54 FISHES OF ILLINOIS 



Key to Species of ARGYROSOMUS found in Lake Michigan 



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



(SV 2 to 4%); 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 3% to 4% in head. 



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



long and numerous, usually about 47 on first gill-arch (15 to 19 + 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. Eye small, shorter than snout, about 5 in head; maxillary very long, 2y 2 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% in length; scales 67 to 74, larger forward and 

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



ARGYROSOMUS ARTEDI (Li: Sueur) 

 lake herring; CISCO 



Le Sueur, Journ. Ac. Nat. Sci. Phila., I, 1818, 231 (Coregonus). 



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

 onus); M. V., 78 (Coregonus); J. & 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 \}A 

 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 4^; nose 4; mouth rather 

 large, the maxillary reaching not quite to the middle of the pupil, 334 to Sj4 

 in head; the mandible 2}/g in head, slightly projecting; gill-rakers very long 

 and slender, 15 to 17+28 to 34, the longest \% 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 catch of 1899 aggregating nearly sixty million pounds, 

 about a third of it from Lake Michigan. The commonest 

 name of the species, it scarcely need be said, is a misnomer, as 

 this is properly a whitefish and not a herring. It should be 



