November, 1913. 



KNOWLEDGE. 



415 



ancient or modern, to our 

 own mandible in a group 

 of some of the earliest 

 reptiles that have yet 

 been discovered. In the 

 Figures 427 and 428 of 

 those strange thero- 



Figure 496. 



Diagram of the genio-glossus 

 pronouncing 



muscle 



in 

 sound 



the 



Oo.' 



Figure 497 



Figure 495. 



Diagram of the genio-glossus 

 muscle at rest. 



morphs, Pariasaurus and 

 Inostransevia, unearthed 

 by Professor Amalitzky in 

 the Permian strata on 

 the shores of the northern 

 Dvvina, we see an extra- 

 ordinary chin which re- 

 sembles our own in several 

 striking anatomical particulars. 



How such a resemblance comes to 

 exist I do not even venture to guess ; 

 but most assuredly Nature's moulding 

 forces, which so shaped the mandibles 

 of these ancient reptiles, were totally 

 different from those cerebral activities 

 largely responsible for the chin of 

 civilised man. We say so more con- 

 fidently because casts of their skull- 

 cavities show that they had no brains 

 to speak of, the whole cerebral cham- 

 ber being of about the same calibre as 

 the tunnel for the spinal marrow. 



When the writer discussed this 

 subject before the British Association 

 at Birmingham, and there suggested that the 

 needs of the mechanism for articulate speech 

 would probably account for the essential changes 

 in man's lower jaw, it was pointed out by Professor 

 Elliot Smith that man's face differs from those 

 of his nearest congeners in many other particulars 

 quite as remarkable as these. I hope some 

 day to show that most of these other changes 

 have been profoundly influenced, if not actually 

 caused, by structural necessities demanded by arti- 

 culate speech. To attempt to do so now would 

 take me beyond the scope of the present subject, 

 and I shall therefore confine my attention merely to 

 the changes that have taken place in the mandible. 



In the many endeavours that have been made to 

 explain the why and wherefore of the chin, the 

 argument as to its being due to sexual selection 

 deserves most notice. It has been rightly said that 

 the chin is essential to the beauty of the human 

 countenance, and therefore in a choice of mates, 

 those deficient in this direction would be losers in 

 life's race. Arguments from aesthetics are very 



Diagram of the genio-glossus 



muscle in pronouncing the 



letter " K." 



difficult to handle, because of the extraordinary 

 differences in the standards of beauty, not only 

 among different species of the lower animals, but 

 among different nearly related races of men. Who 

 can doubt that among the anthropoid apes there is 

 a type of apish beauty (including the retreating 

 lower jaw) which satisfies the most critical and 

 exacting simian taste in choosing a mate ? We need 

 not do more than allude to the peculiar aesthetic 

 standards obviously existing a little lower down the 

 scale among the baboons, drills, and mandrils. 



A chin is now unquestionably a sine qua non of 

 human beauty. But how did it become so ? When 

 did the simian ideal cease to flutter the hearts of our 

 primitive ancestors ? 



Do we not find that almost all the adorable 

 features which have this disturbing and fateful 

 influence nowadays are based upon and are the sign 

 of some intrinsic quality contributing to racial 

 efficiency which lies behind mere appearance ? The 

 lower races are continually, to the great embarrass- 

 ment of sundry Colonial Governments, desirous of 

 mating with a superior race differing from them in 

 physique and in colour. There can be 

 no question that if the colonists in 

 such cases were not the superior race 

 this evidence of the working of sexual 

 selection would not appear. It would 

 seem, therefore, that the primitive 

 man who was manly and, amongst 

 other manly attributes, had a chin, 

 scored all along the evolutionary line 

 in mating contests over the prim- 

 itive man who was apelike. The 

 individual or the race which does not 

 recognise the upward stream of 

 tendency in such particulars by 

 instinct alone cannot be found upon 

 the surface of 



this planet. 

 One argument against 

 the sufficiency of sexual 

 selection in producing a 

 chin, is the well-known 

 fact that man in the 

 early stages of his exis- 

 tence muffled up his 



Figure 498. 



Diagram of the genio-glossus 



muscle in pronouncing the 



letter " T." 



lower jaw with a beard, 

 which is, almost with- 

 out doubt, of purely or- 

 namental value. Hence 

 it would seem that the 



Figure 499. 



Diagram of the genio-glossus 



muscle in pronouncing the 



sound " Ah." 



