Chap. XII.] FISHES. 21 



differ much in color ; but Dr. Gtinther believes that the 

 male Hippocampi are rather brighter than the females. 

 The 'genus Solenostoma, however, offers a very curious ex- 

 ceptional case, ?0 for the female is much more vividly col- 

 ored and spotted than the male, and she alone has a mar- 

 supial sack and hatches the eggs ; so that the female of 

 Solenostoma differs from all the other Lophobranchii in 

 this latter respect, and frdm almost all other fishes, in 

 being more brightly colored than the male. It is improb- 

 able 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 fe- 

 males, and as here the female Solenostoma takes the same 

 charge and is brighter than the male, it might be argued 

 that the conspicuous colors of the sex which is the most 

 important of the two for the welfare of the offspring must 

 serve, in some manner, as a protection. But from the 

 multitude of fishes, the males of which are either perma- 

 nently or periodically brighter than the females, but 

 whose life is not at all more important than that of the 

 female for the welfare of the species, this view can hardly 

 be maintained. When we treat of birds we shall meet 

 with analogous cases in which there has been a complete 

 inversion of the usual attributes of the two sexes, and we 

 shall then give what appears to be the probable explana- 

 tion, namely, that the males have selected the more at- 

 tractive females, instead of the latter having selected, in 

 accordance with the usual rule throughout the animal 

 kingdom, the more attractive males. 



.On the whole, we may conclude that, with most fishes, 

 in which the sexes differ in color or in other ornamental 



36 Dr. Gtinther, since publishing an account of this species in i The 

 Fishes of Zanzibar,' by Colonel Playfair, 1866, p. 137, has reexamined 

 the specimens, and has given me the above information. 



