THE TAPIEID^. 363 



The characters of tlie fcetal membranes and the nature 

 of the placentation are unknown. 



At the present day the genus Bhinoceros is confined to 

 Africa and Asia. The African species all have two horns, 

 a nearly smooth skin, and the adult has no incisors. The 

 Asiatic species have one horn only (except that of Sumatra, 

 which has two). The skin is marked out by deep folds into 

 shields, and the adults have well-developed incisors. 



Rhinoceroses are known in the fossil state as far back 

 as the miocene epoch. B. tichorhinus, with the nasal 

 septum ossified, and a covering of long woolly hair, in- 

 habited Europe and Asia during the cold of the glacial 

 epoch. R. incisivus had four digits in the manus, and 

 larger incisor teeth than any existing species. B. hexa- 

 protodon had more numerous incisors than any other 

 species. 



c. In the Tapiridce there are four toes on the front foot, 

 though the ulnar digit does not reach the ground. The 

 hind foot has three toes. 



The dental formula is i. — — c. ,^-r p.m. ^- m. — . 



o'o I'J. 3'o 3*3 



The molar teeth each present two transverse, or slightly 

 oblique, ridges, connected by a low wall externally. 



The skin is soft and hairy, and the muzzle and snoiit are 

 prolonged into a short proboscis. 



The Tapirs have twenty-three or twenty-four dorsolumbar 

 vertebrse, of which nineteen, or twenty, are usually dorsal. 

 The centra of these vertebrae, and the transverse processes of 

 the last lumbars, have the same peculiarities as those of the 

 Horse and Rhinoceros. There are seven sacral and about 

 twelve caudal vertebrae. The skull is partly Rhinocerotic, 

 partly Equine in its characters. Thus there is a sagittal 

 crest — the post-tympanic processes are large, but they are 

 not so long as the paramastoids, and they do not imite with 

 the post-glenoidal pi'ocesses beneath the meatus. In these 

 respects the Tapir is Horse-like, but in the following it is 

 more Rhinocerotic. 



Thus the tympanic is quite radimentary ; the post- 



