April, igio. Fishes of Chicago — Meek and Hildebraxd. 293 



Argyrosomus nigripinnis Gill. Blackfin. 



Head 4; depth 4; D. 12; A. 12; scales 73 to 77. 



Body elongate, somewhat compressed; head large, snout pointed; 

 mouth large; diameter of eye 4.2; lower jaw slightly projecting; gill 

 rakers about 18 -I- 30 on first gill arch. 



Fig. 63. Blackfin. 

 Argyrosomus nigripinnis Gill. (After Bvermann and Smith.) 



Color bluish above, sides silvery, with dark punctulations ; fins 

 all blue black. 



Lake Michigan and some of the lakes of Wisconsin and Minnesota. 

 Lake Michigan, Chicago. 



Genus Saluio (Artedi) Linnaeus. 



The Trout. 



Body elongate, somewhat compressed; mouth large; jaws with 

 teeth; vomer flat, its shaft not depressed; teeth on anterior part of 

 vomer, followed by a double or irregular series of teeth; scales small. 



Salmo gai dneri Richardson. Steelhead; Salmon Trout. 



Head 4.5; depth 4.3; D. 11; A. 12; scales 130 to 180. 



Body elongate, more or less compressed; head short, slender, the 

 upper surface convex; mouth large, the maxillary reaching middle of 

 eye; lower jaw the shorter; teeth rather small, those on vomer in two 

 long alternating series; gill rakers short and thick, 8 -f 12 on first arch; 

 lateral line complete. 



Color olivaceous green above ; sides silvery; head, back, and upper 

 fins more or less covered with black spots; in the spring both sexes 

 usually have a broad flesh-colored lateral band which rapidly fades. 



