The Descent of Man

treat in the next chapter of the principle of gradation.
The foregoing remarks relate to the secondary
wing-feathers, but the primary wing-feathers,
which in most gallinaceous birds are uniformly
coloured, are in the Argus pheasant equally
wonderful. They are of a soft brown tint with
numerous dark spots, each of which consists of
two or three black dots with a surrounding
dark zone. But the chief ornament is a space
parallel to the dark-blue shaft, which in outline
forms a perfect second feather lying within the
true feather. This inner part is coloured of a
lighter chestnut, and is thickly dotted with minute
white points. I have shewn this feather to
several persons, and many have admired it
even more than the ball and socket feathers,
and have declared that it was more like a work
of art than of nature. Now these feathers are
quite hidden on all ordinary occasions, but are
fully displayed, together with the long secon-