CORYPnODON. 
223 
cingulum is strong; the posterior cingulum, or heel, is well developed, com¬ 
mencing at the base of the inner cusp. On the last molar, it was doubtless 
larger. 
The enamel on all the molars, canines, and incisors, where not worn, 
is finely wrinkled. 
The cranium of this species furnished the opportunity of obtaining a 
cast of the brain. This has been described in its principal features under 
the head of the genus, and is figured on Plate LI of the present work. The 
slight distortion of the skull consequent on pressure is also visible in the 
brain. The cast terminates at the foramen magnum, not extending posterior 
to the cerebellum; here its transverse diameter exceeds that at the cerebral 
hemispheres, but is not equal to that at the middle brain. In excavating 
the matrix from the olfactory chambers, some difficulty was experienced 
in attempting to lay bare the superior and inferior walls, which are doubt¬ 
less of a spongy or cribriform character. On one side of the bulb, this 
boundary was probably passed through, giving a larger vertical diameter 
than the trae one. 
Measurements of the brain. 
M. 
Total length..... 0.150 
Length to the middle brain above..... 0. 024 
Length to the cerebrum above.-. .. 0. 052 
Length to the base of the olfactory lobes... 0. 090 
Vertical diameter at the cerebellum... 0. 034 
Vertical diameter at the middle brain... 0, 041 
Vertical diameter at the hemispheres.. ... 0. 039 
Vertical diameter of the olfactory peduncles. 0. 015 
Width at the cerebellum.... 0. 039 
Width at the middle brain. 0. 053 
Width at the hemispheres. 0. 042 
Width at the olfactory peduncle.... 0.026 
Width at the olfactory bulb... 0. 038 
Length below to the transverse constriction_.... . 0.024 
■Length below to the hypophysis..... 0. 062 
Length below to the optic nerves... 0. 075 
Length below to the base of the olfactobry bulb. 0.106 
Length below to the bifurcation of the bulb ..... 0.135 
Comparison with the skull of a young Tapirus roulinii of two-thirds 
the linear dimensions of the present one shows that the hemispheres are of 
