18 SEXUAL SELECTION. Part IL 



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 (as explained when treat- 

 ing of caterpillars) that tliey were unpalatable ; 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 have been 

 acquired by the males as a sexual ornament, and have 

 been transferred in an equal or nearly equal degree to 

 the other sex. 



We have now to consider whether, when the male 

 differs in a marked manner from the female in colour 

 or in other ornaments, he alone has been modified, 

 with the variations inherited only by his male offspring ; 

 or whether the female has been specially modified and 

 rendered inconspicuous for the sake of protection, such 

 modifications being inherited only by the females. It is 

 impossible to doubt that colour has been acquired by 

 many fishes as a protection: no one can behold the 

 speckled upper surface of a flounder, and overlook its 

 resemblance to the sandv bed of the sea on which it 

 lives. One of the most strikinof instances ever recorded 

 of an animal gaining protection by its colour (as far 

 as can be judged in preserved specimens) and by 

 its form, is that given by Dr. Giinther^^ 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. Fishes offer valuable 



29 ' Proc. Zoolog. Soc' 1865, p. 327, pi. riv. and xv, 



