VII. 



Change in the Direction of the Working of 

 Natural Selection. 



ijN the fresh light which these con- 

 siderations throw upon the prob- 

 lem of man's origin, we can now 

 see more clearly than ever how great a 

 revolution was inaugurated when natural 

 selection began to confine its operations 

 to the surface of the cerebrum. Among 

 the older incidents in the evolution of or- 

 ganic life, the changes were very wonder- 

 ful which out of the pectoral fin of a fish 

 developed the jointed fore-limb of the 

 mammal with its five-toed paw, and thence 

 through much slighter variation brought 

 forth the human arm with its delicate and 

 crafty hand. More wondrous still were 

 the phases of change through which the 

 rudimentary pigment-spot of the worm, by 



