182 ON THE EXTINCT MAMMALIA OF 



the fore part of the lachrymal descends obliquely backward between the malar and 

 maxillary. 



The premaxillaries extend upward and backward between the nasals and maxilla- 

 laries to a point ending above the position of the second premolar. 



Mandible. — The posterior portion of the lower jaw is remarkable for its shallow- 

 ness, resembling in this respect more nearly the condition in the Peccary than the 

 Hog. Its outer surface is depressed into a broad shallow concavity, as in Choerodes, 

 extending from beneath the condyle nearly to the base of the bone. 



The angle of the jaw is obtuselj' angular, and is produced to about the same extent 

 both backward and downward. The posterior border of the jaw is vertically concave. 



The condyle is mutilated, and the coronoid broken away in the specimen under 

 examination, but the former appears to have been a [transverse convexity as in the 

 Peccary, while the latter was also probably broad and short as in this animal. 



The chin in its breadth resembles the condition in recent suilline animals, but 

 most resembles the corresponding part in the Peccary. It is especially remarkable 

 for the possession, on each side, of a large mammillary protuberance, curving out- 

 wardly from the base. It is transversely convex above, but becomes concave below, 

 between the position of the mental protuberances. The slope of the chin is 

 about 45°. 



The outer surface of the horizontal ramus of the jaw is slightly convex below the 

 position of the molars, but is rather concave anteriorly. 



From the thick rounded base of the lower jaw, beneath the position of the third 

 and fourth premolars, there projects another strong mammillary protuberance, like 

 that of the chin, but smaller. A similar process occupies a corresponding position in 

 the extinct Anthracotliermm. 



The principal mental foramen occupies a position just above the base of the mental 

 protuberance. 



Dentition. — The teeth of Elotherium appear to have been as many and to have held 

 nearly the same relative position with one another as in the Hog. Such is certainly 

 the case in the specimens which we have referred to this genus. 



The upper true molars have cuboidal crowns, with convex sides and rounded 

 borders. The lower half of the crowns, forming the triturating surfaces, are com- 

 posed of two rows each of three conical lobes, bounded anteriorly by a thick terrace- 

 like basal ridge. 



The last of the upper true molars is the smallest, and its crown is less cuboidal and 

 more ovoidal than in the others. Its posterior lobes are more rudimental and broken, 

 and of the anterior lobes the intermediate one is feebly developed. 



The second upper true molar is the largest of the series. Of its six lobes the 



