Jordan and Erermann. Fishes of North America. 489 



We find our specimens from the Upper Snake River (Ross Fork and Mink Creek at Pocatello) to be 

 typical mykiss [Salmo m//fris* fetrisiof the present work; see page 493], having smaller scales, in 

 176 to ISO transverse rows, aud a deep-red dash on inner side of mandibles. The spots are moet 

 abundant posteriorly, and the specimens are scarcely to be distinguished from the so-called Salmo 

 mt/kis plfiirilU'its of the Colorado River. When taken in the larger river channels the fish is 

 lighter colored, with finer spots and fainter red marks on lower jaw. 



"Between such typical myl-ifg and the form represented in our collection from such coastwise 

 streams [$<ilmo iiufetu mason i of this work; see page 501], as the Newaukum River at Chehalia, 

 Washington, there seems to be a wide difference. The latter has conspicuously larger scales 

 (in 120 to 130 crossrows) and no red streak on lower jaw. The sea-run individuals of the latter 

 kind we believe to be the Steelhead (S. gainlneri), and between it and the w/A-iss we are now 

 unable to draw any sharp line. Thus the specimens from Wood River, Idaho, have fine scales 

 (150 to 163 transverse rows) aud have usually no red dash under the jaw. Some specimens show 

 traces of the latter, and in such it is usually faint and irregular. From the Umatilla River at 

 Pendletou, the batches River at North Takima, and the Pataha River at Starbuck, Washington, 

 the scales are intermediate in size, ranging from 142 to 163 in number, averaging perhaps 148. 

 Salmo mi/kiss gibbet of this work; see page 493] the lower jaw shows no red. 



"Specimens from the Cteur d'Alene region have the red dashes usually very distinct, but vary 

 greatly in the size of their scales. Examples from Wardner look much like typical tuyAiss, with 

 165 to 170 scales. From Coeur d'Alene Lake we find 130 to 166, with the average about 145, 

 while from the Little Spokane River at Dart's Mill specimens with conspicuous red dash on 

 mandibles ha\e the scales averaging 125 in number. 



"Trout from the Green River at Hot Springs, Washington, and from the Newaukum River at 

 Chehalis have also 123 to 130 scales. We think it not unlikely that the coastwise forms should 

 be recognized as Salmo mykiss gairdneri, though the question is sadly in need of systematic and 

 thorough investigation." Gilbert <fc Evermami. 



Since the above was written, Dr. Gilbert has verified the fact discovered by him in 1880, that 

 in the streams about Astoria, near the mouth of the Columbia, Salmo mykiss and Salmo gairdneri 

 occur together and are perfectly distinct and both easily and unquestionably distinguishable 

 from a third form, here called SHOSOHI, found in the brooks of the same region and not descend- 

 ing to the sea. As already stated, the interpretation of these facts is yet to be given. 



It seems not improbable that the American Trout originated in Asia, 

 ^xtended its range southward to the Upper Columbia, thence to the Yel- 

 lowstone and Missouri : from the Missouri southward to the Platte and the 

 Arkansas, thence from the Platte to the Rio Grande and the Colorado, and 

 from the Colorado across the ISierra Nevada to Kern River,* thence north- 

 ward and coastwise, the sea-running formj passing from stream to stream, 

 as far north as Frazer River, where the variety kamloops would mark one 

 extreme of the series, and reeuteriug as a distinct species the waters long 

 occupied by typical myki$s. The present writers have elsewhere t shown 

 that, beyond a doubt, the Trout of the Yellowstone and the Upper Mis- 

 souri is derived directly from that of the Upper Snake River. To this 

 day the Yellowstone and the Snake are connected by two streams cross- 

 ing the main divide of the Rocky Mountains from the Yellowstone to 

 the Snake across Two-Ocean Pass. 



* It may be that the trout of the Sierra Nevada in California originated from the Lahontan 

 stock (Salmo mykiss hendtatri), rather than from the Colorado River. There are localities between 

 the Truckee Valley and that of the American River or the Feather River, where it is conceivable 

 that such a transfer might have taken place. Or it may be that the California trout are 

 descended through the Steelhead from the trout of the Middle Columbia. This interesting 

 subject merits the fullest investigation. (See Jordan, on How the Trout came to California, in 

 Recreation, Vol. i. No. 1, October, 1894, 5-11.) 



T Evermann, A Reconnaissance of the Streams and Lakes of western Montana and north western 

 Wyoming, in Bull. U. S Fish Comm., xi, 1891. 24-28, pis. i and IT. 



Jordan, The Story of a Strange Land, in Pop. Sci. Month., Feb., 1892, 447-458. 



Evermann, Two-Ocean Pas$, in Proc. Ind. Ac. Sci.. 1892. 29-34, pi. I. 



Evermann, Two-Ocean Pass, in Pop. Sci. Month., June, 1895, with plate. 



