202 Annals of the Carnegie Museum. 



postorbital and zygomatic processes are of the same shape as in 

 P. carrikeri. 



One of the chief characters of this species is the shortening of 

 the nasals and the obliquity of the anterior nares. This is a constant 

 feature of all the specimens of this species at hand, and is distinctly 

 different from what is seen in P. carrikeri. The anterior free ends are 

 rounded to a blunt point and overhang the nares much in the same 

 way, though further back than in P. chelydra, P. hoUandi, and 

 P. carrikeri. 



THE MANDIBLE. 



The right ramus of the type is preserved. In addition to this we 

 possess other lower jaws and fragments of the jaws of other individuals 

 of the same species. The incisor alveolar border is more produced 

 and rounded so that the incisors and canines form a more curved line 

 from side to side between the first premolars than in P. carrikeri. 



Fig. 33. Lateral view of mandible of Promerycochxrus vantasselensis. 

 No. 1230; 5 nat. size. 



The symphysis is quite strong, but the chin is not nearly as wide 

 as in the latter species. The ramus of the type. No. 1230, unfortunately 

 lacks the angle and coronoid process, but No. 1232 has the lower jaws 

 nearly complete and shows no other important differences from 

 P. carrikeri, except those stated above. 



M EASUREMENTS. 



No. 1230 



(Type) 



Mm. 



Skull, total length 320 



Skull, length from occipital condyle to and including incisors 305 



Skull, length from anterior tip of nasals to anterior border of the orbit 115 



Skull, length from anterior border of orbit to condyles 172 



Skull, length of alveolar border from incisors to back of molar three. 170 

 Skull, length from end of alveolar border of maxillary to occipital 

 condyle 127 



