Chap. XIV. Birds — Gradation of Characters. 4o3 



strongly pronounced and the confluence complete, the indentation 

 at the convergent end would tend to disappear. 



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. Iu this respect they 

 differ remarkably from the tail- 

 feathers of Polyplectron, which 

 in most of the species are or- 

 namented 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 their 

 ocelli shewed any tendency to dis- 

 appear; and to my great satis- 

 faction, this appeared to be so. 

 The central tail-feathers of P. 

 napoleon is have the two ocelli on 

 each side of the shaft perfectly 

 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 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. malaccense the two central tail- 

 feathers alone are ornamented, 

 each with two brightly-coloured 

 ocelli, the inner ocellus having 

 completely disappeared from all 

 the other tail-feathers. Conse- 

 quently the tail-coverts and tail-feathers of this species of Poly- 

 plectron make a near approach in structure and ornamentation 

 to the corresponding feathers of the peacock. 



Fi 



5. Part of a tail-covert of Poly- 

 plvctron chinquis, vvilh the two ocelli 

 of nat. size. 



Fig. 56. Part of a tail-covert of Poly- 

 plectron malaccense, with the two 

 ocelli, partially confluent, of hat. size, 



