The Descent of Man

that is, are directed upwards; and the bird
whilst displaying himself on the ground would
naturally be illuminated from above. But here
comes the curious point; the outer feathers are
held almost horizontally, and their ocelli ought
likewise to appear as if illuminated from above,
and consequently the white marks ought to be
placed on the upper sides of the ocelli; and,
wonderful as is the fact, they are thus placed!
Hence the ocelli on the several feathers, though
occupying very different positions with respect
to the light, all appear as if illuminated from
above, just as an artist would have shaded
them. Nevertheless they are not illuminated
from strictly the same point as they ought to be;
for the white marks on the ocelli of the feathers
which are held almost horizontally, are placed
rather too much towards the further end; that
is, they are not sufficiently lateral. We have,
however, no right to expect absolute perfection
in a part rendered ornamental through sexual
selection, any more than we have in a part mo-