322 SEXUAL SELECTION. Part II. 



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 (Actiniae), with some jelly-fish (Me- 

 dusae, Porpita, &c), with some Planariae, Ascidians, 

 numerous Star-fishes, Echini, &e. ; 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 



