328 LAND MAMMALS IN THE WESTERN HEMISPHERE 



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 



Fig. 172. — Skull of the Javan Rhinoceros (fl. sondaicus). Note the single upper inci- 

 sor, and the rough surface on the nasal bones for the attachment of the single horn. 



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 pres- 

 ence 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 



