EVOLUTION OF THE CHIN 



T. T. WATERMAN 

 Assistant Professor op Anthropology 

 University op California 



In the Smithsonian Report for 1914 is an article by 

 Louis Robinson, M.D., on "The Story of the Chin." Dr. 

 Robinson in this article goes so far as to explain the pres- 

 ence of a chin in human beings as the result of the habit 

 of articulate speech. Quite a different explanation is pos- 

 sible for the existence of this extraordinary feature of 

 our anatomy. I should like to suggest some of the evi- 

 dence which would seem to indicate that Dr. Robinson's 

 ideas need rather careful review. 



By chin is to be understood the projection or point on 

 the under jaw, below the mouth (Fig. 1). The jaws of 

 most vertebrates have no projection or prominence in 

 this region. 



It will therefore be recognized at the outset that the 

 chin is a very "human" trait. It is a trait that distin- 

 guishes man from other living primates; even from his 

 near relatives (compare Figs. 1 and 2). It even sets off 



the man of to-day from the more ancient of his progen- 

 itors. The earlier fossil skeletons of man are quite chin- 

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