556 THE WASATCH FAUNA. 



the posterior two, the anterior ridge curves round at the apex, but is 

 separated by a considerable interruption from the posterior. The latter is 

 shortened, and terminates externally in a conic tubercle, which approaches 

 the recurved outer extremity of the anterior ridge. In the last molar the 

 posterior ridge is shorter, nearly straight, terminating abruptly at each 

 extremity. On all the tiiie molars there is a strong anterior basal cingulum 

 below the anterior transverse ridge. In the first there is also a strong pos- 

 terior basal cingulum ; but this is wanting from the second and third. A 

 short curved cingulum passes round the base of the internal extremity of 

 the posterior crest, but none passes around the interior or exterior base of 

 the anterior crest. 



The inferior premolars are represented by the first, third, and fourth. 

 The first has but one root. The crown is compressed, and the posterior heel 

 is very short, consisting of a median keel and two cingula The posterior 

 external basal angle of the V is very prominent in this species in the pos- 

 terior premolars, as in Coryphodon It is much more elevated than the 

 posterior basal angle. The heel has considerable transverse extent in the 

 fourth premolar, the internal cingulum expanding into a table. The cin- 

 gula do not extend to the internal or external bases of the crown. 



The teeth of the 3-ounger animal present the following characteristics: 



The canines are damaged, but were of large size, amounting in the upper 

 jaw to a tusk. The superior is compressed, with acute edges. The inner 

 face is gently convex, the outer more strongly so, with an acute ridge on its 

 anterior convexity inclosing an open groove with the interior cutting edge. 

 The surface of the dentine, when exposed, has a transversely wrinkled 

 character, but no trace of engine-turning in the fractures. The inferior 

 canine is subequilaterally triangular in section at the base. The posterior 

 face is slightly convex, and is separated by a very prominent angle from 

 the external face. The latter is concave next this crest-like angle, and is 

 convex anteriorly. 



The first superior true molar is similar to that of the adult specimen, 

 and is unworn. The large posterior external V is nearly flat on its externo- 

 superior face. The cingula do not pass round the internal base of the 

 crown. The enamel is finely wrinkled ; it is thrown into vertical ridges on 



