200 The Trouts of America 



species, thus producing an offspring more or less 

 similar to the pure breed. . . ." 



To add to this confusion in the identification 

 and classification of species, other potent factors 

 exist, of which the widely variant coloration is 

 not the least. Trout of the same species, when 

 found in widely separated waters, and in some 

 instances in the same habitat, very often present 

 striking differentiation in color and physique. I 

 have found three distinct forms and standards of 

 coloration in the same species of Rocky Moun- 

 tain trout, the cut-throat or black-spotted trout 

 (Salmo clarkii). Those of the Yellowstone River 

 have stout bodies and yellow coloration of rather 

 a dense hue ; those of the Gallatin River are not 

 so stout at the shoulders, and have a bright sil- 

 very coating, while the Elk Creek fish is more 

 clipper-built, has a cleaner run than his congeners 

 of the Yellowstone and Gallatin, with a more brill- 

 iant silvery sheen, barred with brown. Age does 

 not seem to alter these conditions, for a half-pound 

 fish, caught in either of the waters named, is as 

 characteristically marked as one weighing a pound, 

 and these streams are all in Montana and not dis- 

 tant more than three hundred miles, as the crow 

 flies, one from the other. 



