FISHES. 391 



time is attended by the male. 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 con- 

 cerned, 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 offspring. 



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, etc.* But the males of certain fishes do all the 

 work and afterward take exclusive charge of the young. 

 This is the case with the dull-colored gobies, f 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 

 courageously drives away all enemies, including the females 

 of his own species. It would indeed be no small relief to 

 the male if the female after depositing her eggs were 

 immediately devoured by some enemy, for he is forced 

 incessantly to drive her from the nest.J 



The males of certain other fishes inhabiting South Amer- 

 ica and Ceylon, belonging to two distinct orders, have the 

 extraordinary habit of hatching within their mouths, or 

 branchial cavities, the eggs laid by the females. I am 

 informed by Prof. Agassiz that the males of the Amazonian 



* According to the observations of M. Gerbe; see Giinther's 

 " Record of Zoolog. Literature," 1865, p. 194. 



fCuvier, " Regne Animal," vol. ii, 1829, p. 242. 



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

 the Gasterosteus leiurus in "Annals and Mag. of Nat. Hist.," Nov., 

 1855. 



gProf. 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. Giinther has likewise described other 



