Peterson : A New Titanothere from the Uinta Eocene. 35 



pared present no differences of importance. The two Uinta forms 

 agree in the obscure or feeble development of the cusp-like elevations 

 on the anterior face of the molars near the inner angle, more con- 

 spicuously developed in Titanotherium. At the postero-internal angle 

 of the cingulum of M- in the Oligocene forms there is sometimes a 

 distinct tubercle, which is indicated in the Uinta forms by only a 

 slight swelling of the cingulum. 



Fig. I. Crown view of two upper molars Diploceras osborui Peterson. (Para- 

 type. No. 2860a.) X 2- These isolated teeth were found with the Paratype, 

 No. 2860. 



In proportion the inferior incisor dentition is further in advance 

 of the canine than in P. emarginatum. ly and ly are represented 

 only by a portion of their roots buried in the symphysis. Ig- has a 

 very prominent cingulum posteiiorly. Notwithstanding the much 

 smaller size of the specimen, its crown has ver^^ nearly the same 

 diameter as in P. emarginatum, which would indicate that the inferior 

 incisors were possibly larger in proportion, and more nearly equal in 

 size. The crown of the canine is injured, but its diameteis appear 

 to be equal to those in the superior series, though relatively smaller 

 than in P. emarginatum. Py has a single root and a simple conical 

 crown, which has not received any wear due to its somewhat inferior 

 position. Pa" is submolariform and in its general characters does not 

 differ from the same tooth in P. emargi?iatum. P-g is quite molariform, 

 while Py has a complete molar pattern. 



There is no difference in the general features of the lower molars 

 in the two genera here compared, and in turn the molars of Diplacodon 

 are on the whole quite similar in their detailed structure to those of 

 the Oligocene genus. 



The proportion of the alveolar border occupied by the lower pre- 

 molars of this species is in accord with the upper series, i. e. of a greater 



