38 READINGS IN BIOLOGICAL SCIENCE 



The first of these is, that the difference in the volume of the cranial cavity 

 of different races of mankind is far greater, absolutely, than that between 

 the lowest Man and the highest Ape, while relatively, it is about the same. 

 For the largest human skull measured by Morton contained 114 cubic 

 inches, that is to say, had very nearly double the capacity of the smallest; 

 while its absolute preponderance, of 52 cubic inches — is far greater than that 

 by which the lowest adult male human cranium surpasses the largest of the 

 Gorillas (62 — 34^ = 27%)- Secondly, the adult crania of Gorillas which 

 have as yet been measured differ among themselves by nearly one-third, 

 the maximum capacity being 34.5 cubic inches, the minimum 24 cubic 

 inches; and, thirdly, after making all 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. 



Thus, even in the important matter of cranial capacity. Men differ more 

 widely from one another than they do from the Apes; while the lowest 

 Apes differ as much, in proportion, from the highest, as the latter does 

 from Man. The last proposition is still better illustrated by the study of 

 the modifications which other parts of the cranium undergo in the Simian 

 series. 



It is the large proportional size of the facial bones and the great projec- 

 tion of the jaws which confers upon the Gorilla's skull its small facial 

 angle and brutal character. 



But if we consider the proportional size of the facial bones to the skull 

 proper only, the little Chrysothrix * differs very widely from the Gorilla, 

 and in the same way as Man does; while the Baboons (Cynocephahis) exag- 

 gerate the gross proportions of the muzzle of the great Anthropoid, so 

 that its visage looks mild and human by comparison with theirs. The differ- 

 ence between the Gorilla and the Baboon is even greater than it appears at 

 first sight; for the great facial mass of the former is largely due to a down- 

 ward development of the jaws; an essentially human character, super- 

 added upon that almost purely forward, essentially brutal, development 

 of the same parts which characterizes the Baboon, and yet more remark- 

 ably distinguishes the Lemur. 



Similarly the occipital foramen of the Lemurs is situated completely in 

 the posterior face 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; while, as if 

 to render patent the futility of the attempt to base any broad classificatory 

 distinction on such a character, the same group of Platyrrhine, or American 

 monkeys, contains the Chrysothrix, whose occipital foramen is situated far 

 more forward than in any other ape, and nearly approaches the position it 

 holds in Man. 



Again, the Orang's skull is as devoid of excessively developed supra- 

 ciliary prominences as a Man's, though some varieties exhibit great crests 



• Squirrel monkey. — Ed. 



