72 Zoological Society. 



The development of this crest also renders the su})raoccipital sur- 

 face almost Hat in the female Troglodytes Savagei, and it is even con- 

 cave in the great males ; whilst in both adult males and females of 

 the Troglodytes niger it is convex. 



There are specific distinctions in the interior of the cranium of 

 the two species : the olfactory (rhinencephalic) fossa closed by the 

 cribriform plate, though very little wider, is considerably deeper in 

 Troglodytes Savagei than in Troglodytes niger ; and the ' crista galli,' 

 which is small in Troglodytes niger, is absent in Troglodytes Savagei, 

 nor is there any ridge continued from the fossa upon the inner sur- 

 face of the frontal in the line of the frontal suture. 



In Troglodytes niger there is a short ala minor sphenoidei continued 

 outwards from the anterior clinoid process, and the upper and outer 

 angle of the foramen lacerum anterius is produced into a short cleft : 

 in Troglodytes Savagei the rudiment of the ala minor terminates at 

 the upper border of the foramen lacerum anterius, which has a sub- 

 quadrate form, and is not extended outwards into an angular fissure. 

 The sella turcica is relatively shallower in Troglodytes Savagei than 

 in Troglodytes niger, in which it is shallower than in Man. 



Many other minor differences were noted, but these would be 

 better understood by the aid of the figures in the memoir. Some 

 scepticism, the author observed, might be expected as to the alleged 

 specific distinction of the large and small chimpanzees bj' natural- 

 ists who had not been able to realise the differences by actual 

 comparison of the specimens; but Professor Owen felt no doubt 

 that, as in the case of the Pithecus Morio, more extended knowledge 

 of the new species would confirm the validity of its distinction from 

 the Troglodytes niger. 



The stronger zygomatic arches and the more developed sagittal 

 and lambdoidal crests might be viewed as adaptive developments 

 concomitant on the larger canines, and indicative of a larger and 

 more powerful variety of chimpanzee ; but the larger proportional 

 molars and the smaller proportional incisors, the more equal and 

 complex last molar tooth, together with the prominence — slight as 

 it is — of the nasal bones at their median coalescence, their inferior 

 expansion, and, above all, the reappearance of the premaxillaries by 

 their expanded superior extremities upon the face above the nostril, 

 are more than mere differences of size and proportion, and being 

 repeated in both male and female adults of the great chimpanzee of 

 Gaboon, leave no alternative, according to the value assigned to 

 such characters in other Qaadrumanous genera, than to pronounce 

 the Troglodytes Savagei to be specifically distinct from the Troglo- 

 dytes niger, and this to be, as the Pithectis Morio is to the Pithecus 

 Wurmbii in Borneo, a smaller, feebler and more anthropoid species 

 of the genus Troglodytes in Africa. 



In conclusion. Prof. Owen remarked that he had proposed the 

 name of the new species of Chimpanzee provisionally, for the con- 

 venience of its description and comparison ; and that, should he be 

 able to learn that its discoverer had given a name to it, he should 

 ado]it that name, of which Troglodytes Savagei would then be a 

 synonvm. 



