198 EVOLUTION AND GENETICS 



tions coincide very well with the effects of arboreal life. Or on a 

 basis of known facts entirely we may say that anatomical condi- 

 tions which fit existing primates for arboreal life point strongly 

 toward the higher development of similar structures in man as a 

 terrestrial descendant of arboreal ancestors. 



The Geological Record. Inquiry into the fossil record of 

 man's development shows first of all that primates were abundant 

 during the Eocene, even in North America. They became extinct 

 on this continent, but continued their existence in Eurasia, where 

 the remains of several interesting genera have been discovered. 

 Wilder describes two European species, Pliopithecus antiquus and 

 Dryopithecus fontani, as Miocene apes. In Asia Palaeopithecus 

 sivalensis and Pithecanthropus erectus are significant. 



Palaeopithecus. This primate has been called a chimpanzee, 

 but against this identification we are told: "In comparison with 

 the chimpanzee its canine and lateral incisor teeth are much 

 reduced, and the two lines formed by the lower molars converge 

 anteriorly, this character lying midway between the condition in 

 the chimpanzee, in which the two rows are parallel, and that found 

 in Man, where marked anterior convergence of the rows of lateral 

 teeth results in the formation of a gentle curve" (Wilder). 



Pithecanthropus. Pithecanthropus was found in central Java in 

 1891 by a Dutch army surgeon, Eugcn Dubois. The remains first 

 uncovered consisted of a single upper molar tooth and the top of a 

 skull, separated by about a meter in the same deposits. Later a 

 second tooth, also a molar, and a left femur were discovered about 

 fifteen meters away but also in the same deposits. These parts 

 have been literally bones of contention. There seems little reason 

 to doubt that they belonged to the same individual, although that 

 possibility must be admitted. However they are of great im- 

 portance, whatever our opinion of their relationship with each 

 other, for conclusions based upon the single parts are in themselves 

 significant. 



The age of the deposits in which the bones were found has been 

 placed at the early Pleistocene, but Osborn interprets the remains 

 of mammals found in the same strata as late Pliocene. All evi- 

 dence points to the fact that Java was connected with Asia at that 

 period, and contemporary researches are being centered upon the 

 search for fossils in the SiwaHk Hills of India and central Asian 

 regions. 



