[46] Variation of Plants and Animals, vol. ii. p. 315.
[47] The chambers are three in number. The two upper ones are occupied respectively by the male and the sitting female. The lower one serves as a general living room when the young are hatched.
[48] Note C.
[49] Since the above exposition of the theory of sexual selection was written, Mr. Poulton has published his work on the Colours of Animals. He there reproduces some of the illustrations which occur in Mr. and Mrs. Peckham’s work on Sexual Selection in Spiders, and furnishes appropriate descriptions. Therefore, while retaining the illustrations, I have withdrawn my own descriptions.
Mr. Poulton has also in his book supplied a résumé of the arguments for and against the theory of sexual selection in general. Of course in nearly all respects this corresponds with the résumé which is given in the foregoing pages; but I have left the latter as it was originally written, because all the critical part is reproduced verbatim from a review of Mr. Wallace’s Darwinism, of a date still earlier than that of Mr. Poulton’s book—viz. Contemporary Review, August, 1889.
[50] The beauty of autumnal tints in fading leaves may possibly be adduced per contra. But here we have to remember that it is only some kinds of leaves which thus become beautiful when fading, while, even as regards those that do, it is not remarkable that their chlorophyll should, as it were, accidentally assume brilliant tints while breaking down into lower grades of chemical constitution. The case, in fact, is exactly parallel to those in the animal kingdom which are considered in the ensuing paragraphs.
[51] The best treatise on this subject is Prof. Le Conte’s Evolution and its Relation to Religious Thought (Appleton & Co. 1888).
[52] See Mental Evolution in Animals, pp. 110-111.
[53] Origin of Species, 282-5.
[54] Elements of Geology, p. 587.