The Descent of Man

which surrounds the ball of the ocellus is unquestionably
formed by the union and modification
of the three black marks, b, c, d, of the
elliptic ornament. The irregular zigzag black
marks between the successive ocelli (Fig. 57)
are plainly due to the breaking up of the somewhat
more regular but similar marks between
the elliptic ornaments.
The successive steps in the shading of the balland-socket
ocelli can be followed out with
equal clearness. The brown, orange, and paleleadened
narrow zones, which border the lower
black mark of the elliptic ornament, can be
seen gradually to become more and more softened
and shaded into each other, with the upper
lighter part towards the left-hand corner
rendered still lighter, so as to become almost
white, and at the same time more contracted.
But even in the most perfect ball-and-socket
ocelli a slight difference in the tints, though not
in the shading, between the upper and lower