OUR FACE FROM FISH TO MAN 



mal-like reptiles of the Triassic age were already so 

 far advanced toward the mammalian grade that 

 it would not be surprising if the initial stages in 



FiQ. 23. Origin of the Facial Muscles of Man. 



A. Primitive reptile with continuous bony mask covering skull. The 

 mask was covered with thick skin without muscles, as in the alligator. 

 (After Williston.) B. Modern reptile with an open or fenestrated skull 

 covered with thick, non-muscular skin. (From Fiirbringer, modified 

 from Ruge.) C. Primitive mammal in which the sphincter colli system 

 has grown forward over the face. D. Gorilla. E. Man. (C, D and E 

 after Ruge.) For details, see p. xvii. 



42 



