MAN AND HIS STRUCTURAL AFFINITIES. 433 



seems diminished 'when we compare the man-apes with the baboons 

 and lower, tailed monkeys in this respect. The cranium of the gorilla 

 is also very small in proportion to that of man. The contents of the 

 smallest skull of man is given at sixty -two cubic inches ; that of an 

 adult gorilla is given at thirty-four cubic inches. But this difference 

 loses much of its value when we see the amount of variation in men 

 of the skull measurements. Thus the largest human skull shows a ca- 

 pacity of 114 cubic inches, being about twice the size of the smallest 

 adult human skull. 



Now, the difference thus shown in man of fifty-two cubic inches be- 

 tween the capacity of the largest and smallest skulls is greater than 

 that between the smallest human skull and that of the gorilla, which 

 is only twenty-seven inches. These figures will probably be still further 

 modified so soon as we get accurate measurements of the skulls of cer- 

 tain African and Indian hill tribes more recently discovered. Indeed, 

 it is already stated that twelve cubic inches of cranial capacity will 

 cover the difference between the smallest human and the largest simian 

 skull yet known. Again here, as with the prognathic characters, the 

 importance of the difference in cranial size is diminished by the fact of 

 its variation among the apes and monkeys, which latter are found to 

 fall as much below the apes in cranial capacity as the apes do as com- 

 pared with man. The skull of the gorilla exhibits considerable varia- 

 tion in the specimens which have been yet examimed. The males seem 

 to have a prominent bony ridge on the crown of the skull, but this de- 

 velopment of the bone stands in proportion to the muscles of the jaws 

 which reach on each side up to the crest which they deposit. Where the 

 jaws are weaker, as in the female, the crest is undeveloped, the muscles 

 do not reach up so far and they deposit smaller ridges on the side of the 

 skull. These crests are, however, wanting in the orang-outang, a lower 

 kind of man-ape than the gorilla, where they are replaced by two bony 

 ridges, a couple of inches apart, as we learn from Mr. Wallace's inter- 

 esting writings. But the variation among the skulls of the gorilla yet 

 examined is so great in the proportion of the different parts of the face, 

 that it is evident there is a greater amount of individual peculiarity in 

 this than in any other animal except man. This point is worthy of a 

 much more extended examination than it is now possible to give to it. 

 It is sufficient to state that these differences seem to have prompted 

 Dr. Wyman and Du Chaillu to suspect species where in fact we find 

 only one kind of gorilla as more specimens come to hand and supply 

 the intermediary links. With regard to the permanent teeth of the 

 gorilla they are thirty-two in number, just as in man. The principal 

 difference is that the canine teeth, at least in the adult males, are longer 

 than in man, and project. The jaws being more powerful and more con- 

 stantly in use, the teeth are stronger and proportionally stouter than 

 in man. And where we find any difference, such as is offered by the 

 large canines, and the break in the lower series to admit of the play of 

 vol. xm. 28 



