FISHES. 341 



the salmon," the female, during the whole time, is attended by 

 the niale. After the ova are fertilized they are, in most cases, 

 left unprotected by both parents, so that the males and females, 

 as far as oviposition is concerned, are equally exposed to danger, 

 and both are equally important for the production of fertile ova; 

 consequently the more or less brightly-colored individuals of 

 either sex would be equally liable to be destroyed or preserved, 

 and both would have an equal influence on the colors of their off- 

 spring. 



Certain fishes, belonging to several families, make nests, and 

 some of them take care of their young when hatched. Both 

 sexes of the bright colored Crenilabrus massa and melops work 

 together in building their nests with sea-weed, shells, &c." But 

 the males of certain fishes do all the work, and afterwards take 

 exclusive charge of the young. This is the case with the dull- 

 colored gobies,^' in which the sexes are not known to differ in 

 color, and likewise with the sticklebacks (Gasterosteus), in 

 which the males become brilliantly colored during the spawning 

 season. The male of the smooth-tailed stickleback (G. leiurus) 

 performs the duties of a nurse with exemplary care and vigilance 

 during a long time, and is continually employed in gently leading 

 back the young to the nest, when they stray too far. He courage- 

 ously drives away all enemies, including the females of his own 

 species. It would indeed be no small relief to the male, if the fe- 

 male, after depositing her eggs, were immediately devoured by 

 some enemy, for he is forced incessantly to drive her from the 

 nest." 



The males of certain other fishes inhabiting South America 

 and Ceylon, belonging to two distinct Orders, have the extraor- 

 dinary habit of hatching within their mouths or branchial cavi- 

 ties, the eggs laid by the females.^' I am informed by Professor 

 Agassiz that the males of the Amazonian species which follow this 

 habit, "not only are generally brighter than the females, but 

 "the difference is greater at the spawning-season than at any 

 "other time." The species of Geophagus act in the same manner; 

 and in this genus, a conspicuous protuberance becomes developed 

 on the forehead of the males during the breeding-season. With 



3* Yarrell, 'British Pishes,' vol. 11. p. 11. 



36 According to the observations ol M. Gerbe; see Gunther's 'Record 

 of Zoolog. Literature,' 1865, p. 194. 



^ Cuvier, 'Regne Animal,' vol. ii. 1829, p. 242. 



3' See Mr. Warington's most interesting description of the habits of 

 the Gasterosteus leiurus, in 'Annals and Mag. of Nat. Hist.' Novem- 

 ber, 1855. 



28 Prof. Wyman, in 'Proc. Boston Soc. of Nat. Hist.' Sept. 15, 1857. 

 Also Prof. Turner, in 'Journal of Anatomy and Phys.' Nov. 1, 1866, 

 p. 78. Dr. Gunther has likewise described other cases. 

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