Jordan and FA^erniann. — Fishes of North America. 489 



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

 typical mijhm \Sa\mo myldss lewisi of the present work; see page 493], having smaller scales, in 

 176 to 180 transverse rows, and a deep-rod dash on inner side of mandibles. The spots are most 

 abundant jiostcriorly, and the siieciineus are scarcely to be distinguished from the so-called Subiio 

 mtiJciss plenriliriifi 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 mi/kiss and the form represented in our collection from such coastwise 

 streams [Salmo hideus viasoni of this work; see page SOI], as the Newaukum River at Chehalis, 

 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 bo the Steelhead [S. gairdneri), and between it and the myh-m we are now 

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

 (150 to 1G3 transverse rows) and 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 

 Pendleton, the Natches River at North Yakima, and the Pataha River at Starbucl;, Washington, 

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

 In these [Salmo mi/lnss gibb'tii of this work; see page 493] the lower jaw shows no red. 



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

 greatly in the size of their scales. Examples from Warduer look much like tj'pical imjldss, with 

 165 to 170 scales. From Ca'ur d'Alene Lake we find 130 to IGO, with the average about 145, 

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

 mandibles have 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 coastwi.se forms should 

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

 thorough investigation." — Gilbert d: Evermann. 



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 ivyldss and Salmo gairdneri 

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

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

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



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

 extended its range soiithward to the Upper Columbia, thence to the Yel- 

 lowstone and Missouri ; from the Missouri Kouthward to the Platte and the 

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

 from the Colorado across the feierra 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 ^•rt mZoojjs would mark one 

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

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

 that, beyond a doubt, the Tront 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 bo that the trout of the Sierra Nevada in California originated from the Lahontan 

 stock (Salmo myliiss henKhairi), rather than from the Colorado River. There arc 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 tlio 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 northwestern 

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



Jordan, The Story of a Strange I-and, in J'op. Sci. Month., Feb., 1892, 447-458. 



Evermann, Two-Ocean Pass, in Proc. Ind. Ac. Sci., 18il2, 20-34, (d. I. 



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



