BIRDS. 493 



cense, the ocelli on the tail-coverts are, as we have seen, 

 confluent; and these feathers are of unusual length, being 

 two-thirds of the length of the tail-feathers, so that in both 

 these respects they approach the tail -coverts of the peacock. 

 Now in P. tnalaccense the two central tail-feathers alone 

 are ornamented, each with two brightly colored ocelli, the 

 inner occellus having completely disappeared from all the 

 other tail-feathers. Consequently the tail-coverts and tail- 

 feathers of this species of Polyplectron make a near approach 

 in structure and ornamentation to the corresponding feathers 

 of the peacock. 



As far, then, as gradation throws light on the steps by 

 which the magnificent train of the peacock has been 

 acquired, hardly anything more is needed. If we picture 

 to ourselves a progenitor of the peacock in an almost 

 exactly intermediate condition between the existing peacock 

 with his enormously elongated tail-coverts ornamented with 

 single ocelli, and an ordinary gallinaceous bird with short 

 tail-coverts merely spotted with some color, we shall see a 

 bird allied to Polyplectron that is, with tail-coverts capable 

 of erection and expansion, ornamented with two partially 

 confluent ocelli, and long enough almost to conceal the 

 tail-feathers, the latter having already partially lost their 

 ocelli. The indentation of the central disk and of the 

 surrounding zones of the ocellus in both species of peacock 

 speaks plainly in favor of this view and is otherwise inexpli- 

 cable. The males of the Polyplectron are no doubt beautiful 

 birds, but their beauty, when viewed from a little distance, 

 cannot be compared with that of the peacock. Many female 

 progenitors of the peacock must, during a long line of 

 descent, have appreciated this superiority; for they have 

 unconsciously, by the continued preference of the most 

 beautiful males, rendered the peacock the most splendid 

 of living birds. 



Argus Pheasant. Another excellent case for investiga- 

 tion is offered by the ocelli on the wing- feathers of the 

 Argus pheasant/ which are shaded in so wonderful a 

 manner as to resemble balls lying loose within sockets and 

 consequently differ from ordinary ocelli. No one, I pre- 

 sume, will attribute the shading, which has excited the 

 admiration of many experienced artists, to chance to the 

 fortuitous concourse of atoms of coloring matter. That 



