"Chap. XIII.] DECORATION. 71 



be admired by man, so with birds a change of almost any 

 kind in the structure or coloring of the feathers, in tlie 

 male, appears to have been admired by the female. The 

 fact of the feathers in widely-distinct groups having been 

 modified in an analogous manner, no doubt depends pri- 

 marily on all the feathers having nearly the same struct- 

 ure and manner of development, and consequently tend- 

 ing to vary in the same manner. We often see a ten- 

 dency to analogous variability in the plumage of our 

 domestic breeds belonging to distinct species. Thus top- 

 knots have appeared in several species. In an extinct 

 variety of the turkey, the top-knot consisted of bare quills 

 surmounted with plumes of down, so that tliey resembled, 

 to a certain extent, the racket-shaped feathers above de- 

 scribed. In certain breeds of the pigeon and fowl the 

 feathers are plumose, with some tendency in the shafts to 

 be naked. In the Sevastopol goose the scapular feathers 

 are greatly elongated, curled, or even spirally twisted, 

 with the margins plumose,*' 



In regard to color hardly any thing need here be said ; 

 for every one knows how splendid are the tints of birds, 

 and how harmoniously they are combined. The colors 

 are often metallic and ii-idescent. Circular spots are 

 sometimes surrounded by one or more diiferently-shaded 

 zones, and are thus converted into ocelli. Nor need much 

 be said on the wonderful difterences between the sexes, or 

 of the extreme beauty of the males of many birds. The 

 common peacock offers a striking instance. Female Birds 

 of Paradise are obscurely colored and destitute of all orna- 

 ments, while the males are probably the most highly 

 decorated of all birds, and in so many ways, that they 

 must be seen to be ajjpreciated. The elongated and 

 golden-orange plumes which sj^ring from beneath the 



*' See my work on ' The Variation of Animals and Plants under Do- 

 mestication,' vol. i. pp. 289, 293. 



