842 THE JOHN DAY FAUNA. 



by a wide groove. The anterior base is opposite the second molar. The 

 incisive alveolus is continued upwards and backwards, and ceases in a pro- 

 tuberance which is external to the plate which connects the condyle with 

 the coronoid process, and is separated from it by a fossa. The condyle is 

 subglobular, and has considerably more external than internal articular 

 surface. The series of inferior molar teeth is quite oblique, descending- 

 posteriorly. 



Dentition. — The grinding surfaces of the superior molars are none of 

 them longer than wide, and in all but the first, the transverse diameter 

 exceeds the anteroposterior. The dimensions diminish posteriorly in all 

 the measurements. There is one inflection of the sheathing enamel on 

 each side of the crown in all the molars in their present state of wear. 

 The positions of the lakes indicate that in an earlier stage there were two 

 external inflections. At present all the molars display a fossette external 

 to the fundus of the internal inflection. Besides this there are two others 

 in the first molar, and one other in the fourtli. Posterior to the external 

 inflection there is one fossette in the first and third molars, two on the 

 fourth, and none on the second, where it is probably worn out. According 

 to Leidy there are three in this position in all the molars in the C. nehras- 

 censis, and two in the position first described. According to Filhol, there 

 is but one in each position, in about the same stage of wear, in the C. vicia- 

 censis. 



The inferior molars display a deep external inflection, and three trans- 

 verse lakes on the inner side. These probably represent inflections at an 

 earlier stage of wear; the median one is still continuous with the sheathing 

 enamel on the first molar (Pm. IV). The sizes of the inferior molars 

 increase anteriorly regularly, excepting that the first is relativel}' a little 

 longer than the others. 



Measurements of skull. 



u. 



Length from inion to edge of nasals 067 



Length from edge of nasals to interorbital constriction 034 



Length of muzzle to preorhital angle of maxillary 018 



Width of skull at paroccipitals 025- 



Width of skull at posterior edge of squamosal 034 



Width at zygomata posteriorly U56 



Width at interorbital constriction 006 



