[902.] 



Osboni, Oligocene Titanoiheres. 



95 



gate and square; incisors vestigial; canines very long and pointed; 

 cingulum progressively developing ; premolars f ; buccal pro- 

 cesses of zygomata deep rather than broad. 



Genus TITANOTHERIUM Leidy. 



The type of the genus is T. proutii Leidy, represented by 

 the posterior portion of a jaw fortunately preserved in the 

 National Museum, recorded from the base of the Titanothe- 

 rium Beds. The genus is further characterized by a com- 

 parison of T. heloceras, T. trigonoceras, and T. ingens. It 

 may have taken origin from Diplacodon elatus or D. emargi- 

 natus of the Upper Eocene or Uinta Beds. 



s pw 

 Fig. 2. Titanotherium heloceras (Cope). (U. S. Nat. Mus. No. 4260, Sk. Q.) X \. 



LOWER BEDS. 



T. heloceras Cope. — This is probably the earliest and most 

 primitive representative of the long-skulled series. The doubt 



