The Descent of Man

sexual selection of these ornamental appendages.
Elongated feathers or plumes spring from
almost every part of the body. The feathers on
the throat and breast are sometimes developed
into beautiful ruffs and collars. The tail-feathers
are frequently increased in length; as we see in
the tail-coverts of the peacock, and in the tail
itself of the Argus pheasant. With the peacock
even the bones of the tail have been modified to
support the heavy tail- coverts. (66. Dr. W.
Marshall, 'Uber den Vogelschwanz,' ibid. B. I.
Heft 2, 1872.) The body of the Argus is not larger
than that of a fowl; yet the length from the
end of the beak to the extremity of the tail is no
less than five feet three inches (67. Jardine's
'Naturalist Library: Birds,' vol. xiv. p. 166.), and
that of the beautifully ocellated secondary
wing- feathers nearly three feet. In a small African
night-jar (Cosmetornis vexillarius) one of
the primary wing-feathers, during the breeding-season,
attains a length of twenty-six inches,
whilst the bird itself is only ten inches in