130 MAN AND THE LOWER ANIMALS n 



occasionally in the absence of the accessory fleshy 

 bundle. 



Throughout all these modifications it must be 

 recollected that the foot loses no one of its essen- 

 tial characters. Every Monkey and Lemur ex- 

 hibits the characteristic arrangement of tarsal 

 bones, possesses a short flexor and short extensor 

 muscle, and a peronceus longus. Varied as the 

 proportions 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 con- 

 clusion 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. 



