276 THE ORIGIN OF SPECIES 



the sake of mere variety, a view already discussed. Such 

 doctrines, if true, would be absolutely fatal to my theory. 

 I fully admit that many structures are now of no direct 

 use to their possessors, and may never have been of any 

 use to their progenitors; but this does not prove that 

 they were formed solely for beauty or variety. No 

 doubt the definite action of changed conditions, and the 

 various causes of modifications, lately specified, have all 

 produced an effect, probably a great effect, independently 

 of any advantage thus gained. But a still more impor- 

 tant consideration is that the chief part of the organiza- 

 tion of every living creature is due to inheritance; and 

 consequently, though each being assuredly is well fitted 

 for its place in nature, many structures have now no 

 very close and direct relation to present habits of life. 

 Thus, we can hardly believe that the webbed feet of 

 the upland goose or of the frigate-bird are of special 

 use to these birds; we cannot believe that the similar 

 bones in the arm of the monkey, in the foreleg of the 

 horse, in the wing of the bat, and in the flipper of 

 the seal, are of special use to these animals. We may 

 safely attribute these structures to inheritance. But 

 webbed feet no doubt were as useful to the pro- 

 genitor of the upland goose and of the frigate-bird 

 as they now are to the most aquatic of living birds. 

 So we may believe that the progenitor of the seal did 

 not possess a flipper, but a foot with five toes fitted 

 for walking or grasping; and we may further venture 

 to believe that the several bones in the limbs of the 

 monkey, horse, and bat were originally developed, on 

 the principle of utility, probably through the reduction 

 of more numerous bones in the tin of some ancient fish- 



