Peterson : A New Titantothere FROAr the Uinta Eocene. 33 



Measurements. 



Skull. 



No. 2858, No. 2859, 



Mm. Mm. 

 Diameter from incisors to posterior border of glenoid cavity . . 470 



Diameter from incisors to anterior border of orbit 180' 179' 



Antero-posterior diameter of orbit .■ 67 67' 



Vertical diameter of orbit 55 



Diameter from incisors to anterior border of posterior nares . . 260 256 



Transverse diameter at the canines 93' 86 



Transverse diameter at diastema between the canines and the 



premolars 67' 67 



Transverse diameter across the horn-cores 290' 136 



Lower Jaw. 



Total length of jaw fragment 380 



Diameter from incisor to Pj 67 



Vertical diameter of ramus at Py 70^" 



Vertical diameter of ramus at M.o 80' 



Vertical diameter of ramus at Mj 92 



Dentition. 

 Plates VI-VII. 



The upper incisois and canines are well preserved, though much 

 worn in the two crania under description. The molar-premolar series 

 is less completely preserved in No. 2858, while in 2859 the superior 

 dentition is completely represented. The lateral incisor and the 

 canine of the right mandible and the complete molar-premolai series 

 of the left ramus are also present in the latter individual. 



As stated above, the median upper incisors are widely separated by 

 the deeply excavated median notch of the premaxillaiies. As seen 

 in the illustiation, the incisor series is placed well in front of the canine 

 and the arc of the circle, which their arrangement represents, is more 

 convex than in P. emarginatum. Their crowns are nearly circular 

 in outline, covered with a heavy coat of enamel, bluntly conical, 

 with a prominent cingulum at their posteiior bases. They perhaps 

 increase in size more gradually from I- to I- than in P. emarginatum. 

 The canine is relatively smaller than in the latter genus, which imparts 

 a much lighter looking aspect not only to this region of the dentition, 

 but also to the entire outline of the anterior portion of the muzzle 

 in the paratype No. 2858, as well as in the type. No. 2859. Further- 

 more the crown of the canine (especially in No. 2859) is shoiter, 



^ Approximate measurements. 



