Rainbow Trout 



medium, 2 to 8 pounds. Streams of the upper Sacramento 



basin, not running down to sea; shasta, 198 



bb. Scales small in 150 to 185 series. Size large. 



e. Back profusely spotted anteriorly as well as posteriorly; some 



red on lower jaw. Kern River, California; gilberti, 201 



ee. Back with the spots chiefly posteriorly ; no red on lower jaw. 



Upper Sacramento basin ; stonei, 20 1 



aa. Scales very small and not well imbricated; upper ray of 



pectoral unspotted ; agua-bonita, 20 1 



Rainbow Trout 



Salmo iridens Gibbons 



In mountain streams of the Coast Ranges of the Pacific States 

 and on the west slopes of the Sierra Nevada Mountains are found 

 the various forms of trout which are collectively regarded as con- 

 stituting the rainbow trout series. Members of this series are 

 distinguished from those of the steelhead series by their larger 

 scales and, generally, by their smaller size and brighter colouration. 

 From the cut-throat series they differ in their larger scales, brighter 

 colouration, and, usually, in the absence of red on the throat. 

 As already stated, however, in some parts of their range these 

 series are inextricably mixed, and present classifications can be 

 regarded only as provisional. 



The typical rainbow trout (Salmo irideus) is found only 

 in the small brooks of the Coast ranges in California, from 

 the Klamath River to the San Luis Ray in San Diego County. 

 It is subject to large local variations, some of these land-locked 

 in peculiar brooks, as in Purissima Creek in San Mateo County, 



195 



