The modern rhinoceroses are restricted to Africa, southern Asia and some of the larger Malay islands, Borneo, Sumatra and Java, and within these wide geographical limits are to be found the terminal representatives of at least three separate and quite distinct phyla, the African, Indian and Sumatran genera respectively (_Opsiceros_, _Rhinoceros_, _Dicerorhinus_). It will be advisable to begin the study of this peculiarly interesting family with a brief examination of its modern members, even though none of these are found in the western hemisphere. [Illustration: FIG. 172.—Skull of the Javan Rhinoceros (_R. sondaicus_). Note the single upper incisor, and the rough surface on the nasal bones for the attachment of the single horn.] All the existing rhinoceroses are large and massive animals, ranging from four feet to six feet six inches in height at the shoulder, and all have solid dermal horns, except in most females of the Javan species[6] (_R. sondaicus_). The Indian and Javan species have a single horn on the nose, while those of Africa and Sumatra have, in addition to the nasal horn, a second one on the forehead. The horns, thus, do not form a transverse pair, but are placed in the median line of the head, one behind the other; it should also be noted that these horns are solid, dermal structures, made up of agglutinated fibres or hairs and not having a bony core formed by outgrowths of the skull, as do the horns of most ruminants, such as oxen, sheep and antelopes, which are therefore called “hollow-horned” (Cavicornia). The skull, however, betrays the presence of horns by the extremely rough areas which serve for their attachment and thus the presence or absence of these weapons may be readily determined in the case of an extinct species of which only the skeleton remains. The skin is very thick and coarse, typically “pachydermatous,” and is quite naked in most of the species; but in the Sumatran form there is a sparse coat of hair, which is quite thick in the young animal. In the Indian _Rhinoceros unicornis_ the enormously thick skin has conspicuous and regularly arranged folds, which make the creature look as though encased in armour; the ears and tail are tufted with hair. In the African and Sumatran genera the folds are obscurely marked and not definitely arranged, giving the body a smoother appearance. All the existing species, except one, are browsers and feed upon leaves and twigs, and they frequent forests and marshes where their food is abundant. Not that these and other browsing animals do not occasionally eat grass, but it is not their principal diet. The exception noted is the largest of all the living species, the Broad-Lipped Rhinoceros (erroneously called “White”) of Africa, _Opsiceros simus_, which is strictly a grazing animal and therefore frequents more open country than the other African species, _O. bicornis_.