DINOCERATA. 



343 



resembles that of the Ungulata. Its molar teeth are of the 

 ungulate type, the canines are small, and in each jaw there 

 is a pair of large scalpriform incisors, faced with enamel and 

 growing from persistent pulps, as in the Rodents. The 

 second pair of incisors are small, and have not persistent 

 pulps. The adult dentition is as follows 



" There are two distinct families, Tillotkeridce (perhaps 

 identical with Anchippodontidce), in which the large incisors 



FIG. 147 i 1 ). 



571.5. 



grew from persistent pulps, while the molars had roots ; and 

 the Stylinodontidas^ in which all the teeth have persistent 

 pulps. 



One genus (Dryptodon), known only by the lower jaw, had 

 six teeth, described as " clearly incisors," the two inner pairs 

 of which are small and cylindrical, the outer of enormous 

 size, faced in front only with enamel, and with persistent 

 pulps carried back under the premolars. 



C) Upper and lower jaws of Tillotherium (Marsh). 



