Eye-colour, Comb, and Spurs 



fact recorded by Bonhote, on page 245 of the 

 Proceedings of the Fourth International Ornitho- 

 logical Congress, that in the case of ducks de- 

 scended from crosses between the pintail, the 

 mallard, and the spotbill, the drakes in full 

 breeding plumage showed a mixture of pintail 

 and mallard characteristics, while, in their non- 

 breeding plumage, the colouring of the spotbill 

 is predominant. 



An important point, and one which does not 

 seem to have been pointed out by any zoologist, 

 is that eye-colour, comb, and spurs in birds and 

 horns in mammals do not stand in the same 

 relation to the sexual organs as do the other 

 external characteristics. For example, the cas- 

 trated Nilgai (Boselaphus tragocamelus) acquires 

 horns, but not the characteristic male colour. 

 In the common Indian Francolin Partridge 

 {Fr anco Linus pondicerianius), the cock differs from 

 the hen only in the possession of spurs. The 

 same applies to the various species of Snow 

 Cock ( Tetraogallus}. There is a breed of game- 

 cocks which display plumage like that of the 

 hen, but such birds have the comb and spurs 

 developed as in normally feathered cocks. 



The white eye of the white-eyed Pochard 

 Drake (Nyroca africana), and the yellow eye of 

 the cock Golden Pheasant (Chrysolophus pictus], 

 which are purely male characters, show them- 

 selves earlier than the male plumage. Occasion- 

 v 337 



