Chap. XIII.] DECORATION. 75 



rich cobalt blue, crossed by several lines of black velvety- 

 feathers." '' 



Male humming-birds (Figs. 48 and 49) almost vie with 

 Birds of Paradise in their beauty, as every one will admit 

 who has seen Mr. Gould's splendid volumes or his rich 

 collection. It is very remarkable in how many different 

 ways these birds are ornamented. Almost every part of 

 the plumage has been taken advantage of and modified ; 

 and the modifications have been carried, as Mr. Gould 

 showed me, to a wonderful extreme in some species be- 

 longing to nearly every sub-group. Such cases are curi- 

 ously like those which we see in our fancy breeds, reared 

 by man for the sake of ornament : certain individuals 

 originally varied in one character, and other individuals 

 belonging to the same species in other characters ; and 

 these have been seized on by man and augmented to an 

 extreme point — as the tail of the fantail-pigeon, the hood 

 of the jacobin, the beak and wattle of the carrier, etc. 

 The sole difference between these cases is that in the 

 one the result is due to man's selection, while in the 

 other, as with Humming-birds, Birds of Paradise, etc., it 

 is due to sexual selection — that is, to the selection by the 

 females of the more beautiful males. 



I will mention only one other bird, remarkable from 

 the extreme contrast in color between the sexes, namely, 

 fhe famous Bell-bird ( ChasmorhyncJms niveus) of South 

 America, the note of which can be distinguished at the 

 distance of nearly three miles, and astonishes every one 

 who first hears it. The male is pure white, while the fe- 

 male is dusky-green; and the former color with terres- 

 trial species of moderate size and inoffensive habits is very 

 rare. The male, also, as described by Waterton, has a 

 spiral tube, nearly three inches in length, which rises from 

 the base of the beak. It is jet-black, dotted over with 



*9 "Wallace, 'The Malay Archipelago,' vol. ii. 1869, p. 405. 



