THE LIFE OF ISLANDS. 225 



tell, by the colour, " from which particular island 

 a specimen had been brought." We learn from such 

 facts the power which local conditions of life possess 

 over living beings in the direction of inducing varia- 

 tion in form, colour, and other particulars. Now, as 

 regards our big Galapagos tortoises, the same rule 

 holds good. 



Once introduce an animal or plant to new surround- 

 ings, in the shape of food, climate, and so forth, and 

 you may assuredly bargain for alteration of its form 

 and colour. The Galapagos tortoises differ from other 

 big reptiles of that kind ; but that the differences are 

 due to this universal tendency to variation is, at the 

 very least, a reasonable explanation, in face of the 

 facts with which we are acquainted. We therefore 

 see in the 'case of the Galapagos reptiles merely another 

 proof of the wondrous fashion in which living beings 

 suit themselves to new environments : a power of 

 adaptation this, which really prevents the extinction 

 and annihilation of life when placed in strange lands 

 and under untoward conditions. 



