EVOLUTION OF MAN 31 



most familiar species, has perhaps been less studied 

 from the zoological point of view than any other. 

 It is also from this point of view the most difficult, 

 partly because it is our own species and we cannot 

 get far enough away from it to see it in true perspec- 

 tive, partly because it has had such an exceptional 

 history, having spread over the whole earth and 

 become largely independent of physical conditions ; 

 that is to say, it has attained to a great extent the 

 power of making artificially uniform conditions which 

 render it independent of differences of climate, 

 geographical features, and differences of fauna and 

 flora in different habitats. The first question to con- 

 sider is whether man is a single species or several, and 

 what is his relation to other species. This question, as 

 well as most of the others which I propose to consider 

 in this paper, has been discussed with his usual 

 thoroughness and judgment by Darwin in his 

 " Descent of Man," so that I am really only trying 

 to see whether we know any more about these prob- 

 lems than Darwin taught us. 



The chief peculiarities of man, as compared with 

 his nearest allies, the anthropoid apes, are all adaptive 

 and useful characters, namely, the erect position, 

 the structure of the hand and foot, and the faculty 

 of articulate speech. Associated with the possession 

 of language are the size and differentiation of the 

 brain, especially of the cerebral hemispheres, and the 

 correlated size and shape of the cranium. The 

 reduction of the jaws, teeth, and face generally is 

 also a characteristic feature, and adaptive to the 



