THE SKELETON OF APES AND OF MAN 251 



ing bony chin. The bony jaw recedes in these early 

 races of men from the line of the front teeth as it does 

 in the apes. Th^ have no cAin(see Fig. 25, p. 286). 



Since we are all accustomed to regard a well-marked 

 chin as a necessary feature of a beautiful human face, 

 and to deplore or disapprove the receding or evanescent 

 chin, it is not improbable that sexual selection has 

 favoured the recession of the dental arch with the reten- 

 tion of the original bulk of the lower front margin of the 

 jaw and chin, though why the chin should be thus 

 appreciated is a matter of speculation. It is remarkable 

 that in many of the monkeys the hair grows forward as 

 a projecting beard on the front of the jaw, so as to 

 resemble a chin although no chin is there. It is also the 

 fact that some uncivilized races of men trim the beard 

 and train it in a forward growth so as to suggest the 

 possession of a very prominent chin, when in reality 

 their solid chins of flesh and bone are not especially 

 large. 



It is not easy to suggest how the reduction in size 

 of the canines and front teeth and of the length of the 

 jaw could be of such advantage to incipient man as to 

 lead to the survival of those individuals in which these 

 parts were least developed, and so gradually to the 

 crowding of the teeth, reduced in size, into a jaw of 

 reduced length, whilst at a late stage, long after man 

 was man and no ape, the teeth became so reduced in 

 volume as to leave the lower margin of the lower jaw — 

 projecting far in front of them as the "chin," the 

 eminently human chin. The nutrition of these parts 

 placed in the head near the brain, the great canine 

 having so vast a fang that it reaches up to the eye- 

 socket, whence it is called the "eye-tooth," renders it 

 probable that there is a relation depending on nutrition 



