native country, never unite; others thus circumstanced frequently +unite but never produce offspring; others again produce some offspring, but +fewer than in a state of nature; and as bearing on the above cases of man, it +is important to remark that the young are apt to be weak and sickly, or +malformed, and to perish at an early age. +</p> + +<p> +Seeing how general is this law of the susceptibility of the reproductive system +to changed conditions of life, and that it holds good with our nearest allies, +the Quadrumana, I can hardly doubt that it applies to man in his primeval +state. Hence if savages of any race are induced suddenly to change their habits +of life, they become more or less sterile, and their young offspring suffer in +health, in the same manner and from the same cause, as do the elephant and +hunting-leopard in India, many monkeys in America, and a host of animals of all +kinds, on removal from their natural conditions. +</p> + +<p> +We can see why it is that aborigines, who have long inhabited islands, and who +must have been long exposed to nearly uniform conditions, should be specially +affected by any change in their habits, as seems to be the case. Civilised +races can certainly resist changes of all kinds far better than savages; and in +this respect they resemble domesticated animals, for though the latter +sometimes suffer in health (for instance European dogs in India), yet they are +rarely rendered sterile, though a few such instances have been recorded. (47. +‘Variation of Animals,’ etc., vol. ii. p. 16.) The immunity of +civilised races and domesticated animals is probably due to their having been +subjected to a greater extent, and therefore having grown somewhat more +accustomed, to diversified or varying conditions, than the majority of wild +animals; and to their having formerly immigrated or been carried from country +to country, and to different families or sub-races having inter-crossed. It +appears that a cross with civilised races at once gives to an aboriginal race +an immunity from the evil consequences of changed conditions. Thus the crossed +offspring from the Tahitians and English, when settled in Pitcairn Island, +increased so rapidly that the island was soon overstocked; and in June 1856 +they were removed to Norfolk Island. They then consisted of 60 married persons +and 134 children, making a total of 194. Here they likewise increased so +rapidly, that although sixteen of them returned to Pitcairn Island in 1859, +they numbered in January 1868, 300 souls; the males and females being in +exactly equal numbers. What a contrast does this case present with that of the +Tasmanians; the Norfolk Islanders INCREASED in only twelve and a half years +from 194 to 300; whereas the Tasmanians DECREASED during fifteen years from 120 +to 46, of which latter number only ten were children. (48. These details are +taken from ‘The Mutineers of the “Bounty,”’ by Lady +Belcher, 1870; and from ‘Pitcairn Island,’ ordered to be printed by +the House of Commons, May 29, 1863. The following statements about the Sandwich +Islanders are from the ‘Honolulu Gazette,’ and from Mr. Coan.) +</p> + +<p> +So again in the interval between the census of 1866 and 1872 the natives of +full blood in the Sandwich Islands decreased by 8081, whilst the half-castes, +who are believed to be healthier, increased by 847; but I do not know whether +the latter number includes the offspring from the half-castes, or only the +half-castes of the first generation. +</p> + +<p> +The cases which I have here given all relate to aborigines, who have been +subjected to new conditions as the result of the immigration of civilised men. +But sterility and ill-health would probably follow, if savages were compelled +by any cause, such as the inroad of a conquering tribe, to desert their homes +and to change their habits. It is an interesting circumstance that the chief +check to wild animals becoming domesticated, which implies the power of their +breeding freely when first captured, and one chief check to wild men, when +brought into contact with civilisation, surviving to form a civilised race, is +the same, namely, sterility from changed conditions of life. +</p> + +<p> +Finally, although the gradual decrease and ultimate extinction of the races of +man is a highly complex problem, depending on many causes which differ in +different places and at different times; it is the same problem as that +presented by the extinction of one of the higher animals—of the fossil +horse, for instance, which disappeared from South America, soon afterwards to +be replaced, within the same districts, by countless troups of the Spanish +horse. The New Zealander seems conscious of this parallelism, for he compares +his future fate with that of the native rat now almost exterminated by the +European rat. Though the difficulty is great to our imagination, and really +great, if we wish to ascertain the precise causes and their manner of action, +it ought not to be so to our reason, as long as we keep steadily in mind that +the increase of each species and each race is constantly checked in various +ways; so that if any new check, even a slight one, be superadded, the race will +surely decrease in number; and decreasing numbers will sooner or later lead to +extinction; the end, in most cases, being promptly determined by the inroads of +conquering tribes. +</p> + +<h3>ON THE FORMATION OF THE RACES OF MAN.</h3> + +<p> +In some cases the crossing of distinct races has led to the formation of a new +race. The singular fact that the Europeans and Hindoos, who belong to the same +Aryan stock, and speak a language fundamentally the same, differ widely in +appearance, whilst Europeans differ but little from Jews, who belong to the +Semitic stock, and speak quite another language, has been accounted for by +Broca (49. ‘On Anthropology,’ translation, ‘Anthropological +Review,’ Jan. 1868, p. 38.), through certain Aryan branches having been +largely crossed by indigenous tribes during their wide diffusion. When two +races in close contact cross, the first result is a heterogeneous mixture: thus +Mr. Hunter, in describing the Santali or hill-tribes of India, says that +hundreds of imperceptible gradations may be traced “from the black, squat +tribes of the mountains to the tall olive-coloured Brahman, with his +intellectual brow, calm eyes, and high but narrow head”; so that it is +necessary in courts of justice to ask the witnesses whether they are Santalis +or Hindoos. (50. ‘The Annals of Rural Bengal,’ 1868, p. 134.) +Whether a heterogeneous people, such as the inhabitants of some of the +Polynesian islands, formed by the crossing of two distinct races, with few or +no pure members left, would ever become homogeneous, is not known from direct +evidence. But as with our domesticated animals, a cross-breed can certainly be +fixed and made uniform by careful selection (51. ‘The Variation of +Animals and Plants under Domestication,’ vol. ii. p. 95.) in the course +of a few generations, we may infer that the free intercrossing of a +heterogeneous mixture during a long descent would supply the place of +selection, and overcome any tendency to reversion; so that the crossed race +would ultimately become homogeneous, though it might not partake in an equal +degree of the characters of the two parent-races. +</p> + +<p> +Of all the differences between the races of man, the colour of the skin is the +most conspicuous and one of the best marked. It was formerly thought that +differences of this kind could be accounted for by long exposure to different +climates; but Pallas first shewed that this is not tenable, and he has since +been followed by almost all anthropologists. (52. Pallas, ‘Act. Acad. St. +Petersburg,’ 1780, part ii. p. 69. He was followed by Rudolphi, in his +‘Beytrage zur Anthropologie,’ 1812. An excellent summary of the +evidence is given by Godron, ‘De l’Espèce,’ 1859, vol. ii. p. +246, etc.) This view has been rejected chiefly because the distribution of the +variously coloured races, most of whom must have long inhabited their present +homes, does not coincide with corresponding differences of climate. Some little +weight may be given to such cases as that of the Dutch families, who, as we +hear on excellent authority (53. Sir Andrew Smith, as quoted by Knox, +‘Races of Man,’ 1850, p. 473.), have not undergone the least change +of colour after residing for three centuries in South Africa. An argument on +the same side may likewise be drawn from the uniform appearance in various +parts of the world of gipsies and Jews, though the uniformity of the latter has +been somewhat exaggerated. (54. See De Quatrefages on this head, ‘Revue +des Cours Scientifiques,’ Oct. 17, 1868, p. 731.) A very damp or a very +dry atmosphere has been supposed to be more influential in modifying the colour +of the skin than mere heat; but as D’Orbigny in South America, and +Livingstone in Africa, arrived at diametrically opposite conclusions with +respect to dampness and dryness, any conclusion on this head must be considered +as very doubtful. (55. Livingstone’s ‘Travels and Researches in S. +Africa,’ 1857, pp. 338, 339. D’Orbigny, as quoted by Godron, +‘De l’Espece,’ vol. ii. p. 266.) +</p> + +<p> +Various facts, which I have given elsewhere, prove that the colour of the skin +and hair is sometimes correlated in a surprising manner with a complete +immunity from the action of certain vegetable poisons, and from the attacks of +certain parasites. Hence it occurred to me, that negroes and other dark races +might have acquired their dark tints by the darker individuals escaping from +the deadly influence of the miasma of their native countries, during a long +series of generations. +</p> + +<p> +I afterwards found that this same idea had long ago occurred to Dr. Wells. (56. +See a paper read before the Royal Soc. in 1813, and published in his Essays in +1818. I have given an account of Dr. Wells’ views in the Historical +Sketch (p. xvi.) to my ‘Origin of Species.’ Various cases of colour +correlated with constitutional peculiarities are given in my ‘Variation +of Animals and Plants under Domestication,’ vol. ii. pp. 227, 335.) It +has long been known that negroes, and even mulattoes, are almost completely +exempt from the yellow-fever, so destructive in tropical America. (57. See, for +instance, Nott and Gliddon, ‘Types of Mankind,’ p. 68.) They +likewise escape to a large extent the fatal intermittent fevers, that prevail +along at least 2600 miles of the shores of Africa, and which annually cause +one-fifth of the white settlers to die, and another fifth to return home +invalided. (58. Major Tulloch, in a paper read before the Statistical Society, +April 20, 1840, and given in the ‘Athenaeum,’ 1840, p. 353.) This +immunity in the negro seems to be partly inherent, depending on some unknown +peculiarity of constitution, and partly the result of acclimatisation. Pouchet +(59. ‘The Plurality of the Human Race’ (translat.), 1864, p. 60.) +states that the negro regiments recruited near the Soudan, and borrowed from +the Viceroy of Egypt for the Mexican war, escaped the yellow-fever almost +equally with the negroes originally brought from various parts of Africa and +accustomed to the climate of the West Indies. That acclimatisation plays a +part, is shewn by the many cases in which negroes have become somewhat liable +to tropical fevers, after having resided for some time in a colder climate. +(60. Quatrefages, ‘Unité de l’Espèce Humaine,’ 1861, p. 205. +Waitz, ‘Introduction to Anthropology,’ translat., vol. i. 1863, p. +124. Livingstone gives analogous cases in his ‘Travels.’) The +nature of the climate under which the white races have long resided, likewise +has some influence on them; for during the fearful epidemic of yellow fever in +Demerara during 1837, Dr. Blair found that the death-rate of the immigrants was +proportional to the latitude of the country whence they had come. With the +negro the immunity, as far as it is the result of acclimatisation, implies +exposure during a prodigious length of time; for the aborigines of tropical +America who have resided there from time immemorial, are not exempt from yellow +fever; and the Rev. H.B. Tristram states, that there are districts in Northern +Africa which the native inhabitants are compelled annually to leave, though the +negroes can remain with safety. +</p> + +<p> +That the immunity of the negro is in any degree correlated with the colour of +his skin is a mere conjecture: it may be correlated with some difference in his +blood, nervous system, or other tissues. Nevertheless, from the facts above +alluded to, and from some connection apparently existing between complexion and +a tendency to consumption, the conjecture seemed to me not improbable. +Consequently I endeavoured, with but little success (61. In the spring of 1862 +I obtained permission from the Director-General of the Medical department of +the Army, to transmit to the surgeons of the various regiments on foreign +service a blank table, with the following appended remarks, but I have received +no returns. “As several well-marked cases have been recorded with our +domestic animals of a relation between the colour of the dermal appendages and +the constitution; and it being notorious that there is some limited degree of +relation between the colour of the races of man and the climate inhabited by +them; the following investigation seems worth consideration. Namely, whether +there is any relation in Europeans between the colour of their hair, and their +liability to the diseases of tropical countries. If the surgeons of the several +regiments, when stationed in unhealthy tropical districts, would be so good as +first to count, as a standard of comparison, how many men, in the force whence +the sick are drawn, have dark and light-coloured hair, and hair of intermediate +or doubtful tints; and if a similar account were kept by the same medical +gentlemen, of all the men who suffered from malarious and yellow fevers, or +from dysentery, it would soon be apparent, after some thousand cases had been +tabulated, whether there exists any relation between the colour of the hair and +constitutional liability to tropical diseases. Perhaps no such relation would +be discovered, but the investigation is well worth making. In case any positive +result were obtained, it might be of some practical use in selecting men for +any particular service. Theoretically the result would be of high interest, as +indicating one means by which a race of men inhabiting from a remote period an +unhealthy tropical climate, might have become dark-coloured by the better +preservation of dark-haired or dark-complexioned individuals during a long +succession of generations.”), to ascertain how far it holds good. The +late Dr. Daniell, who had long lived on the West Coast of Africa, told me that +he did not believe in any such relation. He was himself unusually fair, and had +withstood the climate in a wonderful manner. When he first arrived as a boy on +the coast, an old and experienced negro chief predicted from his appearance +that this would prove the case. Dr. Nicholson, of Antigua, after having +attended to this subject, writes to me that dark-coloured Europeans escape the +yellow fever more than those that are light-coloured. Mr. J.M. Harris +altogether denies that Europeans with dark hair withstand a hot climate better +than other men: on the contrary, experience has taught him in making a +selection of men for service on the coast of Africa, to choose those with red +hair. (62. ‘Anthropological Review,’ Jan. 1866, p. xxi. Dr. Sharpe +also says, with respect to India (‘Man a Special Creation,’ 1873, +p. 118), “that it has been noticed by some medical officers that +Europeans with light hair and florid complexions suffer less from diseases of +tropical countries than persons with dark hair and sallow complexions; and, so +far as I know, there appear to be good grounds for this remark.” On the +other hand, Mr. Heddle, of Sierra Leone, “who has had more clerks killed +under him than any other man,” by the climate of the West African Coast +(W. Reade, ‘African Sketch Book,’ vol. ii. p. 522), holds a +directly opposite view, as does Capt. Burton.) As far, therefore, as these +slight indications go, there seems no foundation for the hypothesis, that +blackness has resulted from the darker and darker individuals having survived +better during long exposure to fever-generating miasma. +</p> + +<p> +Dr. Sharpe remarks (63. ‘Man a Special Creation,’ 1873, p. 119.), +that a tropical sun, which burns and blisters a white skin, does not injure a +black one at all; and, as he adds, this is not due to habit in the individual, +for children only six or eight months old are often carried about naked, and +are not affected. I have been assured by a medical man, that some years ago +during each summer, but not during the winter, his hands became marked with +light brown patches, like, although larger than freckles, and that these +patches were never affected by sun-burning, whilst the white parts of his skin +have on several occasions been much inflamed and blistered. With the lower +animals there is, also, a constitutional difference in liability to the action +of the sun between those parts of the skin clothed with white hair and other +parts. (64. ‘Variation of Animals and Plants under Domestication,’ +vol. ii. pp. 336, 337.) Whether the saving of the skin from being thus burnt is +of sufficient importance to account for a dark tint having been gradually +acquired by man through natural selection, I am unable to judge. If it be so, +we should have to assume that the natives of tropical America have lived there +for a much shorter time than the Negroes in Africa, or the Papuans in the +southern parts of the Malay archipelago, just as the lighter-coloured Hindoos +have resided in India for a shorter time than the darker aborigines of the +central and southern parts of the peninsula. +</p> + +<p> +Although with our present knowledge we cannot account for the differences of +colour in the races of man, through any advantage thus gained, or from the +direct action of climate; yet we must not quite ignore the latter agency, for +there is good reason to believe that some inherited effect is thus produced. +(65. See, for instance, Quatrefages (‘Revue des Cours +Scientifiques,’ Oct. 10, 1868, p. 724) on the effects of residence in +Abyssinia and Arabia, and other analogous cases. Dr. Rolle (‘Der Mensch, +seine Abstammung,’ etc., 1865, s. 99) states, on the authority of +Khanikof, that the greater number of German families settled in Georgia, have +acquired in the course of two generations dark hair and eyes. Mr. D. Forbes +informs me that the Quichuas in the Andes vary greatly in colour, according to +the position of the valleys inhabited by them.) +</p> + +<p> +We have seen in the second chapter that the conditions of life affect the +development of the bodily frame in a direct manner, and that the effects are +transmitted. Thus, as is generally admitted, the European settlers in the +United States undergo a slight but extraordinary rapid change of appearance. +Their bodies and limbs become elongated; and I hear from Col. Bernys that +during the late war in the United States, good evidence was afforded of this +fact by the ridiculous appearance presented by the German regiments, when +dressed in ready-made clothes manufactured for the American market, and which +were much too long for the men in every way. There is, also, a considerable +body of evidence shewing that in the Southern States the house-slaves of the +third generation present a markedly different appearance from the field-slaves. +(66. Harlan, ‘Medical Researches,’ p. 532. Quatrefages +(‘Unité de l’Espèce Humaine,’ 1861, p. 128) has collected +much evidence on this head.) +</p> + +<p> +If, however, we look to the races of man as distributed over the world, we must +infer that their characteristic differences cannot be accounted for by the +direct action of different conditions of life, even after exposure to them for +an enormous period of time. The Esquimaux live exclusively on animal food; they +are clothed in thick fur, and are exposed to intense cold and to prolonged +darkness; yet they do not differ in any extreme degree from the inhabitants of +Southern China, who live entirely on vegetable food, and are exposed almost +naked to a hot, glaring climate. The unclothed Fuegians live on the marine +productions of their inhospitable shores; the Botocudos of Brazil wander about +the hot forests of the interior and live chiefly on vegetable productions; yet +these tribes resemble each other so closely that the Fuegians on board the +“Beagle” were mistaken by some Brazilians for Botocudos. The +Botocudos again, as well as the other inhabitants of tropical America, are +wholly different from the Negroes who inhabit the opposite shores of the +Atlantic, are exposed to a nearly similar climate, and follow nearly the same +habits of life. +</p> + +<p> +Nor can the differences between the races of man be accounted for by the +inherited effects of the increased or decreased use of parts, except to a quite +insignificant degree. Men who habitually live in canoes, may have their legs +somewhat stunted; those who inhabit lofty regions may have their chests +enlarged; and those who constantly use certain sense-organs may have the +cavities in which they are lodged somewhat increased in size, and their +features consequently a little modified. With civilised nations, the reduced +size of the jaws from lessened use—the habitual play of different muscles +serving to express different emotions—and the increased size of the brain +from greater intellectual activity, have together produced a considerable +effect on their general appearance when compared with savages. (67. See Prof. +Schaaffhausen, translat., in ‘Anthropological Review,’ Oct. 1868, +p. 429.) Increased bodily stature, without any corresponding increase in the +size of the brain, may (judging from the previously adduced case of rabbits), +have given to some races an elongated skull of the dolichocephalic type. +</p> + +<p> +Lastly, the little-understood principle of correlated development has sometimes +come into action, as in the case of great muscular development and strongly +projecting supra-orbital ridges. The colour of the skin and hair are plainly +correlated, as is the texture of the hair with its colour in the Mandans of +North America. (68. Mr. Catlin states (‘N. American Indians,’ 3rd +ed., 1842, vol. i. p. 49) that in the whole tribe of the Mandans, about one in +ten or twelve of the members, of all ages and both sexes, have bright silvery +grey hair, which is hereditary. Now this hair is as coarse and harsh as that of +a horse’s mane, whilst the hair of other colours is fine and soft.) The +colour also of the skin, and the odour emitted by it, are likewise in some +manner connected. With the breeds of sheep the number of hairs within a given +space and the number of excretory pores are related. (69. On the odour of the +skin, Godron, ‘Sur l’Espèce,’ tom. ii. p. 217. On the pores +in the skin, Dr. Wilckens, ‘Die Aufgaben der Landwirth. +Zootechnik,’ 1869, s. 7.) If we may judge from the analogy of our +domesticated animals, many modifications of structure in man probably come +under this principle of correlated development. +</p> + +<p> +We have now seen that the external characteristic differences between the races +of man cannot be accounted for in a satisfactory manner by the direct action of +the conditions of life, nor by the effects of the continued use of parts, nor +through the principle of correlation. We are therefore led to enquire whether +slight individual differences, to which man is eminently liable, may not have +been preserved and augmented during a long series of generations through +natural selection. But here we are at once met by the objection that beneficial +variations alone can be thus preserved; and as far as we are enabled to judge, +although always liable to err on this head, none of the differences between the +races of man are of any direct or special service to him. The intellectual and +moral or social faculties must of course be excepted from this remark. The +great variability of all the external differences between the races of man, +likewise indicates that they cannot be of much importance; for if important, +they would long ago have been either fixed and preserved, or eliminated. In +this respect man resembles those forms, called by naturalists protean or +polymorphic, which have remained extremely variable, owing, as it seems, to +such variations being of an indifferent nature, and to their having thus +escaped the action of natural selection. +</p> + +<p> +We have thus far been baffled in all our attempts to account for the +differences between the races of man; but there remains one important agency, +namely Sexual Selection, which appears to have acted powerfully on man, as on +many other animals. I do not intend to assert that sexual selection will +account for all the differences between the races. An unexplained residuum is +left, about which we can only say, in our ignorance, that as individuals are +continually born with, for instance, heads a little rounder or narrower, and +with noses a little longer or shorter, such slight differences might become +fixed and uniform, if the unknown agencies which induced them were to act in a +more constant manner, aided by long-continued intercrossing. Such variations +come under the provisional class, alluded to in our second chapter, which for +want of a better term are often called spontaneous. Nor do I pretend that the +effects of sexual selection can be indicated with scientific precision; but it +can be shewn that it would be an inexplicable fact if man had not been modified +by this agency, which appears to have acted powerfully on innumerable animals. +It can further be shewn that the differences between the races of man, as in +colour, hairiness, form of features, etc., are of a kind which might have been +expected to come under the influence of sexual selection. But in order to treat +this subject properly, I have found it necessary to pass the whole animal +kingdom in review. I have therefore devoted to it the Second Part of this work. +At the close I shall return to man, and, after attempting to shew how far he +has been modified through sexual selection, will give a brief summary of the +chapters in this First Part. +</p> + +<p> +NOTE ON THE RESEMBLANCES AND DIFFERENCES IN THE STRUCTURE AND THE DEVELOPMENT +OF THE BRAIN IN MAN AND APES BY PROFESSOR HUXLEY, F.R.S. +</p> + +<p> +The controversy respecting the nature and the extent of the differences in the +structure of the brain in man and the apes, which arose some fifteen years ago, +has not yet come to an end, though the subject matter of the dispute is, at +present, totally different from what it was formerly. It was originally +asserted and re-asserted, with singular pertinacity, that the brain of all the +apes, even the highest, differs from that of man, in the absence of such +conspicuous structures as the posterior lobes of the cerebral hemispheres, with +the posterior cornu of the lateral ventricle and the hippocampus minor, +contained in those lobes, which are so obvious in man. +</p> + +<p> +But the truth that the three structures in question are as well developed in +apes’ as in human brains, or even better; and that it is characteristic +of all the Primates (if we exclude the Lemurs) to have these parts well +developed, stands at present on as secure a basis as any proposition in +comparative anatomy. Moreover, it is admitted by every one of the long series +of anatomists who, of late years, have paid special attention to the +arrangement of the complicated sulci and gyri which appear upon the surface of +the cerebral hemispheres in man and the higher apes, that they are disposed +after the very same pattern in him, as in them. Every principal gyrus and +sulcus of a chimpanzee’s brain is clearly represented in that of a man, +so that the terminology which applies to the one answers for the other. On this +point there is no difference of opinion. Some years since, Professor Bischoff +published a memoir (70. ‘Die Grosshirn-Windungen des Menschen;’ +‘Abhandlungen der K. Bayerischen Akademie,’ B. x. 1868.) on the +cerebral convolutions of man and apes; and as the purpose of my learned +colleague was certainly not to diminish the value of the differences between +apes and men in this respect, I am glad to make a citation from him. +</p> + +<p> +“That the apes, and especially the orang, chimpanzee and gorilla, come +very close to man in their organisation, much nearer than to any other animal, +is a well known fact, disputed by nobody. Looking at the matter from the point +of view of organisation alone, no one probably would ever have disputed the +view of Linnaeus, that man should be placed, merely as a peculiar species, at +the head of the mammalia and of those apes. Both shew, in all their organs, so +close an affinity, that the most exact anatomical investigation is needed in +order to demonstrate those differences which really exist. So it is with the +brains. The brains of man, the orang, the chimpanzee, the gorilla, in spite of +all the important differences which they present, come very close to one +another” (loc. cit. p. 101). +</p> + +<p> +There remains, then, no dispute as to the resemblance in fundamental +characters, between the ape’s brain and man’s: nor any as to the +wonderfully close similarity between the chimpanzee, orang and man, in even the +details of the arrangement of the gyri and sulci of the cerebral hemispheres. +Nor, turning to the differences between the brains of the highest apes and that +of man, is there any serious question as to the nature and extent of these +differences. It is admitted that the man’s cerebral hemispheres are +absolutely and relatively larger than those of the orang and chimpanzee; that +his frontal lobes are less excavated by the upward protrusion of the roof of +the orbits; that his gyri and sulci are, as a rule, less symmetrically +disposed, and present a greater number of secondary plications. And it is +admitted that, as a rule, in man, the temporo-occipital or “external +perpendicular” fissure, which is usually so strongly marked a feature of +the ape’s brain is but faintly marked. But it is also clear, that none of +these differences constitutes a sharp demarcation between the man’s and +the ape’s brain. In respect to the external perpendicular fissure of +Gratiolet, in the human brain for instance, Professor Turner remarks: (71. +‘Convolutions of the Human Cerebrum Topographically Considered,’ +1866, p. 12.) +</p> + +<p> +“In some brains it appears simply as an indentation of the margin of the +hemisphere, but, in others, it extends for some distance more or less +transversely outwards. I saw it in the right hemisphere of a female brain pass +more than two inches outwards; and on another specimen, also the right +hemisphere, it proceeded for four-tenths of an inch outwards, and then extended +downwards, as far as the lower margin of the outer surface of the hemisphere. +The imperfect definition of this fissure in the majority of human brains, as +compared with its remarkable distinctness in the brain of most Quadrumana, is +owing to the presence, in the former, of certain superficial, well marked, +secondary convolutions which bridge it over and connect the parietal with the +occipital lobe. The closer the first of these bridging gyri lies to the +longitudinal fissure, the shorter is the external parieto-occipital +fissure” (loc. cit. p. 12). +</p> + +<p> +The obliteration of the external perpendicular fissure of Gratiolet, therefore, +is not a constant character of the human brain. On the other hand, its full +development is not a constant character of the higher ape’s brain. For, +in the chimpanzee, the more or less extensive obliteration of the external +perpendicular sulcus by “bridging convolutions,” on one side or the +other, has been noted over and over again by Prof. Rolleston, Mr. Marshall, M. +Broca and Professor Turner. At the conclusion of a special paper on this +subject the latter writes: (72. Notes more especially on the bridging +convolutions in the Brain of the Chimpanzee, ‘Proceedings of the Royal +Society of Edinburgh,’ 1865-6.) +</p> + +<p> +“The three specimens of the brain of a chimpanzee, just described, prove, +that the generalisation which Gratiolet has attempted to draw of the complete +absence of the first connecting convolution and the concealment of the second, +as essentially characteristic features in the brain of this animal, is by no +means universally applicable. In only one specimen did the brain, in these +particulars, follow the law which Gratiolet has expressed. As regards the +presence of the superior bridging convolution, I am inclined to think that it +has existed in one hemisphere, at least, in a majority of the brains of this +animal which have, up to this time, been figured or described. The superficial +position of the second bridging convolution is evidently less frequent, and has +as yet, I believe, only been seen in the brain (A) recorded in this +communication. The asymmetrical arrangement in the convolutions of the two +hemispheres, which previous observers have referred to in their descriptions, +is also well illustrated in these specimens” (pp. 8, 9). +</p> + +<p> +Even were the presence of the temporo-occipital, or external perpendicular, +sulcus, a mark of distinction between the higher apes and man, the value of +such a distinctive character would be rendered very doubtful by the structure +of the brain in the Platyrrhine apes. In fact, while the temporo-occipital is +one of the most constant of sulci in the Catarrhine, or Old World, apes, it is +never very strongly developed in the New World apes; it is absent in the +smaller Platyrrhini; rudimentary in Pithecia (73. Flower, ‘On the Anatomy +of Pithecia Monachus,’ ‘Proceedings of the Zoological +Society,’ 1862.); and more or less obliterated by bridging convolutions +in Ateles. +</p> + +<p> +A character which is thus variable within the limits of a single group can have +no great taxonomic value. +</p> + +<p> +It is further established, that the degree of asymmetry of the convolution of +the two sides in the human brain is subject to much individual variation; and +that, in those individuals of the Bushman race who have been examined, the gyri +and sulci of the two hemispheres are considerably less complicated and more +symmetrical than in the European brain, while, in some individuals of the +chimpanzee, their complexity and asymmetry become notable. This is particularly +the case in the brain of a young male chimpanzee figured by M. Broca. +(‘L’ordre des Primates,’ p. 165, fig. 11.) +</p> + +<p> +Again, as respects the question of absolute size, it is established that the +difference between the largest and the smallest healthy human brain is greater +than the difference between the smallest healthy human brain and the largest +chimpanzee’s or orang’s brain. +</p> + +<p> +Moreover, there is one circumstance in which the orang’s and +chimpanzee’s brains resemble man’s, but in which they differ from +the lower apes, and that is the presence of two corpora candicantia—the +Cynomorpha having but one. +</p> + +<p> +In view of these facts I do not hesitate in this year 1874, to repeat and +insist upon the proposition which I enunciated in 1863: (74. ‘Man’s +Place in Nature,’ p. 102.) +</p> + +<p> +“So far as cerebral structure goes, therefore, it is clear that man +differs less from the chimpanzee or the orang, than these do even from the +monkeys, and that the difference between the brain of the chimpanzee and of man +is almost insignificant when compared with that between the chimpanzee brain +and that of a Lemur.” +</p> + +<p> +In the paper to which I have referred, Professor Bischoff does not deny the +second part of this statement, but he first makes the irrelevant remark that it +is not wonderful if the brains of an orang and a Lemur are very different; and +secondly, goes on to assert that, “If we successively compare the brain +of a man with that of an orang; the brain of this with that of a chimpanzee; of +this with that of a gorilla, and so on of a Hylobates, Semnopithecus, +Cynocephalus, Cercopithecus, Macacus, Cebus, Callithrix, Lemur, Stenops, +Hapale, we shall not meet with a greater, or even as great a, break in the +degree of development of the convolutions, as we find between the brain of a +man and that of an orang or chimpanzee.” +</p> + +<p> +To which I reply, firstly, that whether this assertion be true or false, it has +nothing whatever to do with the proposition enunciated in ‘Man’s +Place in Nature,’ which refers not to the development of the convolutions +alone, but to the structure of the whole brain. If Professor Bischoff had taken +the trouble to refer to p. 96 of the work he criticises, in fact, he would have +found the following passage: “And it is a remarkable circumstance that +though, so far as our present knowledge extends, there IS one true structural +break in the series of forms of Simian brains, this hiatus does not lie between +man and the manlike apes, but between the lower and the lowest Simians, or in +other words, between the Old and New World apes and monkeys and the Lemurs. +Every Lemur which has yet been examined, in fact, has its cerebellum partially +visible from above; and its posterior lobe, with the contained posterior cornu +and hippocampus minor, more or less rudimentary. Every marmoset, American +monkey, Old World monkey, baboon or manlike ape, on the contrary, has its +cerebellum entirely hidden, posteriorly, by the cerebral lobes, and possesses a +large posterior cornu with a well-developed hippocampus minor.” +</p> + +<p> +This statement was a strictly accurate account of what was known when it was +made; and it does not appear to me to be more than apparently weakened by the +subsequent discovery of the relatively small development of the posterior lobes +in the Siamang and in the Howling monkey. Notwithstanding the exceptional +brevity of the posterior lobes in these two species, no one will pretend that +their brains, in the slightest degree, approach those of the Lemurs. And if, +instead of putting Hapale out of its natural place, as Professor Bischoff most +unaccountably does, we write the series of animals he has chosen to mention as +follows: Homo, Pithecus, Troglodytes, Hylobates, Semnopithecus, Cynocephalus, +Cercopithecus, Macacus, Cebus, Callithrix, Hapale, Lemur, Stenops, I venture to +reaffirm that the great break in this series lies between Hapale and Lemur, and +that this break is considerably greater than that between any other two terms +of that series. Professor Bischoff ignores the fact that long before he wrote, +Gratiolet had suggested the separation of the Lemurs from the other Primates on +the very ground of the difference in their cerebral characters; and that +Professor Flower had made the following observations in the course of his +description of the brain of the Javan Loris: (75. ‘Transactions of the +Zoological Society,’ vol. v. 1862.) +</p> + +<p> +“And it is especially remarkable that, in the development of the +posterior lobes, there is no approximation to the Lemurine, short hemisphered +brain, in those monkeys which are commonly supposed to approach this family in +other respects, viz. the lower members of the Platyrrhine group.” +</p> + +<p> +So far as the structure of the adult brain is concerned, then, the very +considerable additions to our knowledge, which have been made by the researches +of so many investigators, during the past ten years, fully justify the +statement which I made in 1863. But it has been said, that, admitting the +similarity between the adult brains of man and apes, they are nevertheless, in +reality, widely different, because they exhibit fundamental differences in the +mode of their development. No one would be more ready than I to admit the force +of this argument, if such fundamental differences of development really exist. +But I deny that they do exist. On the contrary, there is a fundamental +agreement in the development of the brain in men and apes. +</p> + +<p> +Gratiolet originated the statement that there is a fundamental difference in +the development of the brains of apes and that of man—consisting in this; +that, in the apes, the sulci which first make their appearance are situated on +the posterior region of the cerebral hemispheres, while, in the human foetus, +the sulci first become visible on the frontal lobes. (76. Chez tous les singes, +les plis postérieurs se developpent les premiers; les plis antérieurs se +developpent plus tard, aussi la vertèbre occipitale et la parietale sont-elles +relativement tres-grandes chez le foetus. L’Homme présente une exception +remarquable quant a l’époque de l’apparition des plis frontaux, qui +sont les premiers indiqués; mais le développement general du lobe frontal, +envisagé seulement par rapport a son volume, suit les mêmes lois que dans les +singes: Gratiolet, ‘Mémoire sur les plis cérèbres de l’Homme et des +Primateaux,’ p. 39, Tab. iv, fig. 3.) +</p> + +<p> +This general statement is based upon two observations, the one of a Gibbon +almost ready to be born, in which the posterior gyri were “well +developed,” while those of the frontal lobes were “hardly +indicated” (77. Gratiolet’s words are (loc. cit. p. 39): +“Dans le foetus dont il s’agit les plis cérébraux posterieurs sont +bien developpés, tandis que les plis du lobe frontal sont a peine +indiqués.” The figure, however (Pl. iv, fig. 3), shews the fissure of +Rolando, and one of the frontal sulci plainly enough. Nevertheless, M. Alix, in +his ‘Notice sur les travaux anthropologiques de Gratiolet’ +(‘Mem. de la Societé d’Anthropologie de Paris,’ 1868, page +32), writes thus: “Gratiolet a eu entre les mains le cerveau d’un +foetus de Gibbon, singe eminemment supérieur, et tellement rapproché de +l’orang, que des naturalistes tres-compétents l’ont rangé parmi les +anthropoides. M. Huxley, par exemple, n’hesite pas sur ce point. Eh bien, +c’est sur le cerveau d’un foetus 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 circonvolutions apparaissent +d’a en w, tandis que chez les singes elles se developpent d’w en +a.”), and the other of a human foetus at the 22nd or 23rd week of +uterogestation, in which Gratiolet notes that the insula was uncovered, but +that nevertheless “des incisures sement de lobe anterieur, une scissure +peu profonde indique la separation du lobe occipital, tres-reduit, +d’ailleurs dès cette époque. Le reste de la surface cérébrale est encore +absolument lisse.” +</p> + +<p> +Three views of this brain are given in Plate II, figs. 1, 2, 3, of the work +cited, shewing the upper, lateral and inferior views of the hemispheres, but +not the inner view. It is worthy of note that the figure by no means bears out +Gratiolet’s description, inasmuch as the fissure (antero-temporal) on the +posterior half of the face of the hemisphere is more marked than any of those +vaguely indicated in the anterior half. If the figure is correct, it in no way +justifies Gratiolet’s conclusion: “Il y a donc entre ces cerveaux +[those of a Callithrix and of a Gibbon] et celui du foetus humain une +différence fondamental. Chez celui-ci, longtemps avant que les plis temporaux +apparaissent, les plis frontaux, ESSAYENT d’exister.” +</p> + +<p> +Since Gratiolet’s time, however, the development of the gyri and sulci of +the brain has been made the subject of renewed investigation by Schmidt, +Bischoff, Pansch (78. ‘Ueber die typische Anordnung der Furchen und +Windungen auf den Grosshirn-Hemisphären des Menschen und der Affen,’ +‘Archiv für Anthropologie,’ iii. 1868.), and more particularly by +Ecker (79. ‘Zur Entwicklungs Geschichte der Furchen und Windungen der +Grosshirn-Hemisphären im Foetus des Menschen,’ ‘Archiv für +Anthropologie,’ iii. 1868.), whose work is not only the latest, but by +far the most complete, memoir on the subject. +</p> + +<p> +The final results of their inquiries may be summed up as follows:— 1. In +the human foetus, the sylvian fissure is formed in the course of the third +month of uterogestation. In this, and in the fourth month, the cerebral +hemispheres are smooth and rounded (with the exception of the sylvian +depression), and they project backwards far beyond the cerebellum. +</p> + +<p> +2. The sulci, properly so called, begin to appear in the interval between the +end of the fourth and the beginning of the sixth month of foetal life, but +Ecker is careful to point out that, not only the time, but the order, of their +appearance is subject to considerable individual variation. In no case, +however, are either the frontal or the temporal sulci the earliest. +</p> + +<p> +The first which appears, in fact, lies on the inner face of the hemisphere +(whence doubtless Gratiolet, who does not seem to have examined that face in +his foetus, overlooked it), and is either the internal perpendicular +(occipito-parietal), or the calcarine sulcus, these two being close together +and eventually running into one another. As a rule the occipito-parietal is the +earlier of the two. +</p> + +<p> +3. At the latter part of this period, another sulcus, the +“posterio-parietal,” or “Fissure of Rolando” is +developed, and it is followed, in the course of the sixth month, by the other +principal sulci of the frontal, parietal, temporal and occipital lobes. There +is, however, no clear evidence that one of these constantly appears before the +other; and it is remarkable that, in the brain at the period described and +figured by Ecker (loc. cit. pp. 212-213, Taf. II, figs. 1, 2, 3, 4), the +antero-temporal sulcus (scissure parallele) so characteristic of the +ape’s brain, is as well, if not better developed than the fissure of +Rolando, and is much more marked than the proper frontal sulci. +</p> + +<p> +Taking the facts as they now stand, it appears to me that the order of the +appearance of the sulci and gyri in the foetal human brain is in perfect +harmony with the general doctrine of evolution, and with the view that man has +been evolved from some ape-like form; though there can be no doubt that form +was, in many respects, different from any member of the Primates now living. +</p> + +<p> +Von Baer taught us, half a century ago, that, in the course of their +development, allied animals put on at first, the characters of the greater +groups to which they belong, and, by degrees, assume those which restrict them +within the limits of their family, genus, and species; and he proved, at the +same time, that no developmental stage of a higher animal is precisely similar +to the adult condition of any lower animal. It is quite correct to say that a +frog passes through the condition of a fish, inasmuch as at one period of its +life the tadpole has all the characters of a fish, and if it went no further, +would have to be grouped among fishes. But it is equally true that a tadpole is +very different from any known fish. +</p> + +<p> +In like manner, the brain of a human foetus, at the fifth month, may correctly +be said to be, not only the brain of an ape, but that of an Arctopithecine or +marmoset-like ape; for its hemispheres, with their great posterior lobster, and +with no sulci but the sylvian and the calcarine, present the characteristics +found only in the group of the Arctopithecine Primates. But it is equally true, +as Gratiolet remarks, that, in its widely open sylvian fissure, it differs from +the brain of any actual marmoset. No doubt it would be much more similar to the +brain of an advanced foetus of a marmoset. But we know nothing whatever of the +development of the brain in the marmosets. In the Platyrrhini proper, the only +observation with which I am acquainted is due to Pansch, who found in the brain +of a foetal Cebus Apella, in addition to the sylvian fissure and the deep +calcarine fissure, only a very shallow antero-temporal fissure (scissure +parallele of Gratiolet). +</p> + +<p> +Now this fact, taken together with the circumstance that the antero-temporal +sulcus is present in such Platyrrhini as the Saimiri, which present mere traces +of sulci on the anterior half of the exterior of the cerebral hemispheres, or +none at all, undoubtedly, so far as it goes, affords fair evidence in favour of +Gratiolet’s hypothesis, that the posterior sulci appear before the +anterior, in the brains of the Platyrrhini. But, it by no means follows, that +the rule which may hold good for the Platyrrhini extends to the Catarrhini. We +have no information whatever respecting the development of the brain in the +Cynomorpha; and, as regards the Anthropomorpha, nothing but the account of the +brain of the Gibbon, near birth, already referred to. At the present moment +there is not a shadow of evidence to shew that the sulci of a +chimpanzee’s, or orang’s, brain do not appear in the same order as +a man’s. +</p> + +<p> +Gratiolet opens his preface with the aphorism: “Il est dangereux dans les +sciences de conclure trop vite.” I fear he must have forgotten this sound +maxim by the time he had reached the discussion of the differences between men +and apes, in the body of his work. No doubt, the excellent author of one of the +most remarkable contributions to the just understanding of the mammalian brain +which has ever been made, would have been the first to admit the insufficiency +of his data had he lived to profit by the advance of inquiry. The misfortune is +that his conclusions have been employed by persons incompetent to appreciate +their foundation, as arguments in favour of obscurantism. (80. For example, M. +l’Abbe Lecomte in his terrible pamphlet, ‘Le Darwinisme et +l’origine de l’Homme,’ 1873.) +</p> + +<p> +But it is important to remark that, whether Gratiolet was right or wrong in his +hypothesis respecting the relative order of appearance of the temporal and +frontal sulci, the fact remains; that before either temporal or frontal sulci, +appear, the foetal brain of man presents characters which are found only in the +lowest group of the Primates (leaving out the Lemurs); and that this is exactly +what we should expect to be the case, if man has resulted from the gradual +modification of the same form as that from which the other Primates have +sprung. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2H_4_0014" id="link2H_4_0014"></a> +PART II.<br /> +SEXUAL SELECTION.</h2> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0008" id="link2HCH0008"></a> +CHAPTER VIII.<br /> +PRINCIPLES OF SEXUAL SELECTION.</h2> + +<p class="letter"> +Secondary sexual characters—Sexual selection—Manner of +action—Excess of males—Polygamy—The male alone generally +modified through sexual selection—Eagerness of the male—Variability +of the male—Choice exerted by the female—Sexual compared with +natural selection—Inheritance, at corresponding periods of life, at +corresponding seasons of the year, and as limited by sex—Relations +between the several forms of inheritance—Causes why one sex and the young +are not modified through sexual selection—Supplement on the proportional +numbers of the two sexes throughout the animal kingdom—The proportion of +the sexes in relation to natural selection. +</p> + +<p> +With animals which have their sexes separated, the males necessarily differ +from the females in their organs of reproduction; and these are the primary +sexual characters. But the sexes often differ in what Hunter has called +secondary sexual characters, which are not directly connected with the act of +reproduction; for instance, the male possesses certain organs of sense or +locomotion, of which the female is quite destitute, or has them more +highly-developed, in order that he may readily find or reach her; or again the +male has special organs of prehension for holding her securely. These latter +organs, of infinitely diversified kinds, graduate into those which are commonly +ranked as primary, and in some cases can hardly be distinguished from them; we +see instances of this in the complex appendages at the apex of the abdomen in +male insects. Unless indeed we confine the term “primary” to the +reproductive glands, it is scarcely possible to decide which ought to be called +primary and which secondary. +</p> + +<p> +The female often differs from the male in having organs for the nourishment or +protection of her young, such as the mammary glands of mammals, and the +abdominal sacks of the marsupials. In some few cases also the male possesses +similar organs, which are wanting in the female, such as the receptacles for +the ova in certain male fishes, and those temporarily developed in certain male +frogs. The females of most bees are provided with a special apparatus for +collecting and carrying pollen, and their ovipositor is modified into a sting +for the defence of the larvae and the community. Many similar cases could be +given, but they do not here concern us. There are, however, other sexual +differences quite unconnected with the primary reproductive organs, and it is +with these that we are more especially concerned—such as the greater +size, strength, and pugnacity of the male, his weapons of offence or means of +defence against rivals, his gaudy colouring and various ornaments, his power of +song, and other such characters. +</p> + +<p> +Besides the primary and secondary sexual differences, such as the foregoing, +the males and females of some animals differ in structures related to different +habits of life, and not at all, or only indirectly, to the reproductive +functions. Thus the females of certain flies (Culicidae and Tabanidae) are +blood-suckers, whilst the males, living on flowers, have mouths destitute of +mandibles. (1. Westwood, ‘Modern Classification of Insects,’ vol. +ii. 1840, p. 541. For the statement about Tanais, mentioned below, I am +indebted to Fritz Muller.) The males of certain moths and of some crustaceans +(e.g. Tanais) have imperfect, closed mouths, and cannot feed. The complemental +males of certain Cirripedes live like epiphytic plants either on the female or +the hermaphrodite form, and are destitute of a mouth and of prehensile limbs. +In these cases it is the male which has been modified, and has lost certain +important organs, which the females possess. In other cases it is the female +which has lost such parts; for instance, the female glow-worm is destitute of +wings, as also are many female moths, some of which never leave their cocoons. +Many female parasitic crustaceans have lost their natatory legs. In some +weevil-beetles (Curculionidae) there is a great difference between the male and +female in the length of the rostrum or snout (2. Kirby and Spence, +‘Introduction to Entomology,’ vol. iii. 1826, p. 309.); but the +meaning of this and of many analogous differences, is not at all understood. +Differences of structure between the two sexes in relation to different habits +of life are generally confined to the lower animals; but with some few birds +the beak of the male differs from that of the female. In the Huia of New +Zealand the difference is wonderfully great, and we hear from Dr. Buller (3. +‘Birds of New Zealand,’ 1872, p. 66.) that the male uses his strong +beak in chiselling the larvae of insects out of decayed wood, whilst the female +probes the softer parts with her far longer, much curved and pliant beak: and +thus they mutually aid each other. In most cases, differences of structure +between the sexes are more or less directly connected with the propagation of +the species: thus a female, which has to nourish a multitude of ova, requires +more food than the male, and consequently requires special means for procuring +it. A male animal, which lives for a very short time, might lose its organs for +procuring food through disuse, without detriment; but he would retain his +locomotive organs in a perfect state, so that he might reach the female. The +female, on the other hand, might safely lose her organs for flying, swimming, +or walking, if she gradually acquired habits which rendered such powers +useless. +</p> + +<p> +We are, however, here concerned only with sexual selection. This depends on the +advantage which certain individuals have over others of the same sex and +species solely in respect of reproduction. When, as in the cases above +mentioned, the two sexes differ in structure in relation to different habits of +life, they have no doubt been modified through natural selection, and by +inheritance limited to one and the same sex. So again the primary sexual +organs, and those for nourishing or protecting the young, come under the same +influence; for those individuals which generated or nourished their offspring +best, would leave, ceteris paribus, the greatest number to inherit their +superiority; whilst those which generated or nourished their offspring badly, +would leave but few to inherit their weaker powers. As the male has to find the +female, he requires organs of sense and locomotion, but if these organs are +necessary for the other purposes of life, as is generally the case, they will +have been developed through natural selection. When the male has found the +female, he sometimes absolutely requires prehensile organs to hold her; thus +Dr. Wallace informs me that the males of certain moths cannot unite with the +females if their tarsi or feet are broken. The males of many oceanic +crustaceans, when adult, have their legs and antennae modified in an +extraordinary manner for the prehension of the female; hence we may suspect +that it is because these animals are washed about by the waves of the open sea, +that they require these organs in order to propagate their kind, and if so, +their development has been the result of ordinary or natural selection. Some +animals extremely low in the scale have been modified for this same purpose; +thus the males of certain parasitic worms, when fully grown, have the lower +surface of the terminal part of their bodies roughened like a rasp, and with +this they coil round and permanently hold the females. (4. M. Perrier advances +this case (‘Revue Scientifique,’ Feb. 1, 1873, p. 865) as one fatal +to the belief in sexual election, inasmuch as he supposes that I attribute all +the differences between the sexes to sexual selection. This distinguished +naturalist, therefore, like so many other Frenchmen, has not taken the trouble +to understand even the first principles of sexual selection. An English +naturalist insists that the claspers of certain male animals could not have +been developed through the choice of the female! Had I not met with this +remark, I should not have thought it possible for any one to have read this +chapter and to have imagined that I maintain that the choice of the female had +anything to do with the development of the prehensile organs in the male.) +</p> + +<p> +When the two sexes follow exactly the same habits of life, and the male has the +sensory or locomotive organs more highly developed than those of the female, it +may be that the perfection of these is indispensable to the male for finding +the female; but in the vast majority of cases, they serve only to give one male +an advantage over another, for with sufficient time, the less well-endowed +males would succeed in pairing with the females; and judging from the structure +of the female, they would be in all other respects equally well adapted for +their ordinary habits of life. Since in such cases the males have acquired +their present structure, not from being better fitted to survive in the +struggle for existence, but from having gained an advantage over other males, +and from having transmitted this advantage to their male offspring alone, +sexual selection must here have come into action. It was the importance of this +distinction which led me to designate this form of selection as Sexual +Selection. So again, if the chief service rendered to the male by his +prehensile organs is to prevent the escape of the female before the arrival of +other males, or when assaulted by them, these organs will have been perfected +through sexual selection, that is by the advantage acquired by certain +individuals over their rivals. But in most cases of this kind it is impossible +to distinguish between the effects of natural and sexual selection. Whole +chapters could be filled with details on the differences between the sexes in +their sensory, locomotive, and prehensile organs. As, however, these structures +are not more interesting than others adapted for the ordinary purposes of life +I shall pass them over almost entirely, giving only a few instances under each +class. +</p> + +<p> +There are many other structures and instincts which must have been developed +through sexual selection—such as the weapons of offence and the means of +defence of the males for fighting with and driving away their +rivals—their courage and pugnacity—their various +ornaments—their contrivances for producing vocal or instrumental +music—and their glands for emitting odours, most of these latter +structures serving only to allure or excite the female. It is clear that these +characters are the result of sexual and not of ordinary selection, since +unarmed, unornamented, or unattractive males would succeed equally well in the +battle for life and in leaving a numerous progeny, but for the presence of +better endowed males. We may infer that this would be the case, because the +females, which are unarmed and unornamented, are able to survive and procreate +their kind. Secondary sexual characters of the kind just referred to, will be +fully discussed in the following chapters, as being in many respects +interesting, but especially as depending on the will, choice, and rivalry of +the individuals of either sex. When we behold two males fighting for the +possession of the female, or several male birds displaying their gorgeous +plumage, and performing strange antics before an assembled body of females, we +cannot doubt that, though led by instinct, they know what they are about, and +consciously exert their mental and bodily powers. +</p> + +<p> +Just as man can improve the breeds of his game-cocks by the selection of those +birds which are victorious in the cockpit, so it appears that the strongest and +most vigorous males, or those provided with the best weapons, have prevailed +under nature, and have led to the improvement of the natural breed or species. +A slight degree of variability leading to some advantage, however slight, in +reiterated deadly contests would suffice for the work of sexual selection; and +it is certain that secondary sexual characters are eminently variable. Just as +man can give beauty, according to his standard of taste, to his male poultry, +or more strictly can modify the beauty originally acquired by the parent +species, can give to the Sebright bantam a new and elegant plumage, an erect +and peculiar carriage—so it appears that female birds in a state of +nature, have by a long selection of the more attractive males, added to their +beauty or other attractive qualities. No doubt this implies powers of +discrimination and taste on the part of the female which will at first appear +extremely improbable; but by the facts to be adduced hereafter, I hope to be +able to shew that the females actually have these powers. When, however, it is +said that the lower animals have a sense of beauty, it must not be supposed +that such sense is comparable with that of a cultivated man, with his multiform +and complex associated ideas. A more just comparison would be between the taste +for the beautiful in animals, and that in the lowest savages, who admire and +deck themselves with any brilliant, glittering, or curious object. +</p> + +<p> +From our ignorance on several points, the precise manner in which sexual +selection acts is somewhat uncertain. Nevertheless if those naturalists who +already believe in the mutability of species, will read the following chapters, +they will, I think, agree with me, that sexual selection has played an +important part in the history of the organic world. It is certain that amongst +almost all animals there is a struggle between the males for the possession of +the female. This fact is so notorious that it would be superfluous to give +instances. Hence the females have the opportunity of selecting one out of +several males, on the supposition that their mental capacity suffices for the +exertion of a choice. In many cases special circumstances tend to make the +struggle between the males particularly severe. Thus the males of our migratory +birds generally arrive at their places of breeding before the females, so that +many males are ready to contend for each female. I am informed by Mr. Jenner +Weir, that the bird-catchers assert that this is invariably the case with the +nightingale and blackcap, and with respect to the latter he can himself confirm +the statement. +</p> + +<p> +Mr. Swaysland of Brighton has been in the habit, during the last forty years, +of catching our migratory birds on their first arrival, and he has never known +the females of any species to arrive before their males. During one spring he +shot thirty-nine males of Ray’s wagtail (Budytes Raii) before he saw a +single female. Mr. Gould has ascertained by the dissection of those snipes +which arrive the first in this country, that the males come before the females. +And the like holds good with most of the migratory birds of the United States. +(5. J.A. Allen, on the ‘Mammals and Winter Birds of Florida,’ +Bulletin of Comparative Zoology, Harvard College, p. 268.) The majority of the +male salmon in our rivers, on coming up from the sea, are ready to breed before +the females. So it appears to be with frogs and toads. Throughout the great +class of insects the males almost always are the first to emerge from the pupal +state, so that they generally abound for a time before any females can be seen. +(6. Even with those plants in which the sexes are separate, the male flowers +are generally mature before the female. As first shewn by C.K. Sprengel, many +hermaphrodite plants are dichogamous; that is, their male and female organs are +not ready at the same time, so that they cannot be self-fertilised. Now in such +flowers, the pollen is in general matured before the stigma, though there are +exceptional cases in which the female organs are beforehand.) The cause of this +difference between the males and females in their periods of arrival and +maturity is sufficiently obvious. Those males which annually first migrated +into any country, or which in the spring were first ready to breed, or were the +most eager, would leave the largest number of offspring; and these would tend +to inherit similar instincts and constitutions. It must be borne in mind that +it would have been impossible to change very materially the time of sexual +maturity in the females, without at the same time interfering with the period +of the production of the young—a period which must be determined by the +seasons of the year. On the whole there can be no doubt that with almost all +animals, in which the sexes are separate, there is a constantly recurrent +struggle between the males for the possession of the females. +</p> + +<p> +Our difficulty in regard to sexual selection lies in understanding how it is +that the males which conquer other males, or those which prove the most +attractive to the females, leave a greater number of offspring to inherit their +superiority than their beaten and less attractive rivals. Unless this result +does follow, the characters which give to certain males an advantage over +others, could not be perfected and augmented through sexual selection. When the +sexes exist in exactly equal numbers, the worst-endowed males will (except +where polygamy prevails), ultimately find females, and leave as many offspring, +as well fitted for their general habits of life, as the best-endowed males. +From various facts and considerations, I formerly inferred that with most +animals, in which secondary sexual characters are well developed, the males +considerably exceeded the females in number; but this is not by any means +always true. If the males were to the females as two to one, or as three to +two, or even in a somewhat lower ratio, the whole affair would be simple; for +the better-armed or more attractive males would leave the largest number of +offspring. But after investigating, as far as possible, the numerical +proportion of the sexes, I do not believe that any great inequality in number +commonly exists. In most cases sexual selection appears to have been effective +in the following manner. +</p> + +<p> +Let us take any species, a bird for instance, and divide the females inhabiting +a district into two equal bodies, the one consisting of the more vigorous and +better-nourished individuals, and the other of the less vigorous and healthy. +The former, there can be little doubt, would be ready to breed in the spring +before the others; and this is the opinion of Mr. Jenner Weir, who has +carefully attended to the habits of birds during many years. There can also be +no doubt that the most vigorous, best-nourished and earliest breeders would on +an average succeed in rearing the largest number of fine offspring. (7. Here is +excellent evidence on the character of the offspring from an experienced +ornithologist. Mr. J.A. Allen, in speaking (‘Mammals and Winter Birds of +E. Florida,’ p. 229) of the later broods, after the accidental +destruction of the first, says, that these “are found to be smaller and +paler-coloured than those hatched earlier in the season. In cases where several +broods are reared each year, as a general rule the birds of the earlier broods +seem in all respects the most perfect and vigorous.”) The males, as we +have seen, are generally ready to breed before the females; the strongest, and +with some species the best armed of the males, drive away the weaker; and the +former would then unite with the more vigorous and better-nourished females, +because they are the first to breed. (8. Hermann Müller has come to this same +conclusion with respect to those female bees which are the first to emerge from +the pupa each year. See his remarkable essay, ‘Anwendung der +Darwin’schen Lehre auf Bienen,’ ‘Verh. d. V. Jahrg.’ +xxix. p. 45.) Such vigorous pairs would surely rear a larger number of +offspring than the retarded females, which would be compelled to unite with the +conquered and less powerful males, supposing the sexes to be numerically equal; +and this is all that is wanted to add, in the course of successive generations, +to the size, strength and courage of the males, or to improve their weapons. +</p> + +<p> +But in very many cases the males which conquer their rivals, do not obtain +possession of the females, independently of the choice of the latter. The +courtship of animals is by no means so simple and short an affair as might be +thought. The females are most excited by, or prefer pairing with, the more +ornamented males, or those which are the best songsters, or play the best +antics; but it is obviously probable that they would at the same time prefer +the more vigorous and lively males, and this has in some cases been confirmed +by actual observation. (9. With respect to poultry, I have received +information, hereafter to be given, to this effect. Even with birds, such as +pigeons, which pair for life, the female, as I hear from Mr. Jenner Weir, will +desert her mate if he is injured or grows weak.) Thus the more vigorous +females, which are the first to breed, will have the choice of many males; and +though they may not always select the strongest or best armed, they will select +those which are vigorous and well armed, and in other respects the most +attractive. Both sexes, therefore, of such early pairs would as above +explained, have an advantage over others in rearing offspring; and this +apparently has sufficed during a long course of generations to add not only to +the strength and fighting powers of the males, but likewise to their various +ornaments or other attractions. +</p> + +<p> +In the converse and much rarer case of the males selecting particular females, +it is plain that those which were the most vigorous and had conquered others, +would have the freest choice; and it is almost certain that they would select +vigorous as well as attractive females. Such pairs would have an advantage in +rearing offspring, more especially if the male had the power to defend the +female during the pairing-season as occurs with some of the higher animals, or +aided her in providing for the young. The same principles would apply if each +sex preferred and selected certain individuals of the opposite sex; supposing +that they selected not only the more attractive, but likewise the more vigorous +individuals. +</p> + +<h3>NUMERICAL PROPORTION OF THE TWO SEXES.</h3> + +<p> +I have remarked that sexual selection would be a simple affair if the males +were considerably more numerous than the females. Hence I was led to +investigate, as far as I could, the proportions between the two sexes of as +many animals as possible; but the materials are scanty. I will here give only a +brief abstract of the results, retaining the details for a supplementary +discussion, so as not to interfere with the course of my argument. Domesticated +animals alone afford the means of ascertaining the proportional numbers at +birth; but no records have been specially kept for this purpose. By indirect +means, however, I have collected a considerable body of statistics, from which +it appears that with most of our domestic animals the sexes are nearly equal at +birth. Thus 25,560 births of race-horses have been recorded during twenty-one +years, and the male births were to the female births as 99.7 to 100. In +greyhounds the inequality is greater than with any other animal, for out of +6878 births during twelve years, the male births were to the female as 110.1 to +100. It is, however, in some degree doubtful whether it is safe to infer that +the proportion would be the same under natural conditions as under +domestication; for slight and unknown differences in the conditions affect the +proportion of the sexes. Thus with mankind, the male births in England are as +104.5, in Russia as 108.9, and with the Jews of Livonia as 120, to 100 female +births. But I shall recur to this curious point of the excess of male births in +the supplement to this chapter. At the Cape of Good Hope, however, male +children of European extraction have been born during several years in the +proportion of between 90 and 99 to 100 female children. +</p> + +<p> +For our present purpose we are concerned with the proportions of the sexes, not +only at birth, but also at maturity, and this adds another element of doubt; +for it is a well-ascertained fact that with man the number of males dying +before or during birth, and during the first two years of infancy, is +considerably larger than that of females. So it almost certainly is with male +lambs, and probably with some other animals. The males of some species kill one +another by fighting; or they drive one another about until they become greatly +emaciated. They must also be often exposed to various dangers, whilst wandering +about in eager search for the females. In many kinds of fish the males are much +smaller than the females, and they are believed often to be devoured by the +latter, or by other fishes. The females of some birds appear to die earlier +than the males; they are also liable to be destroyed on their nests, or whilst +in charge of their young. With insects the female larvae are often larger than +those of the males, and would consequently be more likely to be devoured. In +some cases the mature females are less active and less rapid in their movements +than the males, and could not escape so well from danger. Hence, with animals +in a state of nature, we must rely on mere estimation, in order to judge of the +proportions of the sexes at maturity; and this is but little trustworthy, +except when the inequality is strongly marked. Nevertheless, as far as a +judgment can be formed, we may conclude from the facts given in the supplement, +that the males of some few mammals, of many birds, of some fish and insects, +are considerably more numerous than the females. +</p> + +<p> +The proportion between the sexes fluctuates slightly during successive years: +thus with race-horses, for every 100 mares born the stallions varied from 107.1 +in one year to 92.6 in another year, and with greyhounds from 116.3 to 95.3. +But had larger numbers been tabulated throughout an area more extensive than +England, these fluctuations would probably have disappeared; and such as they +are, would hardly suffice to lead to effective sexual selection in a state of +nature. Nevertheless, in the cases of some few wild animals, as shewn in the +supplement, the proportions seem to fluctuate either during different seasons +or in different localities in a sufficient degree to lead to such selection. +For it should be observed that any advantage, gained during certain years or in +certain localities by those males which were able to conquer their rivals, or +were the most attractive to the females, would probably be transmitted to the +offspring, and would not subsequently be eliminated. During the succeeding +seasons, when, from the equality of the sexes, every male was able to procure a +female, the stronger or more attractive males previously produced would still +have at least as good a chance of leaving offspring as the weaker or less +attractive. +</p> + +<h3>POLYGAMY.</h3> + +<p> +The practice of polygamy leads to the same results as would follow from an +actual inequality in the number of the sexes; for if each male secures two or +more females, many males cannot pair; and the latter assuredly will be the +weaker or less attractive individuals. Many mammals and some few birds are +polygamous, but with animals belonging to the lower classes I have found no +evidence of this habit. The intellectual powers of such animals are, perhaps, +not sufficient to lead them to collect and guard a harem of females. That some +relation exists between polygamy and the development of secondary sexual +characters, appears nearly certain; and this supports the view that a numerical +preponderance of males would be eminently favourable to the action of sexual +selection. Nevertheless many animals, which are strictly monogamous, especially +birds, display strongly-marked secondary sexual characters; whilst some few +animals, which are polygamous, do not have such characters. +</p> + +<p> +We will first briefly run through the mammals, and then turn to birds. The +gorilla seems to be polygamous, and the male differs considerably from the +female; so it is with some baboons, which live in herds containing twice as +many adult females as males. In South America the Mycetes caraya presents +well-marked sexual differences, in colour, beard, and vocal organs; and the +male generally lives with two or three wives: the male of the Cebus capucinus +differs somewhat from the female, and appears to be polygamous. (10. On the +Gorilla, Savage and Wyman, ‘Boston Journal of Natural History,’ +vol. v. 1845-47, p. 423. On Cynocephalus, Brehm, ‘Thierleben,’ B. +i. 1864, s. 77. On Mycetes, Rengger, ‘Naturgeschichte der Säugethiere von +Paraguay,’ 1830, ss. 14, 20. On Cebus, Brehm, ibid. s. 108.) Little is +known on this head with respect to most other monkeys, but some species are +strictly monogamous. The ruminants are eminently polygamous, and they present +sexual differences more frequently than almost any other group of mammals; this +holds good, especially in their weapons, but also in other characters. Most +deer, cattle, and sheep are polygamous; as are most antelopes, though some are +monogamous. Sir Andrew Smith, in speaking of the antelopes of South Africa, +says that in herds of about a dozen there was rarely more than one mature male. +The Asiatic Antilope saiga appears to be the most inordinate polygamist in the +world; for Pallas (11. Pallas, ‘Spicilegia Zoolog., Fasc.’ xii. +1777, p. 29. Sir Andrew Smith, ‘Illustrations of the Zoology of S. +Africa,’ 1849, pl. 29, on the Kobus. Owen, in his ‘Anatomy of +Vertebrates’ (vol. iii. 1868, p. 633) gives a table shewing incidentally +which species of antelopes are gregarious.) states that the male drives away +all rivals, and collects a herd of about a hundred females and kids together; +the female is hornless and has softer hair, but does not otherwise differ much +from the male. The wild horse of the Falkland Islands and of the Western States +of N. America is polygamous, but, except in his greater size and in the +proportions of his body, differs but little from the mare. The wild boar +presents well-marked sexual characters, in his great tusks and some other +points. In Europe and in India he leads a solitary life, except during the +breeding-season; but as is believed by Sir W. Elliot, who has had many +opportunities in India of observing this animal, he consorts at this season +with several females. Whether this holds good in Europe is doubtful, but it is +supported by some evidence. The adult male Indian elephant, like the boar, +passes much of his time in solitude; but as Dr. Campbell states, when with +others, “It is rare to find more than one male with a whole herd of +females”; the larger males expelling or killing the smaller and weaker +ones. The male differs from the female in his immense tusks, greater size, +strength, and endurance; so great is the difference in these respects that the +males when caught are valued at one-fifth more than the females. (12. Dr. +Campbell, in ‘Proc. Zoolog. Soc.’ 1869, p. 138. See also an +interesting paper by Lieut. Johnstone, in ‘Proceedings, Asiatic Society +of Bengal,’ May 1868.) The sexes of other pachydermatous animals differ +very little or not at all, and, as far as known, they are not polygamists. Nor +have I heard of any species in the Orders of Cheiroptera, Edentata, Insectivora +and Rodents being polygamous, excepting that amongst the Rodents, the common +rat, according to some rat-catchers, lives with several females. Nevertheless +the two sexes of some sloths (Edentata) differ in the character and colour of +certain patches of hair on their shoulders. (13. Dr. Gray, in ‘Annals and +Magazine of Natural History,’ 1871, p. 302.) And many kinds of bats +(Cheiroptera) present well-marked sexual differences, chiefly in the males +possessing odoriferous glands and pouches, and by their being of a lighter +colour. (14. See Dr. Dobson’s excellent paper in ‘Proceedings of +the Zoological Society,’ 1873, p. 241.) In the great order of Rodents, as +far as I can learn, the sexes rarely differ, and when they do so, it is but +slightly in the tint of the fur. +</p> + +<p> +As I hear from Sir Andrew Smith, the lion in South Africa sometimes lives with +a single female, but generally with more, and, in one case, was found with as +many as five females; so that he is polygamous. As far as I can discover, he is +the only polygamist amongst all the terrestrial Carnivora, and he alone +presents well-marked sexual characters. If, however, we turn to the marine +Carnivora, as we shall hereafter see, the case is widely different; for many +species of seals offer extraordinary sexual differences, and they are eminently +polygamous. Thus, according to Peron, the male sea-elephant of the Southern +Ocean always possesses several females, and the sea-lion of Forster is said to +be surrounded by from twenty to thirty females. In the North, the male sea-bear +of Steller is accompanied by even a greater number of females. It is an +interesting fact, as Dr. Gill remarks (15. ‘The Eared Seals,’ +American Naturalist, vol. iv. Jan. 1871.), that in the monogamous species, +“or those living in small communities, there is little difference in size +between the males and females; in the social species, or rather those of which +the males have harems, the males are vastly larger than the females.” +</p> + +<p> +Amongst birds, many species, the sexes of which differ greatly from each other, +are certainly monogamous. In Great Britain we see well-marked sexual +differences, for instance, in the wild-duck which pairs with a single female, +the common blackbird, and the bullfinch which is said to pair for life. I am +informed by Mr. Wallace that the like is true of the Chatterers or Cotingidae +of South America, and of many other birds. In several groups I have not been +able to discover whether the species are polygamous or monogamous. Lesson says +that birds of paradise, so remarkable for their sexual differences, are +polygamous, but Mr. Wallace doubts whether he had sufficient evidence. Mr. +Salvin tells me he has been led to believe that humming-birds are polygamous. +The male widow-bird, remarkable for his caudal plumes, certainly seems to be a +polygamist. (16. ‘The Ibis,’ vol. iii. 1861, p. 133, on the Progne +Widow-bird. See also on the Vidua axillaris, ibid. vol. ii. 1860, p. 211. On +the polygamy of the Capercailzie and Great Bustard, see L. Lloyd, ‘Game +Birds of Sweden,’ 1867, pp. 19, and 182. Montagu and Selby speak of the +Black Grouse as polygamous and of the Red Grouse as monogamous.) I have been +assured by Mr. Jenner Weir and by others, that it is somewhat common for three +starlings to frequent the same nest; but whether this is a case of polygamy or +polyandry has not been ascertained. +</p> + +<p> +The Gallinaceae exhibit almost as strongly marked sexual differences as birds +of paradise or humming-birds, and many of the species are, as is well known, +polygamous; others being strictly monogamous. What a contrast is presented +between the sexes of the polygamous peacock or pheasant, and the monogamous +guinea-fowl or partridge! Many similar cases could be given, as in the grouse +tribe, in which the males of the polygamous capercailzie and black-cock differ +greatly from the females; whilst the sexes of the monogamous red grouse and +ptarmigan differ very little. In the Cursores, except amongst the bustards, few +species offer strongly-marked sexual differences, and the great bustard (Otis +tarda) is said to be polygamous. With the Grallatores, extremely few species +differ sexually, but the ruff (Machetes pugnax) affords a marked exception, and +this species is believed by Montagu to be a polygamist. Hence it appears that +amongst birds there often exists a close relation between polygamy and the +development of strongly-marked sexual differences. I asked Mr. Bartlett, of the +Zoological Gardens, who has had very large experience with birds, whether the +male tragopan (one of the Gallinaceae) was polygamous, and I was struck by his +answering, “I do not know, but should think so from his splendid +colours.” +</p> + +<p> +It deserves notice that the instinct of pairing with a single female is easily +lost under domestication. The wild-duck is strictly monogamous, the +domestic-duck highly polygamous. The Rev. W.D. Fox informs me that out of some +half-tamed wild-ducks, on a large pond in his neighbourhood, so many mallards +were shot by the gamekeeper that only one was left for every seven or eight +females; yet unusually large broods were reared. The guinea-fowl is strictly +monogamous; but Mr. Fox finds that his birds succeed best when he keeps one +cock to two or three hens. Canary-birds pair in a state of nature, but the +breeders in England successfully put one male to four or five females. I have +noticed these cases, as rendering it probable that wild monogamous species +might readily become either temporarily or permanently polygamous. +</p> + +<p> +Too little is known of the habits of reptiles and fishes to enable us to speak +of their marriage arrangements. The stickle-back (Gasterosteus), however, is +said to be a polygamist (17. Noel Humphreys, ‘River Gardens,’ +1857.); and the male during the breeding-season differs conspicuously from the +female. +</p> + +<p> +To sum up on the means through which, as far as we can judge, sexual selection +has led to the development of secondary sexual characters. It has been shewn +that the largest number of vigorous offspring will be reared from the pairing +of the strongest and best-armed males, victorious in contests over other males, +with the most vigorous and best-nourished females, which are the first to breed +in the spring. If such females select the more attractive, and at the same time +vigorous males, they will rear a larger number of offspring than the retarded +females, which must pair with the less vigorous and less attractive males. So +it will be if the more vigorous males select the more attractive and at the +same time healthy and vigorous females; and this will especially hold good if +the male defends the female, and aids in providing food for the young. The +advantage thus gained by the more vigorous pairs in rearing a larger number of +offspring has apparently sufficed to render sexual selection efficient. But a +large numerical preponderance of males over females will be still more +efficient; whether the preponderance is only occasional and local, or +permanent; whether it occurs at birth, or afterwards from the greater +destruction of the females; or whether it indirectly follows from the practice +of polygamy. +</p> + +<h3>THE MALE GENERALLY MORE MODIFIED THAN THE FEMALE.</h3> + +<p> +Throughout the animal kingdom, when the sexes differ in external appearance, it +is, with rare exceptions, the male which has been the more modified; for, +generally, the female retains a closer resemblance to the young of her own +species, and to other adult members of the same group. The cause of this seems +to lie in the males of almost all animals having stronger passions than the +females. Hence it is the males that fight together and sedulously display their +charms before the females; and the victors transmit their superiority to their +male offspring. Why both sexes do not thus acquire the characters of their +fathers, will be considered hereafter. That the males of all mammals eagerly +pursue the females is notorious to every one. So it is with birds; but many +cock birds do not so much pursue the hen, as display their plumage, perform +strange antics, and pour forth their song in her presence. The male in the few +fish observed seems much more eager than the female; and the same is true of +alligators, and apparently of Batrachians. Throughout the enormous class of +insects, as Kirby remarks, “the law is that the male shall seek the +female.” (18. Kirby and Spence, ‘Introduction to Entomology,’ +vol. iii. 1826, p. 342.) Two good authorities, Mr. Blackwall and Mr. C. Spence +Bate, tell me that the males of spiders and crustaceans are more active and +more erratic in their habits than the females. When the organs of sense or +locomotion are present in the one sex of insects and crustaceans and absent in +the other, or when, as is frequently the case, they are more highly developed +in the one than in the other, it is, as far as I can discover, almost +invariably the male which retains such organs, or has them most developed; and +this shews that the male is the more active member in the courtship of the +sexes. (19. One parasitic Hymenopterous insect (Westwood, ‘Modern Class. +of Insects,’ vol. ii. p. 160) forms an exception to the rule, as the male +has rudimentary wings, and never quits the cell in which it is born, whilst the +female has well-developed wings. Audouin believes that the females of this +species are impregnated by the males which are born in the same cells with +them; but it is much more probable that the females visit other cells, so that +close inter-breeding is thus avoided. We shall hereafter meet in various +classes, with a few exceptional cases, in which the female, instead of the +male, is the seeker and wooer.) +</p> + +<p> +The female, on the other hand, with the rarest exceptions, is less eager than +the male. As the illustrious Hunter (20. ‘Essays and Observations,’ +edited by Owen, vol. i. 1861, p. 194.) long ago observed, she generally +“requires to be courted;” she is coy, and may often be seen +endeavouring for a long time to escape from the male. Every observer of the +habits of animals will be able to call to mind instances of this kind. It is +shewn by various facts, given hereafter, and by the results fairly attributable +to sexual selection, that the female, though comparatively passive, generally +exerts some choice and accepts one male in preference to others. Or she may +accept, as appearances would sometimes lead us to believe, not the male which +is the most attractive to her, but the one which is the least distasteful. The +exertion of some choice on the part of the female seems a law almost as general +as the eagerness of the male. +</p> + +<p> +We are naturally led to enquire why the male, in so many and such distinct +classes, has become more eager than the female, so that he searches for her, +and plays the more active part in courtship. It would be no advantage and some +loss of power if each sex searched for the other; but why should the male +almost always be the seeker? The ovules of plants after fertilisation have to +be nourished for a time; hence the pollen is necessarily brought to the female +organs—being placed on the stigma, by means of insects or the wind, or by +the spontaneous movements of the stamens; and in the Algae, etc., by the +locomotive power of the antherozooids. With lowly-organised aquatic animals, +permanently affixed to the same spot and having their sexes separate, the male +element is invariably brought to the female; and of this we can see the reason, +for even if the ova were detached before fertilisation, and did not require +subsequent nourishment or protection, there would yet be greater difficulty in +transporting them than the male element, because, being larger than the latter, +they are produced in far smaller numbers. So that many of the lower animals +are, in this respect, analogous with plants. (21. Prof. Sachs (‘Lehrbuch +der Botanik,’ 1870, S. 633) in speaking of the male and female +reproductive cells, remarks, “verhält sich die eine bei der Vereinigung +activ,...die andere erscheint bei der Vereinigung passiv.”) The males of +affixed and aquatic animals having been led to emit their fertilising element +in this way, it is natural that any of their descendants, which rose in the +scale and became locomotive, should retain the same habit; and they would +approach the female as closely as possible, in order not to risk the loss of +the fertilising element in a long passage of it through the water. With some +few of the lower animals, the females alone are fixed, and the males of these +must be the seekers. But it is difficult to understand why the males of +species, of which the progenitors were primordially free, should invariably +have acquired the habit of approaching the females, instead of being approached +by them. But in all cases, in order that the males should seek efficiently, it +would be necessary that they should be endowed with strong passions; and the +acquirement of such passions would naturally follow from the more eager leaving +a larger number of offspring than the less eager. +</p> + +<p> +The great eagerness of the males has thus indirectly led to their much more +frequently developing secondary sexual characters than the females. But the +development of such characters would be much aided, if the males were more +liable to vary than the females—as I concluded they were—after a +long study of domesticated animals. Von Nathusius, who has had very wide +experience, is strongly of the same opinion. (22. ‘Vorträge uber +Viehzucht,’ 1872, p. 63.) Good evidence also in favour of this conclusion +can be produced by a comparison of the two sexes in mankind. During the Novara +Expedition (23. ‘Reise der Novara: Anthropolog. Theil,’ 1867, ss. +216-269. The results were calculated by Dr. Weisbach from measurements made by +Drs. K. Scherzer and Schwarz. On the greater variability of the males of +domesticated animals, see my ‘Variation of Animals and Plants under +Domestication,’ vol. ii. 1868, p. 75.) a vast number of measurements was +made of various parts of the body in different races, and the men were found in +almost every case to present a greater range of variation than the women; but I +shall have to recur to this subject in a future chapter. Mr. J. Wood (24. +‘Proceedings of the Royal Society,’ vol. xvi. July 1868, pp. 519 +and 524.), who has carefully attended to the variation of the muscles in man, +puts in italics the conclusion that “the greatest number of abnormalities +in each subject is found in the males.” He had previously remarked that +“altogether in 102 subjects, the varieties of redundancy were found to be +half as many again as in females, contrasting widely with the greater frequency +of deficiency in females before described.” Professor Macalister likewise +remarks (25. ‘Proc. Royal Irish Academy,’ vol. x. 1868, p. 123.) +that variations in the muscles “are probably more common in males than +females.” Certain muscles which are not normally present in mankind are +also more frequently developed in the male than in the female sex, although +exceptions to this rule are said to occur. Dr. Burt Wilder (26. +‘Massachusetts Medical Society,’ vol. ii. No. 3, 1868, p. 9.) has +tabulated the cases of 152 individuals with supernumerary digits, of which 86 +were males, and 39, or less than half, females, the remaining 27 being of +unknown sex. It should not, however, be overlooked that women would more +frequently endeavour to conceal a deformity of this kind than men. Again, Dr. +L. Meyer asserts that the ears of man are more variable in form than those of a +woman. (27. ‘Archiv fur Path. Anat. und Phys.’ 1871, p. 488.) +Lastly the temperature is more variable in man than in woman. (28. The +conclusions recently arrived at by Dr. J. Stockton Hough, on the temperature of +man, are given in the ‘Pop. Sci. Review,’ Jan. 1st, 1874, p. 97.) +</p> + +<p> +The cause of the greater general variability in the male sex, than in the +female is unknown, except in so far as secondary sexual characters are +extraordinarily variable, and are usually confined to the males; and, as we +shall presently see, this fact is, to a certain extent, intelligible. Through +the action of sexual and natural selection male animals have been rendered in +very many instances widely different from their females; but independently of +selection the two sexes, from differing constitutionally, tend to vary in a +somewhat different manner. The female has to expend much organic matter in the +formation of her ova, whereas the male expends much force in fierce contests +with his rivals, in wandering about in search of the female, in exerting his +voice, pouring out odoriferous secretions, etc.: and this expenditure is +generally concentrated within a short period. The great vigour of the male +during the season of love seems often to intensify his colours, independently +of any marked difference from the female. (29. Prof. Mantegazza is inclined to +believe (‘Lettera a Carlo Darwin,’ ‘Archivio per +l’Anthropologia,’ 1871, p. 306) that the bright colours, common in +so many male animals, are due to the presence and retention by them of the +spermatic fluid; but this can hardly be the case; for many male birds, for +instance young pheasants, become brightly coloured in the autumn of their first +year.) In mankind, and even as low down in the organic scale as in the +Lepidoptera, the temperature of the body is higher in the male than in the +female, accompanied in the case of man by a slower pulse. (30. For mankind, see +Dr. J. Stockton Hough, whose conclusions are given in the ‘Popular +Science Review,’ 1874, p. 97. See Girard’s observations on the +Lepidoptera, as given in the ‘Zoological Record,’ 1869, p. 347.) On +the whole the expenditure of matter and force by the two sexes is probably +nearly equal, though effected in very different ways and at different rates. +</p> + +<p> +From the causes just specified the two sexes can hardly fail to differ somewhat +in constitution, at least during the breeding-season; and, although they may be +subjected to exactly the same conditions, they will tend to vary in a different +manner. If such variations are of no service to either sex, they will not be +accumulated and increased by sexual or natural selection. Nevertheless, they +may become permanent if the exciting cause acts permanently; and in accordance +with a frequent form of inheritance they may be transmitted to that sex alone +in which they first appeared. In this case the two sexes will come to present +permanent, yet unimportant, differences of character. For instance, Mr. Allen +shews that with a large number of birds inhabiting the northern and southern +United States, the specimens from the south are darker-coloured than those from +the north; and this seems to be the direct result of the difference in +temperature, light, etc., between the two regions. Now, in some few cases, the +two sexes of the same species appear to have been differently affected; in the +Agelaeus phoeniceus the males have had their colours greatly intensified in the +south; whereas with Cardinalis virginianus it is the females which have been +thus affected; with Quiscalus major the females have been rendered extremely +variable in tint, whilst the males remain nearly uniform. (31. ‘Mammals +and Birds of E. Florida,’ pp. 234, 280, 295.) +</p> + +<p> +A few exceptional cases occur in various classes of animals, in which the +females instead of the males have acquired well pronounced secondary sexual +characters, such as brighter colours, greater size, strength, or pugnacity. +With birds there has sometimes been a complete transposition of the ordinary +characters proper to each sex; the females having become the more eager in +courtship, the males remaining comparatively passive, but apparently selecting +the more attractive females, as we may infer from the results. Certain hen +birds have thus been rendered more highly coloured or otherwise ornamented, as +well as more powerful and pugnacious than the cocks; these characters being +transmitted to the female offspring alone. +</p> + +<p> +It may be suggested that in some cases a double process of selection has been +carried on; that the males have selected the more attractive females, and the +latter the more attractive males. This process, however, though it might lead +to the modification of both sexes, would not make the one sex different from +the other, unless indeed their tastes for the beautiful differed; but this is a +supposition too improbable to be worth considering in the case of any animal, +excepting man. There are, however, many animals in which the sexes resemble +each other, both being furnished with the same ornaments, which analogy would +lead us to attribute to the agency of sexual selection. In such cases it may be +suggested with more plausibility, that there has been a double or mutual +process of sexual selection; the more vigorous and precocious females selecting +the more attractive and vigorous males, the latter rejecting all except the +more attractive females. But from what we know of the habits of animals, this +view is hardly probable, for the male is generally eager to pair with any +female. It is more probable that the ornaments common to both sexes were +acquired by one sex, generally the male, and then transmitted to the offspring +of both sexes. If, indeed, during a lengthened period the males of any species +were greatly to exceed the females in number, and then during another +lengthened period, but under different conditions, the reverse were to occur, a +double, but not simultaneous, process of sexual selection might easily be +carried on, by which the two sexes might be rendered widely different. +</p> + +<p> +We shall hereafter see that many animals exist, of which neither sex is +brilliantly coloured or provided with special ornaments, and yet the members of +both sexes or of one alone have probably acquired simple colours, such as white +or black, through sexual selection. The absence of bright tints or other +ornaments may be the result of variations of the right kind never having +occurred, or of the animals themselves having preferred plain black or white. +Obscure tints have often been developed through natural selection for the sake +of protection, and the acquirement through sexual selection of conspicuous +colours, appears to have been sometimes checked from the danger thus incurred. +But in other cases the males during long ages may have struggled together for +the possession of the females, and yet no effect will have been produced, +unless a larger number of offspring were left by the more successful males to +inherit their superiority, than by the less successful: and this, as previously +shewn, depends on many complex contingencies. +</p> + +<p> +Sexual selection acts in a less rigorous manner than natural selection. The +latter produces its effects by the life or death at all ages of the more or +less successful individuals. Death, indeed, not rarely ensues from the +conflicts of rival males. But generally the less successful male merely fails +to obtain a female, or obtains a retarded and less vigorous female later in the +season, or, if polygamous, obtains fewer females; so that they leave fewer, +less vigorous, or no offspring. In regard to structures acquired through +ordinary or natural selection, there is in most cases, as long as the +conditions of life remain the same, a limit to the amount of advantageous +modification in relation to certain special purposes; but in regard to +structures adapted to make one male victorious over another, either in fighting +or in charming the female, there is no definite limit to the amount of +advantageous modification; so that as long as the proper variations arise the +work of sexual selection will go on. This circumstance may partly account for +the frequent and extraordinary amount of variability presented by secondary +sexual characters. Nevertheless, natural selection will determine that such +characters shall not be acquired by the victorious males, if they would be +highly injurious, either by expending too much of their vital powers, or by +exposing them to any great danger. The development, however, of certain +structures—of the horns, for instance, in certain stags—has been +carried to a wonderful extreme; and in some cases to an extreme which, as far +as the general conditions of life are concerned, must be slightly injurious to +the male. From this fact we learn that the advantages which favoured males +derive from conquering other males in battle or courtship, and thus leaving a +numerous progeny, are in the long run greater than those derived from rather +more perfect adaptation to their conditions of life. We shall further see, and +it could never have been anticipated, that the power to charm the female has +sometimes been more important than the power to conquer other males in battle. +</p> + +<h3>LAWS OF INHERITANCE.</h3> + +<p> +In order to understand how sexual selection has acted on many animals of many +classes, and in the course of ages has produced a conspicuous result, it is +necessary to bear in mind the laws of inheritance, as far as they are known. +Two distinct elements are included under the term +“inheritance”—the transmission, and the development of +characters; but as these generally go together, the distinction is often +overlooked. We see this distinction in those characters which are transmitted +through the early years of life, but are developed only at maturity or during +old age. We see the same distinction more clearly with secondary sexual +characters, for these are transmitted through both sexes, though developed in +one alone. That they are present in both sexes, is manifest when two species, +having strongly-marked sexual characters, are crossed, for each transmits the +characters proper to its own male and female sex to the hybrid offspring of +either sex. The same fact is likewise manifest, when characters proper to the +male are occasionally developed in the female when she grows old or becomes +diseased, as, for instance, when the common hen assumes the flowing +tail-feathers, hackles, comb, spurs, voice, and even pugnacity of the cock. +Conversely, the same thing is evident, more or less plainly, with castrated +males. Again, independently of old age or disease, characters are occasionally +transferred from the male to the female, as when, in certain breeds of the +fowl, spurs regularly appear in the young and healthy females. But in truth +they are simply developed in the female; for in every breed each detail in the +structure of the spur is transmitted through the female to her male offspring. +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. They may remain undeveloped during the early +years of life or during successive generations; and their development into +units or cells, like those from which they were derived, depends on their +affinity for, and union with other units or cells previously developed in the +due order of growth. +</p> + +<h3>INHERITANCE AT CORRESPONDING PERIODS OF LIFE.</h3> + +<p> +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. +</p> + +<h3>INHERITANCE AT CORRESPONDING SEASONS OF THE YEAR.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.”) +</p> + +<p> +ON THE RELATION BETWEEN THE PERIOD OF DEVELOPMENT OF A CHARACTER AND ITS +TRANSMISSION TO ONE SEX OR TO BOTH SEXES. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. But with domesticated sheep the presence or absence of horns is not a +firmly fixed character; for a certain proportion of the merino ewes bear small +horns, and some of the rams are hornless; and in most breeds hornless ewes are +occasionally produced. +</p> + +<p> +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. +</p> + +<p> +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, pp. 249-250.) Between such extreme cases of close sexual resemblance and +wide dissimilarity, as those of the Crossoptilon and peacock, many intermediate +ones could be given, in which the characters follow our two rules in their +order of development. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>A SUMMARY AND CONCLUDING REMARKS.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +SUPPLEMENT ON THE PROPORTIONAL NUMBERS OF THE TWO SEXES IN ANIMALS BELONGING TO +VARIOUS CLASSES. +</p> + +<p> +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. +</p> + +<h3>MAN.</h3> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>HORSES.</h3> + +<p> +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. +</p> + +<h3>DOGS.</h3> + +<p> +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. +</p> + +<h3>SHEEP.</h3> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>BIRDS.</h3> + +<p> +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. +</p> + +<p> +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. Hist. of Selborne,’ +letter xxix. edit. 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. Mr. 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. Mr. 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. Mr. 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. 187.) whilst in Honduras the proportion was the +other way, the species there having the character of a polygamist. +</p> + +<h3>FISH.</h3> + +<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. +</p> + +<p> +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.) +</p> + +<h3>INSECTS.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<pre> + 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 + + Total 934 761 +</pre> + +<p> +(*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.) +</p> + +<p> +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. +</p> + +<p> +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, p. 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, pp. 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. 17, 1868.) With most of these +species (excepting the Tenthredinae) there is at present no evidence that the +females are subject to parthenogenesis; and thus we see how ignorant we are of +the causes of the apparent discrepancy in the proportion of the two sexes. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<h3>THE PROPORTION OF THE SEXES IN RELATION TO NATURAL SELECTION.</h3> + +<p> +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.” +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0009" id="link2HCH0009"></a> +CHAPTER IX.<br /> +SECONDARY SEXUAL CHARACTERS IN THE LOWER CLASSES OF THE ANIMAL KINGDOM.</h2> + +<p class="letter"> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>THE SUB-KINGDOM OF THE MOLLUSCA.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>SUB-KINGDOM OF THE VERMES: CLASS, ANNELIDA (OR SEA-WORMS).</h3> + +<p> +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. +</p> + +<h3>SUB-KINGDOM OF THE ARTHROPODA: CLASS, CRUSTACEA.</h3> + +<p> +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.) +</p> + +<p> +[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.] +</p> + +<p> +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. +</p> + +<p> +[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. +</p> + +<p> +Fig. 6. Second leg of male Orchestia Tucuratinga (from Fritz Müller). +</p> + +<p> +Fig. 7. Ditto of female.] +</p> + +<p> +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. +</p> + +<p> +[Fig.8. Orchestia Darwinii (from Fritz Müller), showing the +differently-constructed chelae of the two male forms.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>CLASS, ARACHNIDA (SPIDERS).</h3> + +<p> +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. +</p> + +<p> +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.” +</p> + +<p> +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.) +</p> + +<h3>CLASS, MYRIAPODA.</h3> + +<p> +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.) +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0010" id="link2HCH0010"></a> +CHAPTER X.<br /> +SECONDARY SEXUAL CHARACTERS OF INSECTS.</h2> + +<p class="letter"> +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. +</p> + +<p> +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. Sir J. 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, s. 164; and Westwood, ‘Transact. Ent. Soc.’ vol. iii. +1842, p. 195) of distinct species having been observed in union. Mr. 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. Aug. Meyer, THEY COUPLED, and one +pair produced fertile ova.), “it is astonishing,” as Mr. B.D. Walsh +(3. ‘The Practical Entomologist,’ Philadelphia, vol. ii. May 1867, +p. 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. Mr. 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, pp. 205, 206. Mr. Walsh, who +called my attention to the double use of the jaws, says that he has repeatedly +observed this fact.); whilst the females use these organs for burrowing in +sand-banks and making their nests. +</p> + +<p> +[Fig. 9. Crabro cribrarius. Upper figure, male; lower figure, female.] +</p> + +<p> +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.) +</p> + +<p> +[Fig. 10. Taphroderes distortus (much enlarged). Upper figure, male; lower +figure, female.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>DIFFERENCE IN SIZE BETWEEN THE SEXES.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>ORDER, THYSANURA.</h3> + +<p> +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.” +</p> + +<h3>ORDER, DIPTERA (FLIES).</h3> + +<p> +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.”) +</p> + +<h3>ORDER, HEMIPTERA (FIELD-BUGS).</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>ORDER: HOMOPTERA.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>ORDER, ORTHOPTERA (CRICKETS AND GRASSHOPPERS).</h3> + +<p> +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.) +</p> + +<p> +[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. +</p> + +<p> +Fig.12. Teeth of Nervure of Gryllus domesticus (from Landois).] +</p> + +<p> +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. +</p> + +<p> +[Fig.13. Chlorocoelus Tanana (from Bates). a,b. Lobes of opposite wing-covers.] +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +[Fig.14. Hind-leg of Stenobothrus pratorum: r, the stridulating ridge; lower +figure, the teeth forming the ridge, much magnified (from Landois). +</p> + +<p> +Fig.15. Pneumora (from specimens in the British Museum). Upper figure, male; +lower figure, female.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>ORDER, NEUROPTERA.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<h3>ORDER, HYMENOPTERA.</h3> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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, p. 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? The acquirement of new characters by the sterile +worker-bees is a much more difficult case, but I have endeavoured to shew in my +‘Origin of Species,’ how these sterile beings are subjected to the +power of natural selection.) +</p> + +<p> +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. +</p> + +<h3>ORDER, COLEOPTERA (BEETLES).</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig.16. Chalcosoma atlas. Upper figure, male (reduced); lower figure, female +(nat. size). +</p> + +<p> +Fig. 17. Copris isidis. +</p> + +<p> +Fig. 18. Phanaeus faunus. +</p> + +<p> +Fig. 19. Dipelicus cantori. +</p> + +<p> +Fig. 20. Onthophagus rangifer, enlarged. (In Figs. 17 to 20 the left-hand +figures are males.)] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig.21. Onitis furcifer, male viewed from beneath. +</p> + +<p> +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.] +</p> + +<p> +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). +</p> + +<p> +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. +</p> + +<p> +[Fig. 23. Bledius taurus, magnified. Left-hand figure, male; right-hand figure, +female.] +</p> + +<p> +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. +</p> + +<h3>LAW OF BATTLE.</h3> + +<p> +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.) +</p> + +<p> +[Fig. 24. Chiasognathus Grantii, reduced. Upper figure, male; lower figure, +female.] +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<h3>STRIDULATING ORGANS.</h3> + +<p> +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. +</p> + +<p> +[Fig.25. Necrophorus (from Landois). r. The two rasps. Left-hand figure, part +of the rasp highly magnified.] +</p> + +<p> +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. +</p> + +<p> +[Fig.26. Hind-leg of Geotrupes stercorarius (from Landois). r. Rasp. c. Coxa. +f. Femur. t. Tibia. tr. Tarsi.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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 +</p> + +<p> +of this latter structure. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0011" id="link2HCH0011"></a> +CHAPTER XI.<br /> +INSECTS, continued. ORDER LEPIDOPTERA. (BUTTERFLIES AND MOTHS.)</h2> + +<p class="letter"> +Courtship of butterflies—Battles—Ticking noise—Colours common +to both +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.” +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.” +</p> + +<h3>DISPLAY.</h3> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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.” +</p> + +<p> +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. +</p> + +<p> +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.” +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>MIMICRY.</h3> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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.” +</p> + +<h3>BRIGHT COLOURS OF CATERPILLARS.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>A SUMMARY AND CONCLUDING REMARKS ON INSECTS.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0012" id="link2HCH0012"></a> +CHAPTER XII.<br /> +SECONDARY SEXUAL CHARACTERS OF FISHES, AMPHIBIANS, AND REPTILES.</h2> + +<p class="letter"> +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. +</p> + +<p class="letter"> +AMPHIBIANS: Differences in structure and colour between the sexes—Vocal +organs. +</p> + +<p class="letter"> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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.” +</p> + +<p> +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. +</p> + +<p> +[Fig. 27. Head of male common salmon (Salmo salar) during the breeding-season. +[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.] +</p> + +<p> +Fig. 28. Head of female salmon.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig. 29. Callionymus lyra. Upper figure, male; lower figure, female. N.B. The +lower figure is more reduced than the upper.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig. 30. Xiphophorus Hellerii. Upper figure, male; lower figure, female.] +</p> + +<p> +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.) +</p> + +<p> +[Fig.31. Plecostomus barbatus. Upper figure, head of male; lower figure, +female.] +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>AMPHIBIANS.</h3> <h3>URODELA.</h3> + +<p> +[Fig. 32. Triton cristatus (half natural size, from Bell’s ‘British +Reptiles’). Upper figure, male during the breeding season; lower figure, +female.] +</p> + +<p> +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. +</p> + +<h3>ANURA OR BATRACHIA.</h3> + +<p> +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. +</p> + +<p> +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.” +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>REPTILES.</h3> <h3>CHELONIA.</h3> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<h3>CROCODILIA.</h3> + +<p> +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.) +</p> + +<h3>OPHIDIA.</h3> + +<p> +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.) +</p> + +<p> +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.” +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>LACERTILIA.</h3> + +<p> +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.) +</p> + +<p> +[Fig.33. Sitana minor. Male with the gular pouch expanded (from Gunther’s +‘Reptiles of India’)’] +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +[Fig. 34. Ceratophora Stoddartii. Upper figure; lower figure, female.] +</p> + +<p> +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. +</p> + +<p> +[Fig. 35. Chamaeleo bifurcus. Upper figure, male; lower figure, female. +</p> + +<p> +Fig. 36. Chamaeleo Owenii. Upper figure, male; lower figure, female.] +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0013" id="link2HCH0013"></a> +CHAPTER XIII.<br /> +SECONDARY SEXUAL CHARACTERS OF BIRDS.</h2> + +<p class="letter"> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>LAW OF BATTLE.</h3> + +<p> +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.) +</p> + +<p> +[Fig. 37. The Ruff or Machetes pugnax (from Brehm’s +‘Thierleben’).] +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig.38. Palamedea cornuta (from Brehm), shewing the double wing-spurs, and the +filament on the head.] +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<h3>VOCAL AND INSTRUMENTAL MUSIC.</h3> + +<p> +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. +</p> + +<p> +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.” +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig. 39. Tetrao cupido: male. (T.W. Wood.)] +</p> + +<p> +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.) +</p> + +<p> +[Fig. 40. The Umbrella-bird or Cephalopterus ornatus, male (from Brehm).] +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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, pp. 84, 88, 89, and 95. On the Hoopoe, Mr. Swinhoe, in ‘Proc. +Zoolog. Soc.’ June 23, 1863 and 1871, p. 348. On the Night-jar, Audubon, +ibid. vol. ii. p. 255, and ‘American Naturalist,’ 1873, p. 672. The +English Night-jar likewise makes in the spring a curious noise during its rapid +flight.) +</p> + +<p> +[Fig. 41. Outer tail-feather of Scolopax gallinago (from ‘Proc. Zool. +Soc.’ 1858). +</p> + +<p> +Fig. 42. Outer tail-feather of Scolopax frenata. +</p> + +<p> +Fig. 43. Outer tail-feather of Scolopax javensis.] +</p> + +<p> +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.) +</p> + +<p> +[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.] +</p> + +<p> +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. +</p> + +<p> +[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.] +</p> + +<p> +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.) +</p> + +<p> +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.” +</p> + +<h3>LOVE ANTICS AND DANCES.</h3> + +<p> +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.) +</p> + +<p> +[Fig. 46. Bower-bird, Chlamydera maculata, with bower (from Brehm).] +</p> + +<p> +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. +</p> + +<h3>DECORATION.</h3> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig. 47. Paradisea Papuana (T.W. Wood).] +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +[Fig. 48. Lophornis ornatus, male and female (from Brehm). +</p> + +<p> +Fig. 49. Spathura underwoodi, male and female (from Brehm).] +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. pp. 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. pp. 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, p. 133. On the +Drongo-shrikes, Jerdon, ibid. vol. i. p. 435. On the vernal moult of the +Herodias bubulcus, Mr. S.S. Allen, in ‘Ibis,’ 1863, p. 33. On +Gallus bankiva, Blyth, in ‘Annals and Mag. of Natural History,’ +vol. i. 1848, p. 455; see, also, on this subject, my ‘Variation of +Animals under Domestication,’ vol. i. p. 236.) +</p> + +<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.) +</p> + +<p> +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.) +</p> + +<h3>DISPLAY BY MALE BIRDS OF THEIR PLUMAGE.</h3> + +<p> +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. +</p> + +<p> +[Fig. 50. Rupicola crocea, male (T.W. Wood).] +</p> + +<p> +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.) +</p> + +<p> +[Fig. 51. Polyplectron chinquis, male (T.W. Wood).] +</p> + +<p> +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. +</p> + +<p> +[Fig. 52. Side view of male Argus pheasant, whilst displaying before the +female. Observed and sketched from nature by T.W. Wood.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0014" id="link2HCH0014"></a> +CHAPTER XIV.<br /> +BIRDS—continued.</h2> + +<p class="letter"> +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. +</p> + +<p> +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. +</p> + +<h3>LENGTH OF COURTSHIP.</h3> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<h3>UNPAIRED BIRDS.</h3> + +<p> +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. +</p> + +<p> +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.” +</p> + +<p> +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.) +</p> + +<p> +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. Hist. 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. F.O. Morris, +on the authority of the Hon. and Rev. O.W. Forester. “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? This suspicion will appear somewhat less improbable after we have seen +what strong antipathies and preferences female birds occasionally evince +towards particular males. +</p> + +<h3>MENTAL QUALITIES OF BIRDS, AND THEIR TASTE FOR THE BEAUTIFUL.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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? +</p> + +<p> +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.) +</p> + +<h3>PREFERENCE FOR A PARTICULAR MALES BY THE FEMALES.</h3> + +<p> +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.” +</p> + +<p> +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.” +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +VARIABILITY OF BIRDS, AND ESPECIALLY OF THEIR SECONDARY SEXUAL CHARACTERS. +</p> + +<p> +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. According to Dr. Blasius (‘Ibis,’ +vol. ii. 1860, p. 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. J.A. 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. This result is not incompatible with the belief that +the colours of birds are mainly due to the accumulation of successive +variations through sexual selection; for even after the sexes have been greatly +differentiated, climate might produce an equal effect on both sexes, or a +greater effect on one sex than on the other, owing to some constitutional +difference. +</p> + +<p> +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, p.104. 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. Mr. 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. pp. 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. 381.) +</p> + +<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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +FORMATION AND VARIABILITY OF THE OCELLI OR EYE-LIKE SPOTS ON THE PLUMAGE OF +BIRDS. +</p> + +<p> +[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.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>GRADATION OF SECONDARY SEXUAL CHARACTERS.</h3> + +<p> +[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.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig. 55. Part of a tail-covert of Polyplectron chinquis, with the two ocelli +of natural size. +</p> + +<p> +Fig. 56. Part of a tail-covert of Polyplectron malaccense, with the two ocelli, +partially confluent, of natural size.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>ARGUS PHEASANT.</h3> + +<p> +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. +</p> + +<p> +[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.] +</p> + +<p> +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.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig. 58. Basal part of the secondary wing feather, nearest to the body.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig. 60. An ocellus in an intermediate condition between the elliptic ornament +and the perfect ball-and-socket ocellus.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[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.] +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. 110.) If this be +admitted, we can perceive that the males which during former times were decked +in the most elegant and novel manner would have gained an advantage, not in the +ordinary struggle for life, but in rivalry with other males, and would have +left a larger number of offspring to inherit their newly-acquired beauty. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0015" id="link2HCH0015"></a> +CHAPTER XV.<br /> +BIRDS—continued.</h2> + +<p class="letter"> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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 +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. Mr. 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. Mr. 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, p. 304. On Dicrurus, ‘Ibis,’ 1863, p. +44. On the Platalea, ‘Ibis,’ vol. vi. 1864, p. 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. vol. 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. 496.) +</p> + +<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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0016" id="link2HCH0016"></a> +CHAPTER XVI.<br /> +BIRDS—concluded.</h2> + +<p class="letter"> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>RULES OR CLASSES OF CASES.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +CLASS I. — 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. +</p> + +<p> +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.) +</p> + +<p> +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). +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +CLASS II. — WHEN THE ADULT FEMALE IS MORE CONSPICUOUS THAN THE ADULT +MALE, THE YOUNG OF BOTH SEXES IN THEIR FIRST PLUMAGE RESEMBLE THE ADULT MALE. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig. 62. Rhynchaea capensis (from Brehm).] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +CLASS III. — WHEN THE ADULT MALE RESEMBLES THE ADULT FEMALE, THE YOUNG OF +BOTH SEXES HAVE A PECULIAR FIRST PLUMAGE OF THEIR OWN. +</p> + +<p> +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. +</p> + +<p> +CLASS IV. — WHEN THE ADULT MALE RESEMBLES THE ADULT FEMALE, THE YOUNG OF +BOTH SEXES IN THEIR FIRST PLUMAGE RESEMBLE THE ADULTS. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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).) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +CLASS 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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +CLASS VI. — 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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>ON THE COLOUR OF THE PLUMAGE IN RELATION TO PROTECTION.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. Mr. Bates (‘The Naturalist on +the Amazons,’ vol. ii. 1863, p. 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. But, as Mr. 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. +Mr. 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. Rhamphastos carinatus, Gould’s +‘Monograph of Ramphastidae.’), says that the colours of the beak +“are doubtless in the finest and most brilliant state during the time of +pairing.” There is no greater improbability that toucans should be +encumbered with immense beaks, though rendered as light as possible by their +cancellated structure, for the display of fine colours (an object falsely +appearing to us unimportant), than that the male Argus pheasant and some other +birds should be encumbered with plumes so long as to impede their flight. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>A SUMMARY OF THE FOUR CHAPTERS ON BIRDS.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0017" id="link2HCH0017"></a> +CHAPTER XVII.<br /> +SECONDARY SEXUAL CHARACTERS OF MAMMALS.</h2> + +<p class="letter"> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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.” +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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 +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig. 63. Oryx leucoryx, male (from the Knowsley Menagerie).] +</p> + +<p> +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. +</p> + +<p> +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. Hon. J.D. +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, p. 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. J.D. +Caton’s paper, as above quoted.) +</p> + +<p> +[Fig. 64. Strepsiceros Kudu (from Sir Andrew Smith’s ‘Zoology of +South Africa.’] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. Mr. 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. Mr. 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. As, however, the males do not attain their full +dimensions until rather late in life, they will have tended, in accordance with +the law often indicated, to transmit their characters to their male offspring +alone; and thus the great inequality in size between the sexes of the Scotch +deer-hound may probably be accounted for. +</p> + +<p> +[Fig. 65. Head of Common wild boar, in prime of life (from Brehm).] +</p> + +<p> +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.) +</p> + +<p> +[Fig. 66. Skull of the Babirusa Pig (from Wallace’s ‘Malay +Archipelago’).] +</p> + +<p> +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. +</p> + +<p> +[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.] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>CHOICE IN PAIRING BY EITHER SEX OF QUADRUPEDS.</h3> + +<p> +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.) +</p> + +<p> +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.” +</p> + +<p> +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. +</p> + +<p> +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.” +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0018" id="link2HCH0018"></a> +CHAPTER XVIII.<br /> +SECONDARY SEXUAL CHARACTERS OF MAMMALS—continued.</h2> + +<p class="letter"> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<h3>ODOUR.</h3> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<h3>DEVELOPMENT OF THE HAIR.</h3> + +<p> +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. +</p> + +<p> +[Fig. 68. Pithecia satanas, male (from Brehm).] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>COLOUR OF THE HAIR AND OF THE NAKED SKIN.</h3> + +<p> +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.” +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig. 69. Head of male Mandrill (from Gervais, ‘Hist. Nat. des +Mammifères’).] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>EQUAL TRANSMISSION OF ORNAMENTAL CHARACTERS TO BOTH SEXES.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +[Fig. 70. Tragelaphus scriptus, male (from the Knowsley Menagerie). +</p> + +<p> +Fig. 71. Damalis pygarga, male (from the Knowsley Menagerie).] +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. Mr. 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. 196.) +</p> + +<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. pp. 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. Zool. +Soc.’ 1862, p. 164. See, also, Dr. Hartmann, ‘Ann. d. Landw.’ +Bd. xliii. s. 222.) +</p> + +<h3>QUADRUMANA.</h3> + +<p> +[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. +</p> + +<p> +Fig. 73. Head of Semnopithecus comatus. +</p> + +<p> +Fig. 74. Head of Cebus capucinus. +</p> + +<p> +Fig. 75. Head of Ateles marginatus. +</p> + +<p> +Fig. 76. Head of Cebus vellerosus.] +</p> + +<p> +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. +</p> + +<p> +[Fig. 77. Cercopithecus petaurista (from Brehm).] +</p> + +<p> +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. +</p> + +<p> +[Fig. 78. Cercopithecus diana (from Brehm).] +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<h3>A SUMMARY.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2H_4_0026" id="link2H_4_0026"></a> +PART III.<br /> +SEXUAL SELECTION IN RELATION TO MAN, AND CONCLUSION.</h2> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0019" id="link2HCH0019"></a> +CHAPTER XIX.<br /> +SECONDARY SEXUAL CHARACTERS OF MAN.</h2> + +<p class="letter"> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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 +</p> + +<p> +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.) +</p> + +<p> +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, p. 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. Mr. 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. Forbes has never, as he informs me, seen an +instance with the Aymaras and Quichuas of South America.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<h3>LAW OF BATTLE.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>DIFFERENCE IN THE MENTAL POWERS OF THE TWO SEXES.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>VOICE AND MUSICAL POWERS.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.” +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.”) +</p> + +<p> +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. +</p> + +<h3>THE INFLUENCE OF BEAUTY IN DETERMINING THE MARRIAGES OF MANKIND.</h3> + +<p> +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. +</p> + +<p> +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.” +</p> + +<p> +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.” +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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.’” +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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 he 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.) +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0020" id="link2HCH0020"></a> +CHAPTER XX.<br /> +SECONDARY SEXUAL CHARACTERS OF MAN—continued.</h2> + +<p class="letter"> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +THE CAUSES WHICH PREVENT OR CHECK THE ACTION OF SEXUAL SELECTION WITH SAVAGES. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>INFANTICIDE.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>EARLY BETROTHALS AND SLAVERY OF WOMEN.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>THE MANNER OF ACTION OF SEXUAL SELECTION WITH MANKIND.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>ABSENCE OF HAIR ON THE BODY, AND ITS DEVELOPMENT ON THE FACE AND HEAD.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>COLOUR OF THE SKIN.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>A SUMMARY.</h3> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +</div><!--end chapter--> + +<div class="chapter"> + +<h2><a name="link2HCH0021" id="link2HCH0021"></a> +CHAPTER XXI.<br /> +GENERAL A SUMMARY AND CONCLUSION.</h2> + +<p class="letter"> +Main conclusion that man is descended from some lower form—Manner of +development—Genealogy of man—Intellectual and moral +faculties—Sexual Selection—Concluding remarks. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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-happiness 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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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.) +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<h3>SUPPLEMENTAL NOTE.</h3> <h3>ON SEXUAL SELECTION IN RELATION TO MONKEYS.</h3> + +<p> +Reprinted from NATURE, November 2, 1876, p. 18. +</p> + +<p> +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. The habit with the mandrill and drill seems +to be instinctive or inherited, as it was followed by very young animals; but +it is modified or guided, like so many other instincts, by observation, for Von +Fischer says that they take pains to make their display fully; and if made +before two observers, they turn to him who seems to pay the most attention. +</p> + +<p> +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. +</p> + +<p> +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. However this may be, I have given in my ‘Descent of Man’ +instances of closely-allied birds inhabiting distinct countries, of which the +young and the females cannot be distinguished, whilst the adult males differ +considerably, and this may be attributed with much probability to the action of +sexual selection. +</p> + +<p> +INDEX. — Abbot, C., on the battles of seals. +</p> + +<p> +Abductor of the fifth metatarsal, presence of, in man. +</p> + +<p> +Abercrombie, Dr., on disease of the brain affecting speech. +</p> + +<p> +Abipones, marriage customs of the. +</p> + +<p> +Abortion, prevalence of the practice of. +</p> + +<p> +Abou-Simbel, caves of. +</p> + +<p> +Abramis brama. +</p> + +<p> +Abstraction, power of, in animals. +</p> + +<p> +Acalles, stridulation of. +</p> + +<p> +Acanthodactylus capensis, sexual differences of colour in. +</p> + +<p> +Accentor Modularis. +</p> + +<p> +Acclimatisation, difference of, in different races of men. +</p> + +<p> +Achetidae, stridulation of the; rudimentary stridulating organs in female. +</p> + +<p> +Acilius sulcatus, elytra of the female. +</p> + +<p> +Acomus, development of spurs in the female of. +</p> + +<p> +Acridiidae, stridulation of the; rudimentary stridulating organs in female. +</p> + +<p> +Acromio-basilar muscle, and quadrupedal gait. +</p> + +<p> +Acting. +</p> + +<p> +Actiniae, bright colours of. +</p> + +<p> +Adams, Mr., migration of birds; intelligence of nut-hatch; on the Bombycilla +carolinensis. +</p> + +<p> +Admiral butterfly. +</p> + +<p> +Adoption of the young of other animals by female monkeys. +</p> + +<p> +Advancement in the organic scale, Von Baer’s definition of. +</p> + +<p> +Aeby, on the difference between the skulls of man and the quadrumana. +</p> + +<p> +Aesthetic faculty, not highly developed in savages. +</p> + +<p> +Affection, maternal; manifestation of, by animals; parental and filial, partly +the result of natural selection; mutual, of birds; shewn by birds in +confinement, for certain persons. +</p> + +<p> +Africa, probably the birthplace of man; South, crossed population of; South, +retention of colour by the Dutch in; South, proportion of the sexes in the +butterflies of; tattooing practised in; Northern, coiffure of natives of. +</p> + +<p> +Agassiz, L., on conscience in dogs; on the coincidence of the races of man with +zoological provinces; on the number of species of man; on the courtship of the +land-snails; on the brightness of the colours of male fishes during the +breeding season; on the frontal protuberance of the males of Geophagus and +Cichla; male fishes hatching ova in their mouths; sexual differences in colour +of chromids; on the slight sexual differences of the South Americans; on the +tattooing of the Amazonian Indians. +</p> + +<p> +Age, in relation to the transmission of characters in birds; variation in +accordance with, in birds. +</p> + +<p> +Agelaeus phoeniceus. +</p> + +<p> +Ageronia feronia, noise produced by. +</p> + +<p> +Agrion, dimorphism in. +</p> + +<p> +Agrion Ramburii, sexes of. +</p> + +<p> +Agrionidae, difference in the sexes of. +</p> + +<p> +Agrotis exclamationis. +</p> + +<p> +Ague, tertian, dog suffering from. +</p> + +<p> +Ainos, hairiness of the. +</p> + +<p> +Aitchison, Mr., on sheep. +</p> + +<p> +Aithurus polytmus, young of. +</p> + +<p> +Albino birds. +</p> + +<p> +Alca torda, young of. +</p> + +<p> +Alces palmata. +</p> + +<p> +Alder and Hancock, MM., on the nudi-branch mollusca. +</p> + +<p> +Allen, J.A., vigour of birds earliest hatched; effect of difference of +temperature, light, etc., on birds; colours of birds; on the relative size of +the sexes of Callorhinus ursinus; on the name of Otaria jubata; on the pairing +of seals; on sexual differences in the colour of bats. +</p> + +<p> +Allen, S., on the habits of Hoplopterus; on the plumes of herons; on the vernal +moult of Herodius bubulcus. +</p> + +<p> +Alligator, courtship of the male; roaring of the male. +</p> + +<p> +Amadavat, pugnacity of male. +</p> + +<p> +Amadina Lathami, display of plumage by the male. +</p> + +<p> +Amadina castanotis, display of plumage by the male. +</p> + +<p> +Amazons, butterflies of the; fishes of the. +</p> + +<p> +America, variation in the skulls of aborigines of; wide range of aborigines of; +lice of the natives of; general beardlessness of the natives of. +</p> + +<p> +America, North, butterflies of; Indians of, women a cause of strife among the; +Indians of, their notions of female beauty. +</p> + +<p> +America, South, character of the natives of; population of parts of; piles of +stones in; extinction of the fossil horse of; desert-birds of; slight sexual +difference of the aborigines of; prevalence of infanticide in. +</p> + +<p> +American languages, often highly artificial. +</p> + +<p> +Americans, wide geographical range of; native, variability of; and negroes, +difference of; aversion of, to hair on the face. +</p> + +<p> +Ammophila, on the jaws of. +</p> + +<p> +Ammotragus tragelaphus, hairy forelegs of. +</p> + +<p> +Amphibia, affinity of, to the ganoid fishes; vocal organs of the. +</p> + +<p> +Amphibians, breeding whilst immature. +</p> + +<p> +Amphioxus. +</p> + +<p> +Amphipoda, males sexually mature while young. +</p> + +<p> +Amunoph III., negro character of, features of. +</p> + +<p> +Anal appendages of insects. +</p> + +<p> +Analogous variation in the plumage of birds. +</p> + +<p> +Anas. +</p> + +<p> +Anas acuta, male plumage of. +</p> + +<p> +Anas boschas, male plumage of. +</p> + +<p> +Anas histrionica. +</p> + +<p> +Anas punctata. +</p> + +<p> +Anastomus oscitans, sexes and young of; white nuptial plumage of. +</p> + +<p> +Anatidae, voices of. +</p> + +<p> +Anax junius, differences in the sexes of. +</p> + +<p> +Andaman islanders, susceptible to change of climate. +</p> + +<p> +Anderson, Dr., on the tail of Macacus brunneus; the Bufo sikimmensis; sounds of +Echis carinata. +</p> + +<p> +Andreana fulva. +</p> + +<p> +Anglo-Saxons, estimation of the beard among the. +</p> + +<p> +Animals, domesticated, more fertile than wild; cruelty of savages to; +characters common to man and; domestic, change of breeds of. +</p> + +<p> +Annelida, colours of. +</p> + +<p> +Anobium tessellatum, sounds produced by. +</p> + +<p> +Anolis cristatellus, male, crest of; pugnacity of the male; throat-pouch of. +</p> + +<p> +Anser canadensis. +</p> + +<p> +Anset cygnoides; knob at the base of the beak of. +</p> + +<p> +Anser hyperboreus, whiteness of. +</p> + +<p> +Antelope, prong-horned, horns of. +</p> + +<p> +Antelopes, generally polygamous; horns of; canine teeth of some male; use of +horns of; dorsal crests in; dewlaps of; winter change of two species of; +peculiar markings of. +</p> + +<p> +Antennae, furnished with cushions in the male of Penthe. +</p> + +<p> +Anthidium manicatum, large male of. +</p> + +<p> +Anthocharis cardamines; sexual difference of colour in. +</p> + +<p> +Anthocharis genutia. +</p> + +<p> +Anthocharis sara. +</p> + +<p> +Anthophora acervorum, large male of. +</p> + +<p> +Anthophora retusa, difference of the sexes in. +</p> + +<p> +Anthropidae. +</p> + +<p> +Anthus, moulting of. +</p> + +<p> +Antics of birds. +</p> + +<p> +Antigua, Dr. Nicholson’s observations on yellow fever in. +</p> + +<p> +Antilocapra americana, horns of. +</p> + +<p> +Antilope bezoartica, horned females of; sexual difference in the colour of. +</p> + +<p> +Antilope Dorcas and euchore. +</p> + +<p> +Antilope euchore, horns of. +</p> + +<p> +Antilope montana, rudimentary canines in the young male of. +</p> + +<p> +Antilope niger, sing-sing, caama, and gorgon, sexual differences in the colours +of. +</p> + +<p> +Antilope oreas, horns of. +</p> + +<p> +Antilope saiga, polygamous habits of. +</p> + +<p> +Antilope strepsiceros, horns of. +</p> + +<p> +Antilope subgutturosa, absence of suborbital pits in. +</p> + +<p> +Antipathy, shewn by birds in confinement, to certain persons. +</p> + +<p> +Ants, large size of the cerebral ganglia in; soldier, large jaws of; playing +together; memory in; intercommunication of, by means of the antennae; habits +of; difference of the sexes in; recognition of each other by, after separation. +</p> + +<p> +Ants White, habits of. +</p> + +<p> +Anura. +</p> + +<p> +Apatania muliebris, male unknown. +</p> + +<p> +Apathus, difference of the sexes in. +</p> + +<p> +Apatura Iris. +</p> + +<p> +Apes, difference of the young, from the adult; semi-erect attitude of some; +mastoid processes of; influences of the jaw-muscles on the physiognomy of; +female, destitute of large canines; building platforms; imitative faculties of; +anthropomorphous; probable speedy extermination of the; Gratiolet on the +evolution of; canine teeth of male; females of some, less hairy beneath than +the males. +</p> + +<p> +Apes, long-armed, their mode of progression. +</p> + +<p> +Aphasia, Dr. Bateman on. +</p> + +<p> +Apis mellifica, large male of. +</p> + +<p> +Apollo, Greek statues of. +</p> + +<p> +Apoplexy in Cebus Azarae. +</p> + +<p> +Appendages, anal, of insects. +</p> + +<p> +Approbation, influence of the love of. +</p> + +<p> +Aprosmictus scapulatus. +</p> + +<p> +Apus, proportion of sexes. +</p> + +<p> +Aquatic birds, frequency of white plumage in. +</p> + +<p> +Aquila chrysaetos. +</p> + +<p> +Arab women, elaborate and peculiar coiffure of. +</p> + +<p> +Arabs, fertility of crosses with other races; gashing of cheeks and temples +among the. +</p> + +<p> +Arachnida. +</p> + +<p> +Arakhan, artificial widening of the forehead by the natives of. +</p> + +<p> +Arboricola, young of. +</p> + +<p> +Archeopteryx. +</p> + +<p> +Arctiidae, coloration of the. +</p> + +<p> +Ardea asha, rufescens, and coerulea, change of colour in. +</p> + +<p> +Ardea coerulea, breeding in immature plumage. +</p> + +<p> +Ardea gularis, change of plumage in. +</p> + +<p> +Ardea herodias, love-gestures of the male. +</p> + +<p> +Ardea ludoviciana, age of mature plumage in; continued growth of crest and +plumes in the male of. +</p> + +<p> +Ardea nycticorax, cries of. +</p> + +<p> +Ardeola, young of. +</p> + +<p> +Ardetta, changes of plumage in. +</p> + +<p> +Argenteuil. +</p> + +<p> +Argus pheasant, display of plumage by the male; ocellated spots of the; +gradation of characters in the. +</p> + +<p> +Argyll, Duke of, on the physical weakness of man; the fashioning of implements +peculiar to man; on the contest in man between right and wrong; on the +primitive civilisation of man; on the plumage of the male Argus pheasant; on +Urosticte Benjamini; on the nests of birds. +</p> + +<p> +Argynnis, colouring of the lower surface of. +</p> + +<p> +Aricoris epitus, sexual differences in the wings of. +</p> + +<p> +Aristocracy, increased beauty of the. +</p> + +<p> +Arms, proportions of, in soldiers and sailors; direction of the hair on the. +</p> + +<p> +Arms and hands, free use of, indirectly correlated with diminution of canines. +</p> + +<p> +Arrest of development. +</p> + +<p> +Arrow-heads, stone, general resemblance of. +</p> + +<p> +Arrows, use of. +</p> + +<p> +Arteries, variations in the course of the. +</p> + +<p> +Artery, effect of tying, upon the lateral channels. +</p> + +<p> +Arthropoda. +</p> + +<p> +Arts practised by savages. +</p> + +<p> +Ascension, coloured incrustation on the rocks of. +</p> + +<p> +Ascidia, affinity of the lancelet to; tad-pole like larvae of. +</p> + +<p> +Ascidians, bright colours of some. +</p> + +<p> +Asinus, Asiatic and African species of. +</p> + +<p> +Asinus taeniopus. +</p> + +<p> +Ass, colour-variations of the. +</p> + +<p> +Ateles, effects of brandy on an; absence of the thumb in. +</p> + +<p> +Ateles beelzebuth, ears of. +</p> + +<p> +Ateles marginatus, colour of the ruff of; hair on the head of. +</p> + +<p> +Ateuchus cicatricosus, habits of. +</p> + +<p> +Ateuchus, stridulation of. +</p> + +<p> +Athalia, proportions of the sexes in. +</p> + +<p> +Atropus pulsatorius. +</p> + +<p> +Attention, manifestations of, in animals. +</p> + +<p> +Audouin, V., on a hymenopterous parasite with a sedentary male. +</p> + +<p> +Audubon, J.J., on the pinioned goose; on the speculum of Mergus cucullatus; on +the pugnacity of male birds; on courtship of Caprimulgus; on Tetrao cupido; on +Ardea nycticorax; on Sturnella ludoviciana; on the vocal organs of Tetra +cupido; on the drumming of the male Tetrao umbellus; on sounds produced by the +nightjar; on Ardea herodias and Cathartes jota; on Mimus polyglottus; on +display in male birds; on the spring change of colour in some finches; on +migration of mocking thrushes; recognition of a dog by a turkey; selection of +mate by female birds; on the turkey; on variation in the male scarlet tanager; +on the musk-rat; on the habits of Pyranga aestiva; on local differences in the +nests of the same species of birds; on the habits of woodpeckers; on Bombycilla +carolinensis; on young females of Pyranga aestiva acquiring male characters; on +the immature plumage of thrushes; on the immature plumage of birds; on birds +breeding in immature plumage; on the growth of the crest and plume in the male +Ardea ludoviciana; on the change of colour in some species of Ardea. +</p> + +<p> +Audobon and Bachman, MM., on squirrels fighting; on the Canadian lynx. +</p> + +<p> +Aughey, Prof., on rattlesnakes. +</p> + +<p> +Austen, N.L., on Anolis cristatellus. +</p> + +<p> +Australia, not the birthplace of man; half-castes killed by the natives of; +lice of the natives of. +</p> + +<p> +Australia, South, variation in the skulls of aborigines of. +</p> + +<p> +Australians, colour of new-born children of; relative height of the sexes of; +women a cause of war among the. +</p> + +<p> +Axis deer, sexual difference in the colour of the. +</p> + +<p> +Aymaras, measurements of the; no grey hair among the; hairlessness of the face +in the; long hair of the. +</p> + +<p> +Azara, on the proportion of men and women among the Guaranys; on Palamedea +cornuta; on the beards of the Guaranys; on strife for women among the Guanas; +on infanticide; on the eradication of the eyebrows and eyelashes by the Indians +of Paraguay; on polyandry among the Guanas; celibacy unknown among the savages +of South America; on the freedom of divorce among the Charruas. +</p> + +<p> +Babbage C., on the greater proportion of illegitimate female births. +</p> + +<p> +Babirusa, tusks of the. +</p> + +<p> +Baboon, revenge in a; rage excited in, by reading; manifestation of memory by +a; employing a mat for shelter against the sun; protected from punishment by +its companions. +</p> + +<p> +Baboon, Cape, mane of the male; Hamadryas, mane of the male. +</p> + +<p> +Baboon, effects of intoxicating liquors on; ears of; diversity of the mental +faculties in; hands of; habits of; variability of the tail in; manifestation of +maternal affection by; using stones and sticks as weapons; co-operation of; +silence of, on plundering expeditions; apparent polygamy of; polygamous and +social habits of. +</p> + +<p> +Baboons, courtship of. +</p> + +<p> +Bachman, Dr., on the fertility of mulattoes. +</p> + +<p> +Baer, K.E. von, on embryonic development; definition of advancement in the +organic scale. +</p> + +<p> +Bagehot, W., on the social virtues among primitive men; slavery formerly +beneficial; on the value of obedience; on human progress; on the persistence of +savage tribes in classical times. +</p> + +<p> +Bailly, E.M., on the mode of fighting of the Italian buffalo; on the fighting +of stags. +</p> + +<p> +Bain, A., on the sense of duty; aid springing from sympathy; on the basis of +sympathy; on the love of approbation etc.; on the idea of beauty. +</p> + +<p> +Baird, W., on a difference in colour between the males and females of some +Entozoa. +</p> + +<p> +Baker, Mr., observation on the proportion of the sexes in pheasant-chicks. +</p> + +<p> +Baker, Sir S., on the fondness of the Arabs for discordant music; on sexual +difference in the colours of an antelope; on the elephant and rhinoceros +attacking white or grey horses; on the disfigurements practised by the negroes; +on the gashing of the cheeks and temples practised in Arab countries; on the +coiffure of the North Africans; on the perforation of the lower lip by the +women of Latooka; on the distinctive characters of the coiffure of central +African tribes; on the coiffure of Arab women. +</p> + +<p> +“Balz” of the Black-cock. +</p> + +<p> +Bantam, Sebright. +</p> + +<p> +Banteng, horns of; sexual differences in the colours of the. +</p> + +<p> +Banyai, colour of the. +</p> + +<p> +Barbarism, primitive, of civilised nations. +</p> + +<p> +Barbs, filamentous, of the feathers, in certain birds. +</p> + +<p> +Barr, Mr., on sexual preference in dogs. +</p> + +<p> +Barrago, F., on the Simian resemblances of man. +</p> + +<p> +Barrington, Daines, on the language of birds; on the clucking of the hen; on +the object of the song of birds; on the singing of female birds; on birds +acquiring the songs of other birds; on the muscles of the larynx in song-birds; +on the want of the power of song by female birds. +</p> + +<p> +Barrow, on the widow-bird. +</p> + +<p> +Bartels, Dr., supernumerary mammae in men. +</p> + +<p> +Bartlett, A.D., period of hatching of bird’s eggs; on the tragopan; on +the development of the spurs in Crossoptilon auritum; on the fighting of the +males of Plectopterus gambensis; on the Knot; on display in male birds; on the +display of plumage by the male Polyplectron; on Crossoptilon auritum and +Phasianus Wallichii; on the habits of Lophophorus; on the colour of the mouth +in Buceros bicornis; on the incubation of the cassowary; on the Cape Buffalo; +on the use of the horns of antelopes; on the fighting of male wart-hogs; on +Ammotragus tragelaphus; on the colours of Cercopithecus cephus; on the colours +of the faces of monkeys; on the naked surfaces of monkeys. +</p> + +<p> +Bartlett, on courting of Argus pheasant. +</p> + +<p> +Bartram, on the courtship of the male alligator. +</p> + +<p> +Basque language, highly artificial. +</p> + +<p> +Bate, C.S., on the superior activity of male crustacea; on the proportions of +the sexes in crabs; on the chelae of crustacea; on the relative size of the +sexes in crustacea; on the colours of crustacea. +</p> + +<p> +Bateman, Dr., tendency to imitation in certain diseased states; on Aphasia. +</p> + +<p> +Bates, H.W., on variation in the form of the head of Amazonian Indians; on the +proportion of the sexes among Amazonian butterflies; on sexual differences in +the wings of butterflies; on the field-cricket; on Pyrodes pulcherrimus; on the +horns of Lamellicorn beetles; on the colours of Epicaliae, etc.; on the +coloration of tropical butterflies; on the variability of Papilio Sesostris and +Childrenae; on male and female butterflies inhabiting different stations; on +mimicry; on the caterpillar of a Sphinx; on the vocal organs of the +umbrella-bird; on the toucans; on Brackyurus calvus. +</p> + +<p> +Batokas, knocking out two upper incisors. +</p> + +<p> +Batrachia, eagerness of male. +</p> + +<p> +Bats, scent-glands; sexual differences in the colour of; fur of male +frugivorous. +</p> + +<p> +Battle, law of; among beetles; among birds; among mammals; in man. +</p> + +<p> +Beak, sexual difference in the forms of the; in the colour of the. +</p> + +<p> +Beaks, of birds, bright colours of. +</p> + +<p> +Beard, development of, in man; analogy of the, in man and the quadrumana; +variation of the development of the, in different races of men; estimation of, +among bearded nations; probable origin of the. +</p> + +<p> +Beard, in monkeys; of mammals. +</p> + +<p> +Beautiful, taste for the, in birds; in the quadrumana. +</p> + +<p> +Beauty, sense of, in animals; appreciation of, by birds; influence of; +variability of the standard of. +</p> + +<p> +Beauty, sense of, sufficiently permanent for action of sexual selection. +</p> + +<p> +Beaven, Lieut., on the development of the horns in Cervus Eldi. +</p> + +<p> +Beaver, instinct and intelligence of the; voice of the; castoreum of the. +</p> + +<p> +Beavers, battles of male. +</p> + +<p> +Bechstein, on female birds choosing the best singers among the males; on +rivalry in song-birds; on the singing of female birds; on birds acquiring the +songs of other birds; on pairing the canary and siskin; on a sub-variety of the +monk pigeon; on spurred hens. +</p> + +<p> +Beddoe, Dr., on causes of difference in stature. +</p> + +<p> +Bee-eater. +</p> + +<p> +Bees, pollen-baskets and stings of; destruction of drones and queens by; +female, secondary sexual characters of; proportion of sexes; difference of the +sexes in colour and sexual selection. +</p> + +<p> +Beetle, luminous larva of a. +</p> + +<p> +Beetles, size of the cerebral ganglia in; dilatation of the foretarsi in male; +blind; stridulation of. +</p> + +<p> +Belgium, ancient inhabitants of. +</p> + +<p> +Bell, Sir C., on emotional muscles in man; “snarling muscles;” on +the hand. +</p> + +<p> +Bell, T., on the numerical proportion of the sexes in moles; on the newts; on +the croaking of the frog; on the difference in the coloration of the sexes in +Zootoca vivipara; on moles fighting. +</p> + +<p> +Bell-bird, sexual difference in the colour of the. +</p> + +<p> +Bell-birds, colours of. +</p> + +<p> +Belt, Mr., on the nakedness of tropical mankind; on a spider-monkey and eagle; +habits of ants; Lampridae distasteful to mammals; mimicry of Leptalides; +colours of Nicaraguan frogs; display of humming-birds; on the toucans; +protective colouring of skunk. +</p> + +<p> +Benevolence, manifested by birds. +</p> + +<p> +Bennett, A.W., attachment of mated birds; on the habits of Dromaeus irroratus. +</p> + +<p> +Bennett, Dr., on birds of paradise. +</p> + +<p> +Berbers, fertility of crosses with other races. +</p> + +<p> +Bernicla antarctica, colours of. +</p> + +<p> +Bernicle gander pairing with a Canada goose. +</p> + +<p> +Bert, M., crustaceans distinguish colours. +</p> + +<p> +Bettoni, E., on local differences in the nests of Italian birds. +</p> + +<p> +Beyle, M., see Bombet. +</p> + +<p> +Bhoteas, colour of the beard in. +</p> + +<p> +Bhringa, disc-formed tail-feathers of. +</p> + +<p> +Bianconi, Prof., on structures as explained through mechanical principles. +</p> + +<p> +Bibio, sexual differences in the genus. +</p> + +<p> +Bichat, on beauty. +</p> + +<p> +Bickes, proportion of sexes in man. +</p> + +<p> +Bile, coloured, in many animals. +</p> + +<p> +Bimana. +</p> + +<p> +Birds, imitations of the songs of other birds by; dreaming; killed by telegraph +wires; language of; sense of beauty in; pleasure of, in incubation; male, +incubation by; and reptiles, alliance of; sexual differences in the beak of +some; migratory, arrival of the male before the female; apparent relation +between polygamy and marked sexual differences in; monogamous, becoming +polygamous under domestication; eagerness of male in pursuit of the female; +wild, numerical proportion of the sexes in; secondary sexual characters of; +difference of size in the sexes of; fights of male, witnessed by females; +display of male, to captivate the females; close attention of, to the songs of +others; acquiring the song of their foster-parents; brilliant, rarely good +songsters; love-antics and dances of; coloration of; moulting of; unpaired; +male, singing out of season; mutual affection of; in confinement, distinguish +persons; hybrid, production of; Albino; European, number of species of; +variability of; geographical distribution of colouring; gradation of secondary +sexual characters in; obscurely coloured, building concealed nests; young +female, acquiring male characters; breeding in immature plumage; moulting of; +aquatic, frequency of white plumage in; vocal courtship of; naked skin of the +head and neck in. +</p> + +<p> +Birgus latro, habits of. +</p> + +<p> +Birkbeck, Mr., on the finding of new mates by golden eagles. +</p> + +<p> +Birthplace of man. +</p> + +<p> +Births, numerical proportions of the sexes in, in animals and man; male and +female, numerical proportion of, in England. +</p> + +<p> +Bischoff, Prof., on the agreement between the brains of man and of the orang; +figure of the embryo of the dog; on the convolutions of the brain in the human +foetus; on the difference between the skulls of man and the quadrumana; +resemblance between the ape’s and man’s. +</p> + +<p> +Bishop, J., on the vocal organs of frogs; on the vocal organs of cervine birds; +on the trachea of the Merganser. +</p> + +<p> +Bison, American, co-operation of; mane of the male. +</p> + +<p> +Bitterns, dwarf, coloration of the sexes of. +</p> + +<p> +Biziura lobata, musky odour of the male; large size of male. +</p> + +<p> +Blackbird, sexual differences in the; proportion of the sexes in the; +acquisition of a song by; colour of the beak in the sexes of the; pairing with +a thrush; colours and nidification of the; young of the; sexual difference in +coloration of the. +</p> + +<p> +Black-buck, Indian, sexual difference in the colour of the. +</p> + +<p> +Blackcap, arrival of the male, before the female; young of the. +</p> + +<p> +Black-cock, polygamous; proportion of the sexes in the; pugnacity and +love-dance of the; call of the; moulting of the; duration of the courtship of +the; and pheasant, hybrids of; sexual difference in coloration of the; crimson +eye-cere of the. +</p> + +<p> +Black-grouse, characters of young. +</p> + +<p> +Blacklock, Dr., on music. +</p> + +<p> +Blackwall, J., on the speaking of the magpie; on the desertion of their young +by swallows; on the superior activity of male spiders; on the proportion of the +sexes in spiders; on sexual variation of colour in spiders; on male spiders. +</p> + +<p> +Bladder-nose Seal, hood of the. +</p> + +<p> +Blaine, on the affections of dogs. +</p> + +<p> +Blair, Dr., on the relative liability of Europeans to yellow fever. +</p> + +<p> +Blake, C.C., on the jaw from La Naulette. +</p> + +<p> +Blakiston, Captain, on the American snipe; on the dances of Tetrao +phasianellus. +</p> + +<p> +Blasius, Dr., on the species of European birds. +</p> + +<p> +Bledius taurus, hornlike processes of male. +</p> + +<p> +Bleeding, tendency to profuse. +</p> + +<p> +Blenkiron, Mr., on sexual preference in horses. +</p> + +<p> +Blennies, crest developed on the head of male, during the breeding season. +</p> + +<p> +Blethisa multipunctata, stridulation of. +</p> + +<p> +Bloch, on the proportions of the sexes in fishes. +</p> + +<p> +Blood, arterial, red colour of. +</p> + +<p> +Blood pheasant, number of spurs in. +</p> + +<p> +Blow-fly, sounds made by. +</p> + +<p> +Bluebreast, red-throated, sexual differences of the. +</p> + +<p> +Blumenbach, on Man; on the large size of the nasal cavities in American +aborigines; on the position of man; on the number of species of man. +</p> + +<p> +Blyth, E., on the structure of the hand in the species of Hylobates; +observations on Indian crows; on the development of the horns in the Koodoo and +Eland antelopes; on the pugnacity of the males of Gallicrex cristatus; on the +presence of spurs in the female Euplocamus erythrophthalmus; on the pugnacity +of the amadavat; on the spoonbill; on the moulting of Anthus; on the moulting +of bustards, plovers, and Gallus bankiva; on the Indian honey-buzzard; on +sexual differences in the colour of the eyes of hornbills; on Oriolus +melanocephalus; on Palaeornis javanicus; on the genus Ardetta; on the peregrine +falcon; on young female birds acquiring male characters; on the immature +plumage of birds; on representative species of birds; on the young of Turnix; +on anomalous young of Lanius rufus and Colymbus glacialis; on the sexes and +young of the sparrows; on dimorphism in some herons; on the ascertainment of +the sex of nestling bullfinches by pulling out breast-feathers; on orioles +breeding in immature plumage; on the sexes and young of Buphus and Anastomus; +on the young of the blackcap and blackbird; on the young of the stonechat; on +the white plumage of Anastomus; on the horns of Bovine animals; on the horns of +Antilope bezoartica; on the mode of fighting of Ovis cycloceros; on the voice +of the Gibbons; on the crest of the male wild goat; on the colours of Portax +picta; on the colours of Antilope bezoartica; on the colour of the Axis deer; +on sexual difference of colour in Hylobates hoolock; on the hog-deer; on the +beard and whiskers in a monkey, becoming white with age. +</p> + +<p> +Boar, wild, polygamous in India; use of the tusks by the; fighting of. +</p> + +<p> +Boardman, Mr., Albino birds in U.S. +</p> + +<p> +Boitard and Corbie, MM., on the transmission of sexual peculiarities in +pigeons; on the antipathy shewn by some female pigeons to certain males. +</p> + +<p> +Bold, Mr., on the singing of a sterile hybrid canary. +</p> + +<p> +Bombet, on the variability of the standard of beauty in Europe. +</p> + +<p> +Bombus, difference of the sexes in. +</p> + +<p> +Bombycidae, coloration of; pairing of the; colours of. +</p> + +<p> +Bombycilla carolinensis, red appendages of. +</p> + +<p> +Bombyx cynthia, proportion of the sexes in; pairing of. +</p> + +<p> +Bombyx mori, difference of size of the male and female cocoons of; pairing of. +</p> + +<p> +Bombyx Pernyi, proportion of sexes of. +</p> + +<p> +Bombyx Yamamai, M. Personnat on; proportion of sexes of. +</p> + +<p> +Bonaparte, C.L., on the call-notes of the wild turkey. +</p> + +<p> +Bond, F., on the finding of new mates by crows. +</p> + +<p> +Bone, implements of, skill displayed in making. +</p> + +<p> +Boner, C., on the transfer of male characters to an old female chamois; on the +habits of stags; on the pairing of red deer. +</p> + +<p> +Bones, increase of, in length and thickness, when carrying a greater weight. +</p> + +<p> +Bonizzi, P., difference of colour in sexes of pigeons. +</p> + +<p> +Bonnet monkey. +</p> + +<p> +Bonwick, J., extinction of Tasmanians. +</p> + +<p> +Boomerang. +</p> + +<p> +Boreus hyemalis, scarcity of the male. +</p> + +<p> +Bory St. Vincent, on the number of species of man; on the colours of Labrus +pavo. +</p> + +<p> +Bos etruscus. +</p> + +<p> +Bos gaurus, horns of. +</p> + +<p> +Bos moschatus. +</p> + +<p> +Bos primigenius. +</p> + +<p> +Bos sondaicus, horns of, colours of. +</p> + +<p> +Botocudos, mode of life of; disfigurement of the ears and lower lip of the. +</p> + +<p> +Boucher de Perthes, J.C. de, on the antiquity of man. +</p> + +<p> +Bourbon, proportion of the sexes in a species of Papilio from. +</p> + +<p> +Bourien on the marriage-customs of the savages of the Malay Archipelago. +</p> + +<p> +Bovidae, dewlaps of. +</p> + +<p> +Bower-birds, habits of the; ornamented playing-places of. +</p> + +<p> +Bows, use of. +</p> + +<p> +Brachycephalic structure, possible explanation of. +</p> + +<p> +Brachyura. +</p> + +<p> +Brachyurus calvus, scarlet face of. +</p> + +<p> +Bradley, Mr., abductor ossis metatarsi quinti in man. +</p> + +<p> +Brain, of man, agreement of the, with that of lower animals; convolutions of, +in the human foetus; influence of development of mental faculties upon the size +of the; influence of the development of on the spinal column and skull; larger +in some existing mammals than in their tertiary prototypes; relation of the +development of the, to the progress of language; disease of the, affecting +speech; difference in the convolutions of, in different races of men; +supplement on, by Prof. Huxley; development of the gyri and sulci. +</p> + +<p> +Brakenridge, Dr., on the influence of climate. +</p> + +<p> +Brandt, A., on hairy men. +</p> + +<p> +Braubach, Prof., on the quasi-religious feeling of a dog towards his master; on +the self-restraint of dogs. +</p> + +<p> +Brauer, F., on dimorphism in Neurothemis. +</p> + +<p> +Brazil, skulls found in caves of; population of; compression of the nose by the +natives of. +</p> + +<p> +Break between man and the apes. +</p> + +<p> +Bream, proportion of the sexes in the. +</p> + +<p> +Breeding, age of, in birds. +</p> + +<p> +Breeding season, sexual characters making their appearance in the, in birds. +</p> + +<p> +Brehm, on the effects of intoxicating liquors on monkeys; on the recognition of +women by male Cynocephali; on the diversity of the mental faculties of monkeys; +on the habits of baboons; on revenge taken by monkeys; on manifestations of +maternal affection by monkeys and baboons; on the instinctive dread of monkeys +for serpents; on the use of stones as missiles by baboons; on a baboon using a +mat for shelter from the sun; on the signal-cries of monkeys; on sentinels +posted by monkeys; on co-operation of animals; on an eagle attacking a young +Cercopithecus; on baboons in confinement protecting one of their number from +punishment; on the habits of baboons when plundering; on polygamy in +Cynocephalus and Cebus; on the numerical proportion of the sexes in birds; on +the love-dance of the blackcock; Palamedea cornuta; on the habits of the +Black-grouse; on sounds produced by birds of paradise; on assemblages of +grouse; on the finding of new mates by birds; on the fighting of wild boars; on +sexual differences in Mycetes; on the habits of Cynocephalus hamadryas. +</p> + +<p> +Brent, Mr., on the courtship of fowls. +</p> + +<p> +Breslau, numerical proportion of male and female births in. +</p> + +<p> +Bridgeman, Laura. +</p> + +<p> +Brimstone butterfly, sexual difference of colour in the. +</p> + +<p> +British, ancient, tattooing practised by. +</p> + +<p> +Broca, Prof., on the occurrence of the supra-condyloid foramen in the human +humerus; anthropomorphous apes more bipedal than quadrupedal; on the capacity +of Parisian skulls at different periods; comparison of modern and mediaeval +skulls; on tails of quadrupeds; on the influence of natural selection; on +hybridity in man; on human remains from Les Eyzies; on the cause of the +difference between Europeans and Hindoos. +</p> + +<p> +Brodie, Sir B., on the origin of the moral sense in man. +</p> + +<p> +Bronn, H.G., on the copulation of insects of distinct species. +</p> + +<p> +Bronze period, men of, in Europe. +</p> + +<p> +Brown, R., sentinels of seals generally females; on the battles of seals; on +the narwhal; on the occasional absence of the tusks in the female walrus; on +the bladder-nose seal; on the colours of the sexes in Phoca Groenlandica; on +the appreciation of music by seals; on plants used as love-philters, by North +American women. +</p> + +<p> +Browne, Dr. Crichton, injury to infants during parturition. +</p> + +<p> +Brown-Sequard, Dr., on the inheritance of the effects of operations by +guinea-pig. +</p> + +<p> +Bruce, on the use of the elephant’s tusks. +</p> + +<p> +Brulerie, P. de la, on the habits of Ateuchus cicatricosus; on the stridulation +of Ateuchus. +</p> + +<p> +Brunnich, on the pied ravens of the Feroe islands. +</p> + +<p> +Bryant, Dr., preference of tame pigeon for wild mate. +</p> + +<p> +Bryant, Captain, on the courtship of Callorhinus ursinus. +</p> + +<p> +Bubas bison, thoracic projection of. +</p> + +<p> +Bubalus caffer, use of horns. +</p> + +<p> +Bucephalus capensis, difference of the sexes of, in colour. +</p> + +<p> +Buceros, nidification and incubation of. +</p> + +<p> +Buceros bicornis, sexual differences in the colouring of the casque, beak, and +mouth in. +</p> + +<p> +Buceros corrugatus, sexual differences in the beak of. +</p> + +<p> +Buchner, L., on the origin of man; on the use of the human foot as a prehensile +organ; on the mode of progression of the apes; on want of self-consciousness, +etc., in savages. +</p> + +<p> +Bucholz, Dr., quarrels of chamaeleons. +</p> + +<p> +Buckinghamshire, numerical proportion of male and female births in. +</p> + +<p> +Buckland, F., on the numerical proportion of the sexes in rats; on the +proportion of the sexes in the trout; on Chimaera monstrosa. +</p> + +<p> +Buckland, W., on the complexity of crinoids. +</p> + +<p> +Buckler, W., proportion of sexes of Lepidoptera reared by. +</p> + +<p> +Bucorax abyssinicus, inflation of the neck-wattle of the male during courtship. +</p> + +<p> +Budytes Raii. +</p> + +<p> +Buffalo, Cape. +</p> + +<p> +Buffalo, Indian, horns of the. +</p> + +<p> +Buffalo, Italian, mode of fighting of the. +</p> + +<p> +Buffon, on the number of species of man. +</p> + +<p> +Bufo sikimmensis. +</p> + +<p> +Bugs. +</p> + +<p> +Buist, R., on the proportion of the sexes in salmon; on the pugnacity of the +male salmon. +</p> + +<p> +Bulbul, pugnacity of the male; display of under tail-coverts by the male. +</p> + +<p> +Bull, mode of fighting of the; curled frontal hair of the. +</p> + +<p> +Buller, Dr., on the Huia; the attachment of birds. +</p> + +<p> +Bullfinch, sexual differences in the; piping; female, singing of the; courtship +of the; widowed, finding a new mate; attacking a reed-bunting; nestling, sex +ascertained by pulling out breast feathers. +</p> + +<p> +Bullfinches, distinguishing persons; rivalry of female. +</p> + +<p> +Bulls, two young, attacking an old one; wild, battles of. +</p> + +<p> +Bull-trout, male, colouring of, during the breeding season. +</p> + +<p> +Bunting, reed, head feathers of the male; attacked by a bullfinch. +</p> + +<p> +Buntings, characters of young. +</p> + +<p> +Buphus coromandus, sexes and young of; change of colour in. +</p> + +<p> +Burchell, Dr., on the zebra; on the extravagance of a Bushwoman in adorning +herself; celibacy unknown among the savages of South Africa; on the +marriage-customs of the Bushwomen. +</p> + +<p> +Burke, on the number of species of man. +</p> + +<p> +Burmese, colour of the beard in. +</p> + +<p> +Burton, Captain, on negro ideas of female beauty; on a universal ideal of +beauty. +</p> + +<p> +Bushmen, marriage among. +</p> + +<p> +Bushwoman, extravagant ornamentation of a. +</p> + +<p> +Bushwomen, hair of; marriage-customs of. +</p> + +<p> +Bustard, throat-pouch of the male; humming noise produced by a male; Indian, +ear-tufts of. +</p> + +<p> +Bustards, occurrence of sexual differences and of polygamy among the; +love-gestures of the male; double moult in. +</p> + +<p> +Butler, A.G., on sexual differences in the wings of Aricoris epitus; courtship +of butterflies; on the colouring of the sexes in species of Thecla; on the +resemblance of Iphias glaucippe to a leaf; on the rejection of certain moths +and caterpillars by lizards and frogs. +</p> + +<p> +Butterfly, noise produced by a; Emperor; meadow brown, instability of the +ocellated spots of. +</p> + +<p> +Butterflies, proportion of the sexes in; forelegs atrophied in some males; +sexual difference in the neuration of the wings of; pugnacity of male; +protective resemblances of the lower surface of; display of the wings by; +white, alighting upon bits of paper; attracted by a dead specimen of the same +species; courtship of; male and female, inhabiting different stations. +</p> + +<p> +Buxton, C., observations on macaws; on an instance of benevolence in a parrot. +</p> + +<p> +Buzzard, Indian honey-; variation in the crest of. +</p> + +<p> +Cabbage butterflies. +</p> + +<p> +Cachalot, large head of the male. +</p> + +<p> +Cadences, musical, perception of, by animals. +</p> + +<p> +Caecum, large, in the early progenitors of man. +</p> + +<p> +Cairina moschata, pugnacity of the male. +</p> + +<p> +Californian Indians, decrease of. +</p> + +<p> +Callianassa, chelae of, figured. +</p> + +<p> +Callidryas, colours of sexes. +</p> + +<p> +Callionymus lyra, characters of the male. +</p> + +<p> +Callorhinus ursinus, relative size of the sexes of; courtship of. +</p> + +<p> +Calotes maria. +</p> + +<p> +Calotes nigrilabris, sexual difference in the colour of. +</p> + +<p> +Cambridge, O. Pickard, on the sexes of spiders; on the size of male Nephila. +</p> + +<p> +Camel, canine teeth of male. +</p> + +<p> +Campbell, J., on the Indian elephant; on the proportion of male and female +births in the harems of Siam. +</p> + +<p> +Campylopterus hemileucurus. +</p> + +<p> +Canaries distinguishing persons. +</p> + +<p> +Canary, polygamy of the; change of plumage in, after moulting; female, +selecting the best singing male; sterile hybrid, singing of a; female, singing +of the; selecting a greenfinch; and siskin, pairing of. +</p> + +<p> +Cancer pagurus. +</p> + +<p> +Canestrini, G., on rudimentary characters and the origin of man; on rudimentary +characters; on the movement of the ear in man; of the variability of the +vermiform appendage in man; on the abnormal division of the malar bone in man; +on abnormal conditions of the human uterus; on the persistence of the frontal +suture in man; on the proportion of the sexes in silk-moths; secondary sexual +characters of spiders. +</p> + +<p> +Canfield, Dr., on the horns of the Antilocapra. +</p> + +<p> +Canine teeth in man, diminution of, in man; diminution of, in horses; +disappearance of, in male ruminants; large in the early progenitors of man. +</p> + +<p> +Canines, and horns, inverse development of. +</p> + +<p> +Canoes, use of. +</p> + +<p> +Cantharis, difference of colour in the sexes of a species of. +</p> + +<p> +Cantharus lineatus. +</p> + +<p> +Capercailzie, polygamous; proportion of the sexes in the; pugnacity of the +male; pairing of the; autumn meetings of the; call of the; duration of the +courtship of; behaviour of the female; inconvenience of black colour to the +female; sexual difference in the coloration of the; crimson eye-cere of the +male. +</p> + +<p> +Capitonidae, colours and nidification of the. +</p> + +<p> +Capra aegagrus, crest of the male; sexual difference in the colour of. +</p> + +<p> +Capreolus Sibiricus subecaudatus. +</p> + +<p> +Caprice, common to man and animals. +</p> + +<p> +Caprimulgus, noise made by the males of some species of, with their wings. +</p> + +<p> +Caprimulgus virginianus, pairing of. +</p> + +<p> +Carabidae. +</p> + +<p> +Carbonnier, on the natural history of the pike; on the relative size of the +sexes in fishes; courtship of Chinese Macropus. +</p> + +<p> +Carcineutes, sexual difference of colour in. +</p> + +<p> +Carcinus moenas. +</p> + +<p> +Cardinalis virginianus. +</p> + +<p> +Carduelis elegans, sexual differences of the beak in. +</p> + +<p> +Carnivora, marine, polygamous habits of; sexual differences in the colours of. +</p> + +<p> +Carp, numerical proportion of the sexes in the. +</p> + +<p> +Carr, R., on the peewit. +</p> + +<p> +Carrier pigeon, late development of the wattle in the. +</p> + +<p> +Carrion beetles, stridulation of. +</p> + +<p> +Carrion-hawk, bright coloured female of. +</p> + +<p> +Carus, Prof. V., on the development of the horns in merino sheep; on antlers of +red deer. +</p> + +<p> +Cassowary, sexes and incubation of the. +</p> + +<p> +Castnia, mode of holding wings. +</p> + +<p> +Castoreum. +</p> + +<p> +Castration, effects of. +</p> + +<p> +Casuarius galeatus. +</p> + +<p> +Cat, convoluted body in the extremity of the tail of a; sick, sympathy of a dog +with a. +</p> + +<p> +Cataract in Cebus Azarae. +</p> + +<p> +Catarrh, liability of Cebus Azarae to. +</p> + +<p> +Catarrhine monkeys. +</p> + +<p> +Caterpillars, bright colours of. +</p> + +<p> +Cathartes aura. +</p> + +<p> +Cathartes jota, love-gestures of the male. +</p> + +<p> +Catlin, G., correlation of colour and texture of hair in the Mandans; on the +development of the beard among the North American Indians; on the great length +of the hair in some North American tribes. +</p> + +<p> +Caton, J.D., on the development of the horns in Cervus virginianus and +strongyloceros; on the wild turkey; on the presence of traces of horns in the +female wapiti; on the fighting of deer; on the crest of the male wapiti; on the +colours of the Virginian deer; on sexual differences of colour in the wapiti; +on the spots of the Virginian deer. +</p> + +<p> +Cats, dreaming; tortoise-shell; enticed by valerian; colours of. +</p> + +<p> +Cattle, rapid increase of, in South America; domestic, lighter in winter in +Siberia; horns of; domestic, sexual differences of, late developed; numerical +proportion of the sexes in. +</p> + +<p> +Caudal vertebrae, number of, in macaques and baboons; basal, of monkeys, +imbedded in the body. +</p> + +<p> +Cavolini, observations on Serranus. +</p> + +<p> +Cebus, maternal affection in a; gradation of species of. +</p> + +<p> +Cebus Apella. +</p> + +<p> +Cebus Azarae, liability of, to the same diseases as man; distinct sounds +produced by; early maturity of the female. +</p> + +<p> +Cebus capucinus, polygamous; sexual differences of colour in; hair on the head +of. +</p> + +<p> +Cebus vellerosus, hair on the head of. +</p> + +<p> +Cecidomyiidae, proportions of the sexes in. +</p> + +<p> +Celibacy, unknown among the savages of South Africa and South America. +</p> + +<p> +Centipedes. +</p> + +<p> +Cephalopoda, absence of secondary sexual characters in. +</p> + +<p> +Cephalopterus ornatus. +</p> + +<p> +Cephalopterus penduliger. +</p> + +<p> +Cerambyx heros, stridulant organ of. +</p> + +<p> +Ceratodus, paddle of. +</p> + +<p> +Ceratophora aspera, nasal appendages of. +</p> + +<p> +Ceratophora Stoddartii, nasal horn of. +</p> + +<p> +Cerceris, habits of. +</p> + +<p> +Cercocebus aethiops, whiskers, etc., of. +</p> + +<p> +Cercopithecus, young, seized by an eagle and rescued by the troop; definition +of species of. +</p> + +<p> +Cercopithecus cephus, sexual difference of colour in. +</p> + +<p> +Cercopithecus cynosurus and griseo-viridis, colour of the scrotum in. +</p> + +<p> +Cercopithecus Diana, sexual differences of colour in. +</p> + +<p> +Cercopithecus griseo-viridis. +</p> + +<p> +Cercopithecus petaurista, whiskers, etc., of. +</p> + +<p> +Ceres, of birds, bright colours of. +</p> + +<p> +Ceriornis Temminckii, swelling of the wattles of the male during courtship. +</p> + +<p> +Cervulus, weapons of. +</p> + +<p> +Cervulus moschatus, rudimentary horns of the female. +</p> + +<p> +Cervus alces. +</p> + +<p> +Cervus campestris, odour of. +</p> + +<p> +Cervus canadensis, traces of horns in the female; attacking a man; sexual +difference in the colour of. +</p> + +<p> +Cervus elaphus, battles of male; horns of, with numerous points; long hairs on +the throat of. +</p> + +<p> +Cervus Eldi. +</p> + +<p> +Cervus mantchuricus. +</p> + +<p> +Cervus paludosus, colours of. +</p> + +<p> +Cervus strongyloceros. +</p> + +<p> +Cervus virginianus, horns of, in course of modification. +</p> + +<p> +Ceryle, male black-belted in some species of. +</p> + +<p> +Cetacea, nakedness of. +</p> + +<p> +Ceylon, frequent absence of beard in the natives of. +</p> + +<p> +Chaffinch, proportion of the sexes in the; courtship of the. +</p> + +<p> +Chaffinches, new mates found by. +</p> + +<p> +Chalcophaps indicus, characters of young. +</p> + +<p> +Chalcosoma atlas, sexual differences of. +</p> + +<p> +Chamaeleo, sexual differences in the genus; combats of. +</p> + +<p> +Chamaeleo bifurcus. +</p> + +<p> +Chamaeleo Owenii. +</p> + +<p> +Chamaeleo pumilus. +</p> + +<p> +Chamaepetes unicolor, modified wing-feather in the male. +</p> + +<p> +Chameleons. +</p> + +<p> +Chamois, danger-signals of; transfer of male characters to an old female. +</p> + +<p> +Champneys, Mr., acromio-basilar muscle and quadrupedal gait. +</p> + +<p> +Chapman, Dr., on stridulation in Scolytus. +</p> + +<p> +Chapuis, Dr., on the transmission of sexual peculiarities in pigeons; on +streaked Belgian pigeons. +</p> + +<p> +Char, male, colouring of, during the breeding season. +</p> + +<p> +Characters, male, developed in females; secondary sexual, transmitted through +both sexes; natural, artificial, exaggeration of, by man. +</p> + +<p> +Charadrus hiaticula and pluvialis, sexes and young of. +</p> + +<p> +Chardin on the Persians. +</p> + +<p> +Charms, worn by women. +</p> + +<p> +Charruas, freedom of divorce among the. +</p> + +<p> +Chasmorhynchus, difference of colour in the sexes of; colours of. +</p> + +<p> +Chasmorhynchus niveus. +</p> + +<p> +Chasmorhynchus nudicollis. +</p> + +<p> +Chasmorhynchus tricarunculatus. +</p> + +<p> +Chastity, early estimation of. +</p> + +<p> +Chatterers, sexual differences in. +</p> + +<p> +Cheever, Rev. H.T., census of the Sandwich Islands. +</p> + +<p> +Cheiroptera, absence of secondary sexual characters in. +</p> + +<p> +Chelae of crustacea. +</p> + +<p> +Chelonia, sexual differences in. +</p> + +<p> +Chenalopex aegyptiacus, wing-knobs of. +</p> + +<p> +Chera progne. +</p> + +<p> +Chest, proportions of, in soldiers and sailors; large, of the Quechua and +Aymara Indians. +</p> + +<p> +Chevrotains, canine teeth of. +</p> + +<p> +Chiasognathus, stridulation of. +</p> + +<p> +Chiasognathus Grantii, mandibles of. +</p> + +<p> +Children, legitimate and illegitimate, proportion of the sexes in. +</p> + +<p> +Chiloe, lice of the natives of; population of. +</p> + +<p> +Chimaera monstrosa, bony process on the head of the male. +</p> + +<p> +Chimaeroid fishes, prehensile organs of male. +</p> + +<p> +Chimpanzee, ears of the; representatives of the eyebrows in the; hands of the; +absence of mastoid processes in the; platforms built by the; cracking nuts with +a stone; direction of the hair on the arms of the; supposed evolution of the; +polygamous and social habits of the. +</p> + +<p> +China, North, idea of female beauty in. +</p> + +<p> +China, Southern, inhabitants of. +</p> + +<p> +Chinese, use of flint tools by the; difficulty of distinguishing the races of +the; colour of the beard in; general beardlessness of the; opinions of the, on +the appearance of Europeans and Cingalese; compression of the feet of. +</p> + +<p> +Chinsurdi, his opinion of beards. +</p> + +<p> +Chlamydera maculata. +</p> + +<p> +Chloeon, pedunculated eyes of the male of. +</p> + +<p> +Chloephaga, coloration of the sexes in. +</p> + +<p> +Chlorocoelus Tanana. +</p> + +<p> +Chorda dorsalis. +</p> + +<p> +Chough, red beak of the. +</p> + +<p> +Chromidae, frontal protuberance in male; sexual differences in colour of. +</p> + +<p> +Chrysemys picta, long claws of the male. +</p> + +<p> +Chrysococcyx, characters of young of. +</p> + +<p> +Chrysomelidae, stridulation of. +</p> + +<p> +Cicada pruinosa. +</p> + +<p> +Cicada septendecim. +</p> + +<p> +Cicadae, songs of the; rudimentary sound-organs in females of. +</p> + +<p> +Cicatrix of a burn, causing modification of the facial bones. +</p> + +<p> +Cichla, frontal protuberance of male. +</p> + +<p> +Cimetiere du Sud, Paris. +</p> + +<p> +Cincloramphus cruralis, large size of male. +</p> + +<p> +Cinclus aquaticus. +</p> + +<p> +Cingalese, Chinese opinion of the appearance of the. +</p> + +<p> +Cirripedes, complemental males of. +</p> + +<p> +Civilisation, effects of, upon natural selection; influence of, in the +competition of nations. +</p> + +<p> +Clanging of geese, etc. +</p> + +<p> +Claparede, E., on natural selection applied to man. +</p> + +<p> +Clarke, on the marriage-customs of Kalmucks. +</p> + +<p> +Classification. +</p> + +<p> +Claus, C., on the sexes of Saphirina. +</p> + +<p> +Cleft-palate, inherited. +</p> + +<p> +Climacteris erythrops, sexes of. +</p> + +<p> +Climate, cool, favourable to human progress; power of supporting extremes of, +by man; want of connexion of, with colour; direct action of, on colours of +birds. +</p> + +<p> +Cloaca, existence of a, in the early progenitors of man. +</p> + +<p> +Cloacal passage existing in the human embryo. +</p> + +<p> +Clubs, used as weapons before dispersion of mankind. +</p> + +<p> +Clucking of fowls. +</p> + +<p> +Clythra 4-punctata, stridulation of. +</p> + +<p> +Coan, Mr., Sandwich-islanders. +</p> + +<p> +Cobbe, Miss, on morality in hypothetical bee-community. +</p> + +<p> +Cobra, ingenuity of a. +</p> + +<p> +Coccus. +</p> + +<p> +Coccyx, in the human embryo; convoluted body at the extremity of the; imbedded +in the body. +</p> + +<p> +Cochin-China, notions of beauty of the inhabitants of. +</p> + +<p> +Cock, blind, fed by its companion; game, killing a kite; comb and wattles of +the; preference shewn by the, for young hens; game, transparent zone in the +hackles of a. +</p> + +<p> +Cock of the rock. +</p> + +<p> +Cockatoos, nestling; black, immature plumage of. +</p> + +<p> +Coelenterata, absence of secondary sexual characters in. +</p> + +<p> +Coffee, fondness of monkeys for. +</p> + +<p> +Cold, supposed effects of; power of supporting, by man. +</p> + +<p> +Coleoptera, stridulation of; stridulant organs of, discussed. +</p> + +<p> +Colias edusa and hyale. +</p> + +<p> +Collingwood, C., on the pugnacity of the butterflies of Borneo; on butterflies +being attracted by a dead specimen of the same species. +</p> + +<p> +Colobus, absence of the thumb. +</p> + +<p> +Colombia, flattened heads of savages of. +</p> + +<p> +Colonists, success of the English as. +</p> + +<p> +Coloration, protective, in birds. +</p> + +<p> +Colour, supposed to be dependent on light and heat; correlation of, with +immunity from certain poisons and parasites; purpose of, in lepidoptera; +relation of, to sexual functions, in fishes; difference of, in the sexes of +snakes; sexual differences of, in lizards; influence of, in the pairing of +birds of different species; relation of, to nidification; sexual differences +of, in mammals; recognition of, by quadrupeds; of children, in different races +of man; of the skin in man. +</p> + +<p> +Colours, admired alike by man and animals; bright, due to sexual selection; +bright, among the lower animals; bright, protective to butterflies and moths; +bright, in male fishes; transmission of, in birds. +</p> + +<p> +Colquhoun, example of reasoning in a retriever. +</p> + +<p> +Columba passerina, young of. +</p> + +<p> +Colymbus glacialis, anomalous young of. +</p> + +<p> +Comb, development of, in fowls. +</p> + +<p> +Combs and wattles in male birds. +</p> + +<p> +Community, preservation of variations useful to the, by natural selection. +</p> + +<p> +Complexion, different in men and women, in an African tribe. +</p> + +<p> +Compositae, gradation of species among the. +</p> + +<p> +Comte, C., on the expression of the ideal of beauty by sculpture. +</p> + +<p> +Conditions of life, action of changed, upon man; influence of, on plumage of +birds. +</p> + +<p> +Condor, eyes and comb of the. +</p> + +<p> +Conjugations, origin of. +</p> + +<p> +Conscience, absence of, in some criminals. +</p> + +<p> +Constitution, difference of, in different races of men. +</p> + +<p> +Consumption, liability of Cebus Azarae to; connection between complexion and. +</p> + +<p> +Convergence of characters. +</p> + +<p> +Cooing of pigeons and doves. +</p> + +<p> +Cook, Captain, on the nobles of the Sandwich Islands. +</p> + +<p> +Cope, E.D., on the Dinosauria. +</p> + +<p> +Cophotis ceylanica, sexual differences of. +</p> + +<p> +Copris. +</p> + +<p> +Copris Isidis, sexual differences of. +</p> + +<p> +Copris lunaris, stridulation of. +</p> + +<p> +Corals, bright colours of. +</p> + +<p> +Coral-snakes. +</p> + +<p> +Cordylus, sexual difference of colour in a species of. +</p> + +<p> +Corfu, habits of the Chaffinch in. +</p> + +<p> +Cornelius, on the proportions of the sexes in Lucanus Cervus. +</p> + +<p> +Corpora Wolffiana, agreement of, with the kidneys of fishes. +</p> + +<p> +Correlated variation. +</p> + +<p> +Correlation, influence of, in the production of races. +</p> + +<p> +Corse, on the mode of fighting of the elephant. +</p> + +<p> +Corvus corone. +</p> + +<p> +Corvus graculus, red beak of. +</p> + +<p> +Corvus pica, nuptial assembly of. +</p> + +<p> +Corydalis cornutus, large jaws of the male. +</p> + +<p> +Cosmetornis. +</p> + +<p> +Cosmetornis vexillarius, elongation of wing-feathers in. +</p> + +<p> +Cotingidae, sexual differences in; coloration of the sexes of; resemblance of +the females of distinct species of. +</p> + +<p> +Cottus scorpius, sexual differences in. +</p> + +<p> +Coulter, Dr., on the Californian Indians. +</p> + +<p> +Counting, origin of; limited power of, in primeval man. +</p> + +<p> +Courage, variability of, in the same species; universal high appreciation of; +importance of; characteristic of men. +</p> + +<p> +Courtship, greater eagerness of males in; of fishes; of birds. +</p> + +<p> +Cow, winter change of colour. +</p> + +<p> +Crab, devil. +</p> + +<p> +Crab, shore, habits of. +</p> + +<p> +Crabro cribrarius, dilated tibiae of the male. +</p> + +<p> +Crabs, proportions of the sexes in. +</p> + +<p> +Cranz, on the inheritance of dexterity in seal-catching. +</p> + +<p> +Crawfurd, on the number of species of man. +</p> + +<p> +Crenilabrus massa and C. melops, nests, built by. +</p> + +<p> +Crest, origin of, in Polish fowls. +</p> + +<p> +Crests, of birds, difference of, in the sexes; dorsal hairy, of mammals. +</p> + +<p> +Cricket, field-, stridulation of the; pugnacity of male. +</p> + +<p> +Cricket, house-, stridulation of the. +</p> + +<p> +Crickets, sexual differences in. +</p> + +<p> +Crinoids, complexity of. +</p> + +<p> +Crioceridae, stridulation of the. +</p> + +<p> +Croaking of frogs. +</p> + +<p> +Crocodiles, musky odour of, during the breeding season. +</p> + +<p> +Crocodilia. +</p> + +<p> +Crossbills, characters of young. +</p> + +<p> +Crosses in man. +</p> + +<p> +Crossing of races, effects of the. +</p> + +<p> +Crossoptilon auritum, adornment of both sexes of; sexes alike in. +</p> + +<p> +Crotch, G.R., on the stridulation of beetles; on the stridulation of +Heliopathes; on the stridulation of Acalles; habit of female deer at breeding +time. +</p> + +<p> +Crow, Indians, long hair of the. +</p> + +<p> +Crow, young of the. +</p> + +<p> +Crows, vocal organs of the; living in triplets. +</p> + +<p> +Crows, carrion, new mates found by. +</p> + +<p> +Crows, Indian, feeding their blind companions. +</p> + +<p> +Cruelty of savages to animals. +</p> + +<p> +Crustacea, parasitic, loss of limbs by female; prehensile feet and antennae of; +male, more active than female; parthenogenesis in; secondary sexual characters +of; amphipod, males sexually mature while young; auditory hairs of. +</p> + +<p> +Crystal worn in the lower lip by some Central African women. +</p> + +<p> +Cuckoo fowls. +</p> + +<p> +Culicidae, attracted by each other’s humming. +</p> + +<p> +Cullen, Dr., on the throat-pouch of the male bustard. +</p> + +<p> +Cultivation of plants, probable origin of. +</p> + +<p> +Cupples, Mr., on the numerical proportion of the sexes in dogs, sheep, and +cattle; on the Scotch deerhound; on sexual preference in dogs. +</p> + +<p> +Curculionidae, sexual difference in length of snout in some; hornlike processes +in male; musical. +</p> + +<p> +Curiosity, manifestations of, by animals. +</p> + +<p> +Curlews, double moult in. +</p> + +<p> +Cursores, comparative absence of sexual differences among the. +</p> + +<p> +Curtis, J., on the proportion of the sexes in Athalia. +</p> + +<p> +Cuvier, F., on the recognition of women by male quadrumana. +</p> + +<p> +Cuvier, G., on the number of caudal vertebrae in the mandrill; on instinct and +intelligence; views of, as to the position of man; on the position of the +seals; on Hectocotyle. +</p> + +<p> +Cyanalcyon, sexual difference in colours of; immature plumage of. +</p> + +<p> +Cyanecula suecica, sexual differences of. +</p> + +<p> +Cychrus, sounds produced by. +</p> + +<p> +Cycnia mendica, sexual difference of, in colour. +</p> + +<p> +Cygnus ferus, trachea of. +</p> + +<p> +Cygnus immutabilis. +</p> + +<p> +Cygnus olor, white young of. +</p> + +<p> +Cyllo Leda, instability of the ocellated spots of. +</p> + +<p> +Cynanthus, variation in the genus. +</p> + +<p> +Cynipidae, proportion of the sexes in. +</p> + +<p> +Cynocephalus, difference of the young from the adult; male, recognition of +women by; polygamous habits of species of. +</p> + +<p> +Cynocephalus babouin. +</p> + +<p> +Cynocephalus chacma. +</p> + +<p> +Cynocephalus gelada. +</p> + +<p> +Cynocephalus hamadryas, sexual difference of colour in. +</p> + +<p> +Cynocephalus leucophaeus, colours of the sexes of. +</p> + +<p> +Cynocephalus mormon, colours of the male. +</p> + +<p> +Cynocephalus porcarius, mane of the male. +</p> + +<p> +Cynocephalus sphinx. +</p> + +<p> +Cynopithecus niger, ear of. +</p> + +<p> +Cypridina, proportions of the sexes in. +</p> + +<p> +Cyprinidae, proportion of the sexes in the. +</p> + +<p> +Cyprinidae, Indian. +</p> + +<p> +Cyprinodontidae, sexual differences in the. +</p> + +<p> +Cyprinus auratus. +</p> + +<p> +Cypris, relation of the sexes in. +</p> + +<p> +Cyrtodactylus rubidus. +</p> + +<p> +Cystophora cristata, hood of. +</p> + +<p> +Dacelo, sexual difference of colour in. +</p> + +<p> +Dacelo Gaudichaudi, young male of. +</p> + +<p> +Dal-ripa, a kind of ptarmigan. +</p> + +<p> +Damalis albifrons, peculiar markings of. +</p> + +<p> +Damalis pygarga, peculiar markings of. +</p> + +<p> +Dampness of climate, supposed influence of, on the colour of the skin. +</p> + +<p> +Danaidae. +</p> + +<p> +Dances of birds. +</p> + +<p> +Dancing, universality of. +</p> + +<p> +Danger-signals of animals. +</p> + +<p> +Daniell, Dr., his experience of residence in West Africa. +</p> + +<p> +Darfur, protuberances artificially produced by natives of. +</p> + +<p> +Darwin, F., on the stridulation of Dermestes murinus. +</p> + +<p> +Dasychira pudibunda, sexual difference of colour in. +</p> + +<p> +Davis, A.H., on the pugnacity of the male stag-beetle. +</p> + +<p> +Davis, J.B., on the capacity of the skull in various races of men; on the +beards of the Polynesians. +</p> + +<p> +Death’s Head Sphinx. +</p> + +<p> +Death-rate higher in towns than in rural districts. +</p> + +<p> +Death-tick. +</p> + +<p> +De Candolle, Alph., on a case of inherited power of moving the scalp. +</p> + +<p> +Declensions, origin of. +</p> + +<p> +Decoration in birds. +</p> + +<p> +Decticus. +</p> + +<p> +Deer, development of the horns in; spots of young; horns of; use of horns of; +horns of a, in course of modification; size of the horns of; female, pairing +with one male whilst others are fighting for her; male, attracted by the voice +of the female; male, odour emitted by. +</p> + +<p> +Deer, Axis, sexual difference in the colour of the. +</p> + +<p> +Deer, fallow, different coloured herds of. +</p> + +<p> +Deer, Mantchurian. +</p> + +<p> +Deer, Virginian, colour of the, not affected by castration; colours of. +</p> + +<p> +Deerhound, Scotch, greater size of the male. +</p> + +<p> +Defensive orders of mammals. +</p> + +<p> +De Geer, C., on a female spider destroying a male. +</p> + +<p> +Dekay, Dr., on the bladder-nose seal. +</p> + +<p> +Delorenzi, G., division of malar bone. +</p> + +<p> +Demerara, yellow fever in. +</p> + +<p> +Dendrocygna. +</p> + +<p> +Dendrophila frontalis, young of. +</p> + +<p> +Denison, Sir W., manner of ridding themselves of vermin among the Australians; +extinction of Tasmanians. +</p> + +<p> +Denny, H., on the lice of domestic animals. +</p> + +<p> +Dermestes murinus, stridulation of. +</p> + +<p> +Descent traced through the mother alone. +</p> + +<p> +Deserts, protective colouring of animals inhabiting. +</p> + +<p> +Desmarest, on the absence of suborbital pits in Antilope subgutturosa; on the +whiskers of Macacus; on the colour of the opossum; on the colours of the sexes +of Mus minutus; on the colouring of the ocelot; on the colours of seals; on +Antilope caama; on the colours of goats; on sexual difference of colour in +Ateles marginatus; on the mandrill; on Macacus cynomolgus. +</p> + +<p> +Desmoulins, on the number of species of man; on the muskdeer. +</p> + +<p> +Desor, on the imitation of man by monkeys. +</p> + +<p> +Despine, P., on criminals destitute of conscience. +</p> + +<p> +Development, embryonic of man; correlated. +</p> + +<p> +Devil, not believed in by the Fuegians. +</p> + +<p> +Devil-crab. +</p> + +<p> +Devonian, fossil-insect from the. +</p> + +<p> +Dewlaps, of Cattle and antelopes. +</p> + +<p> +Diadema, sexual differences of colouring in the species of. +</p> + +<p> +Diamond-beetles, bright colours of. +</p> + +<p> +Diastema, occurrence of, in man. +</p> + +<p> +Diastylidae, proportion of the sexes in. +</p> + +<p> +Dicrurus, racket-shaped feathers in; nidification of. +</p> + +<p> +Dicrurus macrocercus, change of plumage in. +</p> + +<p> +Didelphis opossum, sexual difference in the colour of. +</p> + +<p> +Differences, comparative, between different species of birds of the same sex. +</p> + +<p> +Digits, supernumerary, more frequent in men than in women; supernumerary, +inheritance of; supernumerary, early development of. +</p> + +<p> +Dimorphism, in females of water-beetles; in Neurothemis and Agrion. +</p> + +<p> +Diodorus, on the absence of beard in the natives of Ceylon. +</p> + +<p> +Dipelicus Cantori, sexual differences of. +</p> + +<p> +Diplopoda, prehensile limbs of the male. +</p> + +<p> +Dipsas cynodon, sexual difference in the colour of. +</p> + +<p> +Diptera. +</p> + +<p> +Disease, generated by the contact of distinct peoples. +</p> + +<p> +Diseases, common to man and the lower animals; difference of liability to, in +different races of men; new, effects of, upon savages; sexually limited. +</p> + +<p> +Display, coloration of Lepidoptera for; of plumage by male birds. +</p> + +<p> +Distribution, wide, of man; geographical, as evidence of specific distinctness +in man. +</p> + +<p> +Disuse, effects of, in producing rudimentary organs; and use of parts, effects +of; of parts, influence of, on the races of men. +</p> + +<p> +Divorce, freedom of, among the Charruas. +</p> + +<p> +Dixon, E.S., on the pairing of different species of geese; on the courtship of +peafowl. +</p> + +<p> +Dobrizhoffer, on the marriage-customs of the Abipones. +</p> + +<p> +Dobson, Dr., on the Cheiroptera; scent-glands of bats; frugivorous bats. +</p> + +<p> +Dogs, suffering from tertian ague; memory of; dreaming; diverging when drawing +sledges over thin ice; exercise of reasoning faculties by; domestic, progress +of, in moral qualities; distinct tones uttered by; parallelism between his +affection for his master and religious feeling; sociability of the; sympathy +of, with a sick cat; sympathy of, with his master; their possession of +conscience; possible use of the hair on the fore-legs of the; races of the; +numerical proportion of male and female births in; sexual affection between +individuals of; howling at certain notes; rolling in carrion. +</p> + +<p> +Dolichocephalic structure, possible cause of. +</p> + +<p> +Dolphins, nakedness of. +</p> + +<p> +Domestic animals, races of; change of breeds of. +</p> + +<p> +Domestication, influence of, in removing the sterility of hybrids. +</p> + +<p> +D’Orbigny, A., on the influence of dampness and dryness on the colour of +the skin; on the Yuracaras. +</p> + +<p> +Dotterel. +</p> + +<p> +Doubleday, E., on sexual differences in the wings of butterflies. +</p> + +<p> +Doubleday, H., on the proportion of the sexes in the smaller moths; males of +Lasiocampa quercus and on the attraction of the Saturnia carpini by the female; +on the proportion of the sexes in the Lepidoptera; on the ticking of Anobium +tesselatum; on the structure of Ageronia feronia; on white butterflies +alighting upon paper. +</p> + +<p> +Douglas, J.W., on the sexual differences of the Hemiptera; colours of British +Homoptera. +</p> + +<p> +Down, of birds. +</p> + +<p> +Draco, gular appendages of. +</p> + +<p> +Dragonet, Gemmeous. +</p> + +<p> +Dragon-flies, caudal appendages of male; relative size of the sexes of; +difference in the sexes of; want of pugnacity by the male. +</p> + +<p> +Drake, breeding plumage of the. +</p> + +<p> +Dreams, possible source of the belief in spiritual agencies. +</p> + +<p> +Drill, sexual difference of colour in the. +</p> + +<p> +Dromaeus irroratus. +</p> + +<p> +Dromolaea, Saharan species of. +</p> + +<p> +Drongo shrike. +</p> + +<p> +Drongos, racket-shaped feathers in the tails of. +</p> + +<p> +Dryness of climate, supposed influence of, on the colour of the skin. +</p> + +<p> +Dryopithecus. +</p> + +<p> +Duck, harlequin, age of mature plumage in the; breeding in immature plumage. +</p> + +<p> +Duck, long-tailed, preference of male, for certain females. +</p> + +<p> +Duck, pintail, pairing with a widgeon. +</p> + +<p> +Duck, voice of the; pairing with a shield-drake; immature plumage of the. +</p> + +<p> +Duck, wild, sexual differences in the; speculum and male characters of; pairing +with a pin-tail drake. +</p> + +<p> +Ducks, wild, becoming polygamous under partial domestication; dogs and cats +recognised by. +</p> + +<p> +Dufosse, Dr., sounds produced by fish. +</p> + +<p> +Dugong, nakedness of; tusks of. +</p> + +<p> +Dujardin, on the relative size of the cerebral ganglia, in insects. +</p> + +<p> +Duncan, Dr., on the fertility of early marriages; comparative health of married +and single. +</p> + +<p> +Dupont, M., on the occurrence of the supra-condyloid foramen in the humerus of +man. +</p> + +<p> +Durand, J.P., on causes of variation. +</p> + +<p> +Dureau de la Malle, on the songs of birds; on the acquisition of an air by +blackbirds. +</p> + +<p> +Dutch, retention of their colour by the, in South Africa. +</p> + +<p> +Duty, sense of. +</p> + +<p> +Duvaucel, female Hylobates washing her young. +</p> + +<p> +Dyaks, pride of, in mere homicide. +</p> + +<p> +Dynastes, large size of males of. +</p> + +<p> +Dynastini, stridulation of. +</p> + +<p> +Dytiscus, dimorphism of females of; grooved elytra of the female. +</p> + +<p> +Eagle, young Cercopithecus rescued from, by the troop. +</p> + +<p> +Eagle, white-headed, breeding in immature plumage. +</p> + +<p> +Eagles, golden, new mates found by. +</p> + +<p> +Ear, motion of the; external shell of the, useless in man; rudimentary point of +the, in man. +</p> + +<p> +Ears, more variable in men than women; piercing and ornamentation of the. +</p> + +<p> +Earwigs, parental feeling in. +</p> + +<p> +Echidna. +</p> + +<p> +Echini, bright colours of some. +</p> + +<p> +Echinodermata, absence of secondary sexual characters in. +</p> + +<p> +Echis carinata. +</p> + +<p> +Ecker, figure of the human embryo; on the development of the gyri and sulci of +the brain; on the sexual differences in the pelvis in man; on the presence of a +sagittal crest in Australians. +</p> + +<p> +Edentata, former wide range of, in America; absence of secondary sexual +characters in. +</p> + +<p> +Edolius, racket-shaped feathers in. +</p> + +<p> +Edwards, Mr., on the proportion of the sexes in North American species of +Papilio. +</p> + +<p> +Eels, hermaphroditism of. +</p> + +<p> +Egerton, Sir P., on the use of the antlers of deer; on the pairing of red deer; +on the bellowing of stags. +</p> + +<p> +Eggs, hatched by male fishes. +</p> + +<p> +Egret, Indian, sexes and young of. +</p> + +<p> +Egrets, breeding plumage of; white. +</p> + +<p> +Ehrenberg, on the mane of the male Hamadryas baboon. +</p> + +<p> +Ekstrom, M., on Harelda glacialis. +</p> + +<p> +Elachista rufocinerea, habits of male. +</p> + +<p> +Eland, development of the horns of the. +</p> + +<p> +Elands, sexual differences of colour in. +</p> + +<p> +Elaphomyia, sexual differences in. +</p> + +<p> +Elaphrus uliginosus, stridulation of. +</p> + +<p> +Elaps. +</p> + +<p> +Elateridae, proportion of the sexes in. +</p> + +<p> +Elaters, luminous. +</p> + +<p> +Elephant, rate of increase of the; nakedness of the; using a fan; Indian, +forbearance to his keeper; polygamous habits of the; pugnacity of the male; +tusks of; Indian, mode of fighting of the; male, odour emitted by the; +attacking white or grey horses. +</p> + +<p> +Elevation of abode, modifying influence of. +</p> + +<p> +Elimination of inferior individuals. +</p> + +<p> +Elk, winter change of the. +</p> + +<p> +Elk, Irish, horns of the. +</p> + +<p> +Ellice Islands, beards of the natives. +</p> + +<p> +Elliot, D.G., on Pelecanus erythrorhynchus. +</p> + +<p> +Elliot, R., on the numerical proportion of the sexes in young rats; on the +proportion of the sexes in sheep. +</p> + +<p> +Elliot, Sir W., on the polygamous habits of the Indian wild boar. +</p> + +<p> +Ellis, on the prevalence of infanticide in Polynesia. +</p> + +<p> +Elphinstone, Mr., on local difference of stature among the Hindoos; on the +difficulty of distinguishing the native races of India. +</p> + +<p> +Elytra, of the females of Dytiscus Acilius, Hydroporus. +</p> + +<p> +Emberiza, characters of young. +</p> + +<p> +Emberiza miliaria. +</p> + +<p> +Emberiza schoeniclus, head-feathers of the male. +</p> + +<p> +Embryo of man; of the dog. +</p> + +<p> +Embryos of mammals, resemblance of the. +</p> + +<p> +Emigration. +</p> + +<p> +Emotions experienced by the lower animals in common with man; manifested by +animals. +</p> + +<p> +Emperor butterfly. +</p> + +<p> +Emperor moth. +</p> + +<p> +Emu, sexes and incubation of. +</p> + +<p> +Emulation of singing birds. +</p> + +<p> +Endurance, estimation of. +</p> + +<p> +Energy, a characteristic of men. +</p> + +<p> +England, numerical proportion of male and female births in. +</p> + +<p> +Engleheart, Mr., on the finding of new mates by starlings. +</p> + +<p> +English, success of, as colonists. +</p> + +<p> +Engravers, short-sighted. +</p> + +<p> +Entomostraca. +</p> + +<p> +Entozoa, difference of colour between the males and females of some. +</p> + +<p> +Environment, direct action of the, in causing differences between the sexes. +</p> + +<p> +Envy, persistence of. +</p> + +<p> +Eocene period, possible divergence of men during the. +</p> + +<p> +Eolidae, colours of, produced by the biliary glands. +</p> + +<p> +Epeira nigra, small size of the male of. +</p> + +<p> +Ephemerae. +</p> + +<p> +Ephemeridae. +</p> + +<p> +Ephippiger vitium, stridulating organs of. +</p> + +<p> +Epicalia, sexual differences of colouring in the species of. +</p> + +<p> +Equus hemionus, winter change of. +</p> + +<p> +Erateina, coloration of. +</p> + +<p> +Ercolani, Prof., hermaphroditism in eels. +</p> + +<p> +Erect attitude of man. +</p> + +<p> +Eristalis, courting of. +</p> + +<p> +Eschricht, on the development of hair in man; on a languinous moustache in a +female foetus; on the want of definition between the scalp and the forehead in +some children; on the arrangement of the hair in the human foetus; on the +hairiness of the face in the human foetus of both sexes. +</p> + +<p> +Esmeralda, difference of colour in the sexes of. +</p> + +<p> +Esox lucius. +</p> + +<p> +Esox reticulatus. +</p> + +<p> +Esquimaux, their belief in the inheritance of dexterity in seal-catching; mode +of life of. +</p> + +<p> +Estrelda amandava, pugnacity of the male. +</p> + +<p> +Eubagis, sexual differences of colouring in the species of. +</p> + +<p> +Euchirus longimanus, sound produced by. +</p> + +<p> +Eudromias morinellus. +</p> + +<p> +Eulampis jugularis, colours of the female. +</p> + +<p> +Euler, on the rate of increase in the United States. +</p> + +<p> +Eunomota superciliaris, racket-shaped feathers in the tail of. +</p> + +<p> +Eupetomena macroura, colours of the female. +</p> + +<p> +Euphema splendida. +</p> + +<p> +Euplocamus erythrophthalmus, possession of spurs by the female. +</p> + +<p> +Europe, ancient inhabitants of. +</p> + +<p> +Europeans, difference of, from Hindoos; hairiness of, probably due to +reversion. +</p> + +<p> +Eurostopodus, sexes of. +</p> + +<p> +Eurygnathus, different proportions of the head in the sexes of. +</p> + +<p> +Eustephanus, sexual differences of species of; young of. +</p> + +<p> +Exaggeration of natural characters by man. +</p> + +<p> +Exogamy. +</p> + +<p> +Experience, acquisition of, by animals. +</p> + +<p> +Expression, resemblances in, between man and the apes. +</p> + +<p> +Extinction of races, causes of. +</p> + +<p> +Eye, destruction of the; change of position in; obliquity of, regarded as a +beauty by the Chinese and Japanese. +</p> + +<p> +Eyebrows, elevation of; development of long hairs in; in monkeys; eradicated in +parts of South America and Africa; eradication of, by the Indians of Paraguay. +</p> + +<p> +Eyelashes, eradication of, by the Indians of Paraguay. +</p> + +<p> +Eyelids, coloured black, in part of Africa. +</p> + +<p> +Eyes, pillared, of the male of Chloeon; difference in the colour of, in the +sexes of birds. +</p> + +<p> +Eyton, T.C., observations on the development of the horns in the fallow deer. +</p> + +<p> +Eyzies, Les, human remains from. +</p> + +<p> +Fabre, M., on the habits of Cerceris. +</p> + +<p> +Facial bones, causes of modification of the. +</p> + +<p> +Faculties, diversity of, in the same race of men; inheritance of; diversity of, +in animals of the same species; mental variation of, in the same species; of +birds. +</p> + +<p> +Fakirs, Indian, tortures undergone by. +</p> + +<p> +Falco leucocephalus. +</p> + +<p> +Falco peregrinus. +</p> + +<p> +Falco tinnunclus. +</p> + +<p> +Falcon, peregrine, new mate found by. +</p> + +<p> +Falconer, H., on the mode of fighting of the Indian elephant; on canines in a +female deer; on Hyomoschus aquaticus. +</p> + +<p> +Falkland Islands, horses of. +</p> + +<p> +Fallow-deer, different coloured herds of. +</p> + +<p> +Famines, frequency of, among savages. +</p> + +<p> +Farr, Dr., on the effects of profligacy; on the influence of marriage on +mortality. +</p> + +<p> +Farrar, F.W., on the origin of language; on the crossing or blending of +languages; on the absence of the idea of God in certain races of men; on early +marriages of the poor; on the middle ages. +</p> + +<p> +Farre, Dr., on the structure of the uterus. +</p> + +<p> +Fashions, long prevalence of, among savages. +</p> + +<p> +Faye, Prof., on the numerical proportion of male and female births in Norway +and Russia; on the greater mortality of male children at and before birth. +</p> + +<p> +Feathers, modified, producing sounds; elongated, in male birds; racket-shaped; +barbless and with filamentous barbs in certain birds; shedding of margins of. +</p> + +<p> +Feeding, high, probable influence of, in the pairing of birds of different +species. +</p> + +<p> +Feet, thickening of the skin on the soles of the; modification of, in man. +</p> + +<p> +Felis canadensis, throat-ruff of. +</p> + +<p> +Felis pardalis and F. mitis, sexual difference in the colouring of. +</p> + +<p> +Female, behaviour of the, during courtship. +</p> + +<p> +Female birds, differences of. +</p> + +<p> +Females, presence of rudimentary male organs in; preference of, for certain +males; pursuit of, by males; occurrence of secondary sexual characters in; +development of male character by. +</p> + +<p> +Females and males, comparative numbers of; comparative mortality of, while +young. +</p> + +<p> +Femur and tibia, proportions of, in the Aymara Indians. +</p> + +<p> +Fenton, Mr., decrease of Maories; infanticide amongst the Maories. +</p> + +<p> +Ferguson, Mr., on the courtship of fowls. +</p> + +<p> +Fertilisation, phenomena of, in plants; in the lower animals. +</p> + +<p> +Fertility lessened under changed conditions. +</p> + +<p> +Fevers, immunity of Negroes and Mulattoes from. +</p> + +<p> +Fiber zibethicus, protective colouring of it. +</p> + +<p> +Fick, H., effect of conscription for military service. +</p> + +<p> +Fidelity, in the elephant; of savages to one another; importance of. +</p> + +<p> +Field-slaves, difference of, from house-slaves. +</p> + +<p> +Fiji Archipelago, population of the. +</p> + +<p> +Fiji Islands, beards of the natives; marriage-customs of the. +</p> + +<p> +Fijians, burying their old and sick parents alive; estimation of the beard +among the; admiration of, for a broad occiput. +</p> + +<p> +Filial affection, partly the result of natural selection. +</p> + +<p> +Filum terminale. +</p> + +<p> +Finch, racket-shaped feathers in the tail of a. +</p> + +<p> +Finches, spring change of colour in; British, females of the. +</p> + +<p> +Fingers, partially coherent, in species of Hylobates. +</p> + +<p> +Finlayson, on the Cochin Chinese. +</p> + +<p> +Fire, use of. +</p> + +<p> +Fischer, on the pugnacity of the male of Lethrus cephalotes. +</p> + +<p> +Fischer, F. Von, on display of brightly coloured parts by monkeys in courtship. +</p> + +<p> +Fish, eagerness of male; proportion of the sexes in; sounds produced by. +</p> + +<p> +Fishes, kidneys of, represented by Corpora Wolffiana in the human embryo; male, +hatching ova in their mouths; receptacles for ova possessed by; relative size +of the sexes in; fresh-water, of the tropics; protective resemblances in; +change of colour in; nest-building; spawning of; sounds produced by; continued +growth of. +</p> + +<p> +Flamingo, age of mature plumage. +</p> + +<p> +Flexor pollicis longus, similar variation of, in man. +</p> + +<p> +Flies, humming of. +</p> + +<p> +Flint tools. +</p> + +<p> +Flints, difficulty of chipping into form. +</p> + +<p> +Florida, Quiscalus major in. +</p> + +<p> +Florisuga mellivora. +</p> + +<p> +Flounder, coloration of the. +</p> + +<p> +Flower, W.H., on the abductor of the fifth metatarsal in apes; on the position +of the Seals; on the Pithecia monachu; on the throat-pouch of the male bustard. +</p> + +<p> +Fly-catchers, colours and nidification of. +</p> + +<p> +Foetus, human, woolly covering of the; arrangement of the hair on. +</p> + +<p> +Food, influence of, upon stature. +</p> + +<p> +Foot, prehensile power of the, retained in some savages; prehensile, in the +early progenitors of man. +</p> + +<p> +Foramen, supra-condyloid, exceptional occurrence of in the humerus of man; in +the early progenitors of man. +</p> + +<p> +Forbes, D., on the Aymara Indians; on local variation of colour in the +Quichuas; on the hairlessness of the Aymaras and Quichuas; on the long hair of +the Aymaras and Quichaus. +</p> + +<p> +Forel, F., on white young swans. +</p> + +<p> +Forester, Hon. O.W., on an orphan hawk. +</p> + +<p> +Formica rufa, size of the cerebral ganglia in. +</p> + +<p> +Fossils, absence of, connecting man with the apes. +</p> + +<p> +Fowl, occurrence of spurs in the female; game, early pugnacity of; Polish, +early development of cranial peculiarities of; variations in plumage of; +examples of correlated development in the; domestic, breeds and sub-breeds of. +</p> + +<p> +Fowls, spangled Hamburg; inheritance of changes of plumage by; sexual +peculiarities in, transmitted only to the same sex; loss of secondary sexual +characters by male; Polish, origin of the crest in; period of inheritance of +characters by; cuckoo-; development of the comb in; numerical proportion of the +sexes in; courtship of; mongrel, between a black Spanish cock and different +hens; pencilled Hamburg, difference of the sexes in; Spanish, sexual +differences of the comb in; spurred, in both sexes. +</p> + +<p> +Fox, W.D., on some half-tamed wild ducks becoming polygamous, and on polygamy +in the guinea-fowl and canary-bird; on the proportion of the sexes in cattle; +on the pugnacity of the peacock; on a nuptial assembly of magpies; on the +finding of new mates by crows; on partridges living in triplets; on the pairing +of a goose with a Chinese gander. +</p> + +<p> +Foxes, wariness of young, in hunting districts; black. +</p> + +<p> +Fraser, C., on the different colours of the sexes in a species of Squilla. +</p> + +<p> +Fraser, G., colours of Thecla. +</p> + +<p> +Frere, Hookham, quoting Theognis on selection in mankind. +</p> + +<p> +Fringilla cannabina. +</p> + +<p> +Fringilla ciris, age of mature plumage in. +</p> + +<p> +Fringilla cyanea, age of mature plumage in. +</p> + +<p> +Fringilla leucophrys, young of. +</p> + +<p> +Fringilla spinus. +</p> + +<p> +Fringilla tristis, change of colour in, in spring; young of. +</p> + +<p> +Fringillidae, resemblance of the females of distinct species of. +</p> + +<p> +Frog, bright coloured and distasteful to birds. +</p> + +<p> +Frogs, male; temporary receptacles for ova possessed by; ready to breed before +the females; fighting of; vocal organs of. +</p> + +<p> +Frontal bone, persistence of the suture in. +</p> + +<p> +Fruits, poisonous, avoided by animals. +</p> + +<p> +Fuegians, difference of stature among the; power of sight in the; skill of, in +stone-throwing; resistance of the, to their severe climate; mental capacity of +the; quasi-religious sentiments of the; resemblance of, in mental characters, +to Europeans; mode of life of the; aversion of, to hair on the face; said to +admire European women. +</p> + +<p> +Fulgoridae, songs of the. +</p> + +<p> +Fur, whiteness of, in Arctic animals in winter. +</p> + +<p> +Fur-bearing animals, acquired sagacity of. +</p> + +<p> +Gallicrex, sexual difference in the colour of the irides in. +</p> + +<p> +Gallicrex cristatus, pugnacity of male; red carbuncle occurring in the male +during the breeding-season. +</p> + +<p> +Gallinaceae, frequency of polygamous habits and of sexual differences in the; +love-gestures of; decomposed feathers in; stripes of young; comparative sexual +differences between the species of; plumage of. +</p> + +<p> +Gallinaceous birds, weapons of the male; racket-shaped feathers on the heads +of. +</p> + +<p> +Gallinula chloropus, pugnacity of the male. +</p> + +<p> +Galloperdix, spurs of; development of spurs in the female. +</p> + +<p> +Gallophasis, young of. +</p> + +<p> +Galls. +</p> + +<p> +Gallus bankiva, neck-hackles of. +</p> + +<p> +Gallus Stanleyi, pugnacity of the male. +</p> + +<p> +Galton, Mr., on hereditary genius; gregariousness and independence in animals; +on the struggle between the social and personal impulses; on the effects of +natural selection on civilised nations; on the sterility of sole daughters; on +the degree of fertility of people of genius; on the early marriages of the +poor; on the ancient Greeks; on the Middle Ages; on the progress of the United +States; on South African notions of beauty. +</p> + +<p> +Gammarus, use of the chelae of. +</p> + +<p> +Gammarus marinus. +</p> + +<p> +Gannets, white only when mature. +</p> + +<p> +Ganoid fishes. +</p> + +<p> +Gaour, horns of the. +</p> + +<p> +Gap between man and the apes. +</p> + +<p> +Gaper, sexes and young of. +</p> + +<p> +Gardner, on an example of rationality in a Gelasimus. +</p> + +<p> +Garrulus glandarius. +</p> + +<p> +Gartner, on sterility of hybrid plants. +</p> + +<p> +Gasteropoda, pulmoniferous, courtship of. +</p> + +<p> +Gasterosteus, nidification of. +</p> + +<p> +Gasterosteus leiurus. +</p> + +<p> +Gasterosteus trachurus. +</p> + +<p> +Gastrophora, wings of, brightly coloured beneath. +</p> + +<p> +Gauchos, want of humanity among the. +</p> + +<p> +Gaudry, M., on a fossil monkey. +</p> + +<p> +Gavia, seasonal change of plumage in. +</p> + +<p> +Geese, clanging noise made by; pairing of different species of; Canada, +selection of mates by. +</p> + +<p> +Gegenbaur, C., on the number of digits in the Ichthyopterygia; on the +hermaphroditism of the remote progenitors of the vertebrata; two types of +nipple in mammals. +</p> + +<p> +Gelasimus, proportions of the sexes in a species of; use of the enlarged chelae +of the male; pugnacity of males of; rational actions of a; difference of colour +in the sexes of a species of. +</p> + +<p> +Gemmules, dormant in one sex. +</p> + +<p> +Genius, hereditary. +</p> + +<p> +Genius, fertility of men and women of. +</p> + +<p> +Geoffroy St.-Hilaire, Isid., on the recognition of women by male quadrumana; on +monstrosities; coincidences of arrested development with polydactylism; on +animal-like anomalies in the human structure; on the correlation of +monstrosities; on the distribution of hair in man and monkeys; on the caudal +vertebrae of monkeys; on correlated variability; on the classification of man; +on the long hair on the heads of species of Semnopithecus; on the hair in +monkeys; on the development of horns in female deer; and F. Cuvier, on the +mandrill; on Hylobates. +</p> + +<p> +Geographical distribution, as evidence of specific distinctions in man. +</p> + +<p> +Geometrae, brightly coloured beneath. +</p> + +<p> +Geophagus, frontal protuberance of, male; eggs hatched by the male, in the +mouth or branchial cavity. +</p> + +<p> +Georgia, change of colour in Germans settled in. +</p> + +<p> +Geotrupes, stridulation of. +</p> + +<p> +Gerbe, M., on the nest-building of Crenilabus massa and C. Melops. +</p> + +<p> +Gerland, Dr., on the prevalence of infanticide; on the extinction of races. +</p> + +<p> +Gervais, P., on the hairiness of the gorilla; on the mandrill. +</p> + +<p> +Gesture-language. +</p> + +<p> +Ghost-moth, sexual difference of colour in the. +</p> + +<p> +Giard, M., disputes descent of vertebrates from Ascidians; colour of sponges +and Ascidians; musky odour of Sphinx. +</p> + +<p> +Gibbon, voice of. +</p> + +<p> +Gibbon, Hoolock, nose of. +</p> + +<p> +Gibbs, Sir D., on differences of the voice in different races of men. +</p> + +<p> +Gill, Dr., male seals larger than females; sexual differences in seals. +</p> + +<p> +Giraffe, its mode of using the horns; mute, except in the rutting season. +</p> + +<p> +Giraud-Teulon, on the cause of short sight. +</p> + +<p> +Glanders, communicable to man from the lower animals. +</p> + +<p> +Glands, odoriferous, in mammals. +</p> + +<p> +Glareola, double moult in. +</p> + +<p> +Glomeris limbata, difference of colour in the sexes of. +</p> + +<p> +Glow-worm, female, apterous; luminosity of the. +</p> + +<p> +Gnats, dances of; auditory powers of. +</p> + +<p> +Gnu, skeletons of, found locked together; sexual differences in colour of the. +</p> + +<p> +Goat, male, wild, falling on his horns; male, odour emitted by; male, wild, +crest of the; Berbura, mane, dewlap, etc., of the male; Kemas, sexual +difference in the colour of the. +</p> + +<p> +Goats, sexual differences in the horns of; horns of; mode of fighting of; +domestic, sexual differences of, late developed; beards of. +</p> + +<p> +Goatsucker, Virginian, pairing of the. +</p> + +<p> +Gobies, nidification of. +</p> + +<p> +God, want of the idea of, in some races of men. +</p> + +<p> +Godron, M., on variability; on difference of stature; on the want of connexion +between climate and the colour of the skin; on the colour of the skin; on the +colour of infants. +</p> + +<p> +Goldfinch, proportion of the sexes in the; sexual differences of the beak in +the; courtship of the. +</p> + +<p> +Goldfinch, North American, young of. +</p> + +<p> +Goldfish. +</p> + +<p> +Gomphus, proportions of the sexes in; difference in the sexes of. +</p> + +<p> +Gonepteryx Rhamni, sexual difference of colour in. +</p> + +<p> +Goodsir, Prof., on the affinity of the lancelet to the ascidians. +</p> + +<p> +Goosander, young of. +</p> + +<p> +Goose, Antarctic, colours of the. +</p> + +<p> +Goose, Canada, pairing with a Bernicle gander. +</p> + +<p> +Goose, Chinese, knob on the beak of the. +</p> + +<p> +Goose, Egyptian. +</p> + +<p> +Goose, Sebastopol, plumage of. +</p> + +<p> +Goose, Snow-, whiteness of the. +</p> + +<p> +Goose, Spur-winged. +</p> + +<p> +Gorilla, semi-erect attitude of the; mastoid processes of the; protecting +himself from rain with his hands; manner of sitting; supposed to be a kind of +mandrill; polygamy of the; voice of the; cranium of; fighting of male. +</p> + +<p> +Gosse, P.H., on the pugnacity of the male Humming-bird. +</p> + +<p> +Gosse, M., on the inheritance of artificial modifications of the skull. +</p> + +<p> +Gould, B.A., on variation in the length of the legs in man; measurements of +American soldiers; on the proportions of the body and capacity of the lungs in +different races of men; on the inferior vitality of mulattoes. +</p> + +<p> +Gould, J., on migration of swifts; on the arrival of male snipes before the +females; on the numerical proportion of the sexes in birds; on Neomorpha +Grypus; on the species of Eustephanus; on the Australian musk-duck; on the +relative size of the sexes in Briziura lobata and Cincloramphus cruralis; on +Lobivanellus lobatus; on habits of Menura Alberti; on the rarity of song in +brilliant birds; on Selasphorus platycerus; on the Bower-birds; on the +ornamental plumage of the Humming-birds; on the moulting of the ptarmigan; on +the display of plumage by the male Humming-birds; on the shyness of adorned +male birds; on the decoration of the bowers of Bower-birds; on the decoration +of their nest by Humming-birds; on variation in the genus Cynanthus; on the +colour of the thighs in a male parrakeet; on Urosticte Benjamini; on the +nidification of the Orioles; on obscurely-coloured birds building concealed +nests; on trogons and king-fishers; on Australian parrots; on Australian +pigeons; on the moulting of the ptarmigan; on the immature plumage of birds; on +the Australian species of Turnix; on the young of Aithurus polytmus; on the +colours of the bills of toucans; on the relative size of the sexes in the +marsupials of Australia; on the colours of the Marsupials. +</p> + +<p> +Goureaux, on the stridulation of Mutilla europaea. +</p> + +<p> +Gout, sexually transmitted. +</p> + +<p> +Graba, on the Pied Ravens of the Feroe Islands; variety of the Guillemot. +</p> + +<p> +Gradation of secondary sexual characters in birds. +</p> + +<p> +Grallatores, absence of secondary sexual characters in; double moult in some. +</p> + +<p> +Grallina, nidification of. +</p> + +<p> +Grasshoppers, stridulation of the. +</p> + +<p> +Gratiolet, Prof., on the anthropomorphous apes; on the evolution of the +anthropomorphous apes; on the difference in the development of the brains of +apes and of man. +</p> + +<p> +Gray, Asa, on the gradation of species among the Compositae. +</p> + +<p> +Gray, J.E., on the caudal vertebrae of monkeys; on the presence of rudiments of +horns in the female of Cervulus moschatus; on the horns of goats and sheep; on +crests of male antelopes; on the beard of the ibex; on the Berbura goat; on +sexual differences in the coloration of Rodents; ornaments of male sloth; on +the colours of the Elands; on the Sing-sing antelope; on the colours of goats; +on Lemur Macaco; on the hog-deer. +</p> + +<p> +“Greatest happiness principle.” +</p> + +<p> +Greeks, ancient. +</p> + +<p> +Green, A.H., on beavers fighting; on the voice of the beaver. +</p> + +<p> +Greenfinch, selected by a female canary. +</p> + +<p> +Greg, W.R., on the effects of natural selection on civilised nations; on the +early marriages of the poor; on the Ancient Greeks. +</p> + +<p> +Grenadiers, Prussian. +</p> + +<p> +Greyhounds, numerical proportion of the sexes in; numerical proportion of male +and female births in. +</p> + +<p> +Grouse, red, monogamous; pugnacity of young male; producing a sound by beating +their wings together; duration of courtship of; colours and nidification of. +</p> + +<p> +Gruber, Dr., on the occurrence of the supra-condyloid foramen in the humerus of +man; on division of malar bone; stridulation of locust; on ephippiger. +</p> + +<p> +Grus americanus, age of mature plumage in; breeding in immature plumage. +</p> + +<p> +Grus virgo, trachea of. +</p> + +<p> +Gryllus campestris, pugnacity of male. +</p> + +<p> +Gryllus domesticus. +</p> + +<p> +Grypus, sexual differences in the beak in. +</p> + +<p> +Guanacoes, battles of; canine teeth of. +</p> + +<p> +Guanas, strife for women among the; polyandry among the. +</p> + +<p> +Guanche skeletons, occurrence of the supra-condyloid foramen in the humerus of. +</p> + +<p> +Guaranys, proportion of men and women among; colour of new-born children of +the; beards of the. +</p> + +<p> +Guenee, A., on the sexes of Hyperythra. +</p> + +<p> +Guilding, L., on the stridulation of the Locustidae. +</p> + +<p> +Guillemot, variety of the. +</p> + +<p> +Guinea, sheep of, with males only horned. +</p> + +<p> +Guinea-fowl, monogamous; occasional polygamy of the; markings of the. +</p> + +<p> +Guinea-pigs, inheritance of the effects of operations by. +</p> + +<p> +Gulls, seasonal change of plumage in; white. +</p> + +<p> +Gunther, Dr., on paddle of Ceradotus; on hermaphroditism in Serranus; on male +fishes hatching ova in their mouths; on mistaking infertile female fishes for +males; on the prehensile organs of male Plagiostomous fishes; spines and +brushes on fishes; on the pugnacity of the male salmon and trout; on the +relative size of the sexes in fishes; on sexual differences in fishes; on the +genus Callionymus; on a protective resemblance of a pipe-fish; on the genus +Solenostoma; on the coloration of frogs and toads; combat of Testudo elegans; +on the sexual differences in the Ophidia; on differences of the sexes of +lizards. +</p> + +<p> +Gynanisa Isis, ocellated spots of. +</p> + +<p> +Gypsies, uniformity of, in various parts of the world. +</p> + +<p> +Habits, bad, facilitated by familiarity; variability of the force of. +</p> + +<p> +Haeckel, E., on the origin of man; on rudimentary characters; on death caused +by inflammation of the vermiform appendage; on the canine teeth in man; on the +steps by which man became a biped; on man as a member of the Catarrhine group; +on the position of the Lemuridae; on the genealogy of the Mammalia; on the +lancelet; on the transparency of pelagic animals; on the musical powers of +women. +</p> + +<p> +Hagen, H., and Walsh, B.D., on American Neuroptera. +</p> + +<p> +Hair, development of, in man; character of, supposed to be determined by light +and heat; distribution of, in man; possibly removed for ornamental purposes; +arrangement and direction of; of the early progenitors of man; different +texture of, in distinct races; and skin, correlation of colour of; development +of, in mammals; management of, among different peoples; great length of, in +some North American tribes; elongation of the, on the human head; possible +inherited effect of plucking out. +</p> + +<p> +Hairiness, difference of, in the sexes in man; variation of, in races of men. +</p> + +<p> +Hairs and excretory pores, numerical relation of, in sheep. +</p> + +<p> +Hairy family, Siamese. +</p> + +<p> +Halbertsma, Prof., hermaphroditism in Serranus. +</p> + +<p> +Hamadryas baboon, turning over stones; mane of the male. +</p> + +<p> +Hamilton, C., on the cruelty of the Kaffirs to animals; on the engrossment of +the women by the Kaffir chiefs. +</p> + +<p> +Hammering, difficulty of. +</p> + +<p> +Hancock, A., on the colours of the nudibranch Mollusca. +</p> + +<p> +Hands, larger at birth, in the children of labourers; structure of, in the +quadrumana; and arms, freedom of, indirectly correlated with diminution of +canines. +</p> + +<p> +Handwriting, inherited. +</p> + +<p> +Handyside, Dr., supernumerary mammae in men. +</p> + +<p> +Harcourt, E. Vernon, on Fringilla cannabina. +</p> + +<p> +Hare, protective colouring of the. +</p> + +<p> +Harelda glacialis. +</p> + +<p> +Hares, battles of male. +</p> + +<p> +Harlan, Dr., on the difference between field-and house-slaves. +</p> + +<p> +Harris, J.M., on the relation of complexion to climate. +</p> + +<p> +Harris, T.W., on the Katy-did locust; on the stridulation of the grasshoppers; +on Oecanthus nivalis; on the colouring of Lepidoptera; on the colouring of +Saturnia Io. +</p> + +<p> +Harting, spur of the Ornithorhynchus. +</p> + +<p> +Hartman, Dr., on the singing of Cicada septendecim. +</p> + +<p> +Hatred, persistence of. +</p> + +<p> +Haughton, S., on a variation of the flexor pollicis longus in man. +</p> + +<p> +Hawks, feeding orphan nestling. +</p> + +<p> +Hayes, Dr., on the diverging of sledge-dogs on thin ice. +</p> + +<p> +Haymond, R., on the drumming of the male Tetrao umbellus; on the drumming of +birds. +</p> + +<p> +Head, altered position of, to suit the erect attitude of man; hairiness of, in +man; processes of, in male beetles; artificial alterations of the form of the. +</p> + +<p> +Hearne, on strife for women among the North American Indians; on the North +American Indians’ notion of female beauty; repeated elopements of a North +American woman. +</p> + +<p> +Heart, in the human embryo. +</p> + +<p> +Heat, supposed effects of. +</p> + +<p> +Hectocotyle. +</p> + +<p> +Hedge-warbler, young of the. +</p> + +<p> +Heel, small projection of, in the Aymara Indians. +</p> + +<p> +Hegt, M., on the development of the spurs in peacocks. +</p> + +<p> +Heliconidae, mimicry of, by other butterflies. +</p> + +<p> +Heliopathes, stridulation peculiar to the male. +</p> + +<p> +Heliothrix auriculata, young of. +</p> + +<p> +Helix pomatia, example of individual attachment in. +</p> + +<p> +Hellins, J., proportions of sexes of Lepidoptera reared by. +</p> + +<p> +Helmholtz, on pleasure derived from harmonies; on the human eye; on the +vibration of the auditory hairs of crustacea; the physiology of harmony. +</p> + +<p> +Hemiptera. +</p> + +<p> +Hemitragus, beardless in both sexes. +</p> + +<p> +Hemsbach, M. von, on medial mamma in man. +</p> + +<p> +Hen, clucking of. +</p> + +<p> +Hepburn, Mr., on the autumn song of the water-ouzel. +</p> + +<p> +Hepialus humuli, sexual difference of colour in the. +</p> + +<p> +Herbs, poisonous, avoided by animals. +</p> + +<p> +Hermaphroditism, of embryos; in fishes. +</p> + +<p> +Herodias bubulcus, vernal moult of. +</p> + +<p> +Heron, Sir R., on the habits of peafowl. +</p> + +<p> +Herons, love-gestures of; decomposed feathers in; breeding plumage of; young of +the; sometimes dimorphic; continued growth of crest and plumes in the males of +some; change of colour in some. +</p> + +<p> +Hesperomys cognatus. +</p> + +<p> +Hetaerina, proportion of the sexes in; difference in the sexes of. +</p> + +<p> +Heterocerus, stridulation of. +</p> + +<p> +Hewitt, Mr., on a game-cock killing a kite; on the recognition of dogs and cats +by ducks; on the pairing of a wild duck with a pintail drake; on the courtship +of fowls; on the coupling of pheasants with common hens. +</p> + +<p> +Hilgendorf, sounds produced by crustaceans. +</p> + +<p> +Hindoo, his horror of breaking his caste. +</p> + +<p> +Hindoos, local difference of stature among; difference of, from Europeans; +colour of the beard in. +</p> + +<p> +Hipparchia Janira, instability of the ocellated spots of. +</p> + +<p> +Hippocampus, development of; marsupial receptacles of the male. +</p> + +<p> +Hippocampus minor. +</p> + +<p> +Hippopotamus, nakedness of. +</p> + +<p> +Hips, proportions of, in soldiers and sailors. +</p> + +<p> +Hodgson, S., on the sense of duty. +</p> + +<p> +Hoffberg, on the horns of the reindeer; on sexual preferences shewn by +reindeer. +</p> + +<p> +Hoffman, Prof., protective colours; fighting of frogs. +</p> + +<p> +Hog, wart-; river-. +</p> + +<p> +Hog-deer. +</p> + +<p> +Holland, Sir H., on the effects of new diseases. +</p> + +<p> +Homologous structures, correlated variation of. +</p> + +<p> +Homoptera, stridulation of the, and Orthoptera, discussed. +</p> + +<p> +Honduras, Quiscalus major in. +</p> + +<p> +Honey-buzzard of India, variation in the crest of. +</p> + +<p> +Honey-sucker, females and young of. +</p> + +<p> +Honey-suckers, moulting of the; Australian, nidification of. +</p> + +<p> +Honour, law of. +</p> + +<p> +Hooker, Dr., forbearance of elephant to his keeper; on the colour of the beard +in man. +</p> + +<p> +Hookham, Mr., on mental concepts in animals. +</p> + +<p> +Hoolock Gibbon, nose of. +</p> + +<p> +Hoopoe, sounds produced by male. +</p> + +<p> +Hoplopterus armatus, wing-spurs of. +</p> + +<p> +Hornbill, African, inflation of the neck-wattle of the male during courtship. +</p> + +<p> +Hornbills, sexual difference in the colour of the eyes in; nidification and +incubation of. +</p> + +<p> +Horne, C., on the rejection of a brightly-coloured locust by lizards and birds. +</p> + +<p> +Horns, sexual differences of, in sheep and goats; loss of, in female merino +sheep; development of, in deer; development in antelopes; from the head and +thorax, in male beetles; of deer; originally a masculine character in sheep; +and canine teeth, inverse development of. +</p> + +<p> +Horse, fossil, extinction of the, in South America; polygamous; canine teeth of +male; winter change of colour. +</p> + +<p> +Horses, rapid increase of, in South America; diminution of canine teeth in; +dreaming; of the Falkland Islands and Pampas; numerical proportion of the +sexes, in; lighter in winter in Siberia; sexual preferences in; pairing +preferently with those of the same colour; numerical proportion of male and +female births in; formerly striped. +</p> + +<p> +Hottentot women, peculiarities of. +</p> + +<p> +Hottentots, lice of; readily become musicians; notions of female beauty of the; +compression of nose by. +</p> + +<p> +Hough, Dr. S., men’s temperature more variable than women’s; +proportion of sexes in man. +</p> + +<p> +House-slaves, difference of, from field-slaves. +</p> + +<p> +Houzeau, on the baying of the dog; on reason in dogs; birds killed by telegraph +wires; on the cries of domestic fowls and parrots; animals feel no pity; +suicide in the Aleutian Islands. +</p> + +<p> +Howorth, H.H., extinction of savages. +</p> + +<p> +Huber, P., on ants playing together; on memory in ants; on the +intercommunication of ants; on the recognition of each other by ants after +separation. +</p> + +<p> +Huc, on Chinese opinions of the appearance of Europeans. +</p> + +<p> +Huia, the, of New Zealand. +</p> + +<p> +Human, man, classed alone in a kingdom. +</p> + +<p> +Human sacrifices. +</p> + +<p> +Humanity, unknown among some savages; deficiency of, among savages. +</p> + +<p> +Humboldt, A. von, on the rationality of mules; on a parrot preserving the +language of a lost tribe; on the cosmetic arts of savages; on the exaggeration +of natural characters by man; on the red painting of American Indians. +</p> + +<p> +Hume, D., on sympathetic feelings. +</p> + +<p> +Humming-bird, racket-shaped feathers in the tail of a; display of plumage by +the male. +</p> + +<p> +Humming-birds, ornament their nests; polygamous; proportion of the sexes in; +sexual differences in; pugnacity of male; modified primaries of male; +coloration of the sexes of; display by; nidification of the; colours of female; +young of. +</p> + +<p> +Humour, sense of, in dogs. +</p> + +<p> +Humphreys, H.N., on the habits of the stickleback. +</p> + +<p> +Hunger, instinct of. +</p> + +<p> +Huns, ancient, flattening of the nose by the. +</p> + +<p> +Hunter, J., on the number of species of man; on secondary sexual characters; on +the general behaviour of female animals during courtship; on the muscles of the +larynx in song-birds; on strength of males; on the curled frontal hair of the +bull; on the rejection of an ass by a female zebra. +</p> + +<p> +Hunter, W.W., on the recent rapid increase of the Santali; on the Santali. +</p> + +<p> +Huss, Dr. Max, on mammary glands. +</p> + +<p> +Hussey, Mr., on a partridge distinguishing persons. +</p> + +<p> +Hutchinson, Col., example of reasoning in a retriever. +</p> + +<p> +Hutton, Captain, on the male wild goat falling on his horns. +</p> + +<p> +Huxley, T.H., on the structural agreement of man with the apes; on the +agreement of the brain in man with that of lower animals; on the adult age of +the orang; on the embryonic development of man; on the origin of man; on +variation in the skulls of the natives of Australia; on the abductor of the +fifth metatarsal in apes; on the nature of the reasoning power; on the position +of man; on the suborders of primates; on the Lemuridae; on the Dinosauria; on +the amphibian affinities of the Ichthyosaurians; on variability of the skull in +certain races of man; on the races of man; Supplement on the brain. +</p> + +<p> +Hybrid birds, production of. +</p> + +<p> +Hydrophobia, communicable between man and the lower animals. +</p> + +<p> +Hydroporus, dimorphism of females of. +</p> + +<p> +Hyelaphus porcinus. +</p> + +<p> +Hygrogonus. +</p> + +<p> +Hyla, singing species of. +</p> + +<p> +Hylobates, absence of the thumb in; upright progression of some species of; +maternal affection in a; direction of the hair on the arms of species of; +females of, less hairy below than males. +</p> + +<p> +Hylobates agilis, hair on the arms of; musical voice of the; superciliary ridge +of; voice of. +</p> + +<p> +Hylobates hoolock, sexual difference of colour in. +</p> + +<p> +Hylobates lar, hair on the arms of; female less hairy. +</p> + +<p> +Hylobates leuciscus, song of. +</p> + +<p> +Hylobates syndactylus, laryngeal sac of. +</p> + +<p> +Hylophila prasinana. +</p> + +<p> +Hymenoptera, large size of the cerebral ganglia in; classification of; sexual +differences in the wings of; aculeate, relative size of the sexes of. +</p> + +<p> +Hymenopteron, parasitic, with a sedentary male. +</p> + +<p> +Hyomoschus aquaticus. +</p> + +<p> +Hyperythra, proportion of the sexes in. +</p> + +<p> +Hypogymna dispar, sexual difference of colour in. +</p> + +<p> +Hypopyra, coloration of. +</p> + +<p> +Ibex, male, falling on his horns; beard of the. +</p> + +<p> +Ibis, white, change of colour of naked skin in, during the breeding season; +scarlet, young of the. +</p> + +<p> +Ibis tantalus, age of mature plumage in; breeding in immature plumage. +</p> + +<p> +Ibises, decomposed feathers in; white; and black. +</p> + +<p> +Ichneumonidae, difference of the sexes in. +</p> + +<p> +Ichthyopterygia. +</p> + +<p> +Ichthyosaurians. +</p> + +<p> +Idiots, microcephalous, their characters and habits; hairiness and animal +nature of their actions; microcephalous, imitative faculties of. +</p> + +<p> +Iguana tuberculata. +</p> + +<p> +Iguanas. +</p> + +<p> +Illegitimate and legitimate children, proportion of the sexes in. +</p> + +<p> +Imagination, existence of, in animals. +</p> + +<p> +Imitation, of man by monkeys; tendency to, in monkeys, microcephalous idiots +and savages; influence of. +</p> + +<p> +Immature plumage of birds. +</p> + +<p> +Implacentata. +</p> + +<p> +Implements, employed by monkeys; fashioning of, peculiar to man. +</p> + +<p> +Impregnation, period of, influence of, upon sex. +</p> + +<p> +Improvement, progressive, man alone supposed to be capable of. +</p> + +<p> +Incisor teeth, knocked out or filed by some savages. +</p> + +<p> +Increase, rate of; necessity of checks in. +</p> + +<p> +Indecency, hatred of, a modern virtue. +</p> + +<p> +India, difficulty of distinguishing the native races of; Cyprinidae of; colour +of the beard in races of men of. +</p> + +<p> +Indian, North American, honoured for scalping a man of another tribe. +</p> + +<p> +Individuality, in animals. +</p> + +<p> +Indolence of man, when free from a struggle for existence. +</p> + +<p> +Indopicus carlotta, colours of the sexes of. +</p> + +<p> +Infanticide, prevalence of; supposed cause of; prevalence and causes of. +</p> + +<p> +Inferiority, supposed physical, of man. +</p> + +<p> +Inflammation of the bowels, occurrence of, in Cebus Azarae. +</p> + +<p> +Inheritance, of long and short sight; of effects of use of vocal and mental +organs; of moral tendencies; laws of; sexual; sexually limited. +</p> + +<p> +Inquisition, influence of the. +</p> + +<p> +Insanity, hereditary. +</p> + +<p> +insect, fossil, from the Devonian. +</p> + +<p> +Insectivora, absence of secondary sexual characters in. +</p> + +<p> +Insects, relative size of the cerebral ganglia in; male, appearance of, before +the females; pursuit of female, by the males; period of development of sexual +characters in; secondary sexual characters of; kept in cages; stridulation. +</p> + +<p> +Insessores, vocal organs of. +</p> + +<p> +Instep, depth of, in soldiers and sailors. +</p> + +<p> +Instinct and intelligence. +</p> + +<p> +Instinct, migratory, vanquishing the maternal. +</p> + +<p> +Instinctive actions, the result of inheritance. +</p> + +<p> +Instinctive impulses, difference of the force; and moral impulses, alliance of. +</p> + +<p> +Instincts, complex origin of, through natural selection; possible origin of +some; acquired, of domestic animals; variability of the force of; difference of +force between the social and other; utilised for new purposes. +</p> + +<p> +Instrumental music of birds. +</p> + +<p> +Intellect, influence of, in natural selection in civilised society. +</p> + +<p> +Intellectual faculties, their influence on natural selection in man; probably +perfected through natural selection. +</p> + +<p> +Intelligence, Mr. H. Spencer on the dawn of. +</p> + +<p> +Intemperance, no reproach among savages; its destructiveness. +</p> + +<p> +Intoxication in monkeys. +</p> + +<p> +Iphias glaucippe. +</p> + +<p> +Iris, sexual difference in the colour of the, in birds. +</p> + +<p> +Ischio-pubic muscle. +</p> + +<p> +Ithaginis cruentus, number of spurs in. +</p> + +<p> +Iulus, tarsal suckers of the males of. +</p> + +<p> +Jackals learning from dogs to bark. +</p> + +<p> +Jack-snipe, coloration of the. +</p> + +<p> +Jacquinot, on the number of species of man. +</p> + +<p> +Jaeger, Dr., length of bones increased from carrying weights; on the difficulty +of approaching herds of wild animals; male Silver-pheasant, rejected when his +plumage was spoilt. +</p> + +<p> +Jaguars, black. +</p> + +<p> +Janson, E.W., on the proportions of the sexes in Tomicus villosus; on +stridulant beetles. +</p> + +<p> +Japan, encouragement of licentiousness in. +</p> + +<p> +Japanese, general beardlessness of the; aversion of the, to whiskers. +</p> + +<p> +Jardine, Sir W., on the Argus pheasant. +</p> + +<p> +Jarrold, Dr., on modifications of the skull induced by unnatural position. +</p> + +<p> +Jarves, Mr., on infanticide in the Sandwich Islands. +</p> + +<p> +Javans, relative height of the sexes of; notions of female beauty. +</p> + +<p> +Jaw, influence of the muscles of the, upon the physiognomy of the apes. +</p> + +<p> +Jaws, smaller proportionately to the extremities; influence of food upon the +size of; diminution of, in man; in man, reduced by correlation. +</p> + +<p> +Jay, young of the; Canada, young of the. +</p> + +<p> +Jays, new mates found by; distinguishing persons. +</p> + +<p> +Jeffreys, J. Gwyn, on the form of the shell in the sexes of the Gasteropoda; on +the influence of light upon the colours of shells. +</p> + +<p> +Jelly-fish, bright colours of some. +</p> + +<p> +Jenner, Dr., on the voice of the rook; on the finding of new mates by magpies; +on retardation of the generative functions in birds. +</p> + +<p> +Jenyns, L., on the desertion of their young by swallows; on male birds singing +after the proper season. +</p> + +<p> +Jerdon, Dr., on birds dreaming; on the pugnacity of the male bulbul; on the +pugnacity of the male Ortygornis gularis; on the spurs of Galloperdix; on the +habits of Lobivanellus; on the spoonbill; on the drumming of the +Kalij-pheasant; on Indian bustards; on Otis bengalensis; on the ear-tufts of +Sypheotides auritus; on the double moults of certain birds; on the moulting of +the honeysuckers; on the moulting of bustards, plovers, and drongos; on the +spring change of colour in some finches; on display in male birds; on the +display of the under-tail coverts by the male bulbul; on the Indian +honey-buzzard; on sexual differences in the colour of the eyes of hornbills; on +the markings of the Tragopan pheasant; on the nidification of the Orioles; on +the nidification of the hornbills; on the Sultan yellow-tit; on Palaeornis +javanicus; on the immature plumage of birds; on representative species of +birds; on the habits of Turnix; on the continued increase of beauty of the +peacock; on coloration in the genus Palaeornis. +</p> + +<p> +Jevons, W.S., on the migrations of man. +</p> + +<p> +Jews, ancient use of flint tools by the; uniformity of, in various parts of the +world; numerical proportion of male and female births among the; ancient, +tattooing practised by. +</p> + +<p> +Johnstone, Lieut., on the Indian elephant. +</p> + +<p> +Jollofs, fine appearance of the. +</p> + +<p> +Jones, Albert, proportion of sexes of Lepidoptera, reared by. +</p> + +<p> +Juan Fernandez, humming-birds of. +</p> + +<p> +Junonia, sexual differences of colouring in species of. +</p> + +<p> +Jupiter, comparison with Assyrian effigies. +</p> + +<p> +Kaffir skull, occurrence of the diastema in a. +</p> + +<p> +Kaffirs, their cruelty to animals; lice of the; colour of the; engrossment of +the handsomest women by the chiefs of the; marriage-customs of the. +</p> + +<p> +Kalij-pheasant, drumming of the male; young of. +</p> + +<p> +Kallima, resemblance of, to a withered leaf. +</p> + +<p> +Kulmucks, general beardlessness of; aversion of, to hairs on the face; +marriage-customs of the. +</p> + +<p> +Kangaroo, great red, sexual difference in the colour of. +</p> + +<p> +Kant, Imm., on duty; on self-restraint; on the number of species of man. +</p> + +<p> +Katy-did, stridulation of the. +</p> + +<p> +Keen, Dr., on the mental powers of snakes. +</p> + +<p> +Keller, Dr., on the difficulty of fashioning stone implements. +</p> + +<p> +Kent, W.S., elongation of dorsal fin of Callionymus lyra; courtship of Labrus +mixtus; colours and courtship of Cantharus lineatus. +</p> + +<p> +Kestrels, new mates found by. +</p> + +<p> +Kidney, one, doing double work in disease. +</p> + +<p> +King, W.R., on the vocal organs of Tetrao cupido; on the drumming of grouse; on +the reindeer; on the attraction of male deer by the voice of the female. +</p> + +<p> +King and Fitzroy, on the marriage-customs of the Fuegians. +</p> + +<p> +King-crows, nidification of. +</p> + +<p> +Kingfisher, racket-shaped feathers in the tail of a. +</p> + +<p> +Kingfishers, colours and nidification of the; immature plumage of the; young of +the. +</p> + +<p> +King Lory, immature plumage of the. +</p> + +<p> +Kingsley, C., on the sounds produced by the Umbrina. +</p> + +<p> +Kirby and Spence, on sexual differences in the length of the snout in +Curculionidae; on the courtship of insects; on the elytra of Dytiscus; on +peculiarities in the legs of male insects; on the relative size of the sexes in +insects; on the Fulgoridae; on the habits of the Termites; on difference of +colour in the sexes of beetles; on the horns of the male lamellicorn beetles; +on hornlike processes in male Curculionidae; on the pugnacity of the male +stag-beetle. +</p> + +<p> +Kite, killed by a game-cock. +</p> + +<p> +Knot, retention of winter plumage by the. +</p> + +<p> +Knox, R., on the semilunar fold; on the occurrence of the supra-condyloid +foramen in the humerus of man; on the features of the young Memmon. +</p> + +<p> +Koala, length of the caecum in. +</p> + +<p> +Kobus ellipsiprymnus, proportion of the sexes in. +</p> + +<p> +Kolreuter, on the sterility of hybrid plants. +</p> + +<p> +Koodoo, development of the horns of the; markings of the. +</p> + +<p> +Koppen, F.T., on the migratory locust. +</p> + +<p> +Koraks, marriage customs of. +</p> + +<p> +Kordofan, protuberances artificially produced by natives of. +</p> + +<p> +Korte, on the proportion of sexes in locusts; Russian locusts. +</p> + +<p> +Kovalevsky, A., on the affinity of the Ascidia to the Vertebrata. +</p> + +<p> +Kovalevsky, W., on the pugnacity of the male capercailzie; on the pairing of +the capercailzie. +</p> + +<p> +Krause, on a convoluted body at the extremity of the tail in a Macacus and a +cat. +</p> + +<p> +Kupffer, Prof., on the affinity of the Ascidia to the Vertebrata. +</p> + +<p> +Labidocera Darwinii, prehensile organs of the male. +</p> + +<p> +Labrus, splendid colours of the species of. +</p> + +<p> +Labrus mixtus, sexual differences in. +</p> + +<p> +Labrus pavo. +</p> + +<p> +Lacertilia, sexual differences of. +</p> + +<p> +Lafresnaye, M. de, on birds of paradise. +</p> + +<p> +Lamarck, on the origin of man. +</p> + +<p> +Lamellibranchiata. +</p> + +<p> +Lamellicorn beetles, horn-like processes from the head and thorax of; influence +of sexual selection on. +</p> + +<p> +Lamellicornia, stridulation of. +</p> + +<p> +Lamont, Mr., on the tusks of the walrus; on the use of its tusks by the walrus; +on the bladder-nose seal. +</p> + +<p> +Lampornis porphyrurus, colours of the female. +</p> + +<p> +Lampyridae, distasteful to mammals. +</p> + +<p> +Lancelet. +</p> + +<p> +Landois, H., gnats attracted by sound; on the production of sound by the +Cicadae; on the stridulating organ of the crickets; on Decticus; on the +stridulating organs of the Acridiidae; stridulating apparatus, in Orthoptera; +on the stridulation of Necrophorus; on the stridulant organ of Cerambyx heros; +on the stridulant organ of Geotrupes; on the stridulating organs in the +Coleoptera; on the ticking of Anobium. +</p> + +<p> +Landor, Dr., on remorse for not obeying tribal custom. +</p> + +<p> +Language, an art; articulate, origin of; relation of the progress of, to the +development of the brain; effects of inheritance in production of; complex +structure of, among barbarous nations; natural selection in; gesture; primeval; +of a lost tribe preserved by a parrot. +</p> + +<p> +Languages, presence of rudiments in; classification of; variability of; +crossing or blending of; complexity of, no test of perfection or proof of +special creation; resemblance of, evidence of community of origin. +</p> + +<p> +Languages and species, identity of evidence of their gradual development. +</p> + +<p> +Lanius, characters of young. +</p> + +<p> +Lanius rufus, anomalous young of. +</p> + +<p> +Lankester, E.R., on comparative longevity; on the destructive effects of +intemperance. +</p> + +<p> +Lanugo of the human foetus. +</p> + +<p> +Lapponian language, highly artificial. +</p> + +<p> +Lark, proportion of the sexes in the; female, singing of the. +</p> + +<p> +Larks, attracted by a mirror. +</p> + +<p> +Lartet, E., comparison of cranial capacities of skulls of recent and tertiary +mammals; on the size of the brain in mammals; on Dryopithecus; on pre-historic +flutes. +</p> + +<p> +Larus, seasonal change of plumage in. +</p> + +<p> +Larva, luminous, of a Brazilian beetle. +</p> + +<p> +Larynx, muscles of the, in songbirds. +</p> + +<p> +Lasiocampa quercus, attraction of males by the female; sexual difference of +colour in. +</p> + +<p> +Latham, R.G., on the migrations of man. +</p> + +<p> +Latooka, perforation of the lower lip by the women of. +</p> + +<p> +Laurillard, on the abnormal division of the malar bone in man. +</p> + +<p> +Lawrence, W., on the superiority of savages to Europeans in power of sight; on +the colour of negro infants; on the fondness of savages for ornaments; on +beardless races; on the beauty of the English aristocracy. +</p> + +<p> +Layard, E.L., on the instance of rationality in a cobra; on the pugnacity of +Gallus Stanleyi. +</p> + +<p> +Laycock, Dr., on vital periodicity; theroid nature of idiots. +</p> + +<p> +Leaves, autumn, tints useless. +</p> + +<p> +Lecky, Mr., on the sense of duty; on suicide; on the practice of celibacy; his +view of the crimes of savages; on the gradual rise of morality. +</p> + +<p> +Leconte, J.L., on the stridulant organ in the Coprini and Dynastini. +</p> + +<p> +Lee, H., on the numerical proportion of the sexes in the trout. +</p> + +<p> +Leg, calf of the, artificially modified. +</p> + +<p> +Legitimate and illegitimate children, proportion of the sexes in. +</p> + +<p> +Legs, variation of the length of the, in man; proportions of, in soldiers and +sailors; front, atrophied in some male butterflies; peculiarities of, in male +insects. +</p> + +<p> +Leguay, on the occurrence of the supra-condyloid foramen in the humerus of man. +</p> + +<p> +Lek of the black-cock and capercailzie. +</p> + +<p> +Lemoine, Albert, on the origin of language. +</p> + +<p> +Lemur macaco, sexual difference of colour in. +</p> + +<p> +Lemuridae, ears of the; variability of the muscles in the; position and +derivation of the; their origin. +</p> + +<p> +Lemurs, uterus in the. +</p> + +<p> +Lenguas, disfigurement of the ears of the. +</p> + +<p> +Leopards, black. +</p> + +<p> +Lepidoptera, numerical proportions of the sexes in the; colouring of; ocellated +spots of. +</p> + +<p> +Lepidosiren. +</p> + +<p> +Leptalides, mimicry of. +</p> + +<p> +Leptorhynchus angustatus, pugnacity of male. +</p> + +<p> +Leptura testacea, difference of colour in the sexes. +</p> + +<p> +Leroy, on the wariness of young foxes in hunting-districts; on the desertion of +their young by swallows. +</p> + +<p> +Leslie, D., marriage customs of Kaffirs. +</p> + +<p> +Lesse, valley of the. +</p> + +<p> +Lesson, on the birds of paradise; on the sea-elephant. +</p> + +<p> +Lessona, M., observations on Serranus. +</p> + +<p> +Lethrus cephalotes, pugnacity of the males of. +</p> + +<p> +Leuciscus phoxinus. +</p> + +<p> +Leuckart, R., on the vesicula prostatica; on the influence of the age of +parents on the sex of offspring. +</p> + +<p> +Levator claviculae muscle. +</p> + +<p> +Libellula depressa, colour of the male. +</p> + +<p> +Libellulidae, relative size of the sexes of; difference in the sexes of. +</p> + +<p> +Lice of domestic animals and man. +</p> + +<p> +Licentiousness a check upon population; prevalence of, among savages. +</p> + +<p> +Lichtenstein, on Chera progne. +</p> + +<p> +Life, inheritance at corresponding periods of. +</p> + +<p> +Light, effects on complexion; influence of, upon the colours of shells. +</p> + +<p> +Lilford, Lord, the ruff attracted by bright objects. +</p> + +<p> +Limosa lapponica. +</p> + +<p> +Linaria. +</p> + +<p> +Linaria montana. +</p> + +<p> +Lindsay, Dr. W.L., diseases communicated from animals to man; madness in +animals; the dog considers his master his God. +</p> + +<p> +Linnaeus, views of, as to the position of man. +</p> + +<p> +Linnet, numerical proportion of the sexes in the; crimson forehead and breast +of the; courtship of the. +</p> + +<p> +Lion, polygamous; mane of the, defensive; roaring of the. +</p> + +<p> +Lions, stripes of young. +</p> + +<p> +Lips, piercing of the, by savages. +</p> + +<p> +Lithobius, prehensile appendages of the female. +</p> + +<p> +Lithosia, coloration in. +</p> + +<p> +Littorina littorea. +</p> + +<p> +Livingstone, Dr., manner of sitting of gorilla; on the influence of dampness +and dryness on the colour of the skin; on the liability of negroes to tropical +fevers after residence in a cold climate; on the spur-winged goose; on +weaverbirds; on an African night-jar; on the battle-scars of South African male +mammals; on the removal of the upper incisors by the Batokas; on the +perforation of the upper lip by the Makalolo; on the Banyai. +</p> + +<p> +Livonia, numerical proportion of male and female births in. +</p> + +<p> +Lizards, relative size of the sexes of; gular pouches of. +</p> + +<p> +Lloyd, L., on the polygamy of the capercailzie and bustard; on the numerical +proportion of the sexes in the capercailzie and blackcock; on the salmon; on +the colours of the sea-scorpion; on the pugnacity of male grouse; on the +capercailzie and blackcock; on the call of the capercailzie; on assemblages of +grouse and snipes; on the pairing of a shield-drake with a common duck; on the +battles of seals; on the elk. +</p> + +<p> +Lobivanellus, wing-spurs in. +</p> + +<p> +Local influences, effect of, upon stature. +</p> + +<p> +Lockwood, Mr., on the development of Hippocampus. +</p> + +<p> +Lockwood, Rev. S., musical mouse. +</p> + +<p> +Locust, bright-coloured, rejected by lizards and birds. +</p> + +<p> +Locust, migratory; selection by female. +</p> + +<p> +Locustidae, stridulation of the; descent of the. +</p> + +<p> +Locusts, proportion of sexes in; stridulation of. +</p> + +<p> +Longicorn beetles, difference of the sexes of, in colour; stridulation of. +</p> + +<p> +Lonsdale, Mr., on an example of personal attachment in Helix pomatia. +</p> + +<p> +Lophobranchii, marsupial receptacles of the male. +</p> + +<p> +Lophophorus, habits of. +</p> + +<p> +Lophorina atra, sexual difference in coloration of. +</p> + +<p> +Lophornis ornatus. +</p> + +<p> +Lord, J.K., on Salmo lycaodon. +</p> + +<p> +Lory, King; immature plumage of the. +</p> + +<p> +Lory, King, constancy of. +</p> + +<p> +Love-antics and dances of birds. +</p> + +<p> +Lowne, B.T., on Musca vomitoria. +</p> + +<p> +Loxia, characters of young of. +</p> + +<p> +Lubbock, Sir J., on the antiquity of man; on the origin of man; on the mental +capacity of savages; on the origin of implements; on the simplification of +languages; on the absence of the idea of God among certain races of men; on the +origin of the belief in spiritual agencies; on superstitions; on the sense of +duty; on the practice of burying the old and sick among the Fijians; on the +immorality of savages; on Mr. Wallace’s claim to the origination of the +idea of natural selection; on the former barbarism of civilised nations; on +improvements in the arts among savages; on resemblances of the mental +characters in different races of men; on the arts practised by savages; on the +power of counting in primeval man; on the prehensile organs of the male +Labidocera Darwinii; on Chloeon; on Smynthurus luteus; finding of new mates by +jays; on strife for women among the North American Indians; on music; on the +ornamental practices of savages; on the estimation of the beard among the +Anglo-Saxons; on artificial deformation of the skull; on “communal +marriages;” on exogamy; on the Veddahs; on polyandry. +</p> + +<p> +Lucanidae, variability of the mandibles in the male. +</p> + +<p> +Lucanus, large size of males of. +</p> + +<p> +Lucanus cervus, numerical proportion of sexes of; weapons of the male. +</p> + +<p> +Lucanus elaphus, use of mandibles of; large jaws of male. +</p> + +<p> +Lucas, Prosper, on pigeons; on sexual preference in horses and bulls. +</p> + +<p> +Luminosity in insects. +</p> + +<p> +Lunar periods. +</p> + +<p> +Lund, Dr., on skulls found in Brazilian caves. +</p> + +<p> +Lungs, enlargement of, in the Quichua and Aymara Indians; a modified +swim-bladder; different capacity of, in races of man. +</p> + +<p> +Luschka, Prof., on the termination of the coccyx. +</p> + +<p> +Luxury, expectation of life uninfluenced by. +</p> + +<p> +Lycaena, sexual differences of colour in species of. +</p> + +<p> +Lycaenae, colours of. +</p> + +<p> +Lyell, Sir C., on the antiquity of man; on the origin of man; on the +parallelism of the development of species and languages; on the extinction of +languages; on the Inquisition; on the fossil remains of vertebrata; on the +fertility of mulattoes. +</p> + +<p> +Lynx, Canadian throat-ruff of the. +</p> + +<p> +Lyre-bird, assemblies of. +</p> + +<p> +Macacus, ears of; convoluted body in the extremity of the tail of; variability +of the tail in species of; whiskers of species of. +</p> + +<p> +Macacus brunneus. +</p> + +<p> +Macacus cynomolgus, superciliary ridge of; beard and whiskers of; becoming +white with age. +</p> + +<p> +Macacus ecaudatus. +</p> + +<p> +Macacus lasiotus, facial spots of. +</p> + +<p> +Macacus nemestrinus. +</p> + +<p> +Macacus radiatus. +</p> + +<p> +Macacus rhesus, sexual difference in the colour of. +</p> + +<p> +Macalister, Prof., on variations of the palmaris accessorius muscle; on +muscular abnormalities in man; on the greater variability of the muscles in men +than in women. +</p> + +<p> +Macaws, Mr. Buxton’s observations on. +</p> + +<p> +McCann, J., on mental individuality. +</p> + +<p> +McClelland, J., on the Indian Cyprinidae. +</p> + +<p> +Macculloch, Col., on an Indian village without any female children. +</p> + +<p> +Macculloch, Dr., on tertian ague in a dog. +</p> + +<p> +Macgillivray, W., on the vocal organs of birds; on the Egyptian goose; on the +habits of woodpeckers; on the habits of the snipe; on the whitethroat; on the +moulting of the snipes; on the moulting of the Anatidae; on the finding of new +mates by magpies; on the pairing of a blackbird and thrush; on pied ravens; on +the guillemots; on the colours of the tits; on the immature plumage of birds. +</p> + +<p> +Machetes, sexes and young of. +</p> + +<p> +Machetes pugnax, supposed to be polygamous; numerical proportion of the sexes +in; pugnacity of the male; double moult in. +</p> + +<p> +McIntosh, Dr., colours of the Nemertians. +</p> + +<p> +McKennan, marriage customs of Koraks. +</p> + +<p> +Mackintosh, on the moral sense. +</p> + +<p> +MacLachlan, R., on Apatania muliebris and Boreus hyemalis; on the anal +appendages of male insects; on the pairing of dragon-flies; on dragon-flies; on +dimorphism in Agrion; on the want of pugnacity in male dragon-flies; colour of +ghost-moth in the Shetland Islands. +</p> + +<p> +M’Lennan, Mr., on infanticide; on the origin of the belief in spiritual +agencies; on the prevalence of licentiousness among savages; on the primitive +barbarism of civilised nations; on traces of the custom of the forcible capture +of wives; on polyandry. +</p> + +<p> +Macnamara, Mr., susceptibility of Andaman islanders and Nepalese to change. +</p> + +<p> +M’Neill, Mr., on the use of the antlers of deer; on the Scotch deerhound; +on the long hairs on the throat of the stag; on the bellowing of stags. +</p> + +<p> +Macropus, courtship of. +</p> + +<p> +Macrorhinus proboscideus, structure of the nose of. +</p> + +<p> +Magpie, power of speech of; vocal organs of the; nuptial assemblies of; new +mates found by; stealing bright objects; young of the; coloration of the. +</p> + +<p> +Maillard, M., on the proportion of the sexes in a species of Papilio from +Bourbon. +</p> + +<p> +Maine, Sir Henry, on the absorption of one tribe by another; a desire for +improvement not general. +</p> + +<p> +Major, Dr. C. Forsyth, on fossil Italian apes; skull of Bos etruscus; tusks of +miocene pigs. +</p> + +<p> +Makalolo, perforation of the upper lip by the. +</p> + +<p> +Malar bone, abnormal division of, in man. +</p> + +<p> +Malay Archipelago, marriage-customs of the savages of the. +</p> + +<p> +Malays, line of separation between the Papuans and the; general beardlessness +of the; staining of the teeth among; aversion of some, to hairs on the face. +</p> + +<p> +Malays and Papuans, contrasted characters of. +</p> + +<p> +Male animals, struggles of, for the possession of the females; eagerness of, in +courtship; generally more modified than female; differ in the same way from +females and young. +</p> + +<p> +Male characters, developed in females; transfer of, to female birds. +</p> + +<p> +Male, sedentary, of a hymenopterous parasite. +</p> + +<p> +Malefactors. +</p> + +<p> +Males, presence of rudimentary female organs in. +</p> + +<p> +Males and females, comparative numbers of; comparative mortality of, while +young. +</p> + +<p> +Malherbe, on the woodpeckers. +</p> + +<p> +Mallotus Peronii. +</p> + +<p> +Mallotus villosus. +</p> + +<p> +Malthus, T., on the rate of increase of population. +</p> + +<p> +Maluridae, nidification of the. +</p> + +<p> +Malurus, young of. +</p> + +<p> +Mammae, rudimentary, in male mammals; supernumerary, in women; of male human +subject. +</p> + +<p> +Mammalia, Prof. Owen’s classification of; genealogy of the. +</p> + +<p> +Mammals, recent and tertiary, comparison of cranial capacity of; nipples of; +pursuit of female, by the males; secondary sexual characters of; weapons of; +relative size of the sexes of; parallelism of, with birds in secondary sexual +characters; voices of, used especially during the breeding season. +</p> + +<p> +Man, variability of; erroneously regarded as more domesticated than other +animals; migrations of; wide distribution of; causes of the nakedness of; +supposed physical inferiority of; a member of the Catarrhine group; early +progenitors of; transition from ape indefinite; numerical proportions of the +sexes in; difference between the sexes; proportion of sexes amongst the +illegitimate; different complexion of male and female negroes; secondary sexual +characters of; primeval condition of. +</p> + +<p> +Mandans, correlation of colour and texture of hair in the. +</p> + +<p> +Mandible, left, enlarged in the male of Taphroderes distortus. +</p> + +<p> +Mandibles, use of the, in Ammophila; large, of Corydalis cornutus; large, of +male Lucanus elaphus. +</p> + +<p> +Mandrill, number of caudal vertebrae in the; colours of the male. +</p> + +<p> +Mantegazza, Prof., on last molar teeth of man; bright colours in male animals; +on the ornaments of savages; on the beardlessness of the New Zealanders; on the +exaggeration of natural characters by man. +</p> + +<p> +Mantell, W., on the engrossment of pretty girls by the New Zealand chiefs. +</p> + +<p> +Mantis, pugnacity of species of. +</p> + +<p> +Maories, mortality of; infanticide and proportion of sexes; distaste for +hairiness amongst men. +</p> + +<p> +Marcus Aurelius, on the origin of the moral sense; on the influence of habitual +thoughts. +</p> + +<p> +Mareca penelope. +</p> + +<p> +Marks, retained throughout groups of birds. +</p> + +<p> +Marriage, restraints upon, among savages; influence of, upon morals; influence +of, on mortality; development of. +</p> + +<p> +Marriages, early; communal. +</p> + +<p> +Marshall, Dr. W., protuberances on birds’ heads; on the moulting of +birds; advantage to older birds of paradise. +</p> + +<p> +Marshall, Col., interbreeding amongst Todas; infanticide and proportion of +sexes with Todas; choice of husband amongst Todas. +</p> + +<p> +Marshall, Mr., on the brain of a Bushwoman. +</p> + +<p> +Marsupials, development of the nictitating membrane in; uterus of; possession +of nipples by; their origin from Monotremata; abdominal sacs of; relative size +of the sexes of; colours of. +</p> + +<p> +Marsupium, rudimentary in male marsupials. +</p> + +<p> +Martin, W.C.L., on alarm manifested by an orang at the sight of a turtle; on +the hair in Hylobates; on a female American deer; on the voice of Hylobates +agilis; on Semnopithecus nemaeus. +</p> + +<p> +Martin, on the beards of the inhabitants of St. Kilda. +</p> + +<p> +Martins deserting their young. +</p> + +<p> +Martins, C., on death caused by inflammation of the vermiform appendage. +</p> + +<p> +Mastoid processes in man and apes. +</p> + +<p> +Maudsley, Dr., on the influence of the sense of smell in man; on idiots +smelling their food; on Laura Bridgman; on the development of the vocal organs; +moral sense failing in incipient madness; change of mental faculties at puberty +in man. +</p> + +<p> +Mayers, W.F., on the domestication of the goldfish in China. +</p> + +<p> +Mayhew, E., on the affection between individuals of different sexes in the dog. +</p> + +<p> +Maynard, C.J., on the sexes of Chrysemys picta. +</p> + +<p> +Meckel, on correlated variation of the muscles of the arm and leg. +</p> + +<p> +Medicines, effect produced by, the same in man and in monkeys. +</p> + +<p> +Medusae, bright colours of some. +</p> + +<p> +Megalithic structures, prevalence of. +</p> + +<p> +Megapicus validus, sexual difference of colour in. +</p> + +<p> +Megasoma, large size of males of. +</p> + +<p> +Meigs, Dr. A., on variation in the skulls of the natives of America. +</p> + +<p> +Meinecke, on the numerical proportion of the sexes in butterflies. +</p> + +<p> +Melanesians, decrease of. +</p> + +<p> +Meldola, Mr., colours and marriage flight of Colias and Pieris. +</p> + +<p> +Meliphagidae, Australian, nidification of. +</p> + +<p> +Melita, secondary sexual characters of. +</p> + +<p> +Meloe, difference of colour in the sexes of a species of. +</p> + +<p> +Memnon, young. +</p> + +<p> +Memory, manifestations of, in animals. +</p> + +<p> +Mental characters, difference of, in different races of men. +</p> + +<p> +Mental faculties, diversity of, in the same race of men; inheritance of; +variation of, in the same species; similarity of the, in different races of +man; of birds. +</p> + +<p> +Mental powers, difference of, in the two sexes in man. +</p> + +<p> +Menura Alberti, song of. +</p> + +<p> +Menura superba, long tails of both sexes of. +</p> + +<p> +Merganser, trachea of the male. +</p> + +<p> +Merganser serrator, male plumage of. +</p> + +<p> +Mergus cucullatus, speculum of. +</p> + +<p> +Mergus merganser, young of. +</p> + +<p> +Metallura, splendid tail-feathers of. +</p> + +<p> +Methoca ichneumonides, large male of. +</p> + +<p> +Meves, M., on the drumming of the snipe. +</p> + +<p> +Mexicans, civilisation of the, not foreign. +</p> + +<p> +Meyer, on a convoluted body at the extremity of the tail in a Macacus and a +cat. +</p> + +<p> +Meyer, Dr. A., on the copulation of Phryganidae of distinct species. +</p> + +<p> +Meyer, Prof. L., on development of helix of ear; men’s ears more variable +than women’s; antennae serving as ears. +</p> + +<p> +Migrations of man, effects of. +</p> + +<p> +Migratory instinct of birds; vanquishing the maternal. +</p> + +<p> +Mill, J.S., on the origin of the moral sense; on the “greatest happiness +principle;” on the difference of the mental powers in the sexes of man. +</p> + +<p> +Millipedes. +</p> + +<p> +Milne-Edwards, H., on the use of enlarged chelae of the male Gelasimus. +</p> + +<p> +Milvago leucurus, sexes and young of. +</p> + +<p> +Mimicry. +</p> + +<p> +Mimus polyglottus. +</p> + +<p> +Mind, difference of, in man and the highest animals; similarity of the, in +different races. +</p> + +<p> +Minnow, proportion of the sexes in the. +</p> + +<p> +Mirror, behaviour of monkeys before. +</p> + +<p> +Mirrors, larks attracted by. +</p> + +<p> +Mitchell, Dr., interbreeding in the Hebrides. +</p> + +<p> +Mitford, selection of children in Sparta. +</p> + +<p> +Mivart, St. George, on the reduction of organs; on the ears of the lemuroidea; +on variability of the muscles in lemuroidea; on the caudal vertebrae of +monkeys; on the classification of the primates; on the orang and on man; on +differences in the lemuroidea; on the crest of the male newt. +</p> + +<p> +Mobius, Prof., on reasoning powers in a pike. +</p> + +<p> +Mocking-thrush, partial migration of; young of the. +</p> + +<p> +Modifications, unserviceable. +</p> + +<p> +Moggridge, J.T., on habits of spiders; on habits of ants. +</p> + +<p> +Moles, numerical proportion of the sexes in; battles of male. +</p> + +<p> +Mollienesia petenensis, sexual difference in. +</p> + +<p> +Mollusca, beautiful colours and shapes of; absence of secondary sexual +characters in the. +</p> + +<p> +Molluscoida. +</p> + +<p> +Monacanthus scopas and M. Peronii. +</p> + +<p> +Monboddo, Lord, on music. +</p> + +<p> +Mongolians, perfection of the senses in. +</p> + +<p> +Monkey, protecting his keeper from a baboon; bonnet-; rhesus-, sexual +difference in colour of the; moustache-, colours of the. +</p> + +<p> +Monkeys, liability of, to the same diseases as man; male, recognition of women +by; diversity of the mental faculties in; breaking hard fruits with stones; +hands of the; basal caudal vertebrae of, imbedded in the body; revenge taken +by; maternal affection in; variability of the faculty of attention in; +American, manifestation of reason in; using stones and sticks; imitative +faculties of; signal-cries of; mutual kindnesses of; sentinels posted by; human +characters of; American, direction of the hair on the arms of some; gradation +of species of; beards of; ornamental characters of; analogy of sexual +differences of, with those of man; different degrees of difference in the sexes +of; expression of emotions by; generally monogamous habits of; polygamous +habits of some; naked surfaces of; courtship of. +</p> + +<p> +Monogamy, not primitive. +</p> + +<p> +Monogenists. +</p> + +<p> +Mononychus pseudacori, stridulation of. +</p> + +<p> +Monotremata, development of the nictitating membrane in; lactiferous glands of; +connecting mammals with reptiles. +</p> + +<p> +Monstrosities, analogous, in man and lower animals; caused by arrest of +development; correlation of; transmission of. +</p> + +<p> +Montagu, G., on the habits of the black and red grouse; on the pugnacity of the +ruff; on the singing of birds; on the double moult of the male pintail. +</p> + +<p> +Monteiro, Mr., on Bucorax abyssinicus. +</p> + +<p> +Montes de Oca, M., on the pugnacity of male Humming-birds. +</p> + +<p> +Monticola cyanea. +</p> + +<p> +Monuments, as traces of extinct tribes. +</p> + +<p> +Moose, battles of; horns of the, an incumbrance. +</p> + +<p> +Moral and instinctive impulses, alliance of. +</p> + +<p> +Moral faculties, their influence on natural selection in man. +</p> + +<p> +Moral rules, distinction between the higher and lower. +</p> + +<p> +Moral sense, so-called, derived from the social instincts; origin of the. +</p> + +<p> +Moral tendencies, inheritance of. +</p> + +<p> +Morality, supposed to be founded in selfishness; test of, the general welfare +of the community; gradual rise of; influence of a high standard of. +</p> + +<p> +Morgan, L.H., on the beaver; on the reasoning powers of the beaver; on the +forcible capture of wives; on the castoreum of the beaver; marriage unknown in +primeval times; on polyandry. +</p> + +<p> +Morley, J., on the appreciation of praise and fear of blame. +</p> + +<p> +Morris, F.O., on hawks feeding an orphan nestling. +</p> + +<p> +Morse, Dr., colours of mollusca. +</p> + +<p> +Morselli, E., division of the malar bone. +</p> + +<p> +Mortality, comparative, of female and male. +</p> + +<p> +Morton on the number of species of man. +</p> + +<p> +Moschkau, Dr. A., on a speaking starling. +</p> + +<p> +Moschus moschiferus, odoriferous organs of. +</p> + +<p> +Motacillae, Indian, young of. +</p> + +<p> +Moth, odoriferous. +</p> + +<p> +Moths, absence of mouth in some males; apterous female; male, prehensile use of +the tarsi by; male, attracted by females; sound produced by; coloration of; +sexual differences of colour in. +</p> + +<p> +Motmot, inheritance of mutilation of tail feathers; racket-shaped feathers in +the tail of a. +</p> + +<p> +Moult, double; double annual, in birds. +</p> + +<p> +Moulting of birds. +</p> + +<p> +Moults, partial. +</p> + +<p> +Mouse, song of. +</p> + +<p> +Moustache-monkey, colours of the. +</p> + +<p> +Moustaches, in monkeys. +</p> + +<p> +Mud-turtle, long claws of the male. +</p> + +<p> +Mulattoes, persistent fertility of; immunity of, from yellow fever. +</p> + +<p> +Mule, sterility and strong vitality of the. +</p> + +<p> +Mules, rational. +</p> + +<p> +Muller, Ferd., on the Mexicans and Peruvians. +</p> + +<p> +Muller, Fritz, on astomatous males of Tanais; on the disappearance of spots and +stripes in adult mammals; on the proportions of the sexes in some Crustacea; on +secondary sexual characters in various Crustaceans; musical contest between +male Cicadae; mode of holding wings in Castina; on birds shewing a preference +for certain colours; on the sexual maturity of young amphipod Crustacea. +</p> + +<p> +Muller, Hermann, emergence of bees, from pupa; pollen-gathering of bees; +proportion of sexes in bees; courting of Eristalis; colour and sexual selection +with bees. +</p> + +<p> +Muller, J., on the nictitating membrane and semilunar fold. +</p> + +<p> +Muller, Max, on the origin of language; language implies power of general +conception; struggle for life among the words, etc., of languages. +</p> + +<p> +Muller, S., on the banteng; on the colours of Semnopithecus chrysomelas. +</p> + +<p> +Muntjac-deer, weapons of the. +</p> + +<p> +Murie, J., on the reduction of organs; on the ears of the Lemuroidea; on +variability of the muscles in the Lemuroidea; basal caudal vertebrae of Macacus +brunneus imbedded in the body; on the manner of sitting in short-tailed apes; +on differences in the Lemuroidea; on the throat-pouch of the male bustard; on +the mane of Otaria jubata; on the sub-orbital pits of Ruminants; on the colours +of the sexes in Otaria nigrescens. +</p> + +<p> +Murray, A., on the Pediculi of different races of men. +</p> + +<p> +Murray, T.A., on the fertility of Australian women with white men. +</p> + +<p> +Mus coninga. +</p> + +<p> +Mus minutus, sexual difference in the colour of. +</p> + +<p> +Musca vomitoria. +</p> + +<p> +Muscicapa grisola. +</p> + +<p> +Muscicapa luctuosa. +</p> + +<p> +Muscicapa ruticilla, breeding in immature plumage. +</p> + +<p> +Muscle, ischio-pubic. +</p> + +<p> +Muscles, rudimentary, occurrence of, in man; variability of the; effects of use +and disuse upon; animal-like abnormalities of, in man; correlated variation of, +in the arm and leg; variability of, in the hands and feet; of the jaws, +influence of, on the physiognomy of the Apes; habitual spasms of, causing +modifications of the facial bones, of the early progenitors of man; greater +variability of the, in men than in women. +</p> + +<p> +Musculus sternalis, Prof. Turner on the. +</p> + +<p> +Music, of birds; discordant, love of savages for; reason of power of perception +of notes in animals; power of distinguishing notes; its connection with +primeval speech; different appreciation of, by different peoples; origin of; +effects of. +</p> + +<p> +Musical cadences, perception of, by animals; powers of man. +</p> + +<p> +Musk-deer, canine teeth of male; male, odoriferous organs of the; winter change +of the. +</p> + +<p> +Musk-duck, Australian; large size of male; of Guiana, pugnacity of the male. +</p> + +<p> +Musk-ox, horns of. +</p> + +<p> +Musk-rat, protective resemblance of the, to a clod of earth. +</p> + +<p> +Musophagae, colours and nidification of the; both sexes of, equally brilliant. +</p> + +<p> +Mussels opened by monkeys. +</p> + +<p> +Mustela, winter change of two species of. +</p> + +<p> +Musters, Captain, on Rhea Darwinii; marriages amongst Patagonians. +</p> + +<p> +Mutilations, healing of; inheritance of. +</p> + +<p> +Mutilla europaea, stridulation of. +</p> + +<p> +Mutillidae, absence of ocelli in female. +</p> + +<p> +Mycetes caraya, polygamous; vocal organs of; beard of; sexual differences of +colour in; voice of. +</p> + +<p> +Mycetes seniculus, sexual differences of colour in. +</p> + +<p> +Myriapoda. +</p> + +<p> +Nageli, on the influence of natural selection on plants; on the gradation of +species of plants. +</p> + +<p> +Nails, coloured yellow or purple in part of Africa. +</p> + +<p> +Narwhal, tusks of the. +</p> + +<p> +Nasal cavities, large size of, in American aborigines. +</p> + +<p> +Nascent organs. +</p> + +<p> +Nathusius, H. von, on the improved breeds of pigs; male domesticated animals +more variable than females; horns of castrated sheep; on the breeding of +domestic animals. +</p> + +<p> +Natural selection, its effects on the early progenitors of man; influence of, +on man; limitation of the principle; influence of, on social animals; Mr. +Wallace on the limitation of, by the influence of the mental faculties in man; +influence of, in the progress of the United States; in relation to sex. +</p> + +<p> +Natural and sexual selection contrasted. +</p> + +<p> +Naulette, jaw from, large size of the canines in. +</p> + +<p> +Neanderthal skull, capacity of the. +</p> + +<p> +Neck, proportion of, in soldiers and sailors. +</p> + +<p> +Necrophorus, stridulation of. +</p> + +<p> +Nectarinia, young of. +</p> + +<p> +Nectariniae, moulting of the; nidification of. +</p> + +<p> +Negro, resemblance of a, to Europeans in mental characters. +</p> + +<p> +Negro-women, their kindness to Mungo Park. +</p> + +<p> +Negroes, Caucasian features in; character of; lice of; fertility of, when +crossed with other races; blackness of; variability of; immunity of, from +yellow fever; difference of, from Americans; disfigurements of the; colour of +new-born children of; comparative beardlessness of; readily become musicians; +appreciation of beauty of their women by; idea of beauty among; compression of +the nose by some. +</p> + +<p> +Nemertians, colours of. +</p> + +<p> +Neolithic period. +</p> + +<p> +Neomorpha, sexual difference of the beak in. +</p> + +<p> +Nephila, size of male. +</p> + +<p> +Nests, made by fishes; decoration of, by Humming-birds. +</p> + +<p> +Neumeister, on a change of colour in pigeons after several moultings. +</p> + +<p> +Neuration, difference of, in the two sexes of some butterflies and hymenoptera. +</p> + +<p> +Neuroptera. +</p> + +<p> +Neurothemis, dimorphism in. +</p> + +<p> +New Zealand, expectation by the natives of, of their extinction; practice of +tattooing in; aversion of natives of, to hairs on the face; pretty girls +engrossed by the chiefs in. +</p> + +<p> +Newton, A., on the throat-pouch of the male bustard; on the differences between +the females of two species of Oxynotus; on the habits of the Phalarope, +dotterel, and godwit. +</p> + +<p> +Newts. +</p> + +<p> +Nicholson, Dr., on the non-immunity of dark Europeans from yellow fever. +</p> + +<p> +Nictitating membrane. +</p> + +<p> +Nidification of fishes; relation of, to colour; of British birds. +</p> + +<p> +Night-heron, cries of the. +</p> + +<p> +Nightingale, arrival of the male before the female; object of the song of the. +</p> + +<p> +Nightingales, new mates found by. +</p> + +<p> +Nightjar, selection of a mate by the female; Australian, sexes of; coloration +of the. +</p> + +<p> +Nightjars, noise made by some male, with their wings; elongated feathers in. +</p> + +<p> +Nilghau, sexual differences of colour in the. +</p> + +<p> +Nilsson, Prof., on the resemblance of stone arrow-heads from various places; on +the development of the horns of the reindeer. +</p> + +<p> +Nipples, absence of, in Monotremata. +</p> + +<p> +Nitsche, Dr., ear of foetal orang. +</p> + +<p> +Nitzsch, C.L., on the down of birds. +</p> + +<p> +Noctuae, brightly-coloured beneath. +</p> + +<p> +Noctuidae, coloration of. +</p> + +<p> +Nomadic habits, unfavourable to human progress. +</p> + +<p> +Nordmann, A., on Tetrao urogalloides. +</p> + +<p> +Norfolk Island, half-breeds on. +</p> + +<p> +Norway, numerical proportion of male and female births in. +</p> + +<p> +Nose, resemblance of, in man and the apes; piercing and ornamentation of the; +very flat, not admired in negroes; flattening of the. +</p> + +<p> +Nott and Gliddon, on the features of Rameses II.; on the features of Amunoph +III.; on skulls from Brazilian caves; on the immunity of negroes and mulattoes +from yellow fever; on the deformation of the skull among American tribes. +</p> + +<p> +Novara, voyage of the, suicide in New Zealand. +</p> + +<p> +Nudibranch Mollusca, bright colours of. +</p> + +<p> +Numerals, Roman. +</p> + +<p> +Nunemaya, natives of, bearded. +</p> + +<p> +Nuthatch, of Japan, intelligence of; Indian. +</p> + +<p> +Obedience, value of. +</p> + +<p> +Observation, powers of, possessed by birds. +</p> + +<p> +Occupations, sometimes a cause of diminished stature; effect of, upon the +proportions of the body. +</p> + +<p> +Ocelli, absence of, in female Mutilidae. +</p> + +<p> +Ocelli of birds, formation and variability of the. +</p> + +<p> +Ocelot, sexual differences in the colouring of the. +</p> + +<p> +Ocyhaps lophotes. +</p> + +<p> +Odonata. +</p> + +<p> +Odonestis potatoria, sexual difference of colour in. +</p> + +<p> +Odour, correlation of, with colour of skin; of moths; emitted by snakes in the +breeding season; of mammals. +</p> + +<p> +Oecanthus nivalis, difference of colour in the sexes of. +</p> + +<p> +Oecanthus pellucidus. +</p> + +<p> +Ogle, Dr. W., relation between colour and power of smell. +</p> + +<p> +Oidemia. +</p> + +<p> +Oliver, on sounds produced by Pimelia striata. +</p> + +<p> +Omaloplia brunnea, stridulation of. +</p> + +<p> +Onitis furcifer, processes of anterior femora of the male, and on the head and +thorax of the female. +</p> + +<p> +Onthophagus. +</p> + +<p> +Onthophagus rangifer, sexual differences of; variations in the horns of the +male. +</p> + +<p> +Ophidia, sexual differences of. +</p> + +<p> +Ophidium. +</p> + +<p> +Opossum, wide range of, in America. +</p> + +<p> +Optic nerve, atrophy of the, caused by destruction of the eye. +</p> + +<p> +Orang-Outan, Bischoff on the agreement of the brain of the, with that of man; +adult age of the; ears of the; vermiform appendage of; hands of the; absence of +mastoid processes in the; platforms built by the; alarmed at the sight of a +turtle; using a stick as a lever; using missiles; using the leaves of the +Pandanus as a night covering; direction of the hair on the arms of the; its +aberrant characters; supposed evolution of the; voice of the; monogamous habits +of the; male, beard of the. +</p> + +<p> +Oranges, treatment of, by monkeys. +</p> + +<p> +Orange-tip butterfly. +</p> + +<p> +Orchestia Darwinii, dimorphism of males of. +</p> + +<p> +Orchestia Tucuratinga, limbs of. +</p> + +<p> +Ordeal, trial by. +</p> + +<p> +Oreas canna, colours of. +</p> + +<p> +Oreas Derbianus, colours of. +</p> + +<p> +Organs, prehensile; utilised for new purposes. +</p> + +<p> +Organic scale, von Baer’s definition of progress in. +</p> + +<p> +Orioles, nidification of. +</p> + +<p> +Oriolus, species of, breeding in immature plumage. +</p> + +<p> +Oriolus melanocephalus, coloration of the sexes in. +</p> + +<p> +Ornaments, prevalence of similar; of male birds; fondness of savages for. +</p> + +<p> +Ornamental characters, equal transmission of, to both sexes, in mammals; of +monkeys. +</p> + +<p> +Ornithoptera croesus. +</p> + +<p> +Ornithorhynchus, reptilian tendency of; spur of the male. +</p> + +<p> +Orocetes erythrogastra, young of. +</p> + +<p> +Orrony, Grotto of. +</p> + +<p> +Orsodacna atra, difference of colour in the sexes of. +</p> + +<p> +Orsodacna ruficollis. +</p> + +<p> +Orthoptera, metamorphosis of; stridulating apparatus of; colours of; +rudimentary stridulating organs in female; stridulation of the, and Homoptera, +discussed. +</p> + +<p> +Ortygornis gularis, pugnacity of the male. +</p> + +<p> +Oryctes, stridulation of; sexual differences in the stridulant organs of. +</p> + +<p> +Oryx leucoryx, use of the horns of. +</p> + +<p> +Osphranter rufus, sexual difference in the colour of. +</p> + +<p> +Ostrich, African, sexes and incubation of the. +</p> + +<p> +Ostriches, stripes of young. +</p> + +<p> +Otaria jubata, mane of the male. +</p> + +<p> +Otaria nigrescens, difference in the coloration of the sexes of. +</p> + +<p> +Otis bengalensis, love-antics of the male. +</p> + +<p> +Otis tarda, throat-pouch of the male; polygamous. +</p> + +<p> +Ouzel, ring-, colours and nidification of the. +</p> + +<p> +Ouzel, water-, singing in the autumn; colours and nidification of the. +</p> + +<p> +Ovibos moschatus, horns of. +</p> + +<p> +Ovipositor of insects. +</p> + +<p> +Ovis cycloceros, mode of fighting of. +</p> + +<p> +Ovule of man. +</p> + +<p> +Owen, Prof., on the Corpora Wolffiana; on the great toe in man; on the +nictitating membrane and semilunar fold; on the development of the posterior +molars in different races of man; on the length of the caecum in the Koala; on +the coccygeal vertebrae; on rudimentary structures belonging to the +reproductive system; on abnormal conditions of the human uterus; on the number +of digits in the Ichthyopterygia; on the canine teeth in man; on the walking of +the chimpanzee and orang; on the mastoid processes in the higher apes; on the +hairiness of elephants in elevated districts; on the caudal vertebrae of +monkeys; classification of mammalia; on the hair in monkeys; on the piscine +affinities of the Ichthyosaurians; on polygamy and monogamy among the +antelopes; on the horns of Antilocapra Americana; on the musky odour of +crocodiles during the breeding season; on the scent-glands of snakes; on the +Dugong, Cachalot, and Ornithorhynchus; on the antlers of the red deer; on the +dentition of the Camelidae; on the horns of the Irish elk; on the voice of the +giraffe, porcupine, and stag; on the laryngeal sac of the gorilla and orang; on +the odoriferous glands of mammals; on the effects of emasculation on the vocal +organs of men; on the voice of Hylobates agilis; on American monogamous +monkeys. +</p> + +<p> +Owls, white, new mates found by. +</p> + +<p> +Oxynotus, difference of the females of two species of. +</p> + +<p> +Pachydermata. +</p> + +<p> +Pachytylus migratorius. +</p> + +<p> +Paget, on the abnormal development of hairs in man; on the thickness of the +skin on the soles of the feet of infants. +</p> + +<p> +Pagurus, carrying the female. +</p> + +<p> +Painting, pleasure of savages in. +</p> + +<p> +Palaemon, chelae of a species of. +</p> + +<p> +Palaeornis, sexual differences of colour in. +</p> + +<p> +Palaeornis javanicus, colour of beak of. +</p> + +<p> +Palaeornis rosa, young of. +</p> + +<p> +Palamedea cornuta, spurs on the wings. +</p> + +<p> +Paleolithic period. +</p> + +<p> +Palestine, habits of the chaffinch in. +</p> + +<p> +Pallas, on the perfection of the senses in the Mongolians; on the want of +connexion between climate and the colour of the skin; on the polygamous habits +of Antilope Saiga; on the lighter colour of horses and cattle in winter in +Siberia; on the tusks of the musk-deer; on the odoriferous glands of mammals; +on the odoriferous glands of the musk-deer; on winter changes of colour in +mammals; on the ideal of female beauty in North China. +</p> + +<p> +Palmaris accessorius, muscle variations of the. +</p> + +<p> +Pampas, horses of the. +</p> + +<p> +Pangenesis, hypothesis of. +</p> + +<p> +Panniculus carnosus. +</p> + +<p> +Pansch, on the brain of a foetal Cebus apella. +</p> + +<p> +Papilio, proportion of the sexes in North American species of; sexual +differences of colouring in species of; coloration of the wings in species of. +</p> + +<p> +Papilio ascanius. +</p> + +<p> +Papilio Sesostris and Childrenae, variability of. +</p> + +<p> +Papilio Turnus. +</p> + +<p> +Papilionidae, variability in the. +</p> + +<p> +Papuans, line of separation between the, and the Malays; beards of the; teeth +of. +</p> + +<p> +Papuans and Malays, contrast in characters of. +</p> + +<p> +Paradise, Birds of; supposed by Lesson to be polygamous; rattling of their +quills by; racket-shaped feathers in; sexual differences in colour of; +decomposed feathers in; display of plumage by the male; sexual differences in +colour of. +</p> + +<p> +Paradisea apoda, barbless feathers in the tail of; plumage of; and P. papuana; +divergence of the females of; increase of beauty with age. +</p> + +<p> +Paradisea papuana, plumage of. +</p> + +<p> +Paraguay, Indians of, eradication of eyebrows and eyelashes by. +</p> + +<p> +Parallelism of development of species and languages. +</p> + +<p> +Parasites, on man and animals; as evidence of specific identity or +distinctness; immunity from, correlated with colour. +</p> + +<p> +Parental feeling in earwigs, starfishes, and spiders; affection, partly a +result of natural selection. +</p> + +<p> +Parents, age of, influence upon sex of offspring. +</p> + +<p> +Parinae, sexual difference of colour in. +</p> + +<p> +Park, Mungo, negro-women teaching their children to love the truth; his +treatment by the negro-women; on negro opinions of the appearance of white men. +</p> + +<p> +Parker, Mr., no bird or reptile in line of mammalian descent. +</p> + +<p> +Parrakeet, young of; Australian, variation in the colour of the thighs of a +male. +</p> + +<p> +Parrot, racket-shaped feathers in the tail of a; instance of benevolence in a. +</p> + +<p> +Parrots, change of colour in; imitative faculties of; living in triplets; +affection of; colours and nidification of the; immature plumage of the; colours +of; sexual differences of colour in; musical powers of. +</p> + +<p> +Parthenogenesis in the Tenthredinae; in Cynipidae; in Crustacea. +</p> + +<p> +Partridge, monogamous; proportion of the sexes in the; Indian; female. +</p> + +<p> +Partridge-“dances.” +</p> + +<p> +Partridges, living in triplets; spring coveys of male; distinguishing persons. +</p> + +<p> +Parus coeruleus. +</p> + +<p> +Passer, sexes and young of. +</p> + +<p> +Passer brachydactylus. +</p> + +<p> +Passer domesticus. +</p> + +<p> +Passer montanus. +</p> + +<p> +Patagonians, self-sacrifice by; marriages of. +</p> + +<p> +Patterson, Mr., on the Agrionidae. +</p> + +<p> +Patteson, Bishop, decrease of Melanesians. +</p> + +<p> +Paulistas of Brazil. +</p> + +<p> +Pavo cristatus. +</p> + +<p> +Pavo muticus, possession of spurs by the female. +</p> + +<p> +Pavo nigripennis. +</p> + +<p> +Payaguas Indians, thin legs and thick arms of the. +</p> + +<p> +Payan, Mr., on the proportion of the sexes in sheep. +</p> + +<p> +Peacock, polygamous; sexual characters of; pugnacity of the; Javan, possessing +spurs; rattling of the quills by; elongated tail-coverts of the; love of +display of the; ocellated spots of the; inconvenience of long tail of the, to +the female; continued increase of beauty of the. +</p> + +<p> +Peacock-butterfly. +</p> + +<p> +Peafowl, preference of females for a particular male; first advances made by +the female. +</p> + +<p> +Pediculi of domestic animals and man. +</p> + +<p> +Pedigree of man. +</p> + +<p> +Pedionomus torquatus, sexes of. +</p> + +<p> +Peel, J., on horned sheep. +</p> + +<p> +Peewit, wing-tubercles of the male. +</p> + +<p> +Pelagic animals, transparency of. +</p> + +<p> +Pelecanus erythrorhynchus, horny crest on the beak of the male, during the +breeding season. +</p> + +<p> +Pelecanus onocrotalus, spring plumage of. +</p> + +<p> +Pelele, an African ornament. +</p> + +<p> +Pelican, blind, fed by his companions; young, guided by old birds; pugnacity of +the male. +</p> + +<p> +Pelicans, fishing in concert. +</p> + +<p> +Pelobius Hermanni, stridulation of. +</p> + +<p> +Pelvis, alteration of, to suit the erect attitude of man; differences of the, +in the sexes of man. +</p> + +<p> +Penelope nigra, sound produced by the male. +</p> + +<p> +Pennant, on the battles of seals; on the bladder-nose seal. +</p> + +<p> +Penthe, antennal cushions of the male. +</p> + +<p> +Perch, brightness of male, during breeding season. +</p> + +<p> +Peregrine falcon, new mate found by. +</p> + +<p> +Period of variability, relation of, to sexual selection. +</p> + +<p> +Periodicity, vital, Dr. Laycock on. +</p> + +<p> +Periods, lunar, followed by functions in man and animals. +</p> + +<p> +Periods of life, inheritance at corresponding. +</p> + +<p> +Perisoreus canadensis, young of. +</p> + +<p> +Peritrichia, difference of colour in the sexes of a species of. +</p> + +<p> +Periwinkle. +</p> + +<p> +Pernis cristata. +</p> + +<p> +Perrier, M., on sexual selection; on bees. +</p> + +<p> +Perseverance, a characteristic of man. +</p> + +<p> +Persians, said to be improved by intermixture with Georgians and Circassians. +</p> + +<p> +Personnat, M., on Bombyx Yamamai. +</p> + +<p> +Peruvians, civilisation of the, not foreign. +</p> + +<p> +Petrels, colours of. +</p> + +<p> +Petrocincla cyanea, young of. +</p> + +<p> +Petrocossyphus. +</p> + +<p> +Petronia. +</p> + +<p> +Pfeiffer, Ida, on Javan ideas of beauty. +</p> + +<p> +Phacochoerus aethiopicus, tusks and pads of. +</p> + +<p> +Phalanger, Vulpine, black varieties of the. +</p> + +<p> +Phalaropus fulicarius. +</p> + +<p> +Phalaropus hyperboreus. +</p> + +<p> +Phanaeus. +</p> + +<p> +Phanaeus carnifex, variation of the horns of the male. +</p> + +<p> +Phanaeus faunus, sexual differences of. +</p> + +<p> +Phanaeus lancifer. +</p> + +<p> +Phaseolarctus cinereus, taste for rum and tobacco. +</p> + +<p> +Phasgonura viridissima, stridulation of. +</p> + +<p> +Phasianus Soemmerringii. +</p> + +<p> +Phasianus versicolor. +</p> + +<p> +Phasianus Wallichii. +</p> + +<p> +Pheasant, polygamous; and black grouse, hybrids of; production of hybrids with +the common fowl; immature plumage of the. +</p> + +<p> +Pheasant, Amherst, display of. +</p> + +<p> +Pheasant, Argus, display of plumage by the male; ocellated spots of the; +gradation of characters in the. +</p> + +<p> +Pheasant, Blood- Pheasant, Cheer. +</p> + +<p> +Pheasant, Eared, length of the tail in the; sexes alike in the. +</p> + +<p> +Pheasant, Fire-backed, possessing spurs. +</p> + +<p> +Pheasant, Golden, display of plumage by the male; age of mature plumage in the; +sex of young, ascertained by pulling out head-feathers. +</p> + +<p> +Pheasant, Kalij, drumming of the male. +</p> + +<p> +Pheasant, Reeve’s, length of the tail in. +</p> + +<p> +Pheasant, Silver, triumphant male, deposed on account of spoiled plumage; +sexual coloration of the. +</p> + +<p> +Pheasant, Soemmerring’s. +</p> + +<p> +Pheasant, Tragopan, display of plumage by the male; marking of the sexes of +the. +</p> + +<p> +Pheasants, period of acquisition of male characters in the family of the; +proportion of sexes in chicks of; length of the tail in. +</p> + +<p> +Philters, worn by women. +</p> + +<p> +Phoca groenlandica, sexual difference in the coloration of. +</p> + +<p> +Phoenicura ruticilla. +</p> + +<p> +Phosphorescence of insects. +</p> + +<p> +Phryganidae, copulation of distinct species of. +</p> + +<p> +Phryniscus nigricans. +</p> + +<p> +Physical inferiority, supposed, of man. +</p> + +<p> +Pickering, on the number of species of man. +</p> + +<p> +Picton, J.A., on the soul of man. +</p> + +<p> +Picus auratus. +</p> + +<p> +Picus major. +</p> + +<p> +Pieris. +</p> + +<p> +Pigeon, female, deserting a weakened mate; carrier, late development of the +wattle in; pouter, late development of crop in; domestic, breeds and sub-breeds +of. +</p> + +<p> +Pigeons, nestling, fed by the secretion of the crop of both parents; +</p> + +<p> +changes of plumage in; transmission of sexual peculiarities in; Belgian, with +black-streaked males; changing colour after several moultings; numerical +proportion of the sexes in; cooing of; variations in plumage of; display of +plumage by male; local memory of; antipathy of female, to certain males; +pairing of; profligate male and female; wing-bars and tail-feathers of; +supposititious breed of; pouter and carrier, peculiarities of, predominant in +males; nidification of; Australian; immature plumage of the. +</p> + +<p> +Pigs, origin of the improved breeds of; numerical proportion of the sexes in; +stripes of young; tusks of miocene; sexual preference shewn by. +</p> + +<p> +Pike, American, brilliant colours of the male, during the breeding season. +</p> + +<p> +Pike, reasoning powers of; male, devoured by females. +</p> + +<p> +Pike, L.O., on the psychical elements of religion. +</p> + +<p> +Pimelia striata, sounds produced by the female. +</p> + +<p> +Pinel, hairiness in idiots. +</p> + +<p> +Pintail, drake, plumage of; pairing with a wild duck. +</p> + +<p> +Pintail Duck, pairing with a widgeon. +</p> + +<p> +Pipe-fish, filamentous; marsupial receptacles of the male. +</p> + +<p> +Pipits, moulting of the. +</p> + +<p> +Pipra, modified secondary wing-feathers of male. +</p> + +<p> +Pipra deliciosa. +</p> + +<p> +Pirates stridulus, stridulation of. +</p> + +<p> +Pitcairn island, half-breeds on. +</p> + +<p> +Pithecia leucocephala, sexual differences of colour in. +</p> + +<p> +Pithecia Satanas, beard of; resemblance of, to a negro. +</p> + +<p> +Pits, suborbital, of Ruminants. +</p> + +<p> +Pittidae, nidification of. +</p> + +<p> +Placentata. +</p> + +<p> +Plagiostomous fishes. +</p> + +<p> +Plain-wanderer, Australian. +</p> + +<p> +Planariae, bright colours of some. +</p> + +<p> +Plantain-eaters, colours and nidification of the; both sexes of, equally +brilliant. +</p> + +<p> +Plants, cultivated, more fertile than wild; Nageli, on natural selection in; +male flowers of, mature before the female; phenomena of fertilisation in. +</p> + +<p> +Platalea, change of plumage in. +</p> + +<p> +Platyblemus. +</p> + +<p> +Platycercus, young of. +</p> + +<p> +Platyphyllum concavum. +</p> + +<p> +Platyrrhine monkeys. +</p> + +<p> +Platysma myoides. +</p> + +<p> +Plecostomus, head-tentacles of the males of a species of. +</p> + +<p> +Plecostomus barbatus, peculiar beard of the male. +</p> + +<p> +Plectropterus gambensis, spurred wings of. +</p> + +<p> +Ploceus. +</p> + +<p> +Plovers, wing-spurs of; double moult in. +</p> + +<p> +Plumage, changes of, inheritance of, by fowls; tendency to analogous variation +in; display of, by male birds; changes of, in relation to season; immature, of +birds; colour of, in relation to protection. +</p> + +<p> +Plumes on the head in birds, difference of, in the sexes. +</p> + +<p> +Pneumora, structure of. +</p> + +<p> +Podica, sexual difference in the colour of the irides. +</p> + +<p> +Poeppig, on the contact of civilised and savage races. +</p> + +<p> +Poison, avoidance of, by animals. +</p> + +<p> +Poisonous fruits and herbs avoided by animals. +</p> + +<p> +Poisons, immunity from, correlated with colour. +</p> + +<p> +Polish fowls, origin of the crest in. +</p> + +<p> +Pollen and van Dam, on the colours of Lemur macaco. +</p> + +<p> +Polyandry, in certain Cyprinidae; among the Elateridae. +</p> + +<p> +Polydactylism in man. +</p> + +<p> +Polygamy, influence of, upon sexual selection; superinduced by domestication; +supposed increase of female births by. In the stickleback. +</p> + +<p> +Polygenists. +</p> + +<p> +Polynesia, prevalence of infanticide in. +</p> + +<p> +Polynesians, wide geographical range of; difference of stature among the; +crosses of; variability of; heterogeneity of the; aversion of, to hairs on the +face. +</p> + +<p> +Polyplectron, number of spurs in; display of plumage by the male; gradation of +characters in; female of. +</p> + +<p> +Polyplectron chinquis. +</p> + +<p> +Polyplectron Hardwickii. +</p> + +<p> +Polyplectron malaccense. +</p> + +<p> +Polyplectron Napoleonis. +</p> + +<p> +Polyzoa. +</p> + +<p> +Pomotis. +</p> + +<p> +Pontoporeia affinis. +</p> + +<p> +Porcupine, mute, except in the rutting season. +</p> + +<p> +Pores, excretory, numerical relation of, to the hairs in sheep. +</p> + +<p> +Porpitae, bright colours of some. +</p> + +<p> +Portax picta, dorsal crest and throat-tuft of; sexual differences of colour in. +</p> + +<p> +Portunus puber, pugnacity of. +</p> + +<p> +Potamochoerus pencillatus, tusks and facial knobs of the. +</p> + +<p> +Pouchet, G., the relation of instinct to intelligence; on the instincts of +ants; on the caves of Abou-Simbel; on the immunity of negroes from yellow +fever; change of colour in fishes. +</p> + +<p> +Pouter pigeon, late development of the large crop in. +</p> + +<p> +Powell, Dr., on stridulation. +</p> + +<p> +Power, Dr., on the different colours of the sexes in a species of Squilla. +</p> + +<p> +Powys, Mr., on the habits of the chaffinch in Corfu. +</p> + +<p> +Pre-eminence of man. +</p> + +<p> +Preference for males by female birds; shewn by mammals, in pairing. +</p> + +<p> +Prehensile organs. +</p> + +<p> +Presbytis entellus, fighting of the male. +</p> + +<p> +Preyer, Dr., on function of shell of ear; on supernumerary mammae in women. +</p> + +<p> +Prichard, on the difference of stature among the Polynesians; on the connection +between the breadth of the skull in the Mongolians and the perfection of their +senses; on the capacity of British skulls of different ages; on the flattened +heads of the Colombian savages; on Siamese notions of beauty; on the +beardlessness of the Siamese; on the deformation of the head among American +tribes and the natives of Arakhan. +</p> + +<p> +Primary sexual organs. +</p> + +<p> +Primates, sexual differences of colour in. +</p> + +<p> +Primogeniture, evils of. +</p> + +<p> +Prionidae, difference of the sexes in colour. +</p> + +<p> +Proctotretus multimaculatus. +</p> + +<p> +Proctotretus tenuis, sexual difference in the colour of. +</p> + +<p> +Profligacy. +</p> + +<p> +Progenitors, early, of man. +</p> + +<p> +Progress, not the normal rule in human society; elements of. +</p> + +<p> +Prong-horn antelope, horns of. +</p> + +<p> +Proportions, difference of, in distinct races. +</p> + +<p> +Protective colouring in butterflies; in lizards; in birds; in mammals. +</p> + +<p> +Protective nature of the dull colouring of female Lepidoptera. +</p> + +<p> +Protective resemblances in fishes. +</p> + +<p> +Protozoa, absence of secondary sexual characters in. +</p> + +<p> +Pruner-Bey, on the occurrence of the supra-condyloid foramen in the humerus of +man; on the colour of negro infants. +</p> + +<p> +Prussia, numerical proportion of male and female births in. +</p> + +<p> +Psocus, proportions of the sexes in. +</p> + +<p> +Ptarmigan, monogamous; summer and winter plumage of the; nuptial assemblages +of; triple moult of the; protective coloration of. +</p> + +<p> +Puff-birds, colours and nidification of the. +</p> + +<p> +Pugnacity of fine-plumaged male birds. +</p> + +<p> +Pumas, stripes of young. +</p> + +<p> +Puppies learning from cats to clean their faces. +</p> + +<p> +Pycnonotus haemorrhous, pugnacity of the male; display of under-tail coverts by +the male. +</p> + +<p> +Pyranga aestiva, male aiding in incubation; male characters in female of. +</p> + +<p> +Pyrodes, difference of the sexes in colour. +</p> + +<p> +Quadrumana, hands of; differences between man and the; sexual differences of +colour in; ornamental characters of; analogy of sexual differences of, with +those of man; fighting of males for the females; monogamous habits of; beards +of the. +</p> + +<p> +Quain, R., on the variation of the muscles in man. +</p> + +<p> +Quatrefages, A. de, on the occurrence of a rudimentary tail in man; on +variability; on the moral sense as a distinction between man and animals; +civilised men stronger than savages; on the fertility of Australian women with +white men; on the Paulistas of Brazil; on the evolution of the breeds of +cattle; on the Jews; on the liability of negroes to tropical fevers after +residence in a cold climate; on the difference between field-and house-slaves; +on the influence of climate on colour; colours of annelids; on the Ainos; on +the women of San Giuliano. +</p> + +<p> +Quechua, see Quichua. +</p> + +<p> +Querquedula acuta. +</p> + +<p> +Quetelet, proportion of sexes in man; relative size in man and woman. +</p> + +<p> +Quichua Indians; local variation of colour in the; no grey hair among the; +hairlessness of the; long hair of the. +</p> + +<p> +Quiscalus major, proportions of the sexes of, in Florida and Honduras. +</p> + +<p> +Rabbit, white tail of the. +</p> + +<p> +Rabbits, domestic, elongation of the skull in; modification of the skull in, by +the lopping of the ear; danger-signals of; numerical proportion of the sexes +in. +</p> + +<p> +Races, distinctive characters of; or species of man; crossed, fertility or +sterility of; of man, variability of the; of man, resemblance of, in mental +characters; formation of; of man, extinction of; effects of the crossing of; of +man, formation of the; of man, children of the; beardless, aversion of, to +hairs on the face. +</p> + +<p> +Raffles, Sir S., on the banteng. +</p> + +<p> +Rafts, use of. +</p> + +<p> +Rage, manifested by animals. +</p> + +<p> +Raia batis, teeth of. +</p> + +<p> +Raia clavata, female spined on the back; sexual difference in the teeth of. +</p> + +<p> +Raia maculata, teeth of. +</p> + +<p> +Rails, spur-winged. +</p> + +<p> +Ram, mode of fighting of the; African, mane of an; fat-tailed. +</p> + +<p> +Rameses II., features of. +</p> + +<p> +Ramsay, Mr., on the Australian musk-duck; on the regent-bird; on the incubation +of Menura superba. +</p> + +<p> +Rana esculenta, vocal sacs of. +</p> + +<p> +Rat, common, general dispersion of, a consequence of superior cunning; +supplantation of the native in New Zealand, by the European rat; common, said +to be polygamous; numerical proportion of the sexes in. +</p> + +<p> +Rats, enticed by essential oils. +</p> + +<p> +Rationality of birds. +</p> + +<p> +Rattlesnakes, difference of the sexes in the; rattles as a call. +</p> + +<p> +Raven, vocal organs of the; stealing bright objects; pied, of the Feroe +Islands. +</p> + +<p> +Rays, prehensile organs of male. +</p> + +<p> +Razor-bill, young of the. +</p> + +<p> +Reade, Winwood, suicide among savages in Africa; mulattoes not prolific; effect +of castration of horned sheep; on the Guinea sheep; on the occurrence of a mane +in an African ram; on singing of negroes; on the negroes’ appreciation of +the beauty of their women; on the admiration of negroes for a black skin; on +the idea of beauty among negroes; on the Jollofs; on the marriage-customs of +the negroes. +</p> + +<p> +Reason in animals. +</p> + +<p> +Redstart, American, breeding in immature plumage. +</p> + +<p> +Redstarts, new mates found by. +</p> + +<p> +Reduvidae, stridulation of. +</p> + +<p> +Reed-bunting, head-feathers of the male; attacked by a bullfinch. +</p> + +<p> +Reefs, fishes frequenting. +</p> + +<p> +Reeks, H., retention of horns by breeding deer; cow rejected by a bull; +destruction of piebald rabbits by cats. +</p> + +<p> +Regeneration, partial, of lost parts in man. +</p> + +<p> +Regent bird. +</p> + +<p> +Reindeer, horns of the; battles of; horns of the female; antlers of, with +numerous points; winter change of the; sexual preferences shown by. +</p> + +<p> +Relationship, terms of. +</p> + +<p> +Religion, deficiency of among certain races; psychical elements of. +</p> + +<p> +Remorse, deficiency of, among savages. +</p> + +<p> +Rengger, on the diseases of Cebus Azarae; on the diversity of the mental +faculties of monkeys; on the Payaguas Indians; on the inferiority of Europeans +to savages in their senses; revenge taken by monkeys; on maternal affection in +a Cebus; on the reasoning powers of American monkeys; on the use of stones by +monkeys for cracking hard nuts; on the sounds uttered by Cebus Azarae; on the +signal-cries of monkeys; on the polygamous habits of Mycetes caraya; on the +voice of the howling monkeys; on the odour of Cervus campestris; on the beards +of Mycetes caraya and Pithecia Satanas; on the colours of Felis mitis; on the +colours of Cervus paludosus; on sexual differences of colour in Mycetes; on the +colour of the infant Guaranys; on the early maturity of the female of Cebus +Azarae; on the beards of the Guaranys; on the emotional notes employed by +monkeys; on American polygamous monkeys. +</p> + +<p> +Representative species, of birds. +</p> + +<p> +Reproduction, unity of phenomena of, throughout the mammalia; period of, in +birds. +</p> + +<p> +Reproductive system, rudimentary structures in the; accessory parts of. +</p> + +<p> +Reptiles. +</p> + +<p> +Reptiles and birds, alliance of. +</p> + +<p> +Resemblances, small, between man and the apes. +</p> + +<p> +Retrievers, exercise of reasoning faculties by. +</p> + +<p> +Revenge, manifested by animals. +</p> + +<p> +Reversion, perhaps the cause of some bad dispositions. +</p> + +<p> +Rhagium, difference of colour in the sexes of a species of. +</p> + +<p> +Rhamphastos carinatus. +</p> + +<p> +Rhea Darwinii. +</p> + +<p> +Rhinoceros, nakedness of; horns of; horns of, used defensively; attacking white +or grey horses. +</p> + +<p> +Rhynchaea, sexes and young of. +</p> + +<p> +Rhynchaea australis. +</p> + +<p> +Rhynchaea bengalensis. +</p> + +<p> +Rhynchaea capensis. +</p> + +<p> +Rhythm, perception of, by animals. +</p> + +<p> +Richard, M., on rudimentary muscles in man. +</p> + +<p> +Richardson, Sir J., on the pairing of Tetrao umbellus; on Tetrao urophasianus; +on the drumming of grouse; on the dances of Tetrao phasianellus; on assemblages +of grouse; on the battles of male deer; on the reindeer; on the horns of the +musk-ox; on antlers of the reindeer with numerous points; on the moose; on the +Scotch deerhound. +</p> + +<p> +Richter, Jean Paul, on imagination. +</p> + +<p> +Riedel, on profligate female pigeons. +</p> + +<p> +Riley, Mr., on mimicry in butterflies; bird’s disgust at taste of certain +caterpillars. +</p> + +<p> +Ring-ouzel, colours and nidification of the. +</p> + +<p> +Ripa, Father, on the difficulty of distinguishing the races of the Chinese. +</p> + +<p> +Rivalry, in singing, between male birds. +</p> + +<p> +River-hog, African, tusks and knobs of the. +</p> + +<p> +Rivers, analogy of, to islands. +</p> + +<p> +Roach, brightness of the male during breeding-season. +</p> + +<p> +Robbery, of strangers, considered honourable. +</p> + +<p> +Robertson, Mr., remarks on the development of the horns in the roebuck and red +deer. +</p> + +<p> +Robin, pugnacity of the male; autumn song of the; female singing of the; +attacking other birds with red in their plumage; young of the. +</p> + +<p> +Robinet, on the difference of size of the male and female cocoons of the +silk-moth. +</p> + +<p> +Rodents, uterus in the; absence of secondary sexual characters in; sexual +differences in the colours of. +</p> + +<p> +Roe, winter changes of the. +</p> + +<p> +Rohfs, Dr., Caucasian features in negro; fertility of mixed races in Sahara; +colours of birds in Sahara; ideas of beauty amongst the Bornuans. +</p> + +<p> +Rolle, F., on the origin of man; on a change in German families settled in +Georgia. +</p> + +<p> +Roller, harsh cry of. +</p> + +<p> +Romans, ancient, gladiatorial exhibitions of the. +</p> + +<p> +Rook, voice of the. +</p> + +<p> +Rossler, Dr., on the resemblance of the lower surface of butterflies to the +bark of trees. +</p> + +<p> +Rostrum, sexual difference in the length of in some weevils. +</p> + +<p> +Royer, Madlle., mammals giving suck. +</p> + +<p> +Rudimentary organs, origin of. +</p> + +<p> +Rudiments, presence of, in languages. +</p> + +<p> +Rudolphi, on the want of connexion between climate and the colour of the skin. +</p> + +<p> +Ruff, supposed to be polygamous; proportion of the sexes in the; pugnacity of +the; double moult in; duration of dances of; attraction of the, to bright +objects. +</p> + +<p> +Ruminants, male, disappearance of canine teeth in; generally polygamous; +suborbital pits of; sexual differences of colour in. +</p> + +<p> +Rupicola crocea, display of plumage by the male. +</p> + +<p> +Ruppell, on canine teeth in deer and antelopes. +</p> + +<p> +Russia, numerical proportion of male and female births in. +</p> + +<p> +Ruticilla. +</p> + +<p> +Rutimeyer, Prof., on the physiognomy of the apes; on tusks of miocene boar; on +the sexual differences of monkeys. +</p> + +<p> +Rutlandshire, numerical proportion of male and female births in. +</p> + +<p> +Sachs, Prof., on the behaviour of the male and female elements in +fertilisation. +</p> + +<p> +Sacrifices, human. +</p> + +<p> +Sagittal crest, in male apes and Australians. +</p> + +<p> +Sahara, fertility of mixed races in; birds of the; animal inhabitants of the. +</p> + +<p> +Sailors, growth of, delayed by conditions of life; long-sighted. +</p> + +<p> +Sailors and soldiers, difference in the proportions of. +</p> + +<p> +St. John, Mr., on the attachment of mated birds. +</p> + +<p> +St. Kilda, beards of the inhabitants of. +</p> + +<p> +Salmo eriox, and Salmo umbla, colouring of the male, during the breeding +season. +</p> + +<p> +Salmo lycaodon. +</p> + +<p> +Salmo salar. +</p> + +<p> +Salmon, leaping out of fresh water; male, ready to breed before the female; +proportion of the sexes in; male, pugnacity of the; male, characters of, during +the breeding season; spawning of the; breeding of immature male. +</p> + +<p> +Salvin, O., inheritance of mutilated feathers; on the Humming-birds; on the +numerical proportion of the sexes in Humming-birds; on Chamaepetes and +Penelope; on Selasphorus platycercus; Pipra deliciosa; on Chasmorhynchus. +</p> + +<p> +Samoa Islands, beardlessness of the natives of. +</p> + +<p> +Sandhoppers, claspers of male. +</p> + +<p> +Sand-skipper. +</p> + +<p> +Sandwich Islands, variation in the skulls of the natives of the; decrease of +native population; population of; superiority of the nobles in the. +</p> + +<p> +Sandwich Islanders, lice of. +</p> + +<p> +San-Giuliano, women of. +</p> + +<p> +Santali, recent rapid increase of the; Mr. Hunter on the. +</p> + +<p> +Saphirina, characters of the males of. +</p> + +<p> +Sarkidiornis melanonotus, characters of the young. +</p> + +<p> +Sars, O., on Pontoporeia affinis. +</p> + +<p> +Saturnia carpini, attraction of males by the female. +</p> + +<p> +Saturnia Io, difference of coloration in the sexes of. +</p> + +<p> +Saturniidae, coloration of the. +</p> + +<p> +Savage, Dr., on the fighting of the male gorillas; on the habits of the +gorilla. +</p> + +<p> +Savage and Wyman on the polygamous habits of the gorilla. +</p> + +<p> +Savages, uniformity of, exaggerated; long-sighted; rate of increase among, +usually small; retention of the prehensile power of the feet by; imitative +faculties of; causes of low morality of; tribes of, supplanting one another; +improvements in the arts among; arts of; fondness of, for rough music; on +long-enduring fashions among; attention paid by, to personal appearance; +relation of the sexes among. +</p> + +<p> +Saviotti, Dr., division of malar bone. +</p> + +<p> +Saw-fly, pugnacity of a male. +</p> + +<p> +Saw-flies, proportions of the sexes in. +</p> + +<p> +Saxicola rubicola, young of. +</p> + +<p> +Scalp, motion of the. +</p> + +<p> +Scent-glands in snakes. +</p> + +<p> +Schaaffhausen, Prof., on the development of the posterior molars in different +races of man; on the jaw from La Naulette; on the correlation between +muscularity and prominent supra-orbital ridges; on the mastoid processes of +man; on modifications of the cranial bones; on human sacrifices; on the +probable speedy extermination of the anthropomorphous apes; on the ancient +inhabitants of Europe; on the effects of use and disuse of parts; on the +superciliary ridge in man; on the absence of race-differences in the infant +skull in man; on ugliness. +</p> + +<p> +Schaum, H., on the elytra of Dytiscus and Hydroporus. +</p> + +<p> +Scherzer and Schwarz, measurements of savages. +</p> + +<p> +Schelver, on dragon-flies. +</p> + +<p> +Schiodte, on the stridulation of Heterocerus. +</p> + +<p> +Schlegel, F. von, on the complexity of the languages of uncivilised peoples. +</p> + +<p> +Schlegel, Prof., on Tanysiptera. +</p> + +<p> +Schleicher, Prof, on the origin of language. +</p> + +<p> +Schomburgk, Sir R., on the pugnacity of the male musk-duck of Guiana; on the +courtship of Rupicola crocea. +</p> + +<p> +Schoolcraft, Mr., on the difficulty of fashioning stone implements. +</p> + +<p> +Schopenhauer, on importance of courtship to mankind. +</p> + +<p> +Schweinfurth, complexion of negroes. +</p> + +<p> +Sciaena aquila. +</p> + +<p> +Sclater, P.L., on modified secondary wing-feathers in the males of Pipra; on +elongated feathers in nightjars; on the species of Chasmorhynchus; on the +plumage of Pelecanus onocrotalus; on the plantain-eaters; on the sexes and +young of Tadorna variegata; on the colours of Lemur macaco; on the stripes in +asses. +</p> + +<p> +Scolecida, absence of secondary sexual characters in. +</p> + +<p> +Scolopax frenata, tail feathers of; +</p> + +<p> +Scolopax gallinago, drumming of. +</p> + +<p> +Scolopax javensis, tail-feathers of. +</p> + +<p> +Scolopax major, assemblies of. +</p> + +<p> +Scolopax Wilsonii, sound produced by. +</p> + +<p> +Scolytus, stridulation of. +</p> + +<p> +Scoter-duck, black, sexual difference in coloration of the; bright beak of +male. +</p> + +<p> +Scott, Dr., on idiots smelling their food. +</p> + +<p> +Scott, J., on the colour of the beard in man. +</p> + +<p> +Scrope, on the pugnacity of the male salmon; on the battles of stags. +</p> + +<p> +Scudder, S.H., imitation of the stridulation of the Orthoptera; on the +stridulation of the Acridiidae; on a Devonian insect; on stridulation. +</p> + +<p> +Sculpture, expression of the ideal of beauty by. +</p> + +<p> +Sea-anemones, bright colours of. +</p> + +<p> +Sea-bear, polygamous. +</p> + +<p> +Sea-elephant, male, structure of the nose of the; polygamous. +</p> + +<p> +Sea-lion, polygamous. +</p> + +<p> +Seal, bladder-nose. +</p> + +<p> +Seals, their sentinels generally females; evidence furnished by, on +classification; polygamous habits of; battles of male; canine teeth of male; +sexual differences; pairing of; sexual peculiarities of; in the coloration of; +appreciation of music by. +</p> + +<p> +Sea-scorpion, sexual differences in. +</p> + +<p> +Season, changes of colour in birds, in accordance with the; changes of plumage +of birds in relation to. +</p> + +<p> +Seasons, inheritance at corresponding. +</p> + +<p> +Sebituani, African chief, trying to alter a fashion. +</p> + +<p> +Sebright Bantam. +</p> + +<p> +Secondary sexual characters; relations of polygamy to; transmitted through both +sexes; gradation of, in birds. +</p> + +<p> +Sedgwick, W., on hereditary tendency to produce twins. +</p> + +<p> +Seemann, Dr., on the different appreciation of music by different peoples; on +the effects of music. +</p> + +<p> +Seidlitz, on horns of reindeer. +</p> + +<p> +Selasphorus platycercus, acuminate first primary of the male. +</p> + +<p> +Selby, P.J., on the habits of the black and red grouse. +</p> + +<p> +Selection as applied to primeval man. +</p> + +<p> +Selection, double. +</p> + +<p> +Selection, injurious forms of, in civilised nations. +</p> + +<p> +Selection of male by female birds. +</p> + +<p> +Selection, methodical, of Prussian grenadiers. +</p> + +<p> +Selection, sexual, explanation of; influence of, on the colouring of +Lepidoptera. +</p> + +<p> +Selection, sexual and natural, contrasted. +</p> + +<p> +Self-command, habit of, inherited; estimation of. +</p> + +<p> +Self-consciousness, in animals. +</p> + +<p> +Self-preservation, instinct of. +</p> + +<p> +Self-sacrifice, by savages; estimation of. +</p> + +<p> +Semilunar fold. +</p> + +<p> +Semnopithecus, long hair on the heads of species of. +</p> + +<p> +Semnopithecus chrysomelas, sexual differences of colour in. +</p> + +<p> +Semnopithecus comatus, ornamental hair on the head of. +</p> + +<p> +Semnopithecus frontatus, beard etc., of. +</p> + +<p> +Semnopithecus nasica, nose of. +</p> + +<p> +Semnopithecus nemaeus, colouring of. +</p> + +<p> +Semnopithecus rubicundus, ornamental hair on the head of. +</p> + +<p> +Senses, inferiority of Europeans to savages in the. +</p> + +<p> +Sentinels, among animals. +</p> + +<p> +Serpents, instinctively dreaded by apes and monkeys. +</p> + +<p> +Serranus, hermaphroditism in. +</p> + +<p> +Setina, noise produced by. +</p> + +<p> +Sex, inheritance limited by. +</p> + +<p> +Sexes, relative proportions of, in man; proportions of, sometimes influenced by +selection; probable relation of the, in primeval man. +</p> + +<p> +Sexual and natural selection, contrasted. +</p> + +<p> +Sexual characters, effects of the loss of; limitation of. +</p> + +<p> +Sexual characters, secondary; relations of polygamy to; transmitted through +both sexes; gradation of, in birds. +</p> + +<p> +Sexual differences in man. +</p> + +<p> +Sexual selection, explanation of; influence of, on the colouring of +Lepidoptera; objections to; action of, in mankind. +</p> + +<p> +Sexual selection in spiders. +</p> + +<p> +Sexual selection, supplemental note on. +</p> + +<p> +Sexual similarity. +</p> + +<p> +Shaler, Prof., sizes of sexes in whales. +</p> + +<p> +Shame. +</p> + +<p> +Sharks, prehensile organs of male. +</p> + +<p> +Sharpe, Dr., Europeans in the tropics. +</p> + +<p> +Sharpe, R.B., on Tanysiptera sylvia; on Ceryle; on the young male of Dacelo +Gaudi-chaudi. +</p> + +<p> +Shaw, Mr., on the pugnacity of the male salmon. +</p> + +<p> +Shaw, J., on the decorations of birds. +</p> + +<p> +Sheep, danger-signals of; sexual differences in the horns of; horns of; +domestic, sexual differences of, late developed; numerical proportion of the +sexes in; inheritance of horns by one sex; effect of castration; mode of +fighting of; arched foreheads of some. +</p> + +<p> +Sheep, Merino, loss of horns in females of; horns of. +</p> + +<p> +Shells, difference in form of, in male and female Gasteropoda; beautiful +colours and shapes of. +</p> + +<p> +Shield-drake, pairing with a common duck; New Zealand, sexes and young of. +</p> + +<p> +Shooter, J., on the Kaffirs; on the marriage-customs of the Kaffirs. +</p> + +<p> +Shrew-mice, odour of. +</p> + +<p> +Shrike, Drongo. +</p> + +<p> +Shrikes, characters of young. +</p> + +<p> +Shuckard, W.E., on sexual differences in the wings of Hymenoptera. +</p> + +<p> +Shyness of adorned male birds; +</p> + +<p> +Siagonium, proportions of the sexes in; dimorphism in males of. +</p> + +<p> +Siam, proportion of male and female births in. +</p> + +<p> +Siamese, general beardlessness of the; notions of beauty of the; hairy family +of. +</p> + +<p> +Sidgwick, H., on morality in hypothetical bee community; our actions not +entirely directed by pain and pleasure. +</p> + +<p> +Siebold, C.T., von, on the proportion of sexes in the Apus; on the auditory +apparatus of the stridulent Orthoptera. +</p> + +<p> +Sight, inheritance of long and short. +</p> + +<p> +Signal-cries of monkeys. +</p> + +<p> +Silk-moth, proportion of the sexes in; Ailanthus, Prof. Canestrini, on the +destruction of its larvae by wasps; difference of size of the male and female +cocoons of the; pairing of the. +</p> + +<p> +Simiadae, their origin and divisions. +</p> + +<p> +Similarity, sexual. +</p> + +<p> +Singing of the Cicadae and Fulgoridae; of tree-frogs; of birds, object of the. +</p> + +<p> +Sirenia, nakedness of. +</p> + +<p> +Sirex juvencus. +</p> + +<p> +Siricidae, difference of the sexes in. +</p> + +<p> +Siskin, pairing with a canary. +</p> + +<p> +Sitana, throat-pouch of the males of. +</p> + +<p> +Size, relative, of the sexes of insects. +</p> + +<p> +Skin, dark colour of, a protection against heat. +</p> + +<p> +Skin, movement of the; nakedness of, in man; colour of the. +</p> + +<p> +Skin and hair, correlation of colour of. +</p> + +<p> +Skull, variation of, in man; cubic contents of, no absolute test of intellect; +Neanderthal, capacity of the; causes of modification of the; difference of, in +form and capacity, in different races of men; variability of the shape of the; +differences of, in the sexes in man; artificial modification of the shape of. +</p> + +<p> +Skunk, odour emitted by the; white tail of, protective. +</p> + +<p> +Slavery, prevalence of; of women. +</p> + +<p> +Slaves, difference between field-and house-slaves. +</p> + +<p> +Sloth, ornaments of male. +</p> + +<p> +Smell, sense of, in man and animals. +</p> + +<p> +Smith, Adam, on the basis of sympathy. +</p> + +<p> +Smith, Sir A., on the recognition of women by male Cynocephali; on revenge by a +baboon; on an instance of memory in a baboon; on the retention of their colour +by the Dutch in South Africa; on the polygamy of the South African antelopes; +on the polygamy of the lion; on the proportion of the sexes in Kobus +ellipsiprymnus; on Bucephalus capensis; on South African lizards; on fighting +gnus; on the horns of rhinoceroses; on the fighting of lions; on the colours of +the Cape Eland; on the colours of the gnu; on Hottentot notions of beauty; +disbelief in communistic marriages. +</p> + +<p> +Smith, F., on the Cynipidae and Tenthredinidae; on the relative size of the +sexes of Aculeate Hymenoptera; on the difference between the sexes of ants and +bees; on the stridulation of Trox sabulosus; on the stridulation of Mononychus +pseudacori. +</p> + +<p> +Smynthurus luteus, courtship of. +</p> + +<p> +Snakes, sexual differences of; mental powers of; male, ardency of. +</p> + +<p> +“Snarling muscles.” +</p> + +<p> +Snipe, drumming of the; coloration of the. +</p> + +<p> +Snipe, painted, sexes and young of. +</p> + +<p> +Snipe, solitary, assemblies of. +</p> + +<p> +Snipes, arrival of male before the female; pugnacity of male; double moult in. +</p> + +<p> +Snow-goose, whiteness of the. +</p> + +<p> +Sociability, the sense of duty connected with; impulse to, in animals; +manifestations of, in man; instinct of, in animals. +</p> + +<p> +Social animals, affection of, for each other; defence of, by the males. +</p> + +<p> +Sociality, probable, of primeval men; influence of, on the development of the +intellectual faculties; origin of, in man. +</p> + +<p> +Soldiers, American, measurements of. +</p> + +<p> +Soldiers and sailors, difference in the proportions of. +</p> + +<p> +Solenostoma, bright colours and marsupial sac of the females of. +</p> + +<p> +Song, of male birds appreciated by their females; want of, in brilliant +plumaged birds; of birds. +</p> + +<p> +Sorex, odour of. +</p> + +<p> +Sounds, admired alike by man and animals; produced by fishes; produced by male +frogs and toads; instrumentally produced by birds. +</p> + +<p> +Spain, decadence of. +</p> + +<p> +Sparassus smaragdulus, difference of colour in the sexes of. +</p> + +<p> +Sparrow, pugnacity of the male; acquisition of the Linnet’s song by a; +coloration of the; immature plumage of the. +</p> + +<p> +Sparrow, white-crowned, young of the. +</p> + +<p> +Sparrows, house-and tree-. +</p> + +<p> +Sparrows, new mates found by. +</p> + +<p> +Sparrows, sexes and young of; learning to sing. +</p> + +<p> +Spathura Underwoodi. +</p> + +<p> +Spawning of fishes. +</p> + +<p> +Spear, used before dispersion of man. +</p> + +<p> +Species, causes of the advancement of; distinctive characters of; or races of +man; sterility and fertility of, when crossed; supposed, of man; gradation of; +difficulty of defining; representative, of birds; of birds, comparative +differences between the sexes of distinct. +</p> + +<p> +Spectrum femoratum, difference of colour in the sexes of. +</p> + +<p> +Speech, connection between the brain and the faculty of; connection of +intonation with music. +</p> + +<p> +Spel, of the black-cock. +</p> + +<p> +Spencer, Herbert, on the influence of food on the size of the jaws; on the dawn +of intelligence; on the origin of the belief in spiritual agencies; on the +origin of the moral sense; on music. +</p> + +<p> +Spengel, disagrees with explanation of man’s hairlessness. +</p> + +<p> +Sperm-whales, battles of male. +</p> + +<p> +Sphingidae, coloration of the. +</p> + +<p> +Sphinx, Humming-bird. +</p> + +<p> +Sphinx, Mr. Bates on the caterpillar of a. +</p> + +<p> +Sphinx moth, musky odour of. +</p> + +<p> +Spiders, parental feeling in; male, more active than female; proportion of the +sexes in; secondary sexual characters of; courtship of male; attracted by +music; male, small size of. +</p> + +<p> +Spilosoma menthastri, rejected by turkeys. +</p> + +<p> +Spine, alteration of, to suit the erect attitude of man. +</p> + +<p> +Spirits, fondness of monkeys for. +</p> + +<p> +Spiritual agencies, belief in, almost universal. +</p> + +<p> +Spiza cyanea and ciris. +</p> + +<p> +Spoonbill, Chinese, change of plumage in. +</p> + +<p> +Spots, retained throughout groups of birds; disappearance of, in adult mammals. +</p> + +<p> +Sprengel, C.K., on the sexuality of plants. +</p> + +<p> +Springboc, horns of the. +</p> + +<p> +Sproat, Mr., on the extinction of savages in Vancouver Island; on the +eradication of facial hair by the natives of Vancouver Island; on the +eradication of the beard by the Indians of Vancouver Island. +</p> + +<p> +Spurs, occurrence of, in female fowls; development of, in various species of +Phasianidae; of Gallinaceous birds; development of, in female Gallinaceae. +</p> + +<p> +Squilla, different colours of the sexes of a species of. +</p> + +<p> +Squirrels, battles of male; African, sexual differences in the colouring of; +black. +</p> + +<p> +Stag, long hairs of the throat of; horns of the; battles of; horns of the, with +numerous branches; bellowing of the; crest of the. +</p> + +<p> +Stag-beetle, numerical proportion of sexes of; use of jaws; large size of male; +weapons of the male. +</p> + +<p> +Stainton, H.T., on the numerical proportion of the sexes in the smaller moths; +habits of Elachista rufocinerea; on the coloration of moths; on the rejection +of Spilosoma menthastri by turkeys; on the sexes of Agrotis exclamationis. +</p> + +<p> +Staley, Bishop, mortality of infant Maories. +</p> + +<p> +Stallion, mane of the. +</p> + +<p> +Stallions, two, attacking a third; fighting; small canine teeth of. +</p> + +<p> +Stansbury, Captain, observations on pelicans. +</p> + +<p> +Staphylinidae, hornlike processes in male. +</p> + +<p> +Starfishes, parental feeling in; bright colours of some. +</p> + +<p> +Stark, Dr., on the death-rate in towns and rural districts; on the influence of +marriage on mortality; on the higher mortality of males in Scotland. +</p> + +<p> +Starling, American field-, pugnacity of male. +</p> + +<p> +Starling, red-winged, selection of a mate by the female. +</p> + +<p> +Starlings, three, frequenting the same nest; new mates found by. +</p> + +<p> +Statues, Greek, Egyptian, Assyrian, etc., contrasted. +</p> + +<p> +Stature, dependence of, upon local influences. +</p> + +<p> +Staudinger, Dr., on breeding Lepidoptera; his list of Lepidoptera. +</p> + +<p> +Staunton, Sir G., hatred of indecency a modern virtue. +</p> + +<p> +Stealing of bright objects by birds. +</p> + +<p> +Stebbing, T.R., on the nakedness of the human body. +</p> + +<p> +Stemmatopus. +</p> + +<p> +Stendhal, see Bombet. +</p> + +<p> +Stenobothrus pratorum, stridulation. +</p> + +<p> +Stephen, Mr. L., on the difference in the minds of men and animals; on general +concepts in animals; distinction between material and formal morality. +</p> + +<p> +Sterility, general, of sole daughters; when crossed, a distinctive character of +species; under changed conditions. +</p> + +<p> +Sterna, seasonal change of plumage in. +</p> + +<p> +Stickleback, polygamous; male, courtship of the; male, brilliant colouring of, +during the breeding season; nidification of the. +</p> + +<p> +Sticks used as implements and weapons by monkeys. +</p> + +<p> +Sting in bees. +</p> + +<p> +Stokes, Captain, on the habits of the great bower-bird. +</p> + +<p> +Stoliczka, Dr., on colours in snakes. +</p> + +<p> +Stoliczka, on the pre-anal pores of lizards. +</p> + +<p> +Stonechat, young of the. +</p> + +<p> +Stone implements, difficulty of making; as traces of extinct tribes. +</p> + +<p> +Stones, used by monkeys for breaking hard fruits and as missiles; piles of. +</p> + +<p> +Stork, black, sexual differences in the bronchi of the; red beak of the. +</p> + +<p> +Storks, sexual difference in the colour of the eyes of. +</p> + +<p> +Strange, Mr., on the satin bowerbird. +</p> + +<p> +Strepsiceros kudu, horns of; markings of. +</p> + +<p> +Stretch, Mr., on the numerical proportion in the sexes of chickens. +</p> + +<p> +Stridulation, by males of Theridion; of Hemiptera; of the Orthoptera and +Homoptera discussed; of beetles. +</p> + +<p> +Stripes, retained throughout groups of birds; disappearance of, in adult +mammals. +</p> + +<p> +Strix flammea. +</p> + +<p> +Structure, existence of unserviceable modifications of. +</p> + +<p> +Struggle for existence, in man. +</p> + +<p> +Struthers, Dr., on the occurrence of the supra-condyloid foramen in the humerus +of man. +</p> + +<p> +Sturnella ludoviciana, pugnacity of the male. +</p> + +<p> +Sturnus vulgaris. +</p> + +<p> +Sub-species. +</p> + +<p> +Suffering, in strangers, indifference of savages to. +</p> + +<p> +Suicide, formerly not regarded as a crime; rarely practised among the lowest +savages. +</p> + +<p> +Suidae, stripes of the young. +</p> + +<p> +Sulivan, Sir B.J., on speaking of parrots; on two stallions attacking a third. +</p> + +<p> +Sumatra, compression of the nose by the Malays of. +</p> + +<p> +Sumner, Archb., man alone capable of progressive improvement. +</p> + +<p> +Sun-birds, nidification of. +</p> + +<p> +Superciliary ridge in man. +</p> + +<p> +Supernumerary digits, more frequent in men than in women; inheritance of; early +development of. +</p> + +<p> +Superstitions, prevalence of. +</p> + +<p> +Superstitious customs. +</p> + +<p> +Supra-condyloid foramen in the early progenitors of man. +</p> + +<p> +Suspicion, prevalence of, among animals. +</p> + +<p> +Swallow-tail butterfly. +</p> + +<p> +Swallows deserting their young. +</p> + +<p> +Swan, black, wild, trachea of the; white, young of; red beak of the; +black-necked. +</p> + +<p> +Swans, young. +</p> + +<p> +Swaysland, Mr., on the arrival of migratory birds. +</p> + +<p> +Swifts, migration of. +</p> + +<p> +Swinhoe, R., on the common rat in Formosa and China; behaviour of lizards when +caught; on the sounds produced by the male hoopoe; on Dicrurus macrocercus and +the spoonbill; on the young of Ardeola; on the habits of Turnix; on the habits +of Rhynchaea bengalensis; on Orioles breeding in immature plumage. +</p> + +<p> +Sylvia atricapilla, young of. +</p> + +<p> +Sylvia cinerea, aerial love-dance of the male. +</p> + +<p> +Sympathy, among animals; its supposed basis. +</p> + +<p> +Sympathies, gradual widening of. +</p> + +<p> +Syngnathous fishes, abdominal pouch in male. +</p> + +<p> +Sypheotides auritus, acuminated primaries of the male; ear-tufts of. +</p> + +<p> +Tabanidae, habits of. +</p> + +<p> +Tadorna variegata, sexes and young of. +</p> + +<p> +Tadorna vulpanser. +</p> + +<p> +Tahitians, compression of the nose by the. +</p> + +<p> +Tail, rudimentary, occurrence of, in man; convoluted body in the extremity of +the; absence of, in man and the higher apes; variability of, in species of +Macacus and in baboons; presence of, in the early progenitors of man; length +of, in pheasants; difference of length of the, in the two sexes of birds. +</p> + +<p> +Tait, Lawson, on the effects of natural selection on civilised nations. +</p> + +<p> +Tanager, scarlet, variation in the male. +</p> + +<p> +Tanagra aestiva, age of mature plumage in. +</p> + +<p> +Tanagra rubra, young of. +</p> + +<p> +Tanais, absence of mouth in the males of some species of; relations of the +sexes in; dimorphic males of a species of. +</p> + +<p> +Tankerville, Earl, on the battles of wild bulls. +</p> + +<p> +Tanysiptera, races of, determined from adult males. +</p> + +<p> +Tanysiptera sylvia, long tail-feathers of. +</p> + +<p> +Taphroderes distortus, enlarged left mandible of the male. +</p> + +<p> +Tapirs, longitudinal stripes of young. +</p> + +<p> +Tarsi, dilatation of front, in male beetles. +</p> + +<p> +Tarsius. +</p> + +<p> +Tasmania, half-castes killed by the natives of. +</p> + +<p> +Tasmanians, extinction of. +</p> + +<p> +Taste, in the Quadrumana. +</p> + +<p> +Tattooing, universality of. +</p> + +<p> +Taylor, G., on Quiscalus major. +</p> + +<p> +Taylor, Rev. R., on tattooing in New Zealand. +</p> + +<p> +Tea, fondness of monkeys for. +</p> + +<p> +Teal, constancy of. +</p> + +<p> +Tear-sacs, of Ruminants. +</p> + +<p> +Teebay, Mr., on changes of plumage in spangled Hamburg fowls. +</p> + +<p> +Teeth, rudimentary incisor, in Ruminants; posterior molar, in man; wisdom; +diversity of; canine, in the early progenitors of man; canine, of male mammals; +in man, reduced by correlation; staining of the; front, knocked out or filed by +some savages. +</p> + +<p> +Tegetmeier, Mr., on the transmission of colours in pigeons by one sex alone; +numerical proportion of male and female births in dogs; on the abundance of +male pigeons; on the wattles of game-cocks; on the courtship of fowls; on the +loves of pigeons; on dyed pigeons; blue dragon pigeons. +</p> + +<p> +Tembeta, S. American ornament. +</p> + +<p> +Temper, in dogs and horses, inherited. +</p> + +<p> +Tench, proportions of the sexes in the; brightness of male, during breeding +season. +</p> + +<p> +Tenebrionidae, stridulation of. +</p> + +<p> +Tennent, Sir J.E., on the tusks of the Ceylon Elephant; on the frequent absence +of beard in the natives of Ceylon; on the Chinese opinion of the aspect of the +Cingalese. +</p> + +<p> +Tennyson, A., on the control of thought. +</p> + +<p> +Tenthredinidae, proportions of the sexes in; fighting habits of male; +difference of the sexes in. +</p> + +<p> +Tephrodornis, young of. +</p> + +<p> +Terai, in India. +</p> + +<p> +Termites, habits of. +</p> + +<p> +Terns, white; and black. +</p> + +<p> +Terns, seasonal change of plumage in. +</p> + +<p> +Terror, common action of, upon the lower animals and man. +</p> + +<p> +Testudo elegans. +</p> + +<p> +Testudo nigra. +</p> + +<p> +Tetrao cupido, battles of; sexual difference in the vocal organs of. +</p> + +<p> +Tetrao phasianellus, dances of; duration of dances of. +</p> + +<p> +Tetrao scoticus. +</p> + +<p> +Tetrao tetrix, pugnacity of the male. +</p> + +<p> +Tetrao umbellus, pairing of; battles of; drumming of the male. +</p> + +<p> +Tetrao urogalloides, dances of. +</p> + +<p> +Tetrao urogallus, pugnacity of the male. +</p> + +<p> +Tetrao urophasianus, inflation of the oesophagus in the male. +</p> + +<p> +Thamnobia, young of. +</p> + +<p> +Thecla, sexual differences of colouring in species of. +</p> + +<p> +Thecla rubi, protective colouring of. +</p> + +<p> +Thecophora fovea. +</p> + +<p> +Theognis, selection in mankind. +</p> + +<p> +Theridion, stridulation of males of. +</p> + +<p> +Theridion lineatum. +</p> + +<p> +Thomisus citreus, and Thomisus floricolens, difference of colour in the sexes +of. +</p> + +<p> +Thompson, J.H., on the battles of sperm-whales. +</p> + +<p> +Thompson, W., on the colouring of the male char during the breeding season; on +the pugnacity of the males of Gallinula chloropus; on the finding of new mates +by magpies; on the finding of new mates by Peregrine falcons. +</p> + +<p> +Thorax, processes of, in male beetles. +</p> + +<p> +Thorell, T., on the proportion of sexes in spiders. +</p> + +<p> +Thornback, difference in the teeth of the two sexes of the. +</p> + +<p> +Thoughts, control of. +</p> + +<p> +Thrush, pairing with a blackbird; colours and nidification of the. +</p> + +<p> +Thrushes, characters of young. +</p> + +<p> +Thug, remorse of a. +</p> + +<p> +Thumb, absence of, in Ateles and Hylobates. +</p> + +<p> +Thury, M., on the numerical proportion of male and female births among the +Jews. +</p> + +<p> +Thylacinus, possession of the marsupial sac by the male. +</p> + +<p> +Thysanura. +</p> + +<p> +Tibia, dilated, of the male Crabro cribrarius. +</p> + +<p> +Tibia and femur, proportions of, in the Aymara Indians. +</p> + +<p> +Tierra del Fuego, marriage-customs of. +</p> + +<p> +Tiger, colours and markings of the. +</p> + +<p> +Tigers, depopulation of districts by, in India. +</p> + +<p> +Tillus elongatus, difference of colour in the sexes of. +</p> + +<p> +Timidity, variability of, in the same species. +</p> + +<p> +Tinca vulgaris. +</p> + +<p> +Tipula, pugnacity of male. +</p> + +<p> +Tits, sexual difference of colour in. +</p> + +<p> +Toads, male, treatment of ova by some; male, ready to breed before the female. +</p> + +<p> +Todas, infanticide and proportion of sexes; practice polyandry; choice of +husbands amongst. +</p> + +<p> +Toe, great, condition of, in the human embryo. +</p> + +<p> +Tomicus villosus, proportion of the sexes in. +</p> + +<p> +Tomtit, blue, sexual difference of colour in the. +</p> + +<p> +Tonga Islands, beardlessness of the natives of. +</p> + +<p> +Tooke, Horne, on language. +</p> + +<p> +Tools, flint; used by monkeys; use of. +</p> + +<p> +Topknots in birds. +</p> + +<p> +Tortoise, voice of the male. +</p> + +<p> +Tortures, submitted to by American savages. +</p> + +<p> +Totanus, double moult in. +</p> + +<p> +Toucans, colours and nidification of the; beaks and ceres of the. +</p> + +<p> +Towns, residence in, a cause of diminished stature. +</p> + +<p> +Toynbee, J., on the external shell of the ear in man. +</p> + +<p> +Trachea, convoluted and imbedded in the sternum, in some birds; structure of +the, in Rhynchaea. +</p> + +<p> +Trades, affecting the form of the skull. +</p> + +<p> +Tragelaphus, sexual differences of colour in. +</p> + +<p> +Tragelaphus scriptus, dorsal crest of; markings of. +</p> + +<p> +Tragopan, swelling of the wattles of the male, during courtship; display of +plumage by the male; marking of the sexes of the. +</p> + +<p> +Tragops dispar, sexual difference in the colour of. +</p> + +<p> +Training, effect of, on the mental difference between the sexes of man. +</p> + +<p> +Transfer of male characters to female birds. +</p> + +<p> +Transmission, equal, of ornamental characters, to both sexes in mammals. +</p> + +<p> +Traps, avoidance of, by animals; use of. +</p> + +<p> +Treachery, to comrades, avoidance of, by savages. +</p> + +<p> +Tremex columbae. +</p> + +<p> +Tribes, extinct; extinction of. +</p> + +<p> +Trichius, difference of colour in the sexes of a species of. +</p> + +<p> +Trigla. +</p> + +<p> +Trigonocephalus, noise made by tail of. +</p> + +<p> +Trimen, R., on the proportion of the sexes in South African butterflies; on the +attraction of males by the female Lasiocampa quercus; on Pneumora; on +difference of colour in the sexes of beetles; on moths brilliantly coloured +beneath; on mimicry in butterflies; on Gynanisa Isis, and on the ocellated +spots of Lepidoptera; on Cyllo Leda. +</p> + +<p> +Tringa, sexes and young of. +</p> + +<p> +Tringa cornuta. +</p> + +<p> +Triphaena, coloration of the species of. +</p> + +<p> +Tristram, H.B., on unhealthy districts in North Africa; on the habits of the +chaffinch in Palestine; on the birds of the Sahara; on the animals inhabiting +the Sahara. +</p> + +<p> +Triton cristatus. +</p> + +<p> +Triton palmipes. +</p> + +<p> +Triton punctatus. +</p> + +<p> +Troglodyte skulls, greater than those of modern Frenchmen. +</p> + +<p> +Troglodytes vulgaris. +</p> + +<p> +Trogons, colours and nidification of the. +</p> + +<p> +Tropic-birds, white only when mature. +</p> + +<p> +Tropics, freshwater fishes of the. +</p> + +<p> +Trout, proportion of the sexes in; male, pugnacity of the. +</p> + +<p> +Trox sabulosus, stridulation of. +</p> + +<p> +Truth, not rare between members of the same tribe; more highly appreciated by +certain tribes. +</p> + +<p> +Tulloch, Major, on the immunity of the negro from certain fevers. +</p> + +<p> +Tumbler, almond, change of plumage in the. +</p> + +<p> +Turdus merula, young of. +</p> + +<p> +Turdus migratorius. +</p> + +<p> +Turdus musicus. +</p> + +<p> +Turdus polyglottus, young of. +</p> + +<p> +Turdus torquatus. +</p> + +<p> +Turkey, wild, pugnacity of young male; wild, notes of the; swelling of the +wattles of the male; variety of, with a top-knot; recognition of a dog by a; +male, wild, acceptable to domesticated females; wild, first advances made by +older females; wild, breast-tuft of bristles of the. +</p> + +<p> +Turkey-cock, scraping of the wings of, upon the ground; wild, display of +plumage by; fighting habits of. +</p> + +<p> +Turner, Prof. W., on muscular fasciculi in man referable to the panniculus +carnosus; on the occurrence of the supra-condyloid foramen in the human +humerus; on muscles attached to the coccyx in man; on the filum terminale in +man; on the variability of the muscles; on abnormal conditions of the human +uterus; on the development of the mammary glands; on male fishes hatching ova +in their mouths; on the external perpendicular fissure of the brain; on the +bridging convolutions in the brain of a chimpanzee. +</p> + +<p> +Turnix, sexes of some species of. +</p> + +<p> +Turtle-dove, cooing of the. +</p> + +<p> +Tuttle, H., on the number of species of man. +</p> + +<p> +Tylor, E.B., on emotional cries, gestures, etc., of man; on the origin of the +belief in spiritual agencies; remorse for violation of tribal usage in +marrying; on the primitive barbarism of civilised nations; on the origin of +counting; inventions of savages; on resemblances, of the mental characters in +different races of man. +</p> + +<p> +Type of structure, prevalence of. +</p> + +<p> +Typhaeus, stridulating organs of; stridulation of. +</p> + +<p> +Twins, tendency to produce, hereditary. +</p> + +<p> +Twite, proportion of the sexes in. +</p> + +<p> +Ugliness, said to consist in an approach to the lower animals. +</p> + +<p> +Umbrella-bird. +</p> + +<p> +Umbrina, sounds produced by. +</p> + +<p> +United States, rate of increase in; influence of natural selection on the +progress of; change undergone by Europeans in the. +</p> + +<p> +Upupa epops, sounds produced by the male. +</p> + +<p> +Uraniidae, coloration of the. +</p> + +<p> +Uria troile, variety of (=U. lacrymans). +</p> + +<p> +Urodela. +</p> + +<p> +Urosticte Benjamini, sexual differences in. +</p> + +<p> +Use and disuse of parts, effects of; influence of, on the races of man. +</p> + +<p> +Uterus, reversion in the; more or less divided, in the human subject; double, +in the early progenitors of man. +</p> + +<p> +Vaccination, influence of. +</p> + +<p> +Vancouver Island, Mr. Sproat on the savages of; natives of, eradication of +facial hair by the. +</p> + +<p> +Vanellus cristatus, wing tubercles of the male. +</p> + +<p> +Vanessae, resemblance of lower surface of, to bark of trees. +</p> + +<p> +Variability, causes of; in man, analogous to that in the lower animals; of the +races of man; greater in men than in women; period of, relation of the, to +sexual selection; of birds; of secondary sexual characters in man. +</p> + +<p> +Variation, laws of; correlated; in man; analogous; analogous, in plumage of +birds. +</p> + +<p> +Variations, spontaneous. +</p> + +<p> +Varieties, absence of, between two species, evidence of their distinctness. +</p> + +<p> +Variety, an object in nature. +</p> + +<p> +Variola, communicable between man and the lower animals. +</p> + +<p> +Vaureal, human bones from. +</p> + +<p> +Veddahs, monogamous habits of. +</p> + +<p> +Veitch, Mr., on the aversion of Japanese ladies to whiskers. +</p> + +<p> +Vengeance, instinct of. +</p> + +<p> +Venus Erycina, priestesses of. +</p> + +<p> +Vermes. +</p> + +<p> +Vermiform appendage. +</p> + +<p> +Verreaux, M., on the attraction of numerous males by the female of an +Australian Bombyx. +</p> + +<p> +Vertebrae, caudal, number of in macaques and baboons; of monkeys, partly +imbedded in the body. +</p> + +<p> +Vertebrata, common origin of the; most ancient progenitors of; origin of the +voice in air-breathing. +</p> + +<p> +Vesicula prostatica, the homologue of the uterus. +</p> + +<p> +Vibrissae, represented by long hairs in the eyebrows. +</p> + +<p> +Vidua. +</p> + +<p> +Vidua axillaris. +</p> + +<p> +Villerme, M., on the influence of plenty upon stature. +</p> + +<p> +Vinson, Aug., courtship of male spider; on the male of Epeira nigra. +</p> + +<p> +Viper, difference of the sexes in the. +</p> + +<p> +Virey, on the number of species of man. +</p> + +<p> +Virtues, originally social only; gradual appreciation of. +</p> + +<p> +Viscera, variability of, in man. +</p> + +<p> +Vlacovich, Prof., on the ischio-pubic muscle. +</p> + +<p> +Vocal music of birds. +</p> + +<p> +Vocal organs of man; of birds; of frogs; of the Insessores; difference of, in +the sexes of birds; primarily used in relation to the propagation of the +species. +</p> + +<p> +Vogt, Karl, on the origin of species; on the origin of man; on the semilunar +fold in man; on microcephalous idiots; on the imitative faculties of +microcephalous idiots; on skulls from Brazilian caves; on the evolution of the +races of man; on the formation of the skull in women; on the Ainos and negroes; +on the increased cranial difference of the sexes in man with race development; +on the obliquity of the eye in the Chinese and Japanese. +</p> + +<p> +Voice in mammals; in monkeys and man; in man; origin of, in air-breathing +vertebrates. +</p> + +<p> +Von Baer, see Baer. +</p> + +<p> +Vulpian, Prof., on the resemblance between the brains of man and the higher +apes. +</p> + +<p> +Vultures, selection of a mate by the female; colours of. +</p> + +<p> +Waders, young of. +</p> + +<p> +Wagner, R., on the occurrence of the diastema in a Kaffir skull; on the bronchi +of the black stork. +</p> + +<p> +Wagtail, Ray’s, arrival of the male before the female. +</p> + +<p> +Wagtails, Indian, young of. +</p> + +<p> +Waist, proportions of, in soldiers and sailors. +</p> + +<p> +Waitz, Prof., on the number of species of man; on the liability of negroes to +tropical fevers after residence in a cold climate; on the colour of Australian +infants; on the beardlessness of negroes; on the fondness of mankind for +ornaments; on negro ideas of female beauty; on Javan and Cochin Chinese ideas +of beauty. +</p> + +<p> +Waldeyer, M., on the hermaphroditism of the vertebrate embryo. +</p> + +<p> +Wales, North, numerical proportion of male and female births in. +</p> + +<p> +Walkenaer and Gervais, spider attracted by music; on the Myriapoda. +</p> + +<p> +Walker, Alex., on the large size of the hands of labourers’ children. +</p> + +<p> +Walker, F., on sexual differences in the diptera. +</p> + +<p> +Wallace, Dr. A., on the prehensile use of the tarsi in male moths; on the +rearing of the Ailanthus silkmoth; on breeding Lepidoptera; proportion of sexes +of Bombyx cynthia, B. yamamai, and B. Pernyi reared by; on the development of +Bombyx cynthia and B. yamamai; on the pairing of Bombyx cynthia. +</p> + +<p> +Wallace, A.R., on the origin of man; on the power of imitation in man; on the +use of missiles by the orang; on the varying appreciation of truth among +different tribes; on the limits of natural selection in man; on the occurrence +of remorse among savages; on the effects of natural selection on civilised +nations; on the use of the convergence of the hair at the elbow in the orang; +on the contrast in the characters of the Malays and Papuans; on the line of +separation between the Papuans and Malays; on the birds of paradise; on the +sexes of Ornithoptera Croesus; on protective resemblances; on the relative +sizes of the sexes of insects; on Elaphomyia; on the pugnacity of the males of +Leptorhynchus angustatus; on sounds produced by Euchirus longimanus; on the +colours of Diadema; on Kallima; on the protective colouring of moths; on bright +coloration as protective in butterflies; on variability in the Papilionidae; on +male and female butterflies, inhabiting different stations; on the protective +nature of the dull colouring of female butterflies; on mimicry in butterflies; +on the bright colours of caterpillars; on brightly-coloured fishes frequenting +reefs; on the coral snakes; on Paradisea apoda; on the display of plumage by +male birds of paradise; on assemblies of birds of paradise; on the instability +of the ocellated spots in Hipparchia Janira; on sexually limited inheritance; +on the sexual coloration of birds; on the relation between the colours and +nidification of birds; on the coloration of the Cotingidae; on the females of +Paradisea apoda and papuana; on the incubation of the cassowary; on protective +coloration in birds; on the Babirusa; on the markings of the tiger; on the +beards of the Papuans; on the hair of the Papuans; on the distribution of hair +on the human body. +</p> + +<p> +Walrus, development of the nictitating membrane in the; tusks of the; use of +the tusks by the. +</p> + +<p> +Walsh, B.D., on the proportion of the sexes in Papilio Turnus; on the Cynipidae +and Cecidomyidae; on the jaws of Ammophila; on Corydalis cornutus; on the +prehensile organs of male insects; on the antennae of Penthe; on the caudal +appendages of dragonflies; on Platyphyllum concavum; on the sexes of the +Ephemeridae; on the difference of colour in the sexes of Spectrum femoratum; on +sexes of dragon-flies; on the difference of the sexes in the Ichneumonidae; on +the sexes of Orsodacna atra; on the variation of the horns of the male Phanaeas +carnifex; on the coloration of the species of Anthocharis. +</p> + +<p> +Wapiti, battles of; traces of horns in the female; attacking a man; crest of +the male; sexual difference in the colour of the. +</p> + +<p> +Warbler, hedge-; young of the. +</p> + +<p> +Warblers, superb, nidification of. +</p> + +<p> +Wariness, acquired by animals. +</p> + +<p> +Warington, R., on the habits of the stickleback; on the brilliant colours of +the male stickleback during the breeding season. +</p> + +<p> +Wart-hog, tusks and pads of the. +</p> + +<p> +Watchmakers, short-sighted. +</p> + +<p> +Waterhen. +</p> + +<p> +Waterhouse, C.O., on blind beetles; on difference of colour in the sexes of +beetles. +</p> + +<p> +Waterhouse, G.R., on the voice of Hylobates agilis. +</p> + +<p> +Water-ouzel, autumn song of the. +</p> + +<p> +Waterton, C., on the Bell-bird; on the pairing of a Canada goose with a +Bernicle gander; on hares fighting. +</p> + +<p> +Wattles, disadvantageous to male birds in fighting. +</p> + +<p> +Weale, J., Mansel, on a South African caterpillar. +</p> + +<p> +Wealth, influence of. +</p> + +<p> +Weapons, used by man; employed by monkeys; offensive, of males; of mammals. +</p> + +<p> +Weaver-bird. +</p> + +<p> +Weaver-birds, rattling of the wings of; assemblies of. +</p> + +<p> +Webb, Dr., on the wisdom teeth. +</p> + +<p> +Wedderburn, Mr., assembly of black game. +</p> + +<p> +Wedgwood, Hensleigh, on the origin of language. +</p> + +<p> +Weevils, sexual difference in length of snout in some. +</p> + +<p> +Weir, Harrison, on the numerical proportion of the sexes in pigs and rabbits; +on the sexes of young pigeons; on the songs of birds; on pigeons; on the +dislike of blue pigeons to other coloured varieties; on the desertion of their +mates by female pigeons. +</p> + +<p> +Weir, J. Jenner, on the nightingale and blackcap; on the relative sexual +maturity of male birds; on female pigeons deserting a feeble mate; on three +starlings frequenting the same nest; on the proportion of the sexes in Machetes +pugnax and other birds; on the coloration of the Triphaenae; on the rejection +of certain caterpillars by birds; on sexual differences of the beak in the +goldfinch; on a piping bullfinch; on the object of the nightingale’s +song; on song-birds; on the pugnacity of male fine-plumaged birds; on the +courtship of birds; on the finding of new mates by Peregrine falcons and +Kestrels; on the bullfinch and starling; on the cause of birds remaining +unpaired; on starlings and parrots living in triplets; on recognition of colour +by birds; on hybrid birds; on the selection of a greenfinch by a female canary; +on a case of rivalry of female bullfinches; on the maturity of the golden +pheasant. +</p> + +<p> +Weisbach, Dr., measurement of men of different races; on the greater +variability of men than of women; on the relative proportions of the body in +the sexes of different races of man. +</p> + +<p> +Weismann, Prof., colours of Lycaenae. +</p> + +<p> +Welcker, M., on brachycephaly and dolichocephaly; on sexual differences in the +skull in man. +</p> + +<p> +Wells, Dr., on the immunity of coloured races from certain poisons. +</p> + +<p> +Westring, on the stridulation of males of Theridion; on the stridulation of +Reduvius personatus; on the stridulation of beetles; on the stridulation of +Omaloplia brunnea; on the stridulating organs of the Coleoptera; on sounds +produced by Cychrus. +</p> + +<p> +Westropp, H.M., on reason in a bear; on the prevalence of certain forms of +ornamentation. +</p> + +<p> +Westwood, J.O., on the classification of the Hymenoptera; on the Culicidae and +Tabanidae; on a Hymenopterous parasite with a sedentary male; on the +proportions of the sexes in Lucanus cervus and Siagonium; on the absence of +ocelli in female Mutillidae; on the jaws of Ammophila; on the copulation of +insects of distinct species; on the male of Crabro cribrarius; on the pugnacity +of the male Tipulae; on the stridulation of Pirates stridulus; on the Cicadae; +on the stridulating organs of the cricket; on Ephippiger vitium; on Pneumora; +on the pugnacity of the Mantides; on Platyblemnus; on difference in the sexes +of the Agrionidae; on the pugnacity of the males of a species of Tenthredinae; +on the pugnacity of the male stag-beetle; on Bledius taurus and Siagonium; on +lamellicorn beetles; on the coloration of Lithosia. +</p> + +<p> +Whale, Sperm-, battles of male. +</p> + +<p> +Whales, nakedness of. +</p> + +<p> +Whately, Arch., language not peculiar to man; on the primitive civilisation of +man. +</p> + +<p> +Whewell, Prof., on maternal affection. +</p> + +<p> +Whiskers, in monkeys. +</p> + +<p> +White, F.B., noise produced by Hylophila. +</p> + +<p> +White, Gilbert, on the proportion of the sexes in the partridge; on the +house-cricket; on the object of the song of birds; on the finding of new mates +by white owls; on spring coveys of male partridges. +</p> + +<p> +Whiteness, a sexual ornament in some birds; of mammals inhabiting snowy +countries. +</p> + +<p> +White-throat, aerial love-dance of the male. +</p> + +<p> +Whitney, Prof., on the development of language; language not indispensable for +thought. +</p> + +<p> +Widgeon, pairing with a pintail duck. +</p> + +<p> +Widow-bird, polygamous; breeding plumage of the male; female, rejecting the +unadorned male. +</p> + +<p> +Widows and widowers, mortality of. +</p> + +<p> +Wilckens, Dr., on the modification of domestic animals in mountainous regions; +on a numerical relation between the hairs and excretory pores in sheep. +</p> + +<p> +Wilder, Dr. Burt, on the greater frequency of supernumerary digits in men than +in women. +</p> + +<p> +Williams, on the marriage-customs of the Fijians. +</p> + +<p> +Wilson, Dr., on the conical heads of the natives of North-Western Africa; on +the Fijians; on the persistence of the fashion of compressing the skull. +</p> + +<p> +Wing-spurs. +</p> + +<p> +Wings, differences of, in the two sexes of butterflies and Hymenoptera; play +of, in the courtship of birds. +</p> + +<p> +Winter, change of colour of mammals in. +</p> + +<p> +Witchcraft. +</p> + +<p> +Wives, traces of the forcible capture of. +</p> + +<p> +Wolf, winter change of the. +</p> + +<p> +Wolff, on the variability of the viscera in man. +</p> + +<p> +Wollaston, T.V., on Eurygnathus; on musical Curculionidae; on the stridulation +of Acalles. +</p> + +<p> +Wolves, learning to bark from dogs; hunting in packs. +</p> + +<p> +Wolves, black. +</p> + +<p> +Wombat, black varieties of the. +</p> + +<p> +Women, distinguished from men by male monkeys; preponderance of, in numbers; +selection of, for beauty; effects of selection of, in accordance with different +standards of beauty; practice of capturing; early betrothals and slavery of; +freedom of selection by, in savage tribes. +</p> + +<p> +Wonder, manifestations of, by animals. +</p> + +<p> +Wonfor, Mr., on sexual peculiarities, in the wings of butterflies. +</p> + +<p> +Wood, J., on muscular variations in man; on the greater variability of the +muscles in men than in women. +</p> + +<p> +Wood, T.W., on the colouring of the orange-tip butterfly; on the habits of the +Saturniidae; quarrels of chamaeleons; on the habits of Menura Alberti; on +Tetrao cupido; on the display of plumage by male pheasants; on the ocellated +spots of the Argus pheasant; on fighting of Menura superba; on the habits of +the female cassowary. +</p> + +<p> +Woodcock, coloration of the. +</p> + +<p> +Woodpecker, selection of a mate by the female. +</p> + +<p> +Woodpeckers, tapping of; colours and nidification of the; characters of young. +</p> + +<p> +Woolner, Mr., observations on the ear in man. +</p> + +<p> +Wormald, Mr., on the coloration of Hypopyra. +</p> + +<p> +Wounds, healing of. +</p> + +<p> +Wren, young of the. +</p> + +<p> +Wright, C.A., on the young of Orocetes and Petrocincla. +</p> + +<p> +Wright, Chauncey, great brain-power requisite for language; on correlative +acquisition; on the enlargement of the brain in man. +</p> + +<p> +Wright, Mr., on the Scotch deer-hound; on sexual preference in dogs; on the +rejection of a horse by a mare. +</p> + +<p> +Wright, W. von, on the protective plumage of the Ptarmigan. +</p> + +<p> +Writing. +</p> + +<p> +Wyman, Prof., on the prolongation of the coccyx in the human embryo; on the +condition of the great toe in the human embryo; on the occurrence of the +supra-condyloid foramen in the humerus of man; on variation in the skulls of +the natives of the Sandwich Islands; on the hatching of the eggs in the mouths +and branchial cavities of male fishes. +</p> + +<p> +Xenarchus, on the Cicadae. +</p> + +<p> +Xenophon, selection in mankind advocated by. +</p> + +<p> +Xenorhynchus, sexual difference in the colour of the eyes in. +</p> + +<p> +Xiphophorus Hellerii, peculiar anal fin of the male. +</p> + +<p> +Xylocopa, difference of the sexes in. +</p> + +<p> +Yarrel, W., on the habits of the Cyprinidae; on Raia clavata; on the characters +of the male salmon during the breeding season; on the characters of the rays; +on the gemmeous dragonet; on colours of salmon; on the spawning of the salmon; +on the incubation of the Lophobranchii; on rivalry in song-birds; on the +trachea of the swan; on the moulting of the Anatidae; on the young of the +waders. +</p> + +<p> +Yellow fever, immunity of negroes and mulattoes from. +</p> + +<p> +Youatt, Mr., on the development of the horns in cattle. +</p> + +<p> +Yura-caras, their notions of beauty. +</p> + +<p> +Zebra, rejection of an ass by a female; stripes of the. +</p> + +<p> +Zebus, humps of. +</p> + +<p> +Zigzags, prevalence of, as ornaments. +</p> + +<p> +Zincke, Mr., on European emigration to America. +</p> + +<p> +Zootoca vivipara, sexual difference in the colour of. +</p> + +<p> +Zouteveen, Dr., polydactylism; proportion of sexes at Cape of Good Hope; +spiders attracted by music; on sounds produced by fish. +</p> + +<p> +Zygaenidae, coloration of the. +</p> + +<h3>THE END.</h3> + +</div><!--end chapter--> + +<div style='display:block; margin-top:4em'>*** END OF THE PROJECT GUTENBERG EBOOK THE DESCENT OF MAN ***</div> +<div style='text-align:left'> + +<div style='display:block; 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