408 THE DESCENT OF MAN. 



taste for the beautiful as we have. This is shown by our 

 enjoyment of the singing of birds, and by our women, both 

 civilized and savage, decking their heads with borrowed 

 plumes and using gems which are hardly more brilliantly 

 colored than the naked skin and wattles of certain birds. 

 In man, however, when cultivated the sense of beauty is 

 manifestly a far more complex feeling and is associated 

 with various intellectual ideas. 



Before treating of the sexual characters with which we 

 are here more particularly concerned, I may just allude to 

 certain differences between the sexes which apparently 

 depend on differences in their habits of life; for such 

 cases, though common in the lower, are rare in the higher 

 classes. Two humming - birds belonging to the genus 

 Eustephanus, which inhabit the Island of Juan Fernandez, 

 were long thought to be specifically distinct, but are 

 now known, as Mr. Gould informs me, to be the male 

 and female of the same species, and they differ slightly 

 in the form of the beak. In another genus of hum- 

 ming-birds ( Grypus) the beak of the male is serrated along 

 the margin and hooked at the extremity, thus differing 

 much from that of the female. In the Neomorpha of New 

 Zealand, there is, as we have seen, a still wider difference 

 in the form of the beak in relation to the manner of feed- 

 ing of the two sexes. Something of the same kind has 

 been observed with the go\di^\\ch. {Car duelis elegans), for I 

 am assured by Mr. Jenner Weir that the bird-catchers 

 can distinguish the males by their slightly longer beaks. 

 The flocks of males are often found feeding on the seeds of 

 the teazle (Dipsacus), which they can reach with their 

 elongated beaks, while the females more commonly feed on 

 the seeds of the betony or Scrophularia. With a slight 

 difference of this kind as a foundation we can see how the 

 beaks of the two sexes might be made to differ greatly 

 through natural selection. In some of the above cases, 

 however, it is possible that the beaks of the males may 

 have been first modified in relation to their contests with 

 other males; and that this afterward led to slightly changed 

 habits of life. 



Law of Battle. Almost all male birds are extremely 

 pugnacious, using their beaks, wings, and legs for fighting 

 together. We see this every spring with our robins and 



