492 Bulletin 47, United States National Museum. 



ggg. Spots few and large, chiefly on the tail; opercles more curved than in bouvicri. 



(Head waters of Arkansas and Platte rivers.) STOMIAS, 779i. 



ff. Spots all small; lower fins bright yellow; a yellow lateral shade. (Twin Lakes, 



Colorado.) MACDONALDI, 779j. 



The typical form from Alaska, Bering Sea, and Kamchatka is 



779. SALMO MYKISS, Walbaum. 

 ; CUT-THROAT TROUT.) 



Head 4 ; depth 4. D. 10 ; A. 10. Coeca 43. Scales small, variable in 

 size, about 39-165 to 170-30. Body moderately elongate, compressed. 

 Head rather short. Mouth moderate, the maxillary not reaching far 

 beyond the eye. Vomerine teeth as usual, set in an irregular zigzag 

 series; teeth on the hyoid (second hypobranchial) normally present, but 

 often obsolete, especially in old examples. Dorsal fin rather low ; caudal 

 fin slightly forked, (more so in young individuals than in the adult, as in 

 all trout). Back and caudal peduncle profusely covered with rounded 

 black spots of varying size ; dorsal, caudal, and adipose fin covered with 

 small spots about as large as the nostril ; a few spots on the head ; belly 

 rarely spotted ; inner edge of the mandibles below with a deep-red 

 blotch. Sea-run specimens are nearly uniform silvery ; males with a 

 lateral band and patches of light red ; lower fins largely red ; extremely 

 variable in color and form. The common trout of all the streams of 

 Alaska and Kamchatka, where it descends to salt water, and reaches a 

 considerable size. The black-spotted trout of British Columbia is proba- 

 bly of the same type, and no character is known by which the similar 

 form in the lower Columbia may be separated. The red blotches on the 

 lower jaw between the dentary bones on the membrane joining them is 

 usually constant and characteristic. (Mylciss, a vernacular name of the 

 species in Kamchatka. ) 



Mykiss, PENNANT, Arctic Zoology, Introd., 126, 1792, Kamchatka ; after KRASCHENINNIKOW, etc. 

 SalmomyJdss, WALBAUM, Artedi Piscium, 59, 1792, Kamchatka ; based on Mykiss of PENNANT. 

 Salnto nmikisi, BLOCK & SCHNEIDER, Syst. Ichth., 419, 1801, Kamchatka ; after STELLER. 

 Salmo purpuratus, PALLAS, Zool. Ross.-Asiat., in, 374, 1811, Bering Sea ; JORDAN & GILBERT, 

 Synopsis, 314, 1883. 



Represented southward by a form provisionally recorded as 



779a. SALMO MYKISS CLABKII (Richardson). 

 (COLUMBIA RIVER TROUT.) 



Not evidently different from the preceding. Usually profusely spotted, 

 with the red cut-throat mark distinct. Scales small, in 150 to 164 cross- 

 series. Back profusely spotted, anteriorly and posteriorly, the spots 

 often extending on the belly. Coastwise streams from Puget Sound, 

 south to Elk River, Humboldt County, California ; locally abundant ; 

 replaced inland by var. gibbsii and var. lewisi. (Named for Capt. William 

 Clark (1770-1838) of the famous expedition of Lewis and Clark.) 

 Salmo clarkii, RICHARDSON, Fauna Bor.-Amer., m, 225, 1836, Cathlapootl River. (Coll. Dr. 



Gairdner.) 

 Fano stellatu*, GIRARD, Proc. Ac. Nat. Sci. Phila., 1856, 219, Fort Steilacoom, Shoalwater 



Bay. 



