214 - M. R. Thorpe — New Species of 



the very small diastema between the canine and P. 3 Both 

 molars are missing, but their alveoli are each 14.5 mm. 

 in length and 6 mm. wide. These molars had two stont 

 roots in a transverse line, and a third, very small, cen- 

 trally located posterior to the transverse. H. oreodontis 

 Cope is from the Upper Oligocene (John Day), while H. 

 marshi is of White River age, probably from the Oreodon 

 zone of Middle Oligocene. 



Measurements. 



mm. 



Prosthion to basion 137 



Prosthion to nasion 66 



Prosthion to bregma* : 109 



Basion to bregma* 65 



Bizygomatic diameter* 94 



Postorbital constriction 31 



Bimastoid diameter 64 



Palatal length 72.5 



Posterior palatal breadth 33 



Inferior orbital margin to alveolar margin 16 



Infraorbital foramen to posterior margin of zygomatic 



process 24 



Length of tooth row, P 3 to M 1 , inc 36 



Diastema, C to P 3 4 



Diastema, I 3 to C 3 



Crown of P 3 , length of base 12 



Crown of P 3 , maximum width 5.5 



Crown of P> length of base 20 



Crown of P 4 , maximum width 11 



* Approximate. 



Hoplophoneus latidens, sp. nov. 

 (Figs. 2 A-C; 3). 



Holotype, Cat. No. 10050, Y. P. M., White Eiver (Oligocene), near Pine 

 Bluffs, Colorado. 



The type of this species, found in 1874 by E. Def endorf , 

 consists of a nearly complete skull, atlas and axis. Both 

 second premolars are missing and the canines have been 

 restored. The left molar has been somewhat laterally 

 compressed. 



In some characteristics this specimen is closer to H. 

 robustus than to the other species of Hoplophoneus, al- 

 though there are close resemblances to H. primcBVUs 

 Leidy, and in several distinct features it differs from 



