1006 dr. j. e. gray on the rhinocerotid^. [dcc. 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 hones produced, conical. Asiatic Rhinocerotes. 



1. Rhinoceros. 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. Ceratorhinus. Horns two, one behind the other. Lumbar and 



neck-folds of the skin rudimentary. Occipital end of the skull 

 flat. Condyle not prominent. 



IL 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. Ceratotherium. 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, sepa- 

 rated by distinct folds. Nose-horn single, or with a small 

 second hinder one ; nasal bones produced, conical, acute ; in- 

 ternasals cartilaginous ; intermaxillary well developed, free; 

 upper cutting-teeth two, compressed, ivell developed. Lower 

 jaw attenuated in front, with a straight lower edge. Teeth 



Rhinoceros § 2, Giebel, 20.5. 



Rhinoceros, Gray, List of Mamm. 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. 



