OUR FACE FROM FISH TO MAN 



The position of the eyes in the human head has 

 likewise been inherited from the common man- 

 anthropoid stock. In Notharctus, a primitive 

 primate of the Eocene epoch (Fig. 35A) the eyes 

 were directed partly outward as well as forward, 

 the large muzzle extended far in front of the orbits 

 and binocular vision was obviously impossible. The 

 large size of the olfactory chamber in Notharctus 

 also indicates that like other mammals and 

 especially like its relatives the modern lemurs, the 

 lowest existing primates, it still depended largely 

 upon its olfactory sense, while the higher primates 

 have a much reduced olfactory apparatus and a 

 predominant visual apparatus. With regard to 

 the direction of the orbital axes, these look partly 

 outward also in most of the modern lemuroids 

 (Fig. 35B) and even the greatly enlarged orbits 

 of the modern Tarsius (Fig. 35C) are directed 

 somewhat away from each other. In the South 

 American monkeys (Fig. 35D) however, the outer 

 angles of the orbits are shifted further forward and 

 the muzzle is reduced; in the Old World monkeys 

 and anthropoid apes (Fig. 35E, F), this process is 

 completed and binocular vision is established. The 



binocular character of the vision of anthropoids and 



196 



