BIRDS-GRADATION OF CHARACTERS. 



427 



The tail-feathers in both species of peacock are entirely destitute 

 of ocelli, and this apparently is related to their being covered up 

 and concealed by the long tail-coverts. In this respect they dif- 

 fer remarkably from the tail-feathers of Polyplectron, which in 

 most of the species are ornamented with larger ocelli than those 

 on the tail-coverts. Hence I was led carefully to examine the 

 tail-feathers of the several species, in order to discover whether 



Fig'. 55. Part of a tail-covert 

 of Polyplectron chlnquis, 

 with the two ocelli of nat. 

 size. 



Fig-. 56. Part of a tail-covert 

 of Polyplectron malac- 

 cense, with the two ocelli, 

 partially confluent, of nat. 

 size. 



their ocelli showed any tendency to disappear; and to my great 

 satisfaction, this appeared to be so. The central tail-feathers 

 of P. napoleonis have the two ocelli on each side of the shaft per- 

 fectly developed; but the inner ocellus becomes less and less 

 conspicuous on the more exterior tail-feathers, until a mere 

 shadow or rudiment is left on the inner side of the outermost 

 feather. Again, in P. malaccense, the ocelli on the tail-coverts 

 are, as we have seen, confluent; and these feathers are of un- 

 usual 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. malaccense the two central tail-feathers 

 alone are ornamented, each with two brightly-colored ocelli, the 

 inner ocellus 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. 



