Page:The Zoologist, 4th series, vol 2 (1898).djvu/503

Rh belonging to all classes, I cannot avoid the conclusion that the curiously-arranged colours of many Antelopes, though common to both sexes, are the result of sexual selection primarily applied to the male." And he subsequently remarks: "Nevertheless, he who attributes the white and dark vertical stripes on the flanks of various Antelopes to this process will probably extend the same view to the royal Tiger and beautiful Zebra." Mr. Wallace estimates the derivative process of spots and stripes as a purely protective one:—"In mammalia we notice the frequency of rounded spots on forest or tree-haunting animals of large size, as the forest Deer and the forest Cats; while those that frequent reedy or grassy places are striped vertically, as the Marsh Antelopes and the Tiger." And again: "It is the black shadows of the vegetation that assimilate with the black stripes of the Tiger; and in like manner, the spotted shadows of leaves in the forest so harmonize with the spots of Ocelots, Jaguars, Tiger-cats, and Spotted Deer, as to afford them a very perfect concealment." This last view seems borne out by all the facts at our disposal, and as adaptation implies a previous state of variation, which again predicates a more or less stable condition from which variation arose, we come to the conclusion that the pre-variable condition was a unicolorous one, and from the data—scanty indeed—at our disposal, are inclined to suggest that the unicolorous hue was originally due to assimilative colouration. The wild Horse of Asia is said to be of a dun colour, while those of South America are described as commonly chestnut or bay coloured. Why is this?—the question bristles with present difficulties. In the writings of pre- and anti-Darwinian naturalists are often found remarks and statements unconsciously supportive of the future theory. Thus Charles Waterton, in describing the faunistic features of the Demerara forest, writes: "The naturalist may exclaim that nature has not known where to stop in forming new species, and painting her requisite shades" ; while Frank Buckland from a teleological point of view had pointed out that the striped coat of the Tiger was "most suited" to his environ-