546 THE WASATCH AND BEIDGEll FAUN^. 



anterior premolar (with three roots) there is no internal cinguhim, and the 



crest of the inner crescent is not carried to the external basis of the tooth, 



• and is entirely wanting on the posterior face of the tooth. The external 



crescent is more vertical and less concave. Outline of crown subtriangular. 



The transverse diameters of all the superior molars exceed their longi- 

 tudinal. In the penultimate, which may serve as a type, this superior or 

 outer plane of the inner crescent ridge extends along about .66 of the 

 posterior of the outer crescent. In the last molar the surface is very wide 

 on the posterior and inner side of the external crescent; it then contracts, 

 and expands again on the posterior side, its outer bounding crest reaching 

 to the external margin of the crown. 



Besides these points, the molars possess a strong cingulum along the 

 posterior base of the ci'own, which unites with the surface near the inner 

 protuberance of the latter in the penultimate; in the last molar it reappears, 

 forming a short lobe on the posterior face. The enamel where not worn is 

 slightly rugose. 



In the mandible the incisors radiate around the narrow extremity of 

 the trough-like symph3'sis, and have transversely expanded crowns. The 

 canine is inclined forwards, and forms part of the same series. Its crown 

 is triangular in section, the outer face convex. In the males it was enor- 

 mously enlarged, as indicated by a symphysis in my possession. The ante- 

 rior premolar approached the canine. The premolars have an external 

 chevron directed inward, whose exterosuperior surface of enamel is acute 

 cordate. Besides this is a little longitudinal ridge, which represents another 

 chevron of the true molars. On the first of the latter, both chevrons are 

 developed, the posterior the least, both with their anterior ridge boundaries 

 lowered; they sink entirely on the last two molars, which become thus 

 two-crested, as in those of some Tapiroids, and the premolars of Binotherium. 

 The last inferior molar has a narrow ledge in place of a heel, which sends 

 a nan*ow ridge upwards and outwards. There is no trace of tubercle or 

 crest in the interval between the external ends of the cross-crests. The 

 oblique anterior connecting ridges are low in the inferior molars of this 

 species. The first and second molars have posterior cingula relatively as 



