The Descent of Man

parts of the ball can be perceived, as before
noticed; and the line of separation is oblique, in
the same direction as the bright coloured shades
of the elliptic ornaments. Thus almost every
minute detail in the shape and colouring of the
ball-and-socket ocelli can be shewn to follow
from gradual changes in the elliptic ornaments;
and the development of the latter can be traced
by equally small steps from the union of two
almost simple spots, the lower one (Fig. 58)
having some dull fulvous shading on its upper
side.
[Fig. 61. Portion near summit of one of the secondary
wing-feathers, bearing perfect balland-socket
ocelli. a. Ornamented upper part. b.
Uppermost, imperfect ball-and-socket ocellus.
(The shading above the white mark on the
summit of the ocellus is here a little too dark.) c.
Perfect ocellus.]
The extremities of the longer secondary feathers
which bear the perfect ball-and-socket oce-