APRIL, 1910. FISHES OF CHICAGO MEEK AND HILDEBRAND. 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+30 on first gill arch. 



FIG. 53. BLACKFIN. 



Argyrosomus nigripinnis Gill. (After Evermann 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 Salnio (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 gairdneri Richardson. STEELHEAD; SALMON TROUT. 



Head 4.5; depth 4.3; D. n; 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 + 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. 



