Chap. XIY. 
GRADATION OF CHARACTERS. 
141 
is needed. We may picture to ourselves a progenitor 
of the peacock in an almost exactly intermediate con- 
dition between the existing peacock, with his enor- 
mously elongated tail-coverts, ornamented with single 
ocelli, and an ordinary gallinaceous bird with short 
tail-coverts, merely spotted with some colour; and we 
shall then see in our mind’s eye, a bird possessing 
tail-coverts, capable of erection and expansion, orna- 
mented with two partially confluent ocelli, and long 
enough almost to conceal the tail-feathers, — the latter 
having already partially lost their ocelli ; we shall 
see in short, a Polyplectron. The indentation of the 
central disc and surrounding zones of the ocellus in both 
species of peacock, seems to me to speak plainly in 
favour of this view ; and this structure is otherwise inex- 
plicable. The males of Polyplectron are no doubt very 
beautiful birds, but their beauty, when viewed from a 
little distance, cannot be compared, as I formerly saw 
in the Zoological Glardens, 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 prefer- 
ence of the most beautiful males, rendered the peacock 
the most splendid of living birds. 
Argus pheasant , — Another excellent case for investi- 
gation 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 within sockets, and 
which consequently differ from ordinary ocelli. No one,. 
I presume, will attribute the shading, which has excited 
the admiration of many experienced artists, to chance 
— to the fortuitous concourse of atoms of colouring 
matter. That these ornaments should have been formed 
through the selection of many successive variations, not 
one of which was originally intended to produce the 
