738 PRIM A TES 



diameter, and also by the larger size of their external as compared 

 with their internal cusps; while the outer border of these teeth is 

 placed internally to that of the upper molars. In all these respects 

 the teeth of the Chimpanzee make a decided approximation to the 

 human type. 



Many young individuals of the Chimpanzee have been brought 

 to Europe, but they appear to succumb sooner or later to the effects 

 of an unsuitable climate. All these examples show that the dis- 

 position of this Ape is gentle, lively, and intelligent, and in all 

 respects markedly opposite to that of the Orang. In a wild state 

 these Apes are essentially forest-dwellers, and are more arboreal in 

 their habits than the Gorilla. They live either in families, or in 

 small parties of several families. Frequently at least they construct 

 a kind of nest in the trees as a sleeping-place ; the male being said 

 to sleep on a forked branch below the level of this nest. In walk- 

 ing the Chimpanzee usually supports himself on the backs of his 

 closed fingers, and either on the soles of the feet or on the closed 

 toes. 



From a distributional point of view the discovery of a fossil 

 Ape in the Pliocene of the Punjab, apparently closely allied to the 

 Chimpanzee, is of great interest. This determination rests upon 

 the evidence of an imperfect palate originally described under the 

 name of Palceopithecus, but subsequently referred to the present 

 genus. The teeth of this jaw present all the essential characters 

 of those of the Chimpanzee, but the two series of cheek-teeth have 

 a slight anterior convergence, the premolars are shorter in the 

 antero-posterior direction than is usually the case in that species, 

 and the outer incisor is relatively narrower than in the latter. In 

 these features the extinct A. sivalensis makes a nearer approxima- 

 tion to the human type than is the case with its living congeners. 



Dryopithecus. 1 The extinct Dryopithecus of the Middle Miocene 

 of France is represented by a single species of the approximate 

 size of the Chimpanzee, and appears to be the most generalised 

 member of the family. According to the recent observations of 

 Professor Gaudry, 2 while it resembles the Gorilla in that the two 

 series of lower cheek-teeth diverge anteriorly and the penultimate 

 premolar is larger than the last of that series, it differs in having a 

 much longer and narrower mandibular symphysis, and thus indicates 

 a transition to the Cercopithecidce. A gradual transition in the form 

 of the mandible may, indeed, be traced from Dryopithecus, through 

 Gorilla, to Anthropopithecus ; the latter having a short and wide 

 symphysis, with the two series of cheek-teeth slightly converging 

 anteriorly, and the penultimate premolar being not larger than the 

 last. In all these specialised characters the jaw of the Chimpanzee 



1 Lartet, Comptes JRendus, vol. xliii. p. 219 (1856). 

 2 Mim. Soc. Geol. France, " Palaeontologie, " vol. i. Mem. No. 1 (1890). 



