146 THE ORIGIN OF SPECIES 



plainer than that the webbed feet of ducks and geese are formed 

 for swimming? Yet there are upland geese with webbed feet which 

 rarely go near the water; and no one, except Audubon, has seen 

 the frigate-bird, which has all its four toes webbed, alight on the 

 surface of the ocean. On the other hand, grebes and coots are emi- 

 nently aquatic, although their toes are only bordered by mem- 

 brane. What seems plainer than that the long toes, not furnished 

 with membrane of the Grallatores, are formed for walking over 

 swamps and floating plants? The water-hen and landrail are mem- 

 bers of this order, yet the first is nearly as aquatic as the coot, and 

 the second is nearly as terrestrial as the quail or partridge. In such 

 cases, and many others could be given, habits have changed with- 

 out a corresponding change of structure. The webbed feet of the 

 upland goose may be said to have become almost rudimentary in 

 function, though not in structure. In the frigate-bird, the deeply 

 scooped membrane between the toes shows that structure has 

 begun to change. 



He who believes in separate and innumerable acts of creation 

 may say, that in these cases it has pleased the Creator to cause a 

 being of one type to take the place of one belonging to another 

 type ; but this seems to me only restating the fact in dignified lan- 

 guage. He who believes in the struggle for existence and in the 

 principle of natural selection, will acknowledge that every organic 

 being is constantly endeavoring to increase in numbers; and that 

 »f any one being varies ever so little, either in habits or structure, 

 and thus gains an advantage over some other inhabitant of the 

 same country, it will seize on the place of that inhabitant, how- 

 ever different that may be from its own place. Hence it will cause 

 him no surprise that there should be geese and frigate-birds with 

 webbed feet, living on the dry land and rarely alighting on the 

 water, that there should be long-toed corncrakes, living in mead- 

 ows instead of in swamps ; that there should be woodpeckers where 

 hardly a tree grows; that there should be diving thrushes and 

 diving Hymenoptera, and petrels with the habits of auks. 



ORGANS OF EXTREME PERFECTION AND COMPLICATION 



To suppose that the eye with all its inimitable contrivances for 

 adjusting the focus to different distances, for admitting different 

 amounts of light, and for the correction of spherical and chromatic 

 aberration, could have been formed by natural selection, seems, I 

 freely confess, absurd in the highest degree. When it was first said 

 that the sun stood still and the world turned round, the common- 

 sense of mankind declared the doctrine false; but the old saying 



