Chap. XII.] FISHES. 7 



adapted for the prehension of the femak', it is possible 

 that their teeth may be used for this purpose. 



In regard to size, M. Carbonnier " maintains tliat with 

 almost all fishes the female is larger than the male ; and 

 Dr. Giliitlier does not know of a single instance in which 

 the male is actually larger than the female. With some 

 Cyprinodonts the male is not even half as large as the 

 female. As with many kinds of fishes, tlie males habitu- 

 ally fight together ; it is surprising that they have not 

 generally become through the efiects of sexual selection 

 larger and stronger than the females. The males suffer 

 from their small size, for according to M. Carbonnier they 

 are liable to be devoured by the females of their own spe- 

 cies when carnivorous, and no doubt by other species. 

 Increased size must be in some manner of more impor- 

 tance to the females, than strength and size are to the 

 males for fighting with other males ; and this perhaps is 

 to allow of the production of a vast number of ova. 



In many species the male alone is ornamented with 

 bright colors ; or these are much brighter in the male 

 than in the female. The male, also, is sometimes provided 

 with apjieiidages which appear to be of no more use to him 

 for the ordinary purposes of life than are the tail-feathers 

 to the peacock. I am indebted for most of the folloAving 

 facts to the great kindness of Dr. Giinther. There is rea- 

 son to suspect that many tropical fislies difier sexually in 

 color and structure ; and there are some striking cases 

 with our British fishes. The male Callionymus lyra has 

 been called the gemmeous dragonet " from its brilliant, 

 gem-like colors." When freshly taken from the sea the 

 body is yellow of various shades, striped and spotted with 

 vivid blue on the hca*! ; tlie dorsal fins are pale brown 

 with dark longitudinal bands; the ventral, caudal, and 

 anal fins being l)luish-l>lack. The female, or sordid drag- 



'0 As quoted in ' The Farmer,' 1808, p. 369. 



