222 
CORYPnODON. 
anterior of which continues as a basal cingulum to the postero-exterior 
angle of the tooth. 
The crowns of the premolars consist of a large external and 
smaller internal V, the latter of which in the first is a mere internal 
cingulum. The external V is concave on its extern-inferior side or back, 
and has a strong convexity at the base of each border. It is nearly flat in 
the first premolar. 
The portions of the mandible which, from the place of their discovery, 
might be supposed to pertain to the cranium described, are found to fit into 
their presumed positions. Thus the symphysis presents the wide and rather 
flat form of the premaxillary region, and the canines and incisors apply 
readily. So also do the premolars and molars, especially in a peculiarity 
of wear of the first premolars and the worn condition of the first true 
molar. The inferior incisors are nearly in contact by the lateral angles of 
their crowns. The external are smallest, and exhibit an obtuse vertical 
ridge just external to the middle of the interior face. The same ridge 
exists in the second incisors nearer the external border, with which it 
incloses a fossa. There is no diastema in front of the canine. The latter 
is robust and is turned outward, the apical portion being at right angles to 
the long axis of the skull. The interior face is flat, as in other species, and 
the exterior very convex. The posterior aspect is worn into a transverse 
face by the attrition of the superior canine. The antero-interior angle of 
the crown is prominent, but its apical portion is worn by the outer edge of 
the external superior incisor. The section of the crown is generally trihedral. 
The diastema is short. The incisive alveolar margin is a regular broad 
curve, and the floor of the mouth gradually deepens to between the diaste- 
mata. The premolars of the left ramus are so crowded as to strongly impress 
each other. The posterior median longitudinal crest is distinct but short in 
all; and, in the third and fourth, the posterior base of the internal V is 
protuberant upward. The first true molar is deeply impressed by the 
adjacent premolar. Its anterior descending cingulum is well developed, 
while the posterior cross-crest abuts immediately on the following molar. 
This, the penultimate, shows cross-crests, which, though worn, have never 
been so elevated as in C. radians and C. latidens. The anterior descending 
