The Trout of Western America 



black spots upon the gill-covers, in shape both round and 

 irregular." 



Mr. J. G. A. Creighton says "the teeth in the ouananiche 

 are larger than in Salmo salar, ... the fins are proportionately 

 much larger, especially the tail. . . . The eye is remarkably large, 

 about three-quarters of an inch in diameter in the adult, with a pupil 

 ^-inch in diameter. These measurements are much greater than in 

 the sea-salmon of 15 to 20 pounds' weight." 



The evidence seems to indicate that the ouananiche is specifi- 

 cally distinct from the Atlantic salmon and from the Sebago 

 salmon, and for the present we prefer to so regard it. 



The Trout of Western America 



In the western part of America are found more than a score 

 of trout of the genus Salmo all closely related and difficult to 

 distinguish. There are representatives in the headwaters of the 

 Rio Grande, Arkansas, Platte, Missouri, and Colorado; also in the 

 Great Salt Lake basin, throughout the Columbia basin, and in all 

 suitable waters from southern California and Chihuahua to Alaska 

 and Kamchatka. 



Among the various more or less tangible forms that may be 

 recognized, 3 distinct series appear which have been regarded 

 provisionally by us as distinct species. These have been termed 

 the cut-throat trout series, the rainbow trout series, and the steel- 

 head series, each of which has been sufficiently characterized in 

 the key on page 163. 



The steelhead, or frairdneri series, is found in the coastwise 

 streams of California and in the streams of Oregon and Washing- 

 ton, below the great Shoshone Falls of Snake River. In the 

 lower course of the Columbia and in neighbouring streams they 

 are entirely distinct from the cut-throat or clarkii series, and no 

 one would question the validity of the 2 species. In the lower 

 Snake River and in other waters east of the Cascade range, the 

 2 forms or species are indistinguishable, being either undifferen- 

 tiated or else inextricably mixed. 



The rainbow forms are chiefly confined to the streams of 

 California and southern Oregon. The cut-throat forms are found 

 from Humboldt Bay northward in the coastwise streams of northern- 

 California, Oregon and Washington, and all the clear streams on 



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