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Show 288 DARWINISM C'liAI'. beak towards tho female, and chuckles with delight," while he has never seen the more plain coloured thrush demonstrative to the female. The linnet distends his rosy breast, and slightly expands his hrown wings and tail ; while ~he various gay coloured Australian finches adopt such attitudes and postures as, in every case, to show off their variously coloured plumage to the best advantagc.1 A 1'he01·,11 of Animal Coloration. Having rejected Mr. Darwin's theory of female choice aR incompetent to account for tho brilliant colours and markings of the higher animals, tho preponderance of these colours and markings in the male sex, and their display during periods of activity or excitement, I may be asked what explanation I have to offer as a preferable substitute. In my Tnpicrrl Nattwe I have already indicated such a theory, which I will now briefly explain, supporting it by some additional fads and arguments, which appear to me to have groat weight, and for which I am mainly indebted to a most interesting atHl suggestive posthumous work by Mr. Alfred Tylor. 2 The fundamental or ground colours of animals arc, as has been shown in preceding chapters, very largely protocti\'C', and it is not improbahle that tho primitive colours of a 11 animals were so. During the long course of animal development other modes of protection than concealment by harmony of colour arose, and thenceforth the normal development of colour due to tho complex chemical and structural changes ever going on in the organism, had full play; and the colours thus produced wore again and again modified by natural selection for purposes of warning, recognition, mimicry, or special protection, as has been already fully explained in the preceding chapters. Mr. Tylor has, however, called attention to an importan t • principle which underlies the various patterns or ornammttal markings of animals-namely, that diversified colomtion follows the chief lines of structure, and changes at points, snch as the joints, where function changes. He says, "If we take highly decorated species-that is, animals marked hy 1 Descent qf Alan, pp. 401, 402. 2 C'olorctlion in Animals and l'lauts, Loudou, 1386. x COLOURS AND ORNAMENTS CITARACTERISTIC OF SEX 28!) alternate dark or light bands or spots, such as the zebra, some deer, or tho carnivora, we find, first, that the region of the spinal column is marked by a dark stripe; secondly, that the regions of the appendages, or limbs, arc differently marked ; thirdly, that the flanks are striped or spotted, along or between tho regions of tho lines of tho ribs; fourthly, that tho shoulder and hip regions are marked by curved lines; fifthly, that tho pattern changes, and the direction of the lines, or spots, at tho head, neck, and every joint of tho limbs; and lastly, that the tips of the ears, nose, tail, and feet, and the eye are emphasised in colour. In spotted animals the greatest length of the spot is generally in the direction of the largest development of the skeleton." This structural decoration is well seen in many insects. In caterpillars, similar spots and markings a.ro repeated in each segment, except where modified for some form of protection. In butterflies, the spots and bands usually have reference to the form of the wing and the arrangement of the nervures ; and there is much evidence to show that the primitive markings arc always spots in tho cells, or between tho ncrvurcs, or at the junctions of norvures, the extension and coalescence of these spots forming borders, bands, or blotches, which have become modified in infinitely varied ways for protection, warning, or recognition. Even in hirds, the distribution of colours and markings follows generally the same law. The crown of the head, the throat, the car-coverts, and tho eyes have usually distinct tints in all highly coloured birds ; the region of the furcula has often a distinct patch of colour, as have the pectoral muscles, the uropygium or root of the tail, and the under tail-coverts.1 Mr. Tylor was of opinion that the primitive form of ornamentation consisted of spots, tho confluence of these in certain directions forming lines or bands; and, these again, sometimes coalescing into blotches, or into more or less uniform tints covering a large portion of the surface of the body. The young lion and tiger are both spotted; and in the Java hog (Sus vittatus) very young animals arc banded, but have spots over the shoulders and thighs. Those spots run into stripes 1 Coloration of Animals, PI. X, p. 90; and Pis. II, III, and IV, pp. 30, 40, 42. u |