Igg THE MERYC01DODONTID/E 



angle of the chin is below P 3 . Beneath M 2 the lower border begins to descend sharply, reaching 

 its maximum below M 3 , where it has twice the depth of that below Mi. The masseteric fossa is con- 

 fined to a small area above a line along the tooth row. The condyle and coronoid are broken away. 

 The length of the dental series is two-thirds that of the total jaw. 



Foramina: The infraorbitals are large and lie above the middle of M 2 . The supraorbitals are 

 on a line above the posterior borders of the orbits, are widely separated, and are slightly nearer to 

 the median line than they are to the supraorbital borders. 



Fig. \\%,—Pronomotheriumlaticep (Douglass). Skull and jaw. GHT. Cat. No. 796 CM. 5/11 nat. size. 



(After Douglass, 1907.) 



Dentition: Superior: The incisors are small, crowded, and nearly uniform in size, although I 3 

 is slightly the largest. The canines are triangular in cross section, with the posterior side the widest. 

 The premolars and molars are strongly hypsodont, increasingly so from the anterior to the posterior 

 ones. This skull is that of a fully adult individual, and the teeth are moderately worn. P 1 is longi- 

 tudinally compressed, is inserted diagonally by two roots, and outwardly overlaps the anterior of P . 

 P 2 , though much worn, shows posteriorly a small, shallow oblique enamel lake. P 3 has a longi- 

 tudinal lake, with two pits, near the inner margin of the tooth. P 4 resembles most closely the corre- 

 sponding tooth in Merychyus elegans. Except for hypsodonty, the molars follow in general the 

 oreodont pattern, with prominent mesostyles and parastyles. 



