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Show 1006 DR. J. E. GRAY ON THE RHINOCEROTID^E. [Dec. 12, SYNOPSIS OF THE GENERA. I. The skin divided into shields by well-marked folds. Skull with the intermaxillary free, elongate; upper cutting-teeth long; nasal bones produced, conical. Asiatic Rhinocerotes. 1. R H I N O C E R O S . Horn single, anterior. Lumbar- and neck-folds of the skin well developed. Part of the occipital bone, near the occipital condyle, and the condyles themselves prominent. 2. C E R A T O R H I N U S . Horns two, one behind the other. Lumbar and neck-folds of the skin rudimentary. Occipital end of the skull flat. Condyle not prominent. II. Skin uniform, not divided into shields. Horns two. Skull:- internasal cartilaginous ; intermaxillary free, very small; upper cutting-teeth none ; nasal bones broad, rounded. African Rhinocerotes. 3. RHINASTER. Head short, compressed; upper lip with a central prominence. Skull short behind ; occiput erect; nasal bones rounded in front; lower jaw thick in front; grinders small, in arched series. 4. C E R A T O T H E R I U M . Head elongate, truncated ; upper lip square. Skull elongate and produced behind; occiput erect, produced above; nasal bones broad, convex, truncated, and sharp-edged in front; lower jaw tapering in front; grinders large, in straight lines. III. Skin uniform, not divided into shields. Horn single. Skull:- internasal bony; nasal, internasal, and intermaxillary all united into one mass. Asia and Europe. 5. CCELODONTA. I. The ASIATIC RHINOCEROTES. Skin divided into shields, separated by distinct folds. Nose-horn single, or with a small second hinder one; nasal bones produced, conical, acute ; internasals cartilaginous; intermaxillary well developed, free; upper cutting-teeth two, compressed, well developed. Lower jaw attenuated in front, with a straight lower edge. Teeth 34-.-J.S- ag. *-*•£• M.&. Rhinoceros § 2, Giebel, 205. Rhinoceros, Gray, List of M a m m . B. M . 1840. Rhinoceros munis de dents incisives, Cuvier, Oss. Foss. ii. 89. The British Museum has a series of skulls of the four Asiatic species, showing the form of the skull in the different ages of the animal, from the just born to the adult or senile state. There is a considerable difference in the form of the skull between the species which has one and that which has two horns, especially in the form of the occipital end of the skull and in the size of the occipital condyles. The difference is well represented in Bell's figure of the skull of the Sumatran animal. |