placed, and followed by sustained efforts at gratification--can not
only modify an organ--that is to say, augment or reduce it--but can
change its position when the case requires its removal.

"Ocean fishes have occasion to see what is on either side of them,
and have their eyes accordingly placed on either side of their head.
Some fishes, however, have their abode near coasts on submarine
banks and inclinations, and are thus forced to flatten themselves as
much as possible in order to get as near as they can to the shore.
In this situation they receive more light from above than from
below, and find it necessary to pay attention to whatever happens to
be above them; this need has involved the displacement of their
eyes, which now take the remarkable position which we observe in the
case of soles, turbots, plaice, etc.  The transfer of position is
not even yet complete in the case of these fishes, and the eyes are
not, therefore, symmetrically placed; but they are so with the
skate, whose head and whole body are equally disposed on either side
a longitudinal section.  Hence the eyes of this fish are placed
symmetrically upon the uppermost side."--Philosophie Zoologique,
tom. i. pp. 250, 251.  Edition C. Martins.  Paris, 1873.

{274a}  Essays on Heredity, etc., Oxford, 1889, p. 171.

{274b}  Ibid., p. 266.

{275}  Darwinism, 1889, p. 440.

{277}  Page 83.

{279}  Vol. i. p. 466, etc.  Ed. 1885.

{286}  Darwinism, p. 440.

{288}  Tom. iv. p. 383.  Ed. 1753.

{290}  Essays, etc., p. 447.

{299}  Zoonomia, 1794, vol. i. p. 480.