2Pt THE ORIGIN OF SPECIES 



effect, but how inucli we cannot say. Thus, when vari 

 eties enter any new station, thej'^ occasionally assume 

 some of the characters proper to the species of that 

 station. With both varieties and species, use and dis- 

 use seem to have produced a considerable effect; for it 

 is impossible to resist this conclusion when we look, for 

 instance, at the logger- headed duck, which has wings 

 incapable of flight, in nearly the same condition as in 

 the domestic duck; or when we look at the burrowing 

 tucutuco, which is occasionally blind, and then at cer- 

 tain moles, which are habitaally blind and have their 

 eyes covered with skin; or when we look at the blind 

 animals inhabiting the dark caves of America and Eu- 

 rope. With varieties and species, correlated variation 

 seems to have played an important part, so that when 

 one part has been modified other parts have been neces- 

 sarily modified. With both varieties and species rever- 

 sions to long-lost characters occasional!}^ occur. How in- 

 explicable on the theory of creation is the occasional 

 appearance of stripes on the shoulders and legs of the 

 several species of the horse-genus and of their hybrids! 

 How simply is this fact explained if we believe that 

 these species are all descended from a striped progenitor, 

 in the same manner as the several domestic breeds of 

 the pigeon are descended from the blue and barred 

 rock -pigeon! 



On the ordinary view of each species having been 

 independently created, why should specific characters, 

 or those by which the species of the same genus differ 

 from each other, be more variable than generic characters 

 in which they all agree? Why, for instance, should the 

 color of a flower be more likely to vary in any one spe- 



