FISHES 39 



tipped with black; rays of dorsal and anal fins lo to 13 ; scales 8 to 10-78 

 to 88-7 or 8; body elliptical, but little compressed; head short, conic: 

 from western Montana into Washington and Oregon; southward in 

 Nevada to the Truckee; common in clear streams and lakes. 



C. couUeri Eigenmann & Eigenmann. Length 200 mm.; color dull 

 silvery; rays of dorsal and anal fins 10 to 11; scales 8-60 to 63-6; body 

 heavy; snout blunt: head waters of the Columbia; rare. 



C. oregorms Jordan & Snyder. Chisel-mouth jack. Length 425 

 mm.; head 4; depth 5; color silvery; rays of dorsal and anal fins 12; 

 scales 9-86-6; body long and slender; snout very long, with a fleshy 

 tip; adipose fin very large: basin of the Columbia; common. 



2. Leucichthys Dybowski. Ciscoes; lake herrings. Similar to 

 Coregonus but difi'ering from it in having a larger mouth and longer 

 jaws, the premaxillaries being horizontal in position and the lower jaw 

 usually more or less projecting; gill-rakers very long and slender; jaws 

 toothless: numerous species, in the northern hemisphere, 14 in the 

 United States, 3 in Arctic America; all valuable food fishes. 



Key to the Species of Leucichthys in the United States 



ai Body elongate, herring-shaped; minute teeth on tongue. 



bi Shallow-water species, spawning in late autumn; fins pale 

 in color; maxillary not reaching past middle of the eye. 

 Ci Adipose fin very small, usually shorter than the eye. 



di Lower jaw not projecting; in the upper Great Lakes. .L. harengus. 



do Lower jaw projecting; in New York State L. osmeriformls. 



Ci Adipose fin longer than the eye. 



di Body elongate, the depth being 4 to 4.5. 



Ci Depth 4.5; in Lakes Huron and Michigan and 



small neighboring lakes L. sisco. 



62 Depth 4; in Lakes Ontario and Cayuga L. ontariensis. 



do Body robust, the depth being usually under 4. 



ei Depth 3.5 to 4 L. artedi. 



e-j Depth 3.5 L. criensis. 



bo Deep-water species, spawning in midsummer. 



Ci Ma.xillary not extending to middle of eye; premaxillaries 

 nearly horizontal, 

 di Lower jaw projecting; fins with little dark color. 



ei Head 4.6; in Lake Superior L. supernas. 



Co Head 4 to 4.25; in Lakes Ontario, Huron and 



Michigan L. prognathus. 



do Lower jaw not projecting; fins dark in color. 



ei In Lake Superior L. nigripinnis. 



Co In Lake Michigan L. cyanopterus. 



