VERTEBRATA: MAMMALIA. 723 



(Pliocene ?) age in India we have the aberrant four-horned types 

 which constitute the genera Sivatherium and Bramatherium. 



True Bovidce occur in the Miocene (Pliocene?) of India, and 

 the Pliocene of Europe, whilst Ovidce, resembling existing types 

 are not known from deposits earlier than the Post-pliocene. 



CHAPTER LXXIII. 



DINOCERATA, TILLODONTIA, AND TOXODONTIA. 



ORDER VII. DINOCERATA. This order comprises certain 

 extraordinary extinct Mammals from the Eocene of North 

 America, which are regarded by Prof. Cope as an aberrant 

 group of Ungulates, whilst Prof. Marsh considers them as a 

 distinct order intermediate between the Perissodactyle Ungulates 

 and the Proboscidea. 



The members of this order are all of gigantic dimensions, 

 and of massive construction. Both the hind-feet and fore-feet 

 possessed five well-developed toes. The nasal bones were elongated, 

 and do not seem to have supported a proboscis. The cranium 

 carries three pairs of horn - cores, which were probably envel- 

 oped in horny sheaths. There are no upper incisors, and the 

 upper canines have the form of long tusks directed downwards. 

 (These characters are taken from Dinoceras, the best-known 

 genus of the group.) The order is distinguished from the 

 Proboscidea by the absence of upper incisors, the presence of 

 canines, the possession of three pairs of horn-cores, and the 

 absence of a proboscis. 



In Dinoceras itself, which may be taken as the type of the 

 group, we have a large animal equal in dimensions to the 

 living Elephants, which it resembles also in the osteology 

 of its limbs, in most essential respects. It is in the skull 

 (fig. 413) and dentition, however, that the most striking pecu- 

 liarities of Dinoceras are to be found. As regards the denti- 

 tion, the front of the upper jaw was destitute of incisors, and 

 probably carried a palatine pad, but there were two very large 

 canines in the form of tusks directed perpendicularly down- 

 wards ; and there was also a series of six small grinders on each 

 side. In the lower jaw are six incisors, small canines, and twelve 

 prsemolars and molars, six on each side. The dental formula 

 is thus 



