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1. The Order Proboscidea contains only the genus Elephas (forming a family Elephantidæ) with two existing species.
2. One of these belongs to the Oriental and the other to the Ethiopian Region.
SECTION III.—GENERAL DISTRIBUTION OF THE
The Ungulates which we now arrive at, and which constitute the ninth order of mammals according to the arrangement here adopted, contain the greater number of the largest and most highly developed forms of the whole class of mammals and embrace in their varied series nearly all the animals (such as the Horse, Sheep, Goat, Ox, Deer, Camel, and Pig) which are most useful to mankind, although we cannot always recognize the original stocks from which the domesticated forms of these animals have descended. The mode of the distribution of these Mammals over the earth's surface is, therefore, of special interest, and we must say something about each of the groups into which they are usually divided in classification. The 300 species of Ungulates usually recognized constitute
about seventy-one genera which are referred to thirteen families. Some of these families, however, have only one or two species at present existing to represent them, and the great mass of Ungulates, taking them as a whole, belong to the Ox-family, Bovide, which contains about 200 species.
SECTION IV.—DISTRIBUTION OF RHINOCEROSES
We will begin the Ungulates with what is called by naturalists the Perissodactyle section, which, although abundant in former ages, is represented in the present state of the earth’s fauna only by three distinct types forming so many families, the Rhinoceroses, the Tapirs, and the Horses. In each of these families there remain a few species only, the relics of a vast number of ancestors which have preceded them.
Of the existing Rhinocerotidæ only five well-ascertained forms are known, two of which belong to Africa and three to India, although many other species have been suggested upon more or less sufficient evidence. The Rhinoceroses of the Ethiopian Region belong to quite a distinct section of the genus from the Oriental form. These two animals commonly, though not very correctly, called the “Black" and "White" Rhinoceroses, are best distinguished by the shape of the upper lip, which in the “Black" Rhinoceros is long, pointed, and extensile, and in the “White" Rhinoceros is short, square, and truncated. The Shortlipped Rhinoceros (Rhinoceros simus), now nearly extinct, has never been met with north of the Zambesi River, which forms the northern boundary of many of the peculiar mammals of the Cape district. On the other hand, the Black Rhinoceros (R. africanus) extends from the Cape all up the Eastern side of Africa into the plains of the Atbara and Upper Nile.
The Oriental Rhinoceroses are three in number. Two of these have only one horn on the nose, while the third is provided with two of these appendages. Of the former the large Indian Rhinoceros (R. unicornis) appears to be confined to the North-eastern provinces of the Indian Peninsula, whilst the smaller one - horned form (R. sondaicus) ranges from the Sunderbunds of Bengal through the Malay Peninsula down to Java, Sumatra, and perhaps Borneo. The third Oriental species, the Sumatran Rhinoceros (R. sumatrensis), has nearly the same range as the last-named species, but appears to extend rather farther north. Thus we may consider the existing Rhinoceroses as typical forms of the Ethiopian and Oriental Regions, but not to be met with in any other part of the world's surface.
SECTION V.-DISTRIBUTION OF TAPIRS
The second family of Perissodactyle Ungulates, the Tapirs, has a still more remarkable distribution. Out of the five known species four belong to the Neotropical Region, while the fifth, which in some respects is more closely allied to one of the American Tapirs than the American Tapirs are to one another, is an inhabitant of the Oriental Region, being met with only in the Malay Peninsula and Sumatra. This is a good instance of the rare phenomenon of “discontinuous distribution” which, however, may be explained by the fact known from geology
that the Tapirs were formerly a prevalent group over a large portion of the earth's surface, so that in these days we have only to deal with a few scattered remnants of a former considerable series.
Of the American Tapirs two (Tapirus bairdi and T. dowi) are found in Central America, a third (T. roulini) occurs in the Andes of Colombia and Peru, and a fourth (T. americanus) is widely distributed over the South American continent from Venezuela to Paraguay.
The Tapirs may be therefore considered as a characteristic form of the Neotropical and Oriental Regions, and a “lipomorph” or absent form in all other parts of the world's surface.
SECTION VI.—DISTRIBUTION OF HORSES
The third family of Perissodactyle Ungulates comprises the Horses (Equidæ), now a very isolated group, although allied to the Tapirs by many extinct intermediate forms. The Horses at present known to exist in a state of nature belong to about nine species, of which three may be attributed to the Palæarctic Region and six to the Ethiopian. Among the Palearctic species the recently discovered Equus prjevalskii of the deserts of Central Asia is the sole living representative of the typical section of the genus Equus with callosities on both the fore and hind limbs. The other eight species all belong to the Asinine section, with callosities upon the hind limbs only. Unless it shall turn out to have been Equus prjevalskii, the exact
1 On the species of Horse, consult Sir William Flower's “The Horse" (London, 1891, Kegan Paul & Co.).
progenitor of our domestic Horse is extinct, but it was in all probability of Palæarctic origin.
The two Asses of Asia are the Kiang of High Tibet (Equus kiang), which is a larger animal clad with a thick coat of fur in winter, and the smaller, more sandy-coloured and thin-coated Onager (Equus onager), which occurs in many parts of the deserts of Western Asia and intrudes into the Oriental Region in Cutch. Passing on to Africa we find two members of the Asinine section still wild in the North-eastern part of that continent. These are Equus täniopus of the deserts of Nubia and E. somalicus of Somaliland. The former of these was probably the origin of our domestic Ass (Equus asinus). Going farther southwards into Africa we meet with four distinct species of the beautifully striped Asses commonly called Zebras, viz. (1) the Quagga (E. quagga) of the Cape Colony, now nearly, if not quite, extinct; (2) the Mountain Zebra (E. zebra) also confined to Africa south of the Zambesi, and now becoming extremely rare; (3) Burchell's Zebra (E. burchelli) distributed under slightly varying characters from the Transvaal to British East Africa along the eastern portion of the continent; and (4) Grévy's Zebra (E. grevii) of southern Abyssinia and Somaliland.
The Horses (Equidae) of the present epoch may, therefore, be regarded as characteristic of the Palæarctic and Ethiopian Regions.
SECTION VII.—DISTRIBUTION OF BOVINE MAMMALS
At the head of the great Arctiodactyle section of the Ungulates, which we now enter upon, we meet with the