CHAPTEE II. 



THE EXTERNAL FORM OF ANTHROPOID APES. 



In the gorilla, the chimpanzee, and the orang-utan 

 the external form is subject to essential modifica- 

 tions, according to the age and sex. The difference 

 between the sexes is most strongly marked in the 

 gorilla, and these differences are least apparent in 

 the gibbon. 



When a young male gorilla is compared with an 

 aged animal of the same species, we are almost 

 tempted to believe that we have to do with two 

 entirely different creatures. While the young male 

 still displays an evident approximation to the 

 human structure, and develops in its bodily habits 

 the same qualities which generally characterize the 

 short-tailed apes of the Old World, with the exception 

 of the baboon, the aged male is otherwise formed. 

 In the latter case the points of resemblance to the 

 human type are far fewer; the aged animal has 

 become a gigantic ape, retaining indeed in the 

 structure of his hands and feet the characteristics 

 of the primates, while the protruding head is some- 

 thing between the muzzle of the baboon, the bear, 



