OUR ANCIEXT RELATI\'ES 



in habit and that the foot of man has been derived 

 from a grasping type with a divergent great toe. 



Tree-living, possibly combined with nocturnal 

 habits, favored the evolution of keen sight, and in 

 the oldest known skulls of primates, from the 



Fig. 33. Skull of a Primitive Primate of the Eocene Epoch 

 (after Gbegort), 



For details, see p. x\-iii. 



Eocene perhaps fifty million years ago, we find 

 the eye orbits already larger and better defined 

 than those of contemporary terrestrial mammals. 

 The skull of one of the best known members of 

 this group is drawn in Fig. 33, from fossil speci- 

 mens in the American Museum of Natural History. 

 In this form the chief advance beyond the primitive 

 mammalian type (Fig. '27) is seen in the increase 

 in the size of the eyes and the beginning of the 



