sexuaa selection 447 



lor kingfishers, 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 conspicuous 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 cater- 

 pillars ; 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 colored, is that their colors were acquired by the 

 males as a sexual ornament, and were transferred equally, 

 or nearly so, to the other sex. 



We have now to consider whether, when the male 

 differs in a marked manner from the female in color or in 

 other ornaments, he alone has been modified, the variations 

 being inherited by his male offspring alone; or whether 

 the female has been specially modified and rendered incon- 

 spicuous for the sake of protection, such modifications being 

 inherited only by the females. It is impossible to doubt 

 that color has been gained by many fishes as a protection: 

 no one can examine the speckled upper surface of a flounder, 

 and overlook its resemblance to the sandy bed of the sea 

 on which it lives. Certain fishes, moreover, can, through 

 the action of the nervous system, change their colors in 

 adaptation to surrounding objects, and that within a short 

 time." One of the most striking instances ever recorded 

 of an animal being protected by its color (as far as it can be 

 judged of in preserved specimens), as well as by its form, 

 is that given by Dr. Gunther" of a pipe-fish, which, with 

 its reddish streaming filaments, is hardly distinguishable 

 from the sea-weed to which it clings with its prehensile 

 tail. But .the question now under consideration is whether 

 the females alone have been modified for this object. We 



82 G. Pouchet, L'lnstitut, Nov. 1, 1871, p. 134. 



^ "Proo. Zoolog Soc," 1865, p. 327, pL xiv. and XV. 



