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cumstances, giving rise often to great confusion in the 

 descriptions, and causing the same species to be de- 

 scribed under several diiferent names. This change is 

 in some cases almost instantaneous. He spoke of the 

 splendid coloring of the male sticklebacks during the 

 spawning season, the deep almost hlackhne of the ocidentalis 

 contrasting strikingly with the white membranes of the ven- 

 tral spines, the brilliant blue and crimson of the biacnleatus 

 and the scarlet blotches of the quadracns, whence its popu- 

 lar name of the "bloody stickleback." The differences in the 

 bottom and feeding grounds produced a marked variation 

 in the color of fishes, as for instance, in Humphries' and Ce- 

 dar Ponds. In the former, all the fish without a single 

 exception, are very light colored ; in the latter all are dark 

 and strongly marked. The bottom of the former pond is 

 sandy ; of the latter, muddy, and filled with water plants. 

 The influence of light has undoubtedly some effect on the 

 coloration of fishes. In the Aquarial Gardens, in Boston, 

 are specimens of Tautoga Americana, the Tautog, which 

 have grown from a very small size to a very considerable 

 size, and which are certainly subjected to a much greater 

 degree of light, than in their accustomed abodes. These 

 have lost that peculiar dark color which has given them, in 

 many places, the popular name of " Black Pish," and are so 

 light that one hardly recognizes them without examination. 

 The same holds good with a specimen of Cottus virginianuSy 

 our common Sculpin. He had noticed a gradual fading of 

 the colors in specimens kept at the Aquarial Gardens, until 

 the original markings had almost entirely disappeared, but 

 this perhaps may have depended on the diet. 



In young fish, too, the coloration is often very different 

 from the adult ; as for instance, — the young of the Catostomiy 

 which have a black band from the snout to the caudal fin, 

 supposed to be characteristic of the black-nosed Dace, with 

 which they are continually confounded. 



