Part 3 — CHAPTER XXI. GENERAL A SUMMARY AND CONCLUSION.

Main conclusion that man is descended from some lower form—Manner of development—Genealogy of man—Intellectual and moral faculties—Sexual Selection—Concluding remarks.

A brief summary will be sufficient to recall to the reader’s mind the more salient points in this work. Many of the views which have been advanced are highly speculative, and some no doubt will prove erroneous; but I have in every case given the reasons which have led me to one view rather than to another. It seemed worth while to try how far the principle of evolution would throw light on some of the more complex problems in the natural history of man. False facts are highly injurious to the progress of science, for they often endure long; but false views, if supported by some evidence, do little harm, for every one takes a salutary pleasure in proving their falseness: and when this is done, one path towards error is closed and the road to truth is often at the same time opened.

The main conclusion here arrived at, and now held by many naturalists who are well competent to form a sound judgment, is that man is descended from some less highly organised form. The grounds upon which this conclusion rests will never be shaken, for the close similarity between man and the lower animals in embryonic development, as well as in innumerable points of structure and constitution, both of high and of the most trifling importance,—the rudiments which he retains, and the abnormal reversions to which he is occasionally liable,—are facts which cannot be disputed. They have long been known, but until recently they told us nothing with respect to the origin of man. Now when viewed by the light of our knowledge of the whole organic world, their meaning is unmistakable. The great principle of evolution stands up clear and firm, when these groups or facts are considered in connection with others, such as the mutual affinities of the members of the same group, their geographical distribution in past and present times, and their geological succession. It is incredible that all these facts should speak falsely. He who is not content to look, like a savage, at the phenomena of nature as disconnected, cannot any longer believe that man is the work of a separate act of creation. He will be forced to admit that the close resemblance of the embryo of man to that, for instance, of a dog—the construction of his skull, limbs and whole frame on the same plan with that of other mammals, independently of the uses to which the parts may be put—the occasional re-appearance of various structures, for instance of several muscles, which man does not normally possess, but which are common to the Quadrumana—and a crowd of analogous facts—all point in the plainest manner to the conclusion that man is the co-descendant with other mammals of a common progenitor.

We have seen that man incessantly presents individual differences in all parts of his body and in his mental faculties. These differences or variations seem to be induced by the same general causes, and to obey the same laws as with the lower animals. In both cases similar laws of inheritance prevail. Man tends to increase at a greater rate than his means of subsistence; consequently he is occasionally subjected to a severe struggle for existence, and natural selection will have effected whatever lies within its scope. A succession of strongly-marked variations of a similar nature is by no means requisite; slight fluctuating differences in the individual suffice for the work of natural selection; not that we have any reason to suppose that in the same species, all parts of the organisation tend to vary to the same degree. We may feel assured that the inherited effects of the long-continued use or disuse of parts will have done much in the same direction with natural selection. Modifications formerly of importance, though no longer of any special use, are long-inherited. When one part is modified, other parts change through the principle of correlation, of which we have instances in many curious cases of correlated monstrosities. Something may be attributed to the direct and definite action of the surrounding conditions of life, such as abundant food, heat or moisture; and lastly, many characters of slight physiological importance, some indeed of considerable importance, have been gained through sexual selection.

No doubt man, as well as every other animal, presents structures, which seem to our limited knowledge, not to be now of any service to him, nor to have been so formerly, either for the general conditions of life, or in the relations of one sex to the other. Such structures cannot be accounted for by any form of selection, or by the inherited effects of the use and disuse of parts. We know, however, that many strange and strongly-marked peculiarities of structure occasionally appear in our domesticated productions, and if their unknown causes were to act more uniformly, they would probably become common to all the individuals of the species. We may hope hereafter to understand something about the causes of such occasional modifications, especially through the study of monstrosities: hence the labours of experimentalists, such as those of M. Camille Dareste, are full of promise for the future. In general we can only say that the cause of each slight variation and of each monstrosity lies much more in the constitution of the organism, than in the nature of the surrounding conditions; though new and changed conditions certainly play an important part in exciting organic changes of many kinds.

Through the means just specified, aided perhaps by others as yet undiscovered, man has been raised to his present state. But since he attained to the rank of manhood, he has diverged into distinct races, or as they may be more fitly called, sub-species. Some of these, such as the Negro and European, are so distinct that, if specimens had been brought to a naturalist without any further information, they would undoubtedly have been considered by him as good and true species. Nevertheless all the races agree in so many unimportant details of structure and in so many mental peculiarities that these can be accounted for only by inheritance from a common progenitor; and a progenitor thus characterised would probably deserve to rank as man.

It must not be supposed that the divergence of each race from the other races, and of all from a common stock, can be traced back to any one pair of progenitors. On the contrary, at every stage in the process of modification, all the individuals which were in any way better fitted for their conditions of life, though in different degrees, would have survived in greater numbers than the less well-fitted. The process would have been like that followed by man, when he does not intentionally select particular individuals, but breeds from all the superior individuals, and neglects the inferior. He thus slowly but surely modifies his stock, and unconsciously forms a new strain. So with respect to modifications acquired independently of selection, and due to variations arising from the nature of the organism and the action of the surrounding conditions, or from changed habits of life, no single pair will have been modified much more than the other pairs inhabiting the same country, for all will have been continually blended through free intercrossing.

By considering the embryological structure of man,—the homologies which he presents with the lower animals,—the rudiments which he retains,—and the reversions to which he is liable, we can partly recall in imagination the former condition of our early progenitors; and can approximately place them in their proper place in the zoological series. We thus learn that man is descended from a hairy, tailed quadruped, probably arboreal in its habits, and an inhabitant of the Old World. This creature, if its whole structure had been examined by a naturalist, would have been classed amongst the Quadrumana, as surely as the still more ancient progenitor of the Old and New World monkeys. The Quadrumana and all the higher mammals are probably derived from an ancient marsupial animal, and this through a long line of diversified forms, from some amphibian-like creature, and this again from some fish-like animal. In the dim obscurity of the past we can see that the early progenitor of all the Vertebrata must have been an aquatic animal, provided with branchiae, with the two sexes united in the same individual, and with the most important organs of the body (such as the brain and heart) imperfectly or not at all developed. This animal seems to have been more like the larvae of the existing marine Ascidians than any other known form.

The high standard of our intellectual powers and moral disposition is the greatest difficulty which presents itself, after we have been driven to this conclusion on the origin of man. But every one who admits the principle of evolution, must see that the mental powers of the higher animals, which are the same in kind with those of man, though so different in degree, are capable of advancement. Thus the interval between the mental powers of one of the higher apes and of a fish, or between those of an ant and scale-insect, is immense; yet their development does not offer any special difficulty; for with our domesticated animals, the mental faculties are certainly variable, and the variations are inherited. No one doubts that they are of the utmost importance to animals in a state of nature. Therefore the conditions are favourable for their development through natural selection. The same conclusion may be extended to man; the intellect must have been all-important to him, even at a very remote period, as enabling him to invent and use language, to make weapons, tools, traps, etc., whereby with the aid of his social habits, he long ago became the most dominant of all living creatures.

A great stride in the development of the intellect will have followed, as soon as the half-art and half-instinct of language came into use; for the continued use of language will have reacted on the brain and produced an inherited effect; and this again will have reacted on the improvement of language. As Mr. Chauncey Wright (1. ‘On the Limits of Natural Selection,’ in the ‘North American Review,’ Oct. 1870, p. 295.) has well remarked, the largeness of the brain in man relatively to his body, compared with the lower animals, may be attributed in chief part to the early use of some simple form of language,—that wonderful engine which affixes signs to all sorts of objects and qualities, and excites trains of thought which would never arise from the mere impression of the senses, or if they did arise could not be followed out. The higher intellectual powers of man, such as those of ratiocination, abstraction, self-consciousness, etc., probably follow from the continued improvement and exercise of the other mental faculties.

The development of the moral qualities is a more interesting problem. The foundation lies in the social instincts, including under this term the family ties. These instincts are highly complex, and in the case of the lower animals give special tendencies towards certain definite actions; but the more important elements are love, and the distinct emotion of sympathy. Animals endowed with the social instincts take pleasure in one another’s company, warn one another of danger, defend and aid one another in many ways. These instincts do not extend to all the individuals of the species, but only to those of the same community. As they are highly beneficial to the species, they have in all probability been acquired through natural selection.

A moral being is one who is capable of reflecting on his past actions and their motives—of approving of some and disapproving of others; and the fact that man is the one being who certainly deserves this designation, is the greatest of all distinctions between him and the lower animals. But in the fourth chapter I have endeavoured to shew that the moral sense follows, firstly, from the enduring and ever-present nature of the social instincts; secondly, from man’s appreciation of the approbation and disapprobation of his fellows; and thirdly, from the high activity of his mental faculties, with past impressions extremely vivid; and in these latter respects he differs from the lower animals. Owing to this condition of mind, man cannot avoid looking both backwards and forwards, and comparing past impressions. Hence after some temporary desire or passion has mastered his social instincts, he reflects and compares the now weakened impression of such past impulses with the ever-present social instincts; and he then feels that sense of dissatisfaction which all unsatisfied instincts leave behind them, he therefore resolves to act differently for the future,—and this is conscience. Any instinct, permanently stronger or more enduring than another, gives rise to a feeling which we express by saying that it ought to be obeyed. A pointer dog, if able to reflect on his past conduct, would say to himself, I ought (as indeed we say of him) to have pointed at that hare and not have yielded to the passing temptation of hunting it.

Social animals are impelled partly by a wish to aid the members of their community in a general manner, but more commonly to perform certain definite actions. Man is impelled by the same general wish to aid his fellows; but has few or no special instincts. He differs also from the lower animals in the power of expressing his desires by words, which thus become a guide to the aid required and bestowed. The motive to give aid is likewise much modified in man: it no longer consists solely of a blind instinctive impulse, but is much influenced by the praise or blame of his fellows. The appreciation and the bestowal of praise and blame both rest on sympathy; and this emotion, as we have seen, is one of the most important elements of the social instincts. Sympathy, though gained as an instinct, is also much strengthened by exercise or habit. As all men desire their own happiness, praise or blame is bestowed on actions and motives, according as they lead to this end; and as happiness is an essential part of the general good, the greatest-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.

The moral faculties are generally and justly esteemed as of higher value than the intellectual powers. But we should bear in mind that the activity of the mind in vividly recalling past impressions is one of the fundamental though secondary bases of conscience. This affords the strongest argument for educating and stimulating in all possible ways the intellectual faculties of every human being. No doubt a man with a torpid mind, if his social affections and sympathies are well developed, will be led to good actions, and may have a fairly sensitive conscience. But whatever renders the imagination more vivid and strengthens the habit of recalling and comparing past impressions, will make the conscience more sensitive, and may even somewhat compensate for weak social affections and sympathies.

The moral nature of man has reached its present standard, partly through the advancement of his reasoning powers and consequently of a just public opinion, but especially from his sympathies having been rendered more tender and widely diffused through the effects of habit, example, instruction, and reflection. It is not improbable that after long practice virtuous tendencies may be inherited. With the more civilised races, the conviction of the existence of an all-seeing Deity has had a potent influence on the advance of morality. Ultimately man does not accept the praise or blame of his fellows as his sole guide, though few escape this influence, but his habitual convictions, controlled by reason, afford him the safest rule. His conscience then becomes the supreme judge and monitor. Nevertheless the first foundation or origin of the moral sense lies in the social instincts, including sympathy; and these instincts no doubt were primarily gained, as in the case of the lower animals, through natural selection.

The belief in God has often been advanced as not only the greatest, but the most complete of all the distinctions between man and the lower animals. It is however impossible, as we have seen, to maintain that this belief is innate or instinctive in man. On the other hand a belief in all-pervading spiritual agencies seems to be universal; and apparently follows from a considerable advance in man’s reason, and from a still greater advance in his faculties of imagination, curiosity and wonder. I am aware that the assumed instinctive belief in God has been used by many persons as an argument for His existence. But this is a rash argument, as we should thus be compelled to believe in the existence of many cruel and malignant spirits, only a little more powerful than man; for the belief in them is far more general than in a beneficent Deity. The idea of a universal and beneficent Creator does not seem to arise in the mind of man, until he has been elevated by long-continued culture.

He who believes in the advancement of man from some low organised form, will naturally ask how does this bear on the belief in the immortality of the soul. The barbarous races of man, as Sir J. Lubbock has shewn, possess no clear belief of this kind; but arguments derived from the primeval beliefs of savages are, as we have just seen, of little or no avail. Few persons feel any anxiety from the impossibility of determining at what precise period in the development of the individual, from the first trace of a minute germinal vesicle, man becomes an immortal being; and there is no greater cause for anxiety because the period cannot possibly be determined in the gradually ascending organic scale. (2. The Rev. J.A. Picton gives a discussion to this effect in his ‘New Theories and the Old Faith,’ 1870.)

I am aware that the conclusions arrived at in this work will be denounced by some as highly irreligious; but he who denounces them is bound to shew why it is more irreligious to explain the origin of man as a distinct species by descent from some lower form, through the laws of variation and natural selection, than to explain the birth of the individual through the laws of ordinary reproduction. The birth both of the species and of the individual are equally parts of that grand sequence of events, which our minds refuse to accept as the result of blind chance. The understanding revolts at such a conclusion, whether or not we are able to believe that every slight variation of structure,—the union of each pair in marriage, the dissemination of each seed,—and other such events, have all been ordained for some special purpose.

Sexual selection has been treated at great length in this work; for, as I have attempted to shew, it has played an important part in the history of the organic world. I am aware that much remains doubtful, but I have endeavoured to give a fair view of the whole case. In the lower divisions of the animal kingdom, sexual selection seems to have done nothing: such animals are often affixed for life to the same spot, or have the sexes combined in the same individual, or what is still more important, their perceptive and intellectual faculties are not sufficiently advanced to allow of the feelings of love and jealousy, or of the exertion of choice. When, however, we come to the Arthropoda and Vertebrata, even to the lowest classes in these two great Sub-Kingdoms, sexual selection has effected much.

In the several great classes of the animal kingdom,—in mammals, birds, reptiles, fishes, insects, and even crustaceans,—the differences between the sexes follow nearly the same rules. The males are almost always the wooers; and they alone are armed with special weapons for fighting with their rivals. They are generally stronger and larger than the females, and are endowed with the requisite qualities of courage and pugnacity. They are provided, either exclusively or in a much higher degree than the females, with organs for vocal or instrumental music, and with odoriferous glands. They are ornamented with infinitely diversified appendages, and with the most brilliant or conspicuous colours, often arranged in elegant patterns, whilst the females are unadorned. When the sexes differ in more important structures, it is the male which is provided with special sense-organs for discovering the female, with locomotive organs for reaching her, and often with prehensile organs for holding her. These various structures for charming or securing the female are often developed in the male during only part of the year, namely the breeding-season. They have in many cases been more or less transferred to the females; and in the latter case they often appear in her as mere rudiments. They are lost or never gained by the males after emasculation. Generally they are not developed in the male during early youth, but appear a short time before the age for reproduction. Hence in most cases the young of both sexes resemble each other; and the female somewhat resembles her young offspring throughout life. In almost every great class a few anomalous cases occur, where there has been an almost complete transposition of the characters proper to the two sexes; the females assuming characters which properly belong to the males. This surprising uniformity in the laws regulating the differences between the sexes in so many and such widely separated classes, is intelligible if we admit the action of one common cause, namely sexual selection.

Sexual selection depends on the success of certain individuals over others of the same sex, in relation to the propagation of the species; whilst natural selection depends on the success of both sexes, at all ages, in relation to the general conditions of life. The sexual struggle is of two kinds; in the one it is between individuals of the same sex, generally the males, in order to drive away or kill their rivals, the females remaining passive; whilst in the other, the struggle is likewise between the individuals of the same sex, in order to excite or charm those of the opposite sex, generally the females, which no longer remain passive, but select the more agreeable partners. This latter kind of selection is closely analogous to that which man unintentionally, yet effectually, brings to bear on his domesticated productions, when he preserves during a long period the most pleasing or useful individuals, without any wish to modify the breed.

The laws of inheritance determine whether characters gained through sexual selection by either sex shall be transmitted to the same sex, or to both; as well as the age at which they shall be developed. It appears that variations arising late in life are commonly transmitted to one and the same sex. Variability is the necessary basis for the action of selection, and is wholly independent of it. It follows from this, that variations of the same general nature have often been taken advantage of and accumulated through sexual selection in relation to the propagation of the species, as well as through natural selection in relation to the general purposes of life. Hence secondary sexual characters, when equally transmitted to both sexes can be distinguished from ordinary specific characters only by the light of analogy. The modifications acquired through sexual selection are often so strongly pronounced that the two sexes have frequently been ranked as distinct species, or even as distinct genera. Such strongly-marked differences must be in some manner highly important; and we know that they have been acquired in some instances at the cost not only of inconvenience, but of exposure to actual danger.

The belief in the power of sexual selection rests chiefly on the following considerations. Certain characters are confined to one sex; and this alone renders it probable that in most cases they are connected with the act of reproduction. In innumerable instances these characters are fully developed only at maturity, and often during only a part of the year, which is always the breeding-season. The males (passing over a few exceptional cases) are the more active in courtship; they are the better armed, and are rendered the more attractive in various ways. It is to be especially observed that the males display their attractions with elaborate care in the presence of the females; and that they rarely or never display them excepting during the season of love. It is incredible that all this should be purposeless. Lastly we have distinct evidence with some quadrupeds and birds, that the individuals of one sex are capable of feeling a strong antipathy or preference for certain individuals of the other sex.

Bearing in mind these facts, and the marked results of man’s unconscious selection, when applied to domesticated animals and cultivated plants, it seems to me almost certain that if the individuals of one sex were during a long series of generations to prefer pairing with certain individuals of the other sex, characterised in some peculiar manner, the offspring would slowly but surely become modified in this same manner. I have not attempted to conceal that, excepting when the males are more numerous than the females, or when polygamy prevails, it is doubtful how the more attractive males succeed in leaving a large number of offspring to inherit their superiority in ornaments or other charms than the less attractive males; but I have shewn that this would probably follow from the females,—especially the more vigorous ones, which would be the first to breed,—preferring not only the more attractive but at the same time the more vigorous and victorious males.

Although we have some positive evidence that birds appreciate bright and beautiful objects, as with the bower-birds of Australia, and although they certainly appreciate the power of song, yet I fully admit that it is astonishing that the females of many birds and some mammals should be endowed with sufficient taste to appreciate ornaments, which we have reason to attribute to sexual selection; and this is even more astonishing in the case of reptiles, fish, and insects. But we really know little about the minds of the lower animals. It cannot be supposed, for instance, that male birds of paradise or peacocks should take such pains in erecting, spreading, and vibrating their beautiful plumes before the females for no purpose. We should remember the fact given on excellent authority in a former chapter, that several peahens, when debarred from an admired male, remained widows during a whole season rather than pair with another bird.

Nevertheless I know of no fact in natural history more wonderful than that the female Argus pheasant should appreciate the exquisite shading of the ball-and-socket ornaments and the elegant patterns on the wing-feather of the male. He who thinks that the male was created as he now exists must admit that the great plumes, which prevent the wings from being used for flight, and which are displayed during courtship and at no other time in a manner quite peculiar to this one species, were given to him as an ornament. If so, he must likewise admit that the female was created and endowed with the capacity of appreciating such ornaments. I differ only in the conviction that the male Argus pheasant acquired his beauty gradually, through the preference of the females during many generations for the more highly ornamented males; the aesthetic capacity of the females having been advanced through exercise or habit, just as our own taste is gradually improved. In the male through the fortunate chance of a few feathers being left unchanged, we can distinctly trace how simple spots with a little fulvous shading on one side may have been developed by small steps into the wonderful ball-and-socket ornaments; and it is probable that they were actually thus developed.

Everyone who admits the principle of evolution, and yet feels great difficulty in admitting that female mammals, birds, reptiles, and fish, could have acquired the high taste implied by the beauty of the males, and which generally coincides with our own standard, should reflect that the nerve-cells of the brain in the highest as well as in the lowest members of the Vertebrate series, are derived from those of the common progenitor of this great Kingdom. For we can thus see how it has come to pass that certain mental faculties, in various and widely distinct groups of animals, have been developed in nearly the same manner and to nearly the same degree.

The reader who has taken the trouble to go through the several chapters devoted to sexual selection, will be able to judge how far the conclusions at which I have arrived are supported by sufficient evidence. If he accepts these conclusions he may, I think, safely extend them to mankind; but it would be superfluous here to repeat what I have so lately said on the manner in which sexual selection apparently has acted on man, both on the male and female side, causing the two sexes to differ in body and mind, and the several races to differ from each other in various characters, as well as from their ancient and lowly-organised progenitors.

He who admits the principle of sexual selection will be led to the remarkable conclusion that the nervous system not only regulates most of the existing functions of the body, but has indirectly influenced the progressive development of various bodily structures and of certain mental qualities. Courage, pugnacity, perseverance, strength and size of body, weapons of all kinds, musical organs, both vocal and instrumental, bright colours and ornamental appendages, have all been indirectly gained by the one sex or the other, through the exertion of choice, the influence of love and jealousy, and the appreciation of the beautiful in sound, colour or form; and these powers of the mind manifestly depend on the development of the brain.

Man scans with scrupulous care the character and pedigree of his horses, cattle, and dogs before he matches them; but when he comes to his own marriage he rarely, or never, takes any such care. He is impelled by nearly the same motives as the lower animals, when they are left to their own free choice, though he is in so far superior to them that he highly values mental charms and virtues. On the other hand he is strongly attracted by mere wealth or rank. Yet he might by selection do something not only for the bodily constitution and frame of his offspring, but for their intellectual and moral qualities. Both sexes ought to refrain from marriage if they are in any marked degree inferior in body or mind; but such hopes are Utopian and will never be even partially realised until the laws of inheritance are thoroughly known. Everyone does good service, who aids towards this end. When the principles of breeding and inheritance are better understood, we shall not hear ignorant members of our legislature rejecting with scorn a plan for ascertaining whether or not consanguineous marriages are injurious to man.

The advancement of the welfare of mankind is a most intricate problem: all ought to refrain from marriage who cannot avoid abject poverty for their children; for poverty is not only a great evil, but tends to its own increase by leading to recklessness in marriage. On the other hand, as Mr. Galton has remarked, if the prudent avoid marriage, whilst the reckless marry, the inferior members tend to supplant the better members of society. Man, like every other animal, has no doubt advanced to his present high condition through a struggle for existence consequent on his rapid multiplication; and if he is to advance still higher, it is to be feared that he must remain subject to a severe struggle. Otherwise he would sink into indolence, and the more gifted men would not be more successful in the battle of life than the less gifted. Hence our natural rate of increase, though leading to many and obvious evils, must not be greatly diminished by any means. There should be open competition for all men; and the most able should not be prevented by laws or customs from succeeding best and rearing the largest number of offspring. Important as the struggle for existence has been and even still is, yet as far as the highest part of man’s nature is concerned there are other agencies more important. For the moral qualities are advanced, either directly or indirectly, much more through the effects of habit, the reasoning powers, instruction, religion, etc., than through natural selection; though to this latter agency may be safely attributed the social instincts, which afforded the basis for the development of the moral sense.

The main conclusion arrived at in this work, namely, that man is descended from some lowly organised form, will, I regret to think, be highly distasteful to many. But there can hardly be a doubt that we are descended from barbarians. The astonishment which I felt on first seeing a party of Fuegians on a wild and broken shore will never be forgotten by me, for the reflection at once rushed into my mind—such were our ancestors. These men were absolutely naked and bedaubed with paint, their long hair was tangled, their mouths frothed with excitement, and their expression was wild, startled, and distrustful. They possessed hardly any arts, and like wild animals lived on what they could catch; they had no government, and were merciless to every one not of their own small tribe. He who has seen a savage in his native land will not feel much shame, if forced to acknowledge that the blood of some more humble creature flows in his veins. For my own part I would as soon be descended from that heroic little monkey, who braved his dreaded enemy in order to save the life of his keeper, or from that old baboon, who descending from the mountains, carried away in triumph his young comrade from a crowd of astonished dogs—as from a savage who delights to torture his enemies, offers up bloody sacrifices, practices infanticide without remorse, treats his wives like slaves, knows no decency, and is haunted by the grossest superstitions.

Man may be excused for feeling some pride at having risen, though not through his own exertions, to the very summit of the organic scale; and the fact of his having thus risen, instead of having been aboriginally placed there, may give him hope for a still higher destiny in the distant future. But we are not here concerned with hopes or fears, only with the truth as far as our reason permits us to discover it; and I have given the evidence to the best of my ability. We must, however, acknowledge, as it seems to me, that man with all his noble qualities, with sympathy which feels for the most debased, with benevolence which extends not only to other men but to the humblest living creature, with his god-like intellect which has penetrated into the movements and constitution of the solar system—with all these exalted powers—Man still bears in his bodily frame the indelible stamp of his lowly origin.

SUPPLEMENTAL NOTE.

ON SEXUAL SELECTION IN RELATION TO MONKEYS.

Reprinted from NATURE, November 2, 1876, p. 18.

In the discussion on Sexual Selection in my ‘Descent of Man,’ no case interested and perplexed me so much as the brightly-coloured hinder ends and adjoining parts of certain monkeys. As these parts are more brightly coloured in one sex than the other, and as they become more brilliant during the season of love, I concluded that the colours had been gained as a sexual attraction. I was well aware that I thus laid myself open to ridicule; though in fact it is not more surprising that a monkey should display his bright-red hinder end than that a peacock should display his magnificent tail. I had, however, at that time no evidence of monkeys exhibiting this part of their bodies during their courtship; and such display in the case of birds affords the best evidence that the ornaments of the males are of service to them by attracting or exciting the females. I have lately read an article by Joh. von Fischer, of Gotha, published in ‘Der Zoologische Garten,’ April 1876, on the expression of monkeys under various emotions, which is well worthy of study by any one interested in the subject, and which shews that the author is a careful and acute observer. In this article there is an account of the behaviour of a young male mandrill when he first beheld himself in a looking-glass, and it is added, that after a time he turned round and presented his red hinder end to the glass. Accordingly I wrote to Herr J. von Fischer to ask what he supposed was the meaning of this strange action, and he has sent me two long letters full of new and curious details, which will, I hope, be hereafter published. He says that he was himself at first perplexed by the above action, and was thus led carefully to observe several individuals of various other species of monkeys, which he has long kept in his house. He finds that not only the mandrill (Cynocephalus mormon) but the drill (C. leucophaeus) and three other kinds of baboons (C. hamadryas, sphinx, and babouin), also Cynopithecus niger, and Macacus rhesus and nemestrinus, turn this part of their bodies, which in all these species is more or less brightly coloured, to him when they are pleased, and to other persons as a sort of greeting. He took pains to cure a Macacus rhesus, which he had kept for five years, of this indecorous habit, and at last succeeded. These monkeys are particularly apt to act in this manner, grinning at the same time, when first introduced to a new monkey, but often also to their old monkey friends; and after this mutual display they begin to play together. The young mandrill ceased spontaneously after a time to act in this manner towards his master, von Fischer, but continued to do so towards persons who were strangers and to new monkeys. A young Cynopithecus niger never acted, excepting on one occasion, in this way towards his master, but frequently towards strangers, and continues to do so up to the present time. From these facts Von Fischer concludes that the monkeys which behaved in this manner before a looking-glass (viz., the mandrill, drill, Cynopithecus niger, Macacus rhesus and nemestrinus) acted as if their reflection were a new acquaintance. The mandrill and drill, which have their hinder ends especially ornamented, display it even whilst quite young, more frequently and more ostentatiously than do the other kinds. Next in order comes Cynocephalus hamadryas, whilst the other species act in this manner seldomer. The individuals, however, of the same species vary in this respect, and some which were very shy never displayed their hinder ends. It deserves especial attention that Von Fischer has never seen any species purposely exhibit the hinder part of its body, if not at all coloured. This remark applies to many individuals of Macacus cynomolgus and Cercocebus radiatus (which is closely allied to M. rhesus), to three species of Cercopithecus and several American monkeys. The habit of turning the hinder ends as a greeting to an old friend or new acquaintance, which seems to us so odd, is not really more so than the habits of many savages, for instance that of rubbing their bellies with their hands, or rubbing noses together. 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.

With respect to the origin of the habit, Von Fischer remarks that his monkeys like to have their naked hinder ends patted or stroked, and that they then grunt with pleasure. They often also turn this part of their bodies to other monkeys to have bits of dirt picked off, and so no doubt it would be with respect to thorns. But the habit with adult animals is connected to a certain extent with sexual feelings, for Von Fischer watched through a glass door a female Cynopithecus niger, and she during several days, “umdrehte und dem Männchen mit gurgelnden Tönen die stark geröthete Sitzflache zeigte, was ich früher nie an diesem Thier bemerkt hatte. Beim Anblick dieses Gegenstandes erregte sich das Männchen sichtlich, denn es polterte heftig an den Stäben, ebenfalls gurgelnde Laute ausstossend.” As all the monkeys which have the hinder parts of their bodies more or less brightly coloured live, according to Von Fischer, in open rocky places, he thinks that these colours serve to render one sex conspicuous at a distance to the other; but, as monkeys are such gregarious animals, I should have thought that there was no need for the sexes to recognise each other at a distance. It seems to me more probable that the bright colours, whether on the face or hinder end, or, as in the mandrill, on both, serve as a sexual ornament and attraction. Anyhow, as we now know that monkeys have the habit of turning their hinder ends towards other monkeys, it ceases to be at all surprising that it should have been this part of their bodies which has been more or less decorated. The fact that it is only the monkeys thus characterised which, as far as at present known, act in this manner as a greeting towards other monkeys renders it doubtful whether the habit was first acquired from some independent cause, and that afterwards the parts in question were coloured as a sexual ornament; or whether the colouring and the habit of turning round were first acquired through variation and sexual selection, and that afterwards the habit was retained as a sign of pleasure or as a greeting, through the principle of inherited association. This principle apparently comes into play on many occasions: thus it is generally admitted that the songs of birds serve mainly as an attraction during the season of love, and that the leks, or great congregations of the black-grouse, are connected with their courtship; but the habit of singing has been retained by some birds when they feel happy, for instance by the common robin, and the habit of congregating has been retained by the black-grouse during other seasons of the year.

I beg leave to refer to one other point in relation to sexual selection. It has been objected that this form of selection, as far as the ornaments of the males are concerned, implies that all females within the same district must possess and exercise exactly the same taste. It should, however, be observed, in the first place, that although the range of variation of a species may be very large, it is by no means indefinite. I have elsewhere given a good instance of this fact in the pigeon, of which there are at least a hundred varieties differing widely in their colours, and at least a score of varieties of the fowl differing in the same kind of way; but the range of colour in these two species is extremely distinct. Therefore the females of natural species cannot have an unlimited scope for their taste. In the second place, I presume that no supporter of the principle of sexual selection believes that the females select particular points of beauty in the males; they are merely excited or attracted in a greater degree by one male than by another, and this seems often to depend, especially with birds, on brilliant colouring. Even man, excepting perhaps an artist, does not analyse the slight differences in the features of the woman whom he may admire, on which her beauty depends. The male mandrill has not only the hinder end of his body, but his face gorgeously coloured and marked with oblique ridges, a yellow beard, and other ornaments. We may infer from what we see of the variation of animals under domestication, that the above several ornaments of the mandrill were gradually acquired by one individual varying a little in one way, and another individual in another way. The males which were the handsomest or the most attractive in any manner to the females would pair oftenest, and would leave rather more offspring than other males. The offspring of the former, although variously intercrossed, would either inherit the peculiarities of their fathers or transmit an increased tendency to vary in the same manner. Consequently the whole body of males inhabiting the same country would tend from the effects of constant intercrossing to become modified almost uniformly, but sometimes a little more in one character and sometimes in another, though at an extremely slow rate; all ultimately being thus rendered more attractive to the females. The process is like that which I have called unconscious selection by man, and of which I have given several instances. In one country the inhabitants value a fleet or light dog or horse, and in another country a heavier and more powerful one; in neither country is there any selection of individual animals with lighter or stronger bodies and limbs; nevertheless after a considerable lapse of time the individuals are found to have been modified in the desired manner almost uniformly, though differently in each country. In two absolutely distinct countries inhabited by the same species, the individuals of which can never during long ages have intermigrated and intercrossed, and where, moreover, the variations will probably not have been identically the same, sexual selection might cause the males to differ. Nor does the belief appear to me altogether fanciful that two sets of females, surrounded by a very different environment, would be apt to acquire somewhat different tastes with respect to form, sound, or colour. 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.

INDEX. — Abbot, C., on the battles of seals.

Abductor of the fifth metatarsal, presence of, in man.

Abercrombie, Dr., on disease of the brain affecting speech.

Abipones, marriage customs of the.

Abortion, prevalence of the practice of.

Abou-Simbel, caves of.

Abramis brama.

Abstraction, power of, in animals.

Acalles, stridulation of.

Acanthodactylus capensis, sexual differences of colour in.

Accentor Modularis.

Acclimatisation, difference of, in different races of men.

Achetidae, stridulation of the; rudimentary stridulating organs in female.

Acilius sulcatus, elytra of the female.

Acomus, development of spurs in the female of.

Acridiidae, stridulation of the; rudimentary stridulating organs in female.

Acromio-basilar muscle, and quadrupedal gait.

Acting.

Actiniae, bright colours of.

Adams, Mr., migration of birds; intelligence of nut-hatch; on the Bombycilla carolinensis.

Admiral butterfly.

Adoption of the young of other animals by female monkeys.

Advancement in the organic scale, Von Baer’s definition of.

Aeby, on the difference between the skulls of man and the quadrumana.

Aesthetic faculty, not highly developed in savages.

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.

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.

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.

Age, in relation to the transmission of characters in birds; variation in accordance with, in birds.

Agelaeus phoeniceus.

Ageronia feronia, noise produced by.

Agrion, dimorphism in.

Agrion Ramburii, sexes of.

Agrionidae, difference in the sexes of.

Agrotis exclamationis.

Ague, tertian, dog suffering from.

Ainos, hairiness of the.

Aitchison, Mr., on sheep.

Aithurus polytmus, young of.

Albino birds.

Alca torda, young of.

Alces palmata.

Alder and Hancock, MM., on the nudi-branch mollusca.

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.

Allen, S., on the habits of Hoplopterus; on the plumes of herons; on the vernal moult of Herodius bubulcus.

Alligator, courtship of the male; roaring of the male.

Amadavat, pugnacity of male.

Amadina Lathami, display of plumage by the male.

Amadina castanotis, display of plumage by the male.

Amazons, butterflies of the; fishes of the.

America, variation in the skulls of aborigines of; wide range of aborigines of; lice of the natives of; general beardlessness of the natives of.

America, North, butterflies of; Indians of, women a cause of strife among the; Indians of, their notions of female beauty.

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.

American languages, often highly artificial.

Americans, wide geographical range of; native, variability of; and negroes, difference of; aversion of, to hair on the face.

Ammophila, on the jaws of.

Ammotragus tragelaphus, hairy forelegs of.

Amphibia, affinity of, to the ganoid fishes; vocal organs of the.

Amphibians, breeding whilst immature.

Amphioxus.

Amphipoda, males sexually mature while young.

Amunoph III., negro character of, features of.

Anal appendages of insects.

Analogous variation in the plumage of birds.

Anas.

Anas acuta, male plumage of.

Anas boschas, male plumage of.

Anas histrionica.

Anas punctata.

Anastomus oscitans, sexes and young of; white nuptial plumage of.

Anatidae, voices of.

Anax junius, differences in the sexes of.

Andaman islanders, susceptible to change of climate.

Anderson, Dr., on the tail of Macacus brunneus; the Bufo sikimmensis; sounds of Echis carinata.

Andreana fulva.

Anglo-Saxons, estimation of the beard among the.

Animals, domesticated, more fertile than wild; cruelty of savages to; characters common to man and; domestic, change of breeds of.

Annelida, colours of.

Anobium tessellatum, sounds produced by.

Anolis cristatellus, male, crest of; pugnacity of the male; throat-pouch of.

Anser canadensis.

Anset cygnoides; knob at the base of the beak of.

Anser hyperboreus, whiteness of.

Antelope, prong-horned, horns of.

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.

Antennae, furnished with cushions in the male of Penthe.

Anthidium manicatum, large male of.

Anthocharis cardamines; sexual difference of colour in.

Anthocharis genutia.

Anthocharis sara.

Anthophora acervorum, large male of.

Anthophora retusa, difference of the sexes in.

Anthropidae.

Anthus, moulting of.

Antics of birds.

Antigua, Dr. Nicholson’s observations on yellow fever in.

Antilocapra americana, horns of.

Antilope bezoartica, horned females of; sexual difference in the colour of.

Antilope Dorcas and euchore.

Antilope euchore, horns of.

Antilope montana, rudimentary canines in the young male of.

Antilope niger, sing-sing, caama, and gorgon, sexual differences in the colours of.

Antilope oreas, horns of.

Antilope saiga, polygamous habits of.

Antilope strepsiceros, horns of.

Antilope subgutturosa, absence of suborbital pits in.

Antipathy, shewn by birds in confinement, to certain persons.

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.

Ants White, habits of.

Anura.

Apatania muliebris, male unknown.

Apathus, difference of the sexes in.

Apatura Iris.

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.

Apes, long-armed, their mode of progression.

Aphasia, Dr. Bateman on.

Apis mellifica, large male of.

Apollo, Greek statues of.

Apoplexy in Cebus Azarae.

Appendages, anal, of insects.

Approbation, influence of the love of.

Aprosmictus scapulatus.

Apus, proportion of sexes.

Aquatic birds, frequency of white plumage in.

Aquila chrysaetos.

Arab women, elaborate and peculiar coiffure of.

Arabs, fertility of crosses with other races; gashing of cheeks and temples among the.

Arachnida.

Arakhan, artificial widening of the forehead by the natives of.

Arboricola, young of.

Archeopteryx.

Arctiidae, coloration of the.

Ardea asha, rufescens, and coerulea, change of colour in.

Ardea coerulea, breeding in immature plumage.

Ardea gularis, change of plumage in.

Ardea herodias, love-gestures of the male.

Ardea ludoviciana, age of mature plumage in; continued growth of crest and plumes in the male of.

Ardea nycticorax, cries of.

Ardeola, young of.

Ardetta, changes of plumage in.

Argenteuil.

Argus pheasant, display of plumage by the male; ocellated spots of the; gradation of characters in the.

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.

Argynnis, colouring of the lower surface of.

Aricoris epitus, sexual differences in the wings of.

Aristocracy, increased beauty of the.

Arms, proportions of, in soldiers and sailors; direction of the hair on the.

Arms and hands, free use of, indirectly correlated with diminution of canines.

Arrest of development.

Arrow-heads, stone, general resemblance of.

Arrows, use of.

Arteries, variations in the course of the.

Artery, effect of tying, upon the lateral channels.

Arthropoda.

Arts practised by savages.

Ascension, coloured incrustation on the rocks of.

Ascidia, affinity of the lancelet to; tad-pole like larvae of.

Ascidians, bright colours of some.

Asinus, Asiatic and African species of.

Asinus taeniopus.

Ass, colour-variations of the.

Ateles, effects of brandy on an; absence of the thumb in.

Ateles beelzebuth, ears of.

Ateles marginatus, colour of the ruff of; hair on the head of.

Ateuchus cicatricosus, habits of.

Ateuchus, stridulation of.

Athalia, proportions of the sexes in.

Atropus pulsatorius.

Attention, manifestations of, in animals.

Audouin, V., on a hymenopterous parasite with a sedentary male.

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.

Audobon and Bachman, MM., on squirrels fighting; on the Canadian lynx.

Aughey, Prof., on rattlesnakes.

Austen, N.L., on Anolis cristatellus.

Australia, not the birthplace of man; half-castes killed by the natives of; lice of the natives of.

Australia, South, variation in the skulls of aborigines of.

Australians, colour of new-born children of; relative height of the sexes of; women a cause of war among the.

Axis deer, sexual difference in the colour of the.

Aymaras, measurements of the; no grey hair among the; hairlessness of the face in the; long hair of the.

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.

Babbage C., on the greater proportion of illegitimate female births.

Babirusa, tusks of the.

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.

Baboon, Cape, mane of the male; Hamadryas, mane of the male.

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.

Baboons, courtship of.

Bachman, Dr., on the fertility of mulattoes.

Baer, K.E. von, on embryonic development; definition of advancement in the organic scale.

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.

Bailly, E.M., on the mode of fighting of the Italian buffalo; on the fighting of stags.

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.

Baird, W., on a difference in colour between the males and females of some Entozoa.

Baker, Mr., observation on the proportion of the sexes in pheasant-chicks.

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.

“Balz” of the Black-cock.

Bantam, Sebright.

Banteng, horns of; sexual differences in the colours of the.

Banyai, colour of the.

Barbarism, primitive, of civilised nations.

Barbs, filamentous, of the feathers, in certain birds.

Barr, Mr., on sexual preference in dogs.

Barrago, F., on the Simian resemblances of man.

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.

Barrow, on the widow-bird.

Bartels, Dr., supernumerary mammae in men.

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.

Bartlett, on courting of Argus pheasant.

Bartram, on the courtship of the male alligator.

Basque language, highly artificial.

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.

Bateman, Dr., tendency to imitation in certain diseased states; on Aphasia.

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.

Batokas, knocking out two upper incisors.

Batrachia, eagerness of male.

Bats, scent-glands; sexual differences in the colour of; fur of male frugivorous.

Battle, law of; among beetles; among birds; among mammals; in man.

Beak, sexual difference in the forms of the; in the colour of the.

Beaks, of birds, bright colours of.

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.

Beard, in monkeys; of mammals.

Beautiful, taste for the, in birds; in the quadrumana.

Beauty, sense of, in animals; appreciation of, by birds; influence of; variability of the standard of.

Beauty, sense of, sufficiently permanent for action of sexual selection.

Beaven, Lieut., on the development of the horns in Cervus Eldi.

Beaver, instinct and intelligence of the; voice of the; castoreum of the.

Beavers, battles of male.

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.

Beddoe, Dr., on causes of difference in stature.

Bee-eater.

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.

Beetle, luminous larva of a.

Beetles, size of the cerebral ganglia in; dilatation of the foretarsi in male; blind; stridulation of.

Belgium, ancient inhabitants of.

Bell, Sir C., on emotional muscles in man; “snarling muscles;” on the hand.

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.

Bell-bird, sexual difference in the colour of the.

Bell-birds, colours of.

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.

Benevolence, manifested by birds.

Bennett, A.W., attachment of mated birds; on the habits of Dromaeus irroratus.

Bennett, Dr., on birds of paradise.

Berbers, fertility of crosses with other races.

Bernicla antarctica, colours of.

Bernicle gander pairing with a Canada goose.

Bert, M., crustaceans distinguish colours.

Bettoni, E., on local differences in the nests of Italian birds.

Beyle, M., see Bombet.

Bhoteas, colour of the beard in.

Bhringa, disc-formed tail-feathers of.

Bianconi, Prof., on structures as explained through mechanical principles.

Bibio, sexual differences in the genus.

Bichat, on beauty.

Bickes, proportion of sexes in man.

Bile, coloured, in many animals.

Bimana.

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.

Birgus latro, habits of.

Birkbeck, Mr., on the finding of new mates by golden eagles.

Birthplace of man.

Births, numerical proportions of the sexes in, in animals and man; male and female, numerical proportion of, in England.

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.

Bishop, J., on the vocal organs of frogs; on the vocal organs of cervine birds; on the trachea of the Merganser.

Bison, American, co-operation of; mane of the male.

Bitterns, dwarf, coloration of the sexes of.

Biziura lobata, musky odour of the male; large size of male.

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.

Black-buck, Indian, sexual difference in the colour of the.

Blackcap, arrival of the male, before the female; young of the.

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.

Black-grouse, characters of young.

Blacklock, Dr., on music.

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.

Bladder-nose Seal, hood of the.

Blaine, on the affections of dogs.

Blair, Dr., on the relative liability of Europeans to yellow fever.

Blake, C.C., on the jaw from La Naulette.

Blakiston, Captain, on the American snipe; on the dances of Tetrao phasianellus.

Blasius, Dr., on the species of European birds.

Bledius taurus, hornlike processes of male.

Bleeding, tendency to profuse.

Blenkiron, Mr., on sexual preference in horses.

Blennies, crest developed on the head of male, during the breeding season.

Blethisa multipunctata, stridulation of.

Bloch, on the proportions of the sexes in fishes.

Blood, arterial, red colour of.

Blood pheasant, number of spurs in.

Blow-fly, sounds made by.

Bluebreast, red-throated, sexual differences of the.

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.

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.

Boar, wild, polygamous in India; use of the tusks by the; fighting of.

Boardman, Mr., Albino birds in U.S.

Boitard and Corbie, MM., on the transmission of sexual peculiarities in pigeons; on the antipathy shewn by some female pigeons to certain males.

Bold, Mr., on the singing of a sterile hybrid canary.

Bombet, on the variability of the standard of beauty in Europe.

Bombus, difference of the sexes in.

Bombycidae, coloration of; pairing of the; colours of.

Bombycilla carolinensis, red appendages of.

Bombyx cynthia, proportion of the sexes in; pairing of.

Bombyx mori, difference of size of the male and female cocoons of; pairing of.

Bombyx Pernyi, proportion of sexes of.

Bombyx Yamamai, M. Personnat on; proportion of sexes of.

Bonaparte, C.L., on the call-notes of the wild turkey.

Bond, F., on the finding of new mates by crows.

Bone, implements of, skill displayed in making.

Boner, C., on the transfer of male characters to an old female chamois; on the habits of stags; on the pairing of red deer.

Bones, increase of, in length and thickness, when carrying a greater weight.

Bonizzi, P., difference of colour in sexes of pigeons.

Bonnet monkey.

Bonwick, J., extinction of Tasmanians.

Boomerang.

Boreus hyemalis, scarcity of the male.

Bory St. Vincent, on the number of species of man; on the colours of Labrus pavo.

Bos etruscus.

Bos gaurus, horns of.

Bos moschatus.

Bos primigenius.

Bos sondaicus, horns of, colours of.

Botocudos, mode of life of; disfigurement of the ears and lower lip of the.

Boucher de Perthes, J.C. de, on the antiquity of man.

Bourbon, proportion of the sexes in a species of Papilio from.

Bourien on the marriage-customs of the savages of the Malay Archipelago.

Bovidae, dewlaps of.

Bower-birds, habits of the; ornamented playing-places of.

Bows, use of.

Brachycephalic structure, possible explanation of.

Brachyura.

Brachyurus calvus, scarlet face of.

Bradley, Mr., abductor ossis metatarsi quinti in man.

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.

Brakenridge, Dr., on the influence of climate.

Brandt, A., on hairy men.

Braubach, Prof., on the quasi-religious feeling of a dog towards his master; on the self-restraint of dogs.

Brauer, F., on dimorphism in Neurothemis.

Brazil, skulls found in caves of; population of; compression of the nose by the natives of.

Break between man and the apes.

Bream, proportion of the sexes in the.

Breeding, age of, in birds.

Breeding season, sexual characters making their appearance in the, in birds.

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.

Brent, Mr., on the courtship of fowls.

Breslau, numerical proportion of male and female births in.

Bridgeman, Laura.

Brimstone butterfly, sexual difference of colour in the.

British, ancient, tattooing practised by.

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.

Brodie, Sir B., on the origin of the moral sense in man.

Bronn, H.G., on the copulation of insects of distinct species.

Bronze period, men of, in Europe.

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.

Browne, Dr. Crichton, injury to infants during parturition.

Brown-Sequard, Dr., on the inheritance of the effects of operations by guinea-pig.

Bruce, on the use of the elephant’s tusks.

Brulerie, P. de la, on the habits of Ateuchus cicatricosus; on the stridulation of Ateuchus.

Brunnich, on the pied ravens of the Feroe islands.

Bryant, Dr., preference of tame pigeon for wild mate.

Bryant, Captain, on the courtship of Callorhinus ursinus.

Bubas bison, thoracic projection of.

Bubalus caffer, use of horns.

Bucephalus capensis, difference of the sexes of, in colour.

Buceros, nidification and incubation of.

Buceros bicornis, sexual differences in the colouring of the casque, beak, and mouth in.

Buceros corrugatus, sexual differences in the beak of.

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.

Bucholz, Dr., quarrels of chamaeleons.

Buckinghamshire, numerical proportion of male and female births in.

Buckland, F., on the numerical proportion of the sexes in rats; on the proportion of the sexes in the trout; on Chimaera monstrosa.

Buckland, W., on the complexity of crinoids.

Buckler, W., proportion of sexes of Lepidoptera reared by.

Bucorax abyssinicus, inflation of the neck-wattle of the male during courtship.

Budytes Raii.

Buffalo, Cape.

Buffalo, Indian, horns of the.

Buffalo, Italian, mode of fighting of the.

Buffon, on the number of species of man.

Bufo sikimmensis.

Bugs.

Buist, R., on the proportion of the sexes in salmon; on the pugnacity of the male salmon.

Bulbul, pugnacity of the male; display of under tail-coverts by the male.

Bull, mode of fighting of the; curled frontal hair of the.

Buller, Dr., on the Huia; the attachment of birds.

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.

Bullfinches, distinguishing persons; rivalry of female.

Bulls, two young, attacking an old one; wild, battles of.

Bull-trout, male, colouring of, during the breeding season.

Bunting, reed, head feathers of the male; attacked by a bullfinch.

Buntings, characters of young.

Buphus coromandus, sexes and young of; change of colour in.

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.

Burke, on the number of species of man.

Burmese, colour of the beard in.

Burton, Captain, on negro ideas of female beauty; on a universal ideal of beauty.

Bushmen, marriage among.

Bushwoman, extravagant ornamentation of a.

Bushwomen, hair of; marriage-customs of.

Bustard, throat-pouch of the male; humming noise produced by a male; Indian, ear-tufts of.

Bustards, occurrence of sexual differences and of polygamy among the; love-gestures of the male; double moult in.

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.

Butterfly, noise produced by a; Emperor; meadow brown, instability of the ocellated spots of.

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.

Buxton, C., observations on macaws; on an instance of benevolence in a parrot.

Buzzard, Indian honey-; variation in the crest of.

Cabbage butterflies.

Cachalot, large head of the male.

Cadences, musical, perception of, by animals.

Caecum, large, in the early progenitors of man.

Cairina moschata, pugnacity of the male.

Californian Indians, decrease of.

Callianassa, chelae of, figured.

Callidryas, colours of sexes.

Callionymus lyra, characters of the male.

Callorhinus ursinus, relative size of the sexes of; courtship of.

Calotes maria.

Calotes nigrilabris, sexual difference in the colour of.

Cambridge, O. Pickard, on the sexes of spiders; on the size of male Nephila.

Camel, canine teeth of male.

Campbell, J., on the Indian elephant; on the proportion of male and female births in the harems of Siam.

Campylopterus hemileucurus.

Canaries distinguishing persons.

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.

Cancer pagurus.

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.

Canfield, Dr., on the horns of the Antilocapra.

Canine teeth in man, diminution of, in man; diminution of, in horses; disappearance of, in male ruminants; large in the early progenitors of man.

Canines, and horns, inverse development of.

Canoes, use of.

Cantharis, difference of colour in the sexes of a species of.

Cantharus lineatus.

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.

Capitonidae, colours and nidification of the.

Capra aegagrus, crest of the male; sexual difference in the colour of.

Capreolus Sibiricus subecaudatus.

Caprice, common to man and animals.

Caprimulgus, noise made by the males of some species of, with their wings.

Caprimulgus virginianus, pairing of.

Carabidae.

Carbonnier, on the natural history of the pike; on the relative size of the sexes in fishes; courtship of Chinese Macropus.

Carcineutes, sexual difference of colour in.

Carcinus moenas.

Cardinalis virginianus.

Carduelis elegans, sexual differences of the beak in.

Carnivora, marine, polygamous habits of; sexual differences in the colours of.

Carp, numerical proportion of the sexes in the.

Carr, R., on the peewit.

Carrier pigeon, late development of the wattle in the.

Carrion beetles, stridulation of.

Carrion-hawk, bright coloured female of.

Carus, Prof. V., on the development of the horns in merino sheep; on antlers of red deer.

Cassowary, sexes and incubation of the.

Castnia, mode of holding wings.

Castoreum.

Castration, effects of.

Casuarius galeatus.

Cat, convoluted body in the extremity of the tail of a; sick, sympathy of a dog with a.

Cataract in Cebus Azarae.

Catarrh, liability of Cebus Azarae to.

Catarrhine monkeys.

Caterpillars, bright colours of.

Cathartes aura.

Cathartes jota, love-gestures of the male.

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.

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.

Cats, dreaming; tortoise-shell; enticed by valerian; colours of.

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.

Caudal vertebrae, number of, in macaques and baboons; basal, of monkeys, imbedded in the body.

Cavolini, observations on Serranus.

Cebus, maternal affection in a; gradation of species of.

Cebus Apella.

Cebus Azarae, liability of, to the same diseases as man; distinct sounds produced by; early maturity of the female.

Cebus capucinus, polygamous; sexual differences of colour in; hair on the head of.

Cebus vellerosus, hair on the head of.

Cecidomyiidae, proportions of the sexes in.

Celibacy, unknown among the savages of South Africa and South America.

Centipedes.

Cephalopoda, absence of secondary sexual characters in.

Cephalopterus ornatus.

Cephalopterus penduliger.

Cerambyx heros, stridulant organ of.

Ceratodus, paddle of.

Ceratophora aspera, nasal appendages of.

Ceratophora Stoddartii, nasal horn of.

Cerceris, habits of.

Cercocebus aethiops, whiskers, etc., of.

Cercopithecus, young, seized by an eagle and rescued by the troop; definition of species of.

Cercopithecus cephus, sexual difference of colour in.

Cercopithecus cynosurus and griseo-viridis, colour of the scrotum in.

Cercopithecus Diana, sexual differences of colour in.

Cercopithecus griseo-viridis.

Cercopithecus petaurista, whiskers, etc., of.

Ceres, of birds, bright colours of.

Ceriornis Temminckii, swelling of the wattles of the male during courtship.

Cervulus, weapons of.

Cervulus moschatus, rudimentary horns of the female.

Cervus alces.

Cervus campestris, odour of.

Cervus canadensis, traces of horns in the female; attacking a man; sexual difference in the colour of.

Cervus elaphus, battles of male; horns of, with numerous points; long hairs on the throat of.

Cervus Eldi.

Cervus mantchuricus.

Cervus paludosus, colours of.

Cervus strongyloceros.

Cervus virginianus, horns of, in course of modification.

Ceryle, male black-belted in some species of.

Cetacea, nakedness of.

Ceylon, frequent absence of beard in the natives of.

Chaffinch, proportion of the sexes in the; courtship of the.

Chaffinches, new mates found by.

Chalcophaps indicus, characters of young.

Chalcosoma atlas, sexual differences of.

Chamaeleo, sexual differences in the genus; combats of.

Chamaeleo bifurcus.

Chamaeleo Owenii.

Chamaeleo pumilus.

Chamaepetes unicolor, modified wing-feather in the male.

Chameleons.

Chamois, danger-signals of; transfer of male characters to an old female.

Champneys, Mr., acromio-basilar muscle and quadrupedal gait.

Chapman, Dr., on stridulation in Scolytus.

Chapuis, Dr., on the transmission of sexual peculiarities in pigeons; on streaked Belgian pigeons.

Char, male, colouring of, during the breeding season.

Characters, male, developed in females; secondary sexual, transmitted through both sexes; natural, artificial, exaggeration of, by man.

Charadrus hiaticula and pluvialis, sexes and young of.

Chardin on the Persians.

Charms, worn by women.

Charruas, freedom of divorce among the.

Chasmorhynchus, difference of colour in the sexes of; colours of.

Chasmorhynchus niveus.

Chasmorhynchus nudicollis.

Chasmorhynchus tricarunculatus.

Chastity, early estimation of.

Chatterers, sexual differences in.

Cheever, Rev. H.T., census of the Sandwich Islands.

Cheiroptera, absence of secondary sexual characters in.

Chelae of crustacea.

Chelonia, sexual differences in.

Chenalopex aegyptiacus, wing-knobs of.

Chera progne.

Chest, proportions of, in soldiers and sailors; large, of the Quechua and Aymara Indians.

Chevrotains, canine teeth of.

Chiasognathus, stridulation of.

Chiasognathus Grantii, mandibles of.

Children, legitimate and illegitimate, proportion of the sexes in.

Chiloe, lice of the natives of; population of.

Chimaera monstrosa, bony process on the head of the male.

Chimaeroid fishes, prehensile organs of male.

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.

China, North, idea of female beauty in.

China, Southern, inhabitants of.

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.

Chinsurdi, his opinion of beards.

Chlamydera maculata.

Chloeon, pedunculated eyes of the male of.

Chloephaga, coloration of the sexes in.

Chlorocoelus Tanana.

Chorda dorsalis.

Chough, red beak of the.

Chromidae, frontal protuberance in male; sexual differences in colour of.

Chrysemys picta, long claws of the male.

Chrysococcyx, characters of young of.

Chrysomelidae, stridulation of.

Cicada pruinosa.

Cicada septendecim.

Cicadae, songs of the; rudimentary sound-organs in females of.

Cicatrix of a burn, causing modification of the facial bones.

Cichla, frontal protuberance of male.

Cimetiere du Sud, Paris.

Cincloramphus cruralis, large size of male.

Cinclus aquaticus.

Cingalese, Chinese opinion of the appearance of the.

Cirripedes, complemental males of.

Civilisation, effects of, upon natural selection; influence of, in the competition of nations.

Clanging of geese, etc.

Claparede, E., on natural selection applied to man.

Clarke, on the marriage-customs of Kalmucks.

Classification.

Claus, C., on the sexes of Saphirina.

Cleft-palate, inherited.

Climacteris erythrops, sexes of.

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.

Cloaca, existence of a, in the early progenitors of man.

Cloacal passage existing in the human embryo.

Clubs, used as weapons before dispersion of mankind.

Clucking of fowls.

Clythra 4-punctata, stridulation of.

Coan, Mr., Sandwich-islanders.

Cobbe, Miss, on morality in hypothetical bee-community.

Cobra, ingenuity of a.

Coccus.

Coccyx, in the human embryo; convoluted body at the extremity of the; imbedded in the body.

Cochin-China, notions of beauty of the inhabitants of.

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.

Cock of the rock.

Cockatoos, nestling; black, immature plumage of.

Coelenterata, absence of secondary sexual characters in.

Coffee, fondness of monkeys for.

Cold, supposed effects of; power of supporting, by man.

Coleoptera, stridulation of; stridulant organs of, discussed.

Colias edusa and hyale.

Collingwood, C., on the pugnacity of the butterflies of Borneo; on butterflies being attracted by a dead specimen of the same species.

Colobus, absence of the thumb.

Colombia, flattened heads of savages of.

Colonists, success of the English as.

Coloration, protective, in birds.

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.

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.

Colquhoun, example of reasoning in a retriever.

Columba passerina, young of.

Colymbus glacialis, anomalous young of.

Comb, development of, in fowls.

Combs and wattles in male birds.

Community, preservation of variations useful to the, by natural selection.

Complexion, different in men and women, in an African tribe.

Compositae, gradation of species among the.

Comte, C., on the expression of the ideal of beauty by sculpture.

Conditions of life, action of changed, upon man; influence of, on plumage of birds.

Condor, eyes and comb of the.

Conjugations, origin of.

Conscience, absence of, in some criminals.

Constitution, difference of, in different races of men.

Consumption, liability of Cebus Azarae to; connection between complexion and.

Convergence of characters.

Cooing of pigeons and doves.

Cook, Captain, on the nobles of the Sandwich Islands.

Cope, E.D., on the Dinosauria.

Cophotis ceylanica, sexual differences of.

Copris.

Copris Isidis, sexual differences of.

Copris lunaris, stridulation of.

Corals, bright colours of.

Coral-snakes.

Cordylus, sexual difference of colour in a species of.

Corfu, habits of the Chaffinch in.

Cornelius, on the proportions of the sexes in Lucanus Cervus.

Corpora Wolffiana, agreement of, with the kidneys of fishes.

Correlated variation.

Correlation, influence of, in the production of races.

Corse, on the mode of fighting of the elephant.

Corvus corone.

Corvus graculus, red beak of.

Corvus pica, nuptial assembly of.

Corydalis cornutus, large jaws of the male.

Cosmetornis.

Cosmetornis vexillarius, elongation of wing-feathers in.

Cotingidae, sexual differences in; coloration of the sexes of; resemblance of the females of distinct species of.

Cottus scorpius, sexual differences in.

Coulter, Dr., on the Californian Indians.

Counting, origin of; limited power of, in primeval man.

Courage, variability of, in the same species; universal high appreciation of; importance of; characteristic of men.

Courtship, greater eagerness of males in; of fishes; of birds.

Cow, winter change of colour.

Crab, devil.

Crab, shore, habits of.

Crabro cribrarius, dilated tibiae of the male.

Crabs, proportions of the sexes in.

Cranz, on the inheritance of dexterity in seal-catching.

Crawfurd, on the number of species of man.

Crenilabrus massa and C. melops, nests, built by.

Crest, origin of, in Polish fowls.

Crests, of birds, difference of, in the sexes; dorsal hairy, of mammals.

Cricket, field-, stridulation of the; pugnacity of male.

Cricket, house-, stridulation of the.

Crickets, sexual differences in.

Crinoids, complexity of.

Crioceridae, stridulation of the.

Croaking of frogs.

Crocodiles, musky odour of, during the breeding season.

Crocodilia.

Crossbills, characters of young.

Crosses in man.

Crossing of races, effects of the.

Crossoptilon auritum, adornment of both sexes of; sexes alike in.

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.

Crow, Indians, long hair of the.

Crow, young of the.

Crows, vocal organs of the; living in triplets.

Crows, carrion, new mates found by.

Crows, Indian, feeding their blind companions.

Cruelty of savages to animals.

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.

Crystal worn in the lower lip by some Central African women.

Cuckoo fowls.

Culicidae, attracted by each other’s humming.

Cullen, Dr., on the throat-pouch of the male bustard.

Cultivation of plants, probable origin of.

Cupples, Mr., on the numerical proportion of the sexes in dogs, sheep, and cattle; on the Scotch deerhound; on sexual preference in dogs.

Curculionidae, sexual difference in length of snout in some; hornlike processes in male; musical.

Curiosity, manifestations of, by animals.

Curlews, double moult in.

Cursores, comparative absence of sexual differences among the.

Curtis, J., on the proportion of the sexes in Athalia.

Cuvier, F., on the recognition of women by male quadrumana.

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.

Cyanalcyon, sexual difference in colours of; immature plumage of.

Cyanecula suecica, sexual differences of.

Cychrus, sounds produced by.

Cycnia mendica, sexual difference of, in colour.

Cygnus ferus, trachea of.

Cygnus immutabilis.

Cygnus olor, white young of.

Cyllo Leda, instability of the ocellated spots of.

Cynanthus, variation in the genus.

Cynipidae, proportion of the sexes in.

Cynocephalus, difference of the young from the adult; male, recognition of women by; polygamous habits of species of.

Cynocephalus babouin.

Cynocephalus chacma.

Cynocephalus gelada.

Cynocephalus hamadryas, sexual difference of colour in.

Cynocephalus leucophaeus, colours of the sexes of.

Cynocephalus mormon, colours of the male.

Cynocephalus porcarius, mane of the male.

Cynocephalus sphinx.

Cynopithecus niger, ear of.

Cypridina, proportions of the sexes in.

Cyprinidae, proportion of the sexes in the.

Cyprinidae, Indian.

Cyprinodontidae, sexual differences in the.

Cyprinus auratus.

Cypris, relation of the sexes in.

Cyrtodactylus rubidus.

Cystophora cristata, hood of.

Dacelo, sexual difference of colour in.

Dacelo Gaudichaudi, young male of.

Dal-ripa, a kind of ptarmigan.

Damalis albifrons, peculiar markings of.

Damalis pygarga, peculiar markings of.

Dampness of climate, supposed influence of, on the colour of the skin.

Danaidae.

Dances of birds.

Dancing, universality of.

Danger-signals of animals.

Daniell, Dr., his experience of residence in West Africa.

Darfur, protuberances artificially produced by natives of.

Darwin, F., on the stridulation of Dermestes murinus.

Dasychira pudibunda, sexual difference of colour in.

Davis, A.H., on the pugnacity of the male stag-beetle.

Davis, J.B., on the capacity of the skull in various races of men; on the beards of the Polynesians.

Death’s Head Sphinx.

Death-rate higher in towns than in rural districts.

Death-tick.

De Candolle, Alph., on a case of inherited power of moving the scalp.

Declensions, origin of.

Decoration in birds.

Decticus.

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.

Deer, Axis, sexual difference in the colour of the.

Deer, fallow, different coloured herds of.

Deer, Mantchurian.

Deer, Virginian, colour of the, not affected by castration; colours of.

Deerhound, Scotch, greater size of the male.

Defensive orders of mammals.

De Geer, C., on a female spider destroying a male.

Dekay, Dr., on the bladder-nose seal.

Delorenzi, G., division of malar bone.

Demerara, yellow fever in.

Dendrocygna.

Dendrophila frontalis, young of.

Denison, Sir W., manner of ridding themselves of vermin among the Australians; extinction of Tasmanians.

Denny, H., on the lice of domestic animals.

Dermestes murinus, stridulation of.

Descent traced through the mother alone.

Deserts, protective colouring of animals inhabiting.

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.

Desmoulins, on the number of species of man; on the muskdeer.

Desor, on the imitation of man by monkeys.

Despine, P., on criminals destitute of conscience.

Development, embryonic of man; correlated.

Devil, not believed in by the Fuegians.

Devil-crab.

Devonian, fossil-insect from the.

Dewlaps, of Cattle and antelopes.

Diadema, sexual differences of colouring in the species of.

Diamond-beetles, bright colours of.

Diastema, occurrence of, in man.

Diastylidae, proportion of the sexes in.

Dicrurus, racket-shaped feathers in; nidification of.