nm 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, André, 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 
