THE GREAT CHIMPANZEE. 397 



osseous texture of two kinds ; the upper half was finely but irregularly spongy, and this 

 terminated halfway down the mass by a compact, thin surface or Hoor, convex down- 

 wards and backwards, from which a vast number of delicate bony plates and threads 

 proceeded vertically to it, from 5'" to 8'" in length : they interlaced together as they 

 diverged, and expanding and uniting at their extremities, formed the reticulate inner 

 convex plate of the antrum above described : an interspace extends between this plate 

 and the alveoli of the teeth. 



The posterior part of the malo-maxillary suture is finely and deeply indented : the 

 zygomatic suture is beautifully crenulate, so likewise is the infraorbital part of the 

 malo-maxillary suture. The margins of the expanded part of the nasals are joined to 

 the maxillaries and intermaxillaries by true sutures, not harmoniae, as in the TV. niger 

 and in Man. 



As the male Troglodytes Gorilla differs from the male Troglodytes niger in the supe- 

 rior development of the sagittal crest, so the female-TV. Gorilla differs from the female 

 TV. niger in the nearer approximation of the temporal ridges, which meet along the 

 sagittal suture instead of being separated by a smooth tract of between one and two 

 inches in breadth as in the female TV. niger ; a difference which indicates a correspond- 

 ing superiority of size of the temporal muscles in the female of the larger species as 

 compared with the smaller species of Chimpanzee to that which obtains in the males of 

 the two species. 



The larabdoidal crista is also more developed in the female Tr. Gorilla than in the 

 female Tr. niger, and the occiput is flatter and broader. The osfrontis is flatter behind 

 the prominent supraciliary ridge, and the convexity of the calvarium rises more gradually 

 and remotely from the ridge. 



The zygomata offer the same relative superior depth and strength, the same equality 

 of the squamosal portion, and the same elevation and convexity of its upper border. 

 The malar bones show the same superior prominence ; the spheno-maxillary fissure the 

 same greater length, narrowness, and nearer approach to a vertical direction. 



The maxillo-premaxillary sutures have the same degree of persistency in the adult 

 female Tr. Gorilla, being obliterated both upon the face and palate only near the open- 

 ings of the contiguous alveoli, and demonstrating the same upward extension and tri- 

 angular expanse of the preraaxillary bones, above the nasal aperture, which distinguishes 

 the male Tr. Gorilla from the same sex in the Tr. niger. The bony palate shows the 

 same superior length as compared with breadth, and the same difference in the relative 

 position of the postpalatine foramina and in the form of the posterior border, as have 

 been noticed in the male skull. There are two small tuberosities between the post- 

 palatine foramina in Tr. niger, one on each side of the median suture, but there is no 

 trace of such in the female or the younger male of the Tr. Gorilla. The alveolar parts 

 of the premaxillaries have the same relative shortness as compared with the female 

 Tr. niger. Although the canines exhibit the same sexual inferiority of size in the female 



VOL. III. PART VI. 3 I 



