world for instance, the Peacock Labrus (L. pavo), described (28. Bory
Saint Vincent, in Dict. Class. d Hist. Nat. tom. ix. 1826, p. 151.),
with pardonable exaggeration, as formed of polished scales of gold,
encrusting lapis-lazuli, rubies, sapphires, emeralds, and amethysts we
may, with much probability, accept this belief; for we have seen that
the sexes in at least one species of the genus differ greatly in
colour. With some fishes, as with many of the lowest animals, splendid
colours may be the direct result of the nature of their tissues and of
the surrounding conditions, without the aid of selection of any kind.
The gold-fish (Cyprinus auratus), judging from the analogy of the
golden variety of the common carp, is perhaps a case in point, as it
may owe its splendid colours to a single abrupt variation, due to the
conditions to which this fish has been subjected under confinement. It
is, however, more probable that these colours have been intensified
through artificial selection, as this species has been carefully bred
in China from a remote period. (29. Owing to some remarks on this
subject, made in my work On the Variation of Animals under
Domestication, Mr. W.F. Mayers ( Chinese Notes and Queries, Aug.
1868, p. 123) has searched the ancient Chinese encyclopedias. He finds
that gold-fish were first reared in confinement during the Sung
Dynasty, which commenced A.D. 960. In the year 1129 these fishes
abounded. In another place it is said that since the year 1548 there
has been produced at Hangchow a variety called the fire-fish, from its
intensely red colour. It is universally admired, and there is not a
household where it is not cultivated, IN RIVALRY AS TO ITS COLOUR, and
as a source of profit. ) Under natural conditions it does not seem
probable that beings so highly organised as fishes, and which live
under such complex relations, should become brilliantly coloured
without suffering some evil or receiving some benefit from so great a
change, and consequently without the intervention of natural selection.
What, then, are we to conclude in regard to the many fishes, both sexes
of which are splendidly coloured? Mr. Wallace (30. Westminster
Review, July 1867, p. 7.) believes that the species which frequent
reefs, where corals and other brightly-coloured organisms abound, are
brightly coloured in order to escape detection by their enemies; but
according to my recollection they were thus rendered highly
conspicuous. In the fresh-waters of the tropics there are no
brilliantly-coloured corals or other organisms for the fishes to
resemble; yet many species in the Amazons are beautifully coloured, and
371