130 MAN AND THE LOWER ANIMALS. n 



muscle, and a peronceus longus. Varied as the pro- 

 portions and appearance of the organ may be, the 

 terminal division of the hind limb remains, in plan 

 and principle of construction, a foot, and never, 

 in those respects, can be confounded with a hand. 



Hardly any part of the bodily frame, then, 

 could be found better calculated to illustrate the 

 truth that the structural differences between Man 

 and the highest Ape are of less value than those 

 between the highest and the lower Apes, than 

 the hand or the foot; and yet, perhaps, there is 

 one organ the study of which enforces the same 

 conclusion in a still more striking manner — and 

 that is the Brain. 



But before entering upon the precise question 

 of the amount of difference between the Ape's 

 brain and that of Man, it is necessary that we 

 should clearly understand what constitutes a great, 

 and what a small difference in cerebral structure; 

 and we shall be best enabled to do this by a brief 

 study of the chief modifications which the brain 

 exhibits in the series of vertebrate animals. 



The brain of a fish is very small, compared with 

 the spinal cord into which it is continued, and 

 with the nerves which come off from it: of the 

 segments of which it is composed — the olfactory 

 lobes, the cerebral hemispheres, and the succeed- 

 ing divisions — no one predominates so much over 

 the rest as to obscure or cover them; and the so- 

 called optic lobes are, frequently, the largest 



