possessed by the males alone-Orthoptera, musical instruments of the males, much diversified in structure; pugnacity; colours— Neuroptera sexual differences in colour-Hymenoptera, pug- nacity and colours-Coleoptera, colours; furnished with great horns, apparently as an ornament; battles; stridulating organs Courtship of butterflies-Battles-Ticking noise-Colours common to both sexes, or more brilliant in the males-Examples-Not due to the direct action of the conditions of life - Colours adapted for protection-Colours of moths-Display-Perceptive powers of the Lepidoptera-Variability-Causes of the difference in colour between the males and females-Mimicry, female butterflies more brilliantly coloured than the males-Bright colours of caterpillars-Summary and concluding remarks on the secondary sexual characters of insects-Birds and insects PAGE FISHES: Courtship and battles of the males-Larger size of the females-Males, bright colours and ornamental appendages; other strange characters-Colours and appendages acquired by the males during the breeding-season alone-Fishes with both sexes brilliantly coloured-Protective colours-The less con- spicuous colours of the female cannot be accounted for on the principle of protection-Male fishes building nests, and taking charge of the ova and young. AMPHIBIANS: Differences in structure and colour between the sexes-Vocal organs. REP- TILES: Chelonians-Crocodiles-Snakes, colours in some cases protective - Lizards, battles of - Ornamental appendages Choice exerted by the female-Length of courtship-Unpaired birds-Mental qualities and taste for the beautiful-Preference or antipathy shewn by the female for particular males-Vari- ability of birds-Variations sometimes abrupt-Laws of varia- Discussion as to why the males alone of some species, and both sexes of others are brightly coloured-On sexually-limited inheritance, as applied to various structures and to brightly- The immature plumage in relation to the character of the plumage in both sexes when adult-Six classes of cases-Sexual differ- ences between the males of closely-allied or representative species-The female assuming the characters of the male- Plumage of the young in relation to the summer and winter plumage of the adults-On the increase of beauty in the birds SECONDARY SEXUAL CHARACTERS OF MAMMALS. The law of battle-Special weapons, confined to the males-Cause of absence of weapons in the female-Weapons common to both sexes, yet primarily acquired by the male-Other uses of such weapons-Their high importance-Greater size of the male- Means of defence-On the preference shewn by either sex in the case of the female being more ornamented than the male- Colour and ornaments due to sexual selection-Colour acquired for the sake of protection-Colour, though common to both sexes, often due to sexual selection-On the disappearance of spots and stripes in adult quadrupeds-On the colours and orna- PAGE interfere with sexual selection in civilised and savage nations -Conditions favourable to sexual selection during primeval times-On the manner of action of sexual selection with man- kind-On the women in savage tribes having some power to THE DESCENT OF MAN; AND SELECTION IN RELATION TO SEX. INTRODUCTION. THE nature of the following work will be best understood by a brief account of how it came to be written. During many years I collected notes on the origin or descent of man, without any intention of publishing on the subject, but rather with the determination not to publish, as I thought that I should thus only add to the prejudices against my views. It seemed to me sufficient to indicate, in the first edition of my Origin of Species,' that by this work "light would be thrown on the "origin of man and his history;" and this implies that man must be included with other organic beings in any general conclusion respecting his manner of appearance on this earth. Now the case wears a wholly different aspect. When a naturalist like Carl Vogt ventures to say in his address as President of the National Institution of Geneva (1869), "personne, en Europe "au moins, n'ose plus soutenir la création indépendante et de "toutes pièces, des espèces," it is manifest that at least a large number of naturalists must admit that species are the modified descendants of other species; and this especially holds good with the younger and rising naturalists. The greater number accept the agency of natural selection; though some urge, whether with justice the future must decide, that I have greatly overrated its importance. Of the older and honoured chiefs in natural science, many unfortunately are still opposed to evolution in every form. In consequence of the views now adopted by most naturalists, and which will ultimately, as in every other case, be followed by B others who are not scientific, I have been led to put together my notes, so as to see how far the general conclusions arrived at in my former works were applicable to man. This seemed all the more desirable, as I had never deliberately applied these views to a species taken singly. When we confine our attention to any one form, we are deprived of the weighty arguments derived from the nature of the affinities which connect together whole groups of organisms-their geographical distribution in past and present times, and their geological succession. The homological structure, embryological development, and rudimentary organs of a species remain to be considered, whether it be man or any other animal, to which our attention may be directed; but these great classes of facts afford, as it appears to me, ample and conclusive evidence in favour of the principle of gradual evolution. The strong support derived from the other arguments should, however, always be kept before the mind. The sole object of this work is to consider, firstly, whether man, like every other species, is descended from some preexisting form; secondly, the manner of his development; and thirdly, the value of the differences between the so-called races of man. As I shall confine myself to these points, it will not be necessary to describe in detail the differences between the several races-an enormous subject which has been fully discussed in many valuable works. The high antiquity of man has recently been demonstrated by the labours of a host of eminent men, beginning with M. Boucher de Perthes; and this is the indispensable basis for understanding his origin. I shall, therefore, take this conclusion for granted, and may refer my readers to the admirable treatises of Sir Charles Lyell, Sir John Lubbock, and others. Nor shall I have occasion to do more than to allude to the amount of difference between man and the anthropomorphous apes; for Prof. Huxley, in the opinion of most competent judges, has conclusively shewn that in every visible character man differs less from the higher apes, than these do from the lower members of the same order of Primates. This work contains hardly any original facts in regard to man; but as the conclusions at which I arrived, after drawing up a rough draft, appeared to me interesting, I thought that they might interest others. It has often and confidently been asserted, that man's origin can never be known: but ignorance more frequently begets confidence than does knowledge it is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science. The conclusion that man is the co-descendant with other species of some ancient, lower, and extinct form, is not in |