312 lot. E. W. L. HOLT OX THE [Apr. 19 



distinguishes liiui at the first glance from his mate ; that this 

 structural differentiation is accompanied by the development on 

 certain parts of a very conspicuous coloration, wholly absent from 

 the female ; and that the yellow element of this coloration has a 

 distinct association with the ripeness of the genital product, 

 rapidly fading after the early part of the breeding-season. We 

 have seen that the yellow colour is that of a highly soluble 

 pigment, characterized by a peculiar taste and smell, and distinctly 

 irritant. The same pigment is present, in much smaller quantity, 

 in the female ; and the flesh, as well as the skin, of large examples 

 of either sex appears to be unpalatable to at least one predaceous 

 fish, the pollack, while even fully-coloured males are greedily 

 eaten by the turbot. Male, female, and young alike possess a 

 powerful preopercular spine, and are further protected by a copious 

 mucous secretion. The male displays his secondary characters 

 alike, whether in courtship (including the intimidation of younger 

 members of his own sex), in competition for food with his own 

 species, or in the apparent endeavour to prevent the attack of a 

 predaceous enemy, though it is only in courtship that the jaws 

 and teeth are fully exposed. We have no evidence of serious 

 combat among mature males \ 



It remains to endeavour to fix the right interpretation of these 

 various phenomena of form and habit. The coloration of the 

 male sufficiently conforms to Poulton's definition of the epigamic 

 character ", in tliat the most conspicuous parts, at all events, are 

 concealed when the animal is at rest. In the light of the pairing 

 habit, unique, so far as I know, among fishes propagating by 

 pelagic eegs, and of the readiness with which the blue colour 

 is intensified during courtship, it is hard to regard the secondary 

 structure and colour-characters otherwise than as due to some form 

 of sexual selection. It matters little whether the excessive 

 production of yellow pigment at the breeding-season has been 

 evolved by sexual selection or whether it be an adventitious 

 excretory process connected with genital activity. The possibility 

 of the female being degenerate suggests itself, but is hardly 

 supported by any evidence in the ontogeny. Perhaps in C. lyra 

 the female presents a greater contrast to the male than in some 

 other species of the genus ; but, even if there were degeneracy in 

 this sex, it might be regarded as a degeneracy from a condition 

 originally acquired in i-esponse to the sexually-selected charms of 

 the male. 



I think it must be conceded that the account which I have 

 given of the behaviour of the female at the time of pairing does 

 not strongly support the view of an (esthetic sexual selection. 

 In the dim light of 20 to 30 fathoms minute excellencies of 

 design and colour-harmony must be hard to detect. Our female 



' Cf. the perfectly harmless battles of courting spiders (Peckham, Occas. 

 Papers, Nat. Hist. Soc. Wiscons., i. 1889, quoted by Poulton, ' Oolours of 

 Animals,' p. 310). • 



» Op. cit. p. 311. 



