204 



but the occiput slopes less suddenly backward than In the Chimpanzee. 

 There are no traces in either of the occipital and intSr-parietal crests. 

 The superior curved line of the occiput is already well marked in both, 

 while in a child of a corresponding age this line is s'carcely seen, show- 

 ing the feebler attachment of the trapezius in the latter. 



In both species, the brain covers the roofs of the orbits, and ex- 

 tends as far forwards as in man, while in the adult apes nearly the 

 whole of the orbit is in front of the anterior margin of the cerebral 

 hemispheres. If the crania of the young Chimjjanzee and Gorilla 

 are compared with that of man, they will be found, in their propor- 

 tions, to resemble that of an adult rather than that of a child. In the 

 head of the latter, during the first dentition, the face is less prominent 

 than the forehead, and the anterior lobes of the brain project beyond the 

 superciliary ridges, instead of barely reaching to them, as in the young 

 apes. In the latter, the forehead is somewhat retreating and the face 

 somewhat projecting. It is probable that in an earlier stage the cra- 

 nia of the Chimpanzee and Gorilla would resemble that of a child 

 much more closely. 



The bones of the face of the Gorilla resemble most nearly those of a 

 Chimpanzee somewhat younger, and in which the middle incisors only 

 are protruded. AVhen seen in profile, the outhne of the face in both 

 forms an uninterrupted slope from the supra-orbital ridge to the edge 

 of the incisive alveoli. This is well seen in Figs. 6 and 7, PL v. of 

 M. Duvernoy's Memoir on the Gorilla.* In the Gorilla this slope 

 remains permanently, but in the Chimpanzee, by the time the first set 

 of teeth is completed, the jaws have become more prominent, so that 

 their outline forms an angle with the upper part of the face, the nasal 

 bones and the ascending portion of the maxillaries retaining their 

 original direction. Not only do the intermaxillaries become more 

 prominent, but the distance from the lower border of the nostrils to the 

 alveolar margin is considerably lengthened, both in consequence of the 

 extension of this last downwards, and of the lower margin of the 

 nostrils upAvards. 



The anatomical points referred to above, relate to the general con- 

 figuration of the head. There remain some other details which it is 

 important to notice, because of the bearing of them upon the relative 

 position which these two species hold In the animal series. 



1. Nasal hones. — These bones, which in man are so characteristic, 

 are, when taken together, a little broader below than above, somewhat 

 transversely contracted at the upper third, and strongly arched for- 

 wards. In the Gorilla the contraction just noticed is much greater, so 



* Des Caractei-es Anntomiques des Grauds Singes Pseudo-antliropomorplies ; 

 Archives du Mus. d'Hist. Nat. viii., p. 1. 



