Chap. XII. 
FISHES. 
9 
of the dorsal fin. The young males resemble in struc- 
ture and colour the adult females. Throughout the 
genus Callionymus/^ the male is generally much more 
brightly spotted than the female, and in several species, 
not only the dorsal, but the anal fin of the male is much 
elongated. 
The male of the Coitus scorpius, or sea-scorpion, is more 
slender and smaller than the female. There is also a 
great difference in colour between them. It is difficult, 
as Mr. Lloyd remarks, ‘‘ for any one, who has not seen 
this fish during the spawning-season, when its hues are 
brightest, to conceive the admixture of brilliant colours 
with which it, in other respects so ill-favoured, is at 
‘‘ that time adorned.” Both sexes of the Labrus mixtus, 
although very different in colour, are beautiful ; the male 
being orange with bright-blue stripes, and the female 
bright-red witli some black spots on the back. 
In the very distinct family of the Cyprinodontidse — 
inhabitants of the fresh waters of foreign lands — the 
sexes sometimes differ much in various characters. In 
the male of the MolUenesia iJetenensis^"^ the dorsal fin is 
greatly developed and is marked with a row of large, 
round, ocellated, bright-coloured spots ; whilst the same 
fin in the female is smaller, of a different shape, and 
marked only with irregularly-curved brown spots. In 
the male the basal margin of the anal fin is also a little 
produced and dark-coloured. In the male of an allied 
form, the Xiphophorus Hellerii (fig. 29), the inferior 
margin of the anal fin is developed into a long filament. 
‘ Catalogue of Acantli. Fishes in the Bjitish Museum,’ by Dr. 
Gunther, 1861, p. 138-151. 
1^ ‘ Game Birds of Sweden,’ &c., 1867, p. 466. 
1^ With respect to this and the following species I am indebted to 
Dr. Gunther for information : see also his paper on the Fishes of 
Central America, in ‘ Transact. Zoolog. Soc.’ vol. vi. 1868, p. 485. 
