Page:The Zoologist, 4th series, vol 2 (1898).djvu/502

470 are emphasized in colour. In spotted animals the greatest length of the spot is generally in the direction of the largest development of the skeleton." Mr. Tylor had assuredly not read an African observation made by the late Dr. Livingstone, or he would have as certainly incorporated it in his essay as evidence for his theory, and which it may be almost said to have partly anticipated. Dr. Livingstone writes:—"The Poodle Dog Chitane is rapidly changing the colour of its hair. All the parts corresponding to the ribs and neck are rapidly becoming red; the majority of country Dogs are of this colour." Emin Pasha does not corroborate this statement of Livingstone respecting the markings of Central African Dogs. He describes them as "usually of a buff colour." As regards the reddish colour of the Central African Dogs as described by Livingstone, it must be remembered that many domesticated Dogs are considered to have been the result of taming different wild species of Canidae, and that the Black- backed Jackal (Canis mesomelas), which is found from Nubia to the Cape, has a light red skin with a black dorsal stripe. According to Lydekker, in the Prairie Wolf of North America (Canis latrans), "the colour varies considerably at different seasons of the year, being of a bright fulvous-brown in summer, and grey or greyish in winter; this ground colour at both seasons being overlaid with a shading of black, which tends to form stripes along the back and across the shoulders and loins." Another peculiarity in African Dogs has been recorded by Blumenbach:—"The Guinea Dog (which Linnæus calls C. ægyptius—I do not know why) is, like the men of that climate, distinguished for the velvety softness of his smooth skin, and the great and nearly specific cutaneous perspiration." Darwin, discussing the animals under consideration, is inclined to ascribe spots and stripes as due to his theory of "sexual selection," the ornamentation having firstly been acquired by the males, and then transmitted equally, or almost equally, to both sexes. He adds: "After having studied to the best of my ability the sexual differences of animals