TO THE LOWEK ANIMALS. 93 



skull and a Man's are truly immense (Fig. 17). In the 

 former, the face, formed largely by the massive jaw-bones, 

 predominates over the brain case, or cranium proper : in 

 the latter, the proportions of the two are reversed. In 

 the Man, the occipital foramen, through which passes the 

 great nervous cord connecting the brain with the nerves 

 of the body, is placed just behind the centre of the base 

 of the skull, which thus becomes evenly balanced in the 

 erect posture ; in the Gorilla it lies in the posterior third 

 of that base. In the Man, the surface of the skull is com- 

 paratively smooth, and the supraciliary ridges or brow 

 prominences usually project but little — while, in the Go- 

 rilla, vast crests are developed upon the skull, and the 

 brow ridges overhang the cavernous orbits, like great 

 penthouses. 



Sections of the skulls, however, show that some of the 

 apparent defects of the Gorilla's cranium arise, in fact, 

 not so much from deficiency of brain case as from exces- 

 sive development of the parts of the face. The cranial 

 cavity is not ill-shaped, and the forehead is not truly flat- 

 tened or very retreating, its really well-formed curve being 

 simply disguised by the mass of bone which is built up 

 against it (Fig. 17). 



But the roofs of the orbits rise more obliquely into the 

 cranial cavity, thus diminishing the space for the lower 

 part of the anterior lobes of the brain, and the absolute 

 capacity of the cranium is far less than that of Man. So 

 far as I am aware, no human cranium belonging to an 

 adult man has yet been observed with a less cubical ca- 

 pacity than 62 cubic inches, the smallest cranium observed 

 in any race of men by Morton, measuring 63 cubic inches ; 

 while, on the other hand, the most capacious Gorilla skull 

 vet measured has a content of not more than 34^ cubic 

 inches. Let us assume, for simplicity's sake, that the low- 



