» 1877.) The Colors of Animals and Plants. T21 
the females prefer certain males on account of the beauty of 
their plumage.” Again, Mr. Darwin himself says, “ As a gen- 
eral rule, color appears to have little influente on the pairing of 
pigeons.” The oft-quoted case of Sir R. Heron’s peahens, which 
preferred an “old pied cock” to those normally colored, is a 
very unfortunate one, because pied birds are just those that are 
not favored in a state of nature, or the breeds of wild birds would | 
become as varied and mottled as our domestic varieties. If such 
irregular fancies were not rare exceptions, the production of defi- 
nite colors and patterns by the choice of the female birds, or in 
any other way, would be impossible. 
We now come to such wonderful developments of plumage 
and color as are exhibited by the peacock and the Argus pheasant ; 
and I may here mention that it was the latter bird, as fully dis- 
cussed by Mr. Darwin, which first shook my belief in ‘ sexual,” 
or more properly ‘* female,” selection. The long series of grada- 
tions by which the beautifully-shaded ocelli on the secondary 
wing feathers of this bird have been produced are clearly traced 
out, the result being a set of markings so exquisitely shaded as 
to represent “ balls lying loose within sockets,” — purely artificial 
-= objects of which these birds could have no possible knowledge. 
That this result should have been attained through thousands and 
tens of thousands of female birds, all preferring those males whose 
markings varied slightly in this one direction, this uniformity of 
choice continuing through thousands and tens of thousands of 
generations, is to me absolutely incredible. And when, further, 
we remember that those which did not so vary would also, accord- 
ing to all'the evidence, find mates and leave offspring, the actual 
result seems quite impossible of attainment by such means. 
Without pretending to solve completely so difficult a problem, 
I would point out a circumstance which seems to afford a clew. 
It is that the most highly colored and most richly varied mark- 
ings occur on those parts of the plumage which have undergone 
the greatest modification, or have acquired the most abnormal 
_ development. In the peacock the tail coverts are enormously 
4 developed, and the “ eyes ” are situated on the greatly dilated 
ends. In the birds-of-paradise, breast, or neck, or head, or tail 
_ feathers are greatly developed and highly colored. The hackles 
_ of the cock and the scaly breasts of humming-birds are similar 
_ developments ; while in the Argus pheasant the secondary quills 
are so enormously lengthened and broadened as to have become 
almost useless for flight. Now, it is easily conceivable that, dur- 
VOL. XI. — No. 12. 46 . 
