100 



THE GENESIS OF SPECIES. 



[Chap. 



But cases of siniulfnnom.is and similar inodifications 



TUE OiCKAT ^U1ELDED GRASSHOPPER. 



aljound on all sides. Even as regards the human species, 

 there is a very generally admitted opinion that a new 



Those that did not so turn would much more easily become the prey of 

 others (if they were vegetarians), or (if they were carnivorous animals) 

 their i»rey would more readily perceive and avoid them. Here, then, it 

 see«ns at lirst that we have the obvious a<tion of natural selection. Yet, 

 in fact, this faculty now apj^ears to be rather the result of .some obscure 

 internal tendency, intensified, no doubt, by natural selection, but by no 

 means due to the action of the latter on mere accidental minute varia- 

 tions. For in Siberia it is not only timid or predacious animals that 

 tend to become li^dit-coloured in winter, since Pallas tells vis that snch a 

 phenomenon is observable in domestic cattle and in horses. In such 

 juiimals, of course, this character cannot be due to uatuiai selection, and 

 therefore, as we must admit it in this case to be due to some spontiineous 

 internal tendency, it immediately becomes probable that a similar ten- 

 dency also exists in the other cases, and the onus jyrobandi lies with him 

 who denies that such is the case." — Xuvrc Species Qv.adrupedum c Glirivm 

 ordine, 177S, p. 7, (quoted by Mr. Darwin in "Descent of Man:" sc< 

 vol. i. p. 282. 



I 



