LEPOKINE HYRACOTHERE. 421 



principal difference between the dentition of the present 

 genus and that of the Cho3ropotamus, in which the corre- 

 sponding false molars are relatively smaller and of a simpler 

 construction, having only a single external pyramidal cusp, 

 with an internal transverse ridge or talon at its base. 

 The true molars, three in number on each side, closely 

 correspond in structure with those of the Choeropotamus. 

 They present four principal conical tubercles, situated near 

 the four angles of the quadrilateral grinding surface. Each 

 transverse pair of tubercles is connected at the anterior 

 part of their base by a ridge, which is raised midway into 

 a smaller conical tubercle with an excavated apex. The 

 crown of the tooth is surrounded by a well-marked ridge, 

 which is developed, as in the third and fourth false molars, 

 into a sharp-pointed cusp at the anterior and external angle 

 of the tooth. The hindmost molar is more contracted 

 posteriorly, and its quadrilateral figure less regular than 

 the two preceding molar. 



The sockets of the canines or tusks (figs. 165 and 166, c) 

 indicate that these teeth were relatively as large as in the 

 Peccari, and that they were directed downwards. The 

 temporal muscles were as well developed as in the Peccari, 

 the depressed surface for their attachment (figs. 165 and 

 167, t) extending on each side of the cranium as far as the 

 sagittal suture. The frontal bones (ib./*) are divided by 

 a continuation of the sagittal suture. The nasal suture, 

 s, runs transversely across the cranium parallel with the 

 anterior boundary of the orbits. The lachrymal bone, , 

 extends a very little way upon the face. The external 

 angle of the base of the nasal bone, which is of considerable 

 breadth, joins the lachrymal, and separates the superior 

 maxillary from the frontal bone. The anterior margin of 

 the malar bone encroaches a little way upon the face at 



