134 BRITISH LIZARDS 



the circumstances which made this a useful variation 

 continued in operation, those which had not thus 

 varied would in time become exterminated. The 

 offspring of the lizards with the reduced limbs would 

 also have this character, some to a greater degree 

 than others, and those in which it was most marked 

 would in their turn survive. They would vary in 

 their turn, and so the process would finally result 

 again in a species of lizard without limbs. In this 

 case the spontaneous variations have in some instances 

 been adapted to the environment of the creature, 

 and therefore have conferred upon it a commanding 

 advantage, enabling it to survive where others have 

 become exterminated. The environment has not 

 caused the variation during the life of any given 

 members of the species, but these members have given 

 rise to offspring which have varied from their parents, 

 simply because all offspring do vary more or less from 

 their parents. They have thus become adapted to 

 their environment, and given rise to a new species. 

 According to this view, only a certain number of 

 offspring possess the advantageous variation, and they 

 are selected to survive. It only requires that a male 

 and a female each possessed of the new character 

 should pair, in order that it may be possible for the 

 variation to become permanent and intensified. It 

 thus appears that some very profound modifications 

 may arise suddenly, as the result of this spontaneous 

 variation, and in such a case the intermediate stages 



