7 6 



THE HUMAN SPECIES 



unites with the os naviculare in the second half of the third 

 month, whereas in the orang and the majority of the other apes, 

 it occurs regularly as an independent bone and is absent only 

 in the gorilla and chimpanzee. 



With respect to the 

 evolution of the human 

 hand, Darwin believes it 

 to have been brought 



O 



about in accordance with 

 the principle of the divi- 

 sion of labour, in propor- 

 tion as the hands were 

 perfected for prehension 

 the feet became adapted 

 for support and progres- 

 sion. Klaatsch, however, 

 asserts that in the Eocene 

 Period even the carni- 

 vora possessed a hand 

 with an opposable thumb, 

 very similar to the hu- 

 man hand, and that later 

 a reversion of the hand 

 to a claw took place. 

 Thus in Klaatsch's l 

 opinion the human hand 

 has not been evolved 

 from the foot of a quad- 

 rupedal progenitor ; it is 

 no new acquisition nor is 

 it the peculiar property 

 of man, but a very ancient 

 heritage from the re- 

 mote ancestors of man 

 and the mammals. From 

 the earliest times the 



hand has held an important place in the development of the 



land vertebrates owing to the opposable thumb. 



1 Corr.-Blatt f. Anthrop., 1901, p. 102. 



Ill 



FIG. 34. Arm and hand of three anthropoids. 

 I. Chimpanzee. Il.Veddah. III. European 

 (Mediterranean). (From Haeckel, Anthro- 

 pogenic.) 



