322 
SEXUAL SELECTION. 
Part IL 
Many of the lower animals, whether hermaphrodites 
or with the sexes separate, are ornamented with the 
most brilliant tints, or are shaded and striped in an 
elegant manner. This is the case with many corals 
and sea-anemonies (Actineae), with some jelly-fish (Me- 
dusae, Porpita, &c.), with some Planariae, Ascidians, 
numerous Star-fishes, Echini, &c. ; but we may conclude 
from the reasons already indicated, namely the union 
of the two sexes in some of these animals, the per- 
manently affixed condition of others, and the low 
mental powers of all, that such colours do not serve 
as a sexual attraction, and have not been acquired 
through sexual selection. With the higher animals 
the case is very different ; for with them when one sex 
is much more brilliantly or conspicuously coloured 
than the other, and there is no difference in the 
habits of the two sexes which will account for this 
difference, we have reason to believe in the influence 
of sexual selection ; and this belief is strongly con- 
firmed when the more ornamented individuals, which 
are almost always the males, display their attractions 
before the other sex. We may also extend this con- 
clusion to both sexes, when coloured alike, if their 
colours are plainly analogous to those of one sex alone 
in certain other species of the same group. 
How, then, are we to account for the beautiful or 
even gorgeous colours of many animals in the lowest 
classes ? It appears very doubtful whether such colours 
usually serve as a protection ; but we are extremely 
liable to err in regard to characters of all kinds in 
relation to protection, as will be admitted by every one 
who has read Mr. Wallace’s excellent essay on this 
subject. It would not, for instance, at first occur to 
any one that the perfect transparency of the Medusae, 
or jelly-fishes, was of the highest service to them as a 
