LEPORINE HYRACOTHERE, 421 
principal difference between the dentition of the present 
genus and that of the Cheropotamus, 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 Cheropotamus. 
They present four principal conical tubercles, situated near 
1 
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, ¢) 
indicate that these teeth were relatively as large as in the 
Peceari, and that they were directed downwards. The 
temporal muscles were as well developed as in the Peceari, 
the depressed surface for their attachment (figs. 165 and 
167, ¢) 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 
inaxillary from the frontal bone. The anterior margin of 
the malar bone encroaches a little way upon the face at 
