OUR FACE FROM FISH TO MAN 



specialized side line and thus remove themselves 

 from the direct line of ascent to higher forms. 



Much more conservative and central in struc- 

 tural type are the fossil primates of the extinct 

 family Notharctidae from the Eocene of Wyoming 

 and New Mexico. The fossil skeletons of these 

 animals (Fig. 32) have grasping hands and feet 

 of the tree-living type preserved in the modern 

 lemurs of Madagascar. The same is true of the 

 feet of the extinct lemuroid primates of the family 

 Adapidse from the Eocene of Europe. 



Comparative anatomical and paloeontological evi- 

 dence unite to support the view that all the primates 

 first went through an arboreal stage, some of them 

 afterward coming down to the ground and carrying 

 with them many of the structural "patents'* acquired 

 during their long schooling in the trees. 



The hind foot of all known fossil and recent 

 primates below man is of the tree-grasping type 

 with a divergent great toe and there is no substan- 

 tial doubt, after the exhaustive critical discussions 

 of this subject by Gregory (1916, 1921, 1927), 

 Miller (1920), Keith (1923), Schultz (1924), Mor- 

 ton (1924, 1927) and others, that the whole order 



was from its first appearance primarily tree-living 



54 



