510 



LAND MAMMALS IN THE WESTERN HEMISPHERE 



indeed, the first specimen of this genus collected was referred 

 to a large species of ^Nesodon by Owen. On the other hand, 

 the resemblance to the rhinoceros teeth is very decided, and 

 has led several writers to postulate a relationship between the 

 jastrapotheres and the rhinoceroses. The lower molars were 



Fig. 254. — HeadoffAstrapotheriumma^num. Santa Cruz. Re- 

 stored from a skull in the museum of Princeton University. 



of the bicrescentic pattern so frequently met with already; 

 these teeth were very narrow in proportion to their length 

 and strongly suggest those of \Metamynodon, the supposedly 

 aquatic rhinoceros of the North American Oligocene (p. 

 346). It may be confidently inferred that so small a numbfer 

 of premolars was due to reduction from a full series, and this is 

 confirmed by the milk-dentition, in which the premolars were f . 



