Page:Popular Science Monthly Volume 73.djvu/508

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THE POPULAR SCIENCE MONTHLY

scribed in their grayer color and smaller hoofs approximate to the wild asses of Africa, especially to those of Somaliland, whilst it is maintained that in their cry, as well as in their color, the kiang and dzeggetai come closer to the horse, whose next neighbors they are.

Passing to Africa, we find the ass of Nubia and Abyssinia showing a shoulder stripe, and frequently with very strongly defined narrow stripes on the legs, the ears being longer than those of the onager. But in closer proximity to southwestern Asia comes the Somali ass, which differs from those of Nubia and Abyssinia by being grayer in color, by the entire absence of shoulder stripes and by smaller ears, in all which characteristics it comes closer to its neighbors on the Asiatic side than it does to its relations in Abyssinia and Nubia.

Next we meet the zebras. First comes the magnificent Grévy zebra of Somaliland, Shoa and British East Africa. It is completely striped down to its hoofs, but the coloration of the specimens from Shoa differs from that of those from Somaliland, and from those of British East Africa. The Grévy zebra has its hoofs rounded in front like those of a horse, but its ears are more like its neighbors, the asses, than those of any other zebra.

In the region north of the river Tana the Burchelline group of zebras overlaps the Grévy, and though it differs essentially in form, habits and shape of its hoofs from the Grévy, some of those in the neighborhood of Lake Barringo show gridiron markings on the croup like those on the Grévy zebra, whilst, like the latter, they also possess functional premolars.

All the zebras of the equatorial regions are striped to the hoofs, but when we reach the Transvaal, the Burchelline zebra, known as Chapman's, is divesting itself of stripes on its legs, whilst the ground color is getting less white and the stripes less black. Farther south the true Burchell zebra of the Orange River has completely lost the stripes on its legs and under surface, its general coloring being a pale yellowish brown, the stripes being dark brown or nearly black. South of the Orange River the now extinct quagga of Cape Colony had not only begun to lose the stripes of its under part and on the hind quarters, but in Daniell's specimen they only survived on the neck as far as the withers, the animal having its upper surface bay and a tail like that of a horse, whilst all specimens of quagga show a rounded hoof like that of a horse.

In the quagga of 30°-32° S. we have practically a bay horse corresponding to the bay Libyan horse of lat. 30°-32° N.

But the production of such variations in color do not require great differences in latitude. On the contrary, from a study of a series of skins of zebras shot for me in British East Africa, each of which is from a known locality and from a known altitude, there can be no