OUR FACE FROM FISH TO MAN 



edges may have arisen, man shares it with many 

 other mammals, especially with his relatives the 

 anthropoid apes, whose central incisor crowns 

 approach the human type. Remane (1921, Fig. 

 21E) has shown that in certain chimpanzees even 

 the outer rim of the central upper incisor is vertical 

 as in man. 



Hrdlicka has noted that on the rear surface of 

 the central upper incisors of certain anthropoids 

 and monkeys one finds the "rim and ridge" 

 formation (Fig. 72) of many human incisors. 



In the upper central incisors of recent Mon- 

 golians and many Indians the rims along the 

 sides of the crown fold around toward the rear 

 and the "shovel-shaped" incisor is developed. 

 This arrangement was already foreshadowed in 

 certain gorillas and is almost fully attained among 

 the extinct Neanderthals of the Krapina race; it 

 has also recently been discovered in a fossil human 

 tooth from the Pleistocene of China. In its 

 extreme form the shovel-shaped incisor represents 

 a distinct specialization beyond that attained in 

 the anthropoids. Dr. J. Leon Williams has 

 observed among all races of mankind the presence 



of three types of central upper incisors (Fig. 73). 



138 



