426 THE DESCENT OF MAN. 



featliers, which are ornamented with numerous ocelli. I re- 

 quest the reader to turn back to the drawing (fig. 51, p. 391) of a 

 Polyplectron. In P. napoleonis the ocelli are confined to the 

 tail and the back is of a rich metallic blue; in which respects 

 this species approaches the Java peacock. P. hardwickii pos- 

 sesses a peculiar top-knot, which is also somewhat like that ol 

 the Java peacock. In all the species the ocelli on the wings 

 and tail are either circular or oval, and consist of a beautiful, 

 iridescent, greenish-blue or greenish-purple disc, with a black 

 border. This border in P. chinquis shades into brown, edged with 

 cream-color, so that the ocellus is here surrounded with variously 

 shaded, though not bright, concentric zones. The unusual length 

 of the tail-coverts is another remarkable character in Polyplec- 

 tron; for in some of the species they are half, and in others two- 

 thirds as long as the true tail-feathers. The tail-coverts are 

 ocellated as in the peacock. Thus the several species of Poly- 

 plectron manifestly make a graduated approach to the peacock 

 in the length of their tall-coverts, in the zoning of the ocelli, 

 and in some other characters. 



Notwithstanding this approach, the first species of Polyplectron 

 which I examined almost made me give up the search; for 1 

 found not only that the true tail-feathers, which in the peacock 

 are quite plain, were ornamented with ocelli, but that the ocelli 

 on all the feathers differed fundamentally from those of the pea- 

 cock, in there being two on the same feather (flg. 55), one on 

 each side of the shaft. Hence I concluded that the early pro- 

 genitors of the peacock could not have resembled a Polyplectron. 

 But on continuing my search, I observed that in some of the 

 species the two ocelli stood very near each other; that in the 

 tail-feathers of P. hardwickii they touched each other; and, 

 finally, that on the tail-coverts of this same species as well as of 

 P. malaccense (fig. 56) they were actually confluent. As the 

 central part alone is confluent, an indentation is left at both the 

 upper and lower ends; and the surrounding colored zones are 

 likewise indented. A single ocellus is thus formed on each tail- 

 covert, though still plainly betraying its double origin. These 

 confluent ocelli differ from the single ocelli of the peacock in 

 having an indentation at both ends, instead of only at the lower 

 or basal end. The explanation, however, of this difference is 

 not difficult; in some species of Polyplectron the two oval ocelli 

 on the same feather stand parallel to each other; in other spe- 

 cies (as in P. chinquis) they converge towards one end; now the 

 partial confluence of two convergent ocelli would manifestly leave 

 a much deeper indentation at the divergent than at the con- 

 vergent end. It is also manifest that if the convergence were 

 strongly pronounced and the confluence complete, the indentation 

 at the convergent end would tend to disappear. 



