RECAPITULATION AND CONCLUSION 511 



this theory. How strange it is that a bird, under the form 

 of a woodpecker, should prey on insects on the ground ; that 

 upland geese which rarely or never swim, should possess 

 webbed feet; that a thrush-like bird should dive and feed 

 on sub-aquatic insects ; and that a petrel should have the 

 habits and structure fitting it for the life of an auk ! and so 

 in endless other cases. But on the view of each species 

 constantly trying to increase in number, with natural selec- 

 tion always ready to adapt the slowly varying descendants of 

 each to any unoccupied or ill-occupied place in nature, these 

 facts cease to be strange, or might even have been antici- 

 pated. 



We can to a certain extent understand how it is that there 

 is so much beauty throughout nature; for this may be largely 

 attributed to the agency of selection. That beauty, accord- 

 ing to our sense of it, is not universal, must be admitted by 

 every one who will look at some venomous snakes, at some 

 fishes, and at certain hideous bats with a distorted resem- 

 blance to the human face. Sexual selection has given the 

 most brilliant colours, elegant patterns, and other ornaments 

 to the males, and sometimes to both sexes of many birds, 

 butterflies, and other animals. With birds it has often ren- 

 dered the voice of the male musical to the female, as well as 

 to our ears. Flowers and fruit have been rendered con- 

 spicuous by brilliant colours in contrast with the green foli- 

 age, in order that the flowers may be easily seen, visited, 

 and fertilised by insects, and the seeds disseminated by birds. 

 How it comes that certain colours, sounds, and forms should 

 give pleasure to man and the lower animals, — that is, how 

 the sense of beauty in its simplest form was first acquired, — 

 we do not know any more than how certain odours and 

 flavours were first rendered agreeable. 



As natural selection acts by competition, it adapts and 

 improves the inhabitants of each country only in relation to 

 their co-inhabitants; so that we need feel no surprise at the 

 species of any one country, although on the ordinary view 

 supposed to have been created and specially adapted for that 

 country, being beaten and supplanted by the naturalised pro- 

 ductions from another land. Nor ought we to marvel if all 

 the contrivances in nature be not, as far as we can judge, 



