II THE ORIGIN OF SPECIES 37 



remark that, once in existence, many varieties obey 

 the fundamental law of reproduction that like tends 

 to produce like; and their offspring exemplify it by 

 tending to exhibit the same deviation from the 

 parental stock as themselves. Indeed, there seems 

 to be, in many instances, a prepotent influence 

 about a newly-arisen variety which gives it what 

 one may call an unfair advantage over the normal 

 descendants from the same stock. This is strik- 

 ingly exemplified by the case of Gratio Kelleia, 

 who married a woman with the ordinary penta- 

 dactyle extremities, and had by her four children, 

 Salvator, George, Andre", and Marie. Of these 

 children Salvator, the eldest boy, had six fingers 

 and six toes, like his father ; the second and third, 

 also boys, had five fingers and five toes, like their 

 mother, though the hands and feet of George 

 were slightly deformed. The last, a girl, had five 

 fingers and five toes, but the thumbs were slightly 

 deformed. The variety thus reproduced itself 

 purely in the eldest, while the normal type 

 reproduced itself purely in the third, and almost 

 purely in the second and last : so that it would 

 seem, at first, as if the normal type were more 

 powerful than the variety. But all these children 

 grew up and intermarried with normal wives and 

 husband, and then, note what took place : Salvator 

 had four children, three of whom exhibited the 

 hexadactyle members of their grandfather and 

 father, while the youngest had the pentadactyle 



