342 THE DESCENT OP MAN. 



the various species of Chroinids, as Professor Agassiz likewise 

 informs me, sexual differences in color may be observed, "wbetber 

 "they lay their eggs in the water among aquatic plants, or deposit 

 "them in holes, leaving them to come out without further care, 

 "or build shallow nests in the river mud, over which they sit, as 

 "our Pomotis does. It ought also to be observed that these sitters 

 "are among the brightest species in their respective families; for 

 "instance, Hygrogonus is bright green, with large black ocelli, 

 "encircled with the most brilliant red." Whether with all the 

 species of Chromids it is the male alone which sits on the eggs is 

 not known. It is, however, manifest that the fact of the eggs 

 being protected or unprotected by the parents, has had little or 

 no influence on the differences in color between the sexes. It 

 is further manifest, in all the cases in which the males take 

 exclusive charge of the nests and young, that the destruction 

 of the brighter-colored males would be far more influential on 

 the character of the race, than the destruction of the brighter- 

 colored females; for the death of the male during the period of 

 incubation or nursing would entail the death of the young, so 

 that they could not inherit his peculiarities; yet, in many of 

 these very cases the males are more conspicuously colored than 

 the females. 



In most of the Lophobranchii (Pipe-fish, Hippocampi, &c.) the 

 males have either marsupial packs or hemispherical depressions 

 on the abdomen, in which the ova laid by the female are hatched. 

 The males also show great attachment to their young."" Ttie 

 sexes do not commonly differ much in color; but Dr. Giinther 

 believes that the male Hippocampi are rather brighter than the 

 females. The genus Solenostoma, however, offers a curious ex- 

 ceptional case," for the female is much more vividly-colored and 

 spotted than the male, and she alone has a marsupial sack and 

 hatches the eggs; so that the female of Solenostoma differs from 

 all the other Lophobranchii in this latter respect, and from almost 

 all other fishes, in being more brightly-colored than the male. It 

 is improbable that this remarkable double inversion of character in 

 the female should be an accidental coincidence. As the males of 

 several fishes, which take exclusive charge of the eggs and young, 

 are more brightly-colored than the females, and as here the fe- 

 male Solenostoma takes the same charge and is brighter than the 

 male, it might be argued that the conspicuous colors of that sex 

 which is the more important of the two for the welfare of the 

 offspring, must be in some manner protective. But from the 



™ Tarrell, 'Hist, of British Fishes," vol. ii. 1836, pp. 329, 338. 



" Dr. Gunther, since publishing an account of this species in 'The 

 Fishes of Zanzibar,' by Col. Playfair, 1866, p. 137, has re-examined the 

 specimens, and has given me the above information. 



