782 



5174. The bones of the right pectoral extremity. 



V 



5175. The bones of the left pectoral extremity. 



5176. The bones of the right pelvic extremity. 



5177. The bones of the left pelvic extremity. 



5178. The skeleton of an adult male Great Chimpanzee, or Gorilla (Troglodytes Go- 

 rilla). 



This species, discovered by Dr. Savage in the Gaboon District, west coast of tropical Africa, 

 in 1847*, not having been known to Cuvier, nor having been described in the ' Osteographie ' 

 of De Blainville, and being the species of Quadrumanous animal that makes the nearest 

 approach to Man, calls for the following description of the skeleton, which is at present 

 unique in Great Britain. 



Comparison of the Skull of the Troglodytes Gorilla with that of the Troglodytes niger. 



Independently of the superiority of size of the Tr. Gorilla over the Tr. niger (No. 5082), 

 the skull presents well-marked differences of form, differences in the development and propor- 

 tions of the intermuscular ridges, in the disposition of certain sutures and in the structure and 

 proportions of certain teeth. Compared in profile, the skulls of both species present the 

 striking difference from the Orangs (Nos. 5050 & 5051) in the prominence of the superorbital 

 ridge ; but the temporal ridges, after their junction upon the frontal, rise, in the Tr. Gorilla, 

 into a strong and lofty sagittal crest, which is continued to the lambdoidal crest, and the great 

 extent of the lambdoidal crest masks the posterior convexity of the occiput in Tr. Gorilla. The 

 zygomatic arch is proportionally much stronger in the large Chimpanzee, and also differs from 

 that in Tr. niger by the squamosal part being of equal depth with the malar part, and by its 

 having its upper border convex or produced into an angle instead of being straight or slightly 

 concave. The alisphenoid is longer and narrower in Tr. Gorilla, and contributes less to the back 

 wall of the orbit than in Tr. niger, in which it forms a much smaller proportion of that part 

 than in Man. The spheno-maxillary fissure is not only larger in Tr. Gorilla, but is narrower 

 and more vertical, not angularly bent as in Tr. niger. The extent of the premaxillary bones 

 below the nostril is not only relatively but absolutely less in Tr. Gorilla, and the profile of 

 tiie skull less convex at that part, or less ' prognathic,' than in Tr. niger. 



More important differences appear on comparing the two skulls in a front view. The 

 breadth of the premaxillaries and of the incisor teeth is the same in both, whilst in all other 

 dimensions the Tr. Gorilla greatly surpasses the Tr. niger : this is seen in the height of the 

 sagittal crest, the thickness of the great superorbital bar of bone, the prominence of the ect- 



* See 'Transactions of the Zoological Society,' Ho, vol. iii. p. 3M9. 



