6 THE CYPRINODONTS. 
Between the sexes in certain species of these fishes there are great differ- 
ences in size and shapes ; commonly the female is larger and less modified. 
The greater number belong to the fresh waters; many are inhabitants of 
brackish water or of the sea along the shores. 
In the new world the known distribution extends from the basin of the 
great lakes and British America on the north to Argentina and Chili on the 
south, and from the Pacific to the West Indies and the Bermudas; in the old 
world it comprises the whole of Africa, Madagascar, the Seychelles, and the 
southern portions of Europe and Asia, from Spain to India and Japan. 
Marine species are known only near the surface ; fresh water species carry 
the vertical distribution from the sea level up to altitudes of 13,000 feet 
or more; the highest points reached by any of the fishes. 
Brownish or olivaceous, more or less tinted with greenish or yellowish, 
prevail in the ground colors. Metallic tints, especially those of silver, are 
common, most on the males. Apparently some of the species, or individuals, 
pass from the fresh to the salt waters ; on these a change in the coloration 
obtains similar to that affecting Salmo salar, which in the land-locked stage, 
so called, is more brown with numerous spots of black, but which on reach- 
ing the sea becomes more silvery with obsolescent spots. This modification 
is marked in the common minnows of the Gulf coast, Fundulus grandis, and 
in F. heteroclitus, from the Gulf northward along the eastern coasts of the 
United States. Another variation is exemplified by F. heteroclitus, a general 
diffusion of brownish with corresponding decrease in the amount of silver, or 
in the briliancy of coloration; this is noticeable on comparing the more 
modest coloration of the variety, badius, from Grand Menan with the more 
ornate representatives of the species from South Carolina to Florida. The 
male is the more highly colored of the sexes. Of some species the males are 
brilhant with striking combinations of red, orange, yellow, green, blue, gold, 
silver, white, or black, several of which colors sometimes unite in producing 
marked contrasts as compared with the plainer garb of the females. The 
fins of some of the males resemble the wings of gorgeous butterflies, in 
Mollienisia for instance. Among birds the female is commonly more modest 
in color than the male; this according to the Darwinian is beneficial, in that 
it renders the female less conspicuous when nesting; whether the benefit 
caused the difference is another question. Females of these fishes also are 
less conspicuous than the males; but necessarily the fact in this case is pro- 
vocative of some other theory in explanation. Considerable changes in color- 
