Chap. XII. Fishes. 343 



confinement. It is, however, more probable that these colours 

 have been intensified through artificial seleotiou, as this species 

 has been carefully bred in China from a remote period.^' 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*' 

 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 

 many of the carnivorous Cyprinidse in India are ornamented 

 with "bright longitudinal hues of various tints." *^ Mr. M'Clel- 

 land, in describing these fishes, goes so far as to suppose that 

 " the peculiar brilliancy of their colours " serves as " a better 

 " mark for king-fishers, terns, and other birds which are 

 '■ destined to keep the number of these fishes in check ; " but at 

 the present day few naturalists will admit that any animal has 

 been made C' mspicuous as an aid to its own destruction. It is 

 possible that certain fishes may have been rendered conspicuous 

 in order to warn birds and beasts of prey that they were 

 unpalatable, as explained when treating of caterpillars; but it 

 is not, I believe, known that any fish, at least any fresh-water 

 fish, is rejected from being distasteful to fish-devouring animals. 

 On the whole, the most probable view in regard to the fishes, of 

 which both sexes are brilliantly coloured, is that their colours 

 were acquired by the males as a sexual ornament, and were 

 transferred equally, or nearly so, to the other sex. 



'' Owing to some remarks on this has been " produced at Hangchow a 



subject, made in my work ' On the " variety called the fire-fish, from its 



Variation of Animals under Domesti- "intensely red colour. It is uni- 



cation,' Mr. W. F. Mayers (' Chinese " versally admired, and there is not 



Notes and Quei'ies,' Aug. 1868, p. " a household where it, is not cil- 



123) has searched the ancient " tivated, m rira/rj/ as fo sis coioM ■ 



Chin2se encyclopedias. He finds " and as a source of profit." 



that gold-fish were first reared in ='" 'Westminster Keview,' Julj 



confinement during the Sung Dy- 1867, p. 7. 



nasty, which commenced A.o. 960. ^i < Indian Cyprinidse,' by Mr. J 



In the year 1129 these fishes M'Clellnnd, 'Asiatic Researches, 



abounded. In another place it is vol. xix. part ii. 1839, p. 230. 

 ■aid that since the year 1548 there 



