CONCERNING THE HIGHER MAMMALIA. 159 



"Next compare the minimum human skull, - 62 cubic inches. 

 With the maximum skull of the Gorilla, 34.5 '* 



And the difference is only - - - 27 • 5 " 



Secondly, the adult crania of Gorillas differ among themselves 

 nearly one-third. Thus, the maximum that has been measured 

 contains - - - - 34.5 cubic inches, 



And the minimum only - - -24. " 



The difference being - - ~ 10.5 



Thirdly, after making due allowance for difference of size, the 

 cranial capacities of some of the lower Apes fall nearly as much, rela- 

 tively, below those of the higher Apes, as the latter fall below Man. 

 The conclusion from this is, that as regards cranial capacity, men 

 differ more widely from one another than they do from the Apes, 

 whilst the lowest Apes differ as much from the highest as the latter 

 does from Man. In other parts of the skull corresponding differences 

 (relatively) are to be found. For example, the Gorilla has large 

 superciliary ridges, corresponding to internal sinuses, which the 

 Ourang does not possess at all. The occipital foramen in the Lemurs 

 is situated completely in the posterior aspect of the skull, or as much 

 further back than that of the Gorilla, as that of the Gorilla is further 

 back than that of Man ; whilst the Platyrhini contains one member, 

 the Chrysothrix, whose occipital foramen is situated further forward 

 than any other of the Primates except Man. In dentition and in the 

 viscera, the differences are as great between the Gorilla and the lower 

 members of his order, as between Man and the Gorilla. Man has 

 been defined as the only animal possessing two hands terminating his 

 fore-limbs, and two feet terminating his hind-limbs ; but the termina- 

 tion of the fore-limb of the Ape is a true hand, and that of the hind- 

 limb a true foot, with a very moveable great-toe. It differs from the 

 foot of Man in mere proportions — in the degreee of mobility — and in 

 the secondary arrangement of its parts. Every Ape, Monkey, and 

 Lemur possesses a flexor brevis muscle, an extensor brevis, and a pero- 

 n^us longus in the hind extremity. These muscles are never found 

 in a hand. The thumb and great toe of the Ourang differ more from 

 those of the Gorilla than those of the Gorilla do from the correspond- 

 ing organs of Man. As regards the Brain, there is a great difference 



