THE SALMON TRIBE 



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body. On the other hand, the noumigratory forms may be arranged under two 

 types of coloration, some loch trout (which may have been originally migratory, 

 but are now landlocked) being mainly silvery during the smolt stage, and sub- 

 sequently golden and spotted; while the estuarine, lake, and river trout are all golden 

 with purplish reflections, and more or less fully marked with black and vermilion 

 spots. It appears, indeed, that a long residence in fresh water generally leads to 

 the disappearance of the silvery sheen characteristic of the salmonoids while in the 

 sea (and which is probably their primitive type of coloration), and to the promotion 



MAY TROUT AND HUCHO. 



(One-fifteenth natural size.) 



of color. As a partially transitional type between sea trout and river trout may be 

 taken the Lochleven trout, which is somewhat silvery during the smolt stage, with 

 the spots generally black, and no orange border to the fatty fin, but at a later stage 

 assumes the general coloration of the river trout, although lacking the white black- 

 based front margin to the dorsal, anal, and pelvic fins characteristic of the latter. 

 Silvery trout do, however, occasionally occur in fresh water, where there is no 

 possibility of their having migrated from the sea. In concluding his observations 

 concerning the coloration of trout, Day writes that "reasons have been shown for 



