SEXUAL SELECTION 515 



The ocelli on the wing-feathers are wonderfal objects; 

 for they are so shaded that, as the Duke of Argyll re- 

 marks," they stand oat like balls lying loosely within 

 sockets. When I looked at the specimen in the British 

 Museum, which is mounted with the wings expanded and 

 trailing downward, I was, however, greatly disappointed, 

 for the ocelli appeared flat, or even concave. But Mr. 

 Gould soon made the case clear to me, for he held the 

 feathers erect, in the position in which they would natu- 

 rally be displayed, and now, from the light shining on them 

 from above, each ocellus at once resembled the ornament 

 called a ball and socket. These feathers have been shown 

 to several artists, and all have expressed their admiration 

 at the perfect shading. It may well be asked, could such 

 artistically shaded ornaments have been formed by means 

 of sexual selection? But it will be convenient to defer 

 giving an answer to this question until we treat in the 

 next chapter of the principle of gradation. 



The foregoing remarks relate to the secondary wing- 

 feathers, but the primary wing-feathers, which in most 

 gallinaceous birds are uniformly colored, are in the Argus 

 pheasant equally wonderful. They are of a soft brown tint 

 with numerous dark spots, each of which consists of two or 

 three black dots with a surrounding dark zone. But the 

 chief ornament is a space parallel to the dark blue shaft, 

 which in outline forms a perfect second feather lying within 

 the true feather. This inner part is colored of a lighter 

 chestnut, and is thickly dotted with minute white points. 

 I have shown this feather to several persons, and many 

 have admired it even more than the ball and socket 

 feathers, and have declared that it was more like a work 

 of art than of nature. Now these feathers are quite hidden 

 on all ordinary occasions, but are fully displayed, together 

 with the long secondary feathers, when they are all ex- 

 panded together so as to form the great fan or shield. 



«» "The Eeign of Law," 1867, p. 203. 



