Xo..-,<)2] 



EVOLUTION OF THE CHIN 



231) 



It is only proper to say, further, that Robinson's vari- 

 ous statements about the matter are hardly consistent. 

 He states that the chin is, in origin, merely a buttress for 

 the canine teeth ; and he also believes it to be the result of 

 sexual selection. Having accounted for it in these two 

 ways, he throws in his remarks about the genio-glossus 

 muscle for good measure. He closes by spending more 

 discussion on the genial tubercles than on the chin itself. 

 If the first of the statements to which reference has been 

 made is correct, those animals which have large canines 

 ought to be found with the best-developed chins. Quite 

 the opposite is the case. Generally speaking, animals 

 with very large canines, such as the baboons and others, 

 are conspicuous for their very lack of chin. The author 

 also makes certain sensational statements about the lower 

 jaws of the " lower" races, that need full discussion; as- 

 suming in one place that uncivilized peoples have phonet- 

 ically simple languages, an assumption which is start- 

 lingly contrary to the facts. His assumption that the 

 genio-glossus muscle is the one prime factor in speech is 

 not borne out by phoneticians, as he himself notes in one 

 place (page 305). Aside from such minor points, all of 

 which demand argument, I should like to point out what 

 seem to my mind to be some of the more important rea- 

 sons for considering his theory of the origin of the chin 

 imperfect. 



In the first place, if man's chin develops from his talk- 

 ing habit, all other animals, without exception, should 

 lack chins altogether. None of them have a language, 

 properly speaking. Eobinson himself, to go no further, 

 mentions other animals, notably the elephants, who do 

 possess chins. The latter have it, as the saying is, to 

 spare— much more than a human being has. Robinson 

 points out quite correctly that talking and the chin de- 

 velop together, as we observe man evolving through vari- 

 ous types. This does not necessarily mean, as Robinson 

 seems to assume, that talking produces the chin. On the 

 contrary, the gluteus maximus muscle undergoes tremen- 



