54 FISHES OF ILLINOIS 



Key to Species of ARGYROSOMUS found in Lake Michigan 



a. Body elongate, herring-shaped, depth usually considerably more than 3i 



(.Hto4£); scales 73 to 90 in longitudinal series, uniform in shape and size, 

 the free edges convex. 



b. Lower fins pale or merely tipped with dusky; scales punctulate with dark 



specks. 



c. Eye large, not much, if any, shorter than snout, its length 3i to 4^ in head. 



d. Maxillary 34. to 3? in head; lower jaw projecting beyond upper; gill-rakers 



long and numerous, usually about 47 on first gill-arch (15 to 19 4-30 

 to 38) artedi. 



dd. Maxillary 2% to 3 in head; lower jaw scarcely projecting or not at all; gill- 

 rakers usually not more than 39 or 40 on first gill-arch (14 + 25 or 26) . hoyi. 



cc. Eve small, shorter than snout, about 5 in head; maxillary very long, 2 J in 

 head; mandible reaching usually to posterior edge of orbit, half as long 

 as head prognathus. 



bb. Lower fins all blue-black; body stout; mouth large; gill-rakers at least 50 on 

 the first arch (17 + 33) nigripinnis. 



aa. Body short, deep, and compressed, the curve of the back similar to that of 

 the belly; depth 3 to 3 J, in length; scales 67 to 74, larger forward and close- 

 lv imbricated, the free margin often concave or notched tullibee. 



ARGYROSOMUS ARTEDI (Lb Sueur) 

 (lake herring; Cisco) 



Le Sueur, Journ. Ac. Nat. Sci. Phila., I, ISIS, 231 (Coregonus). 



G., VI, 198 and 199 (Coregonus harengus and clupeiformis) ; J. & G., 301 (Coreg- 

 onus); M. V., 78 (Coregonus); ]. & E., I. 468; N., 44 (clupeiformis); J., 54 

 (Coregonus); F.. 73 (Coregonus)"; F. F., II. 7, 436 (Coregonus); L., 20. 



Length 12 inches; body elongate, compressed, not elevated; depth 

 4 j in length. Color bluish black or greenish above; sides silvery, 

 scales with dark specks; fins mostly pale, the lower dusky-tinged. 

 Head 4^ in length, compressed, somewhat pointed and rather long, 

 the distance from occiput to tip of snout usually a little less than half the 

 distance from occiput to dorsal fin; interorbital space 3$ in head; eye 4 

 to 4i ; nose 4 ; mouth rather large, the maxillary reaching not quite to the 

 middle of the pupil, Z\ to 31 in head; the mandible 2\ in head, slightly 

 projecting; gill-rakers very long and slender, IS to 17+28 to 34, the 

 longest If in eye. Dorsal rays 10; anal 12. Scales 8-75 to 90-7, 10 

 rows under base of dorsal; lateral line continuous. 



Great Lakes and neighboring waters, including Lake Cham- 

 plain; north to James Bay, but not in Alaska or Arctic America; 

 abundant in Lake .Michigan. 



This is by far the most abundant food-fish of the Great Lakes, 

 the eateli of 1899 aggregating nearly sixty million pounds, about a 

 third of it from Lake Michigan. The commonest name of the spe- 

 cies, it scarcely need be said, is a misnomer, as this is properly a 

 whitefish and not a herring. It should be generally known by the 



