FISHES OF THE NORTHWEST. 343 



difficult to tempt with anything. Mice and squirrels cut into strips 

 have succeeded where other lures have previously failed. In Lake 

 Tahoe, where S. iridea abound as well as another species, be- 

 lieved to be new, the former are said to reach a weight of thirty 

 pounds. The methods of capture are various, trolling being gen- 

 erally employed, the hook being similar to the one used in the east 

 for catching bluefish ; but on the hook a minnow is placed as bait, 

 and the boat is slowly rowed along the line of shallow and deep 

 water which varies in depth from thirty to seventy-five feet. The 

 fishermen maintain the existence of two distinct species of trout, 

 which they call " Silver Trout," and the " Black or Salmon Trout," 

 and the difference of color is distinctly appreciable. There is also 

 a marked difference in the size of the adipose fin. 



Mason's Trout. — Salmo masoni. Suckley. 



This species may prove to be only a variety of the preceding. 

 Girard calls it Fario clarkii. It is found in Oregon and Washing- 

 ton Territory. As it is marked as a doubtful species, no descrip- 

 tion is here given of it. 



Rocky Mountain Trout ; Yellowstone Trout. — Salmo pleuriiicus. Cope. 



Specific characteristics. — Head rather smaller than its Western 

 congeners ; enters four times in length to notch of caudal, which 

 is well emarginated ; muzzle obtuse ; diameter of eye enters four 

 times in length of head ; depth of body four and five-tenths in 

 length to end of caudal scales ; dorsal fin midway between latter 

 and end of muzzle ; scales small ; Branchiae xi. Color, Bluish 

 silvery lead on back, yellowish-white beneath ; sides with short, 

 broad, longitudinal bars of crimson ; a band of the same colot 

 occupies the fissure within each ramus of the jaw and skin on the 

 median side of it. Fins crimsoned, nope black bordered. This 

 species is well spotted with black, the spots being mostly above 

 the lateral line, on the caudal peduncle, dorsal and caudal fins. I« 

 should be mentioned that Prof. Cope and Dr. Yarrow have de- 

 scribed four different varieties of this species in which the mark- 

 ings vary greatly from the type, for description of which the reader 

 is referred to Vol. V., Zoology of " Expedition for Explorations 

 West of one hundredth Meridian," Fishes, 1876, p. 694. 



