18 
SEXUAL SELECTION. 
Part II. 
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 they 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 roost 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, be 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 sandy bed of the sea on which it 
lives. One of the most striking instances ever recorded 
of an animal gaining protection by its colour (as far 
as can he judged in preserved specimens) and by 
its form, is that given by Dr. Gunther 28 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. xiv. and xv. 
