THE UNGULATA, OR HOOFED ANIMALS. 133 



pression. The animal is called Coryphodon, and is 

 somewhat the size of a rhinoceros. The toes are 

 all complete (Fig. 13) ; but i and iv are strik- 

 ingly weaker, and HI decidedly the strongest, 

 corresponding with the lengthening of the axis of 

 the shank. The form of the skull of this earliest 

 known Hoofed animal does not make any strange 

 impression, any more than do the limbs. The 

 full dentition (forty-four teeth) leads to the con- 

 clusion of its having lived upon different kinds of 

 food. But the brain the circumference of which 

 can be gathered from well-preserved impressions - 

 shows an inferior type of organisation, owing to its 

 insignificant size and the smallness and the flat sur- 

 face of the larger part of the brain. It is, in fact, the 

 lowest and most reptile-like brain known to us. The 

 diameter of the larger portion scarcely exceeds that 

 of the spinal marrow, the middle brain being the 

 broadest section. Further, the form and position 

 of the olfactory lobes remind one of the lower 

 vertebrates. The length of the hemispheres mea- 

 sures one fifteenth of the skull, their volume one 

 twenty-seventh of that of a tapir of the same size. 

 Hence the brain of the Coryphodon has more the 

 appearance of that of a lizard than of any existing 

 mammal. But, nevertheless, this and similar 



