FISHES OF MINNESOTA 45 



Genus ARGTROSOMUS Agassiz. 

 KEY TO THE SPECIES OF ARGYROSOMUS. 



A. Body long; scales small, of about the same size, their free edges 

 not straight but convex, marked with dark dots. 

 B. Lower fins pale or merely tipped with dusky; scales dotted 

 with black. 

 C. Eye large; about equal to the snout, contained 3J to A} 

 times in the head; head long, 4 J in the length; pectoral 

 fins short, reaching about half way to the ventrals; 

 gill-rakers long and numerous, 16-|-30. . . . artedi, 45 

 CC. Eye small, its width less than the length of the snout, 

 contained 5 times in the length of the head ; head 

 long, 4 to 4}^ in the length; maxillary very long, 2J 

 in the head; lower jaw considerably projecting; gill- 

 rakers about 15-J-28 prognathus, 45 



BB. Lower fins all blue-black; body strong; mouth large; eye 



large; gill-rakers 18+30 nigripennis, 46 



AA. Body short, compressed, curved about as much on the back as 

 on the belly; scales large, their free margins almost straight; 

 jaws about equal; mouth rather small tullibee, 46 



Arg^rosomus artedi (Le Sueur). Cisco. Lake Herring. Michigan Herring. 



Sides silTcry, scales dptted with black; bluish or greenish 

 above; fins pale, except the lower, which may be dusky tinged. 

 Body elongate, compressed, back not elevated; head rather long, 

 compressed and pointed ; mouth rather large; maxillary bone reach- 

 ing nearly to the pupil, contained 3^ to 3^ times in the head. Gill 

 rakers long and slender, 15 to 17+28 to 34, the longest contained 

 1 2-5 times in the eye. Head contained 4J times in the length. 

 Depth 4^. Eye 4 to 4^. Dorsal fin with 10 rays, its first rays high, 

 the last much shorter. Anal 12. Scales 8-75 to 90-7. Length 12 

 inches. 



Very common in Lake Superior and possibly in some of the 

 small lakes, but its presence in the latter is still doubtful. 

 Argyrosoiuns prognathus (H. M. Smith). Long Jaws. Bloater. 



Sides bright silvery with bluish reflections; upper parts dusky; 

 lower parts white; scales above the lateral line with their lower 

 edges dotted with black, center of the scales bright, thus forming 

 light longitudinal stripes which extend the whole length of the 

 body. Pins rather pinkish, the dorsal and caudal with dusky 

 edges. Body oblong, compressed, back elevated; mouth large; 

 snout straight; maxillary contained 2^ times in the head, its 

 length 34 times its greatest width; lower jaw projecting beyond 



