458 



EVOLUTION AND ANIJMAL LI5^E 



volves no 

 structure. 



walk like a bear^ four-footed^ and resting on the palms of their 

 hands. The muscles in each case are the same, although in man 

 the gastrocnemius and soleus are enlarged, forming the calf 

 of the leg, while the expanded gluteus maximus forms the 

 buttocks. Both buttocks and calf are scantily developed in 

 the apes and monkeys, but the muscles forming them are 

 essentially the same as in man. 



The monkej^s have been called Quadrumana, fom'-handed^ 

 because the foot like the hand is fitted for gra.sping, and the 



great toe, like the thumb, is 

 opposable to the other digits. 

 But as Huxle}^ .has clearly 

 shown, this modification in- 

 real change of 

 An examination 

 of the bones and muscles 

 involved at once shows that 

 the hinder limb in apes and 

 monkeA^s is truly a foot and 

 not a hand. Part by part 

 the hinder foot of the mon- 

 key is homiologous with the 

 foot of man, not with the 

 hand (Fig. 281). The loss of 

 the power of opposing the 

 great toe, on the part of 

 man, is a result incident to 

 the use of the hinder limbs for walking alone, and not for 

 grasping. In some of the lower races of man the great 

 toe stands apart from the others to a larger extent than in the 

 European races. 



In the apes there is a greater degree of mobility of the muscles 

 of the scalp and the ear than in man, but there are very many 

 cases of men who are able to move these muscles freely. The 

 muscles of the tail in man are quite useless, as are also those of 

 the higher apes, in which the coccyx or tail is scarcely more 

 developed than in man. 



In man, the wisdom teeth are usuall}^ rudimentary, but in 

 the native Australians these teeth are the largest of the series, 

 as is also the case Avith the apes (Fig. 282). 



In structure it is clear that man agrees in aU large matters 



Fig. 288. — A young gorilla of the Leipsig 

 Zoological Garden. (From Illustrirte Zei- 

 tung, after a photograph.) 



