Chap. IX.] SEXUAL SELECTION. 313 



have no reason to suppose that such differences have been 

 augmented through sexual selection. 



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-anem- 

 ones (Actinia?), with some jelly-fish (Medusae, Porpita, 

 etc.), with some Planarise, Ascidians, numerous Star-fishes, 

 Echini, etc. ; but we may conclude, from the reasons al- 

 ready indicated, namely, the union of the two sexes in 

 some of these animals, the permanently affixed condition 

 of others, and the low mental powers of all, that such col- 

 ors do not serve as a sexual attraction, and have not been 

 acquired through sexual selection. With the higher ani- 

 mals the case is very different ; for with them when one 

 sex is much more brilliantly or conspicuously colored 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 confirmed when the more ornament- 

 ed individuals, which are almost always the males, dis- 

 play their attractions before the other sex. We may also 

 extend this conclusion to both sexes, when colored alike, 

 if their colors 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 colors of many animals in the lowest classes ? 

 It appears very doubtful whether such colors usually serve 

 as a protection ; but we are extremely liable to err in re- 

 gard to characters of all kinds in relation to protection, as 

 will be admitted by every one who has read Mr. Wal- 

 lace's excellent essay on this subject. It would not, for 

 instance, at first occur to any one that the perfect trans- 

 parency of the Medusas, or jelly-fishes, was of the highest 

 service to them as a protection ; but when we are remind- 



