21 



Argyrosomus hoyi Gill— Moon- eye Cisco. 



Lake Michigan, in deep water. 



Argyrosomus prognathus (H, M. Smith). — Long-jaw Bloater. 



Lake Michiaran. 



Argyrosomus nigripennis Gill. — Blue-fin; Black-fin. 



Lake Mlchifirao in deep water. 

 Argyrosomus tullibee (Richardson).— Tullibee; "Mongrel Whitefish." 



Lake Michigan. 

 Cristivomer namaycush (Walbaum).— Great Lake Trout; Mackinaw Trout. 



Lake Michigan. 



Salvelinus fontinalis (Mitchill).— Brook Trout; Speckled Trout. 



Attempts have frequently been made to introduce this and other trout into the streams 

 of Illinois, but apparently entirely without success. Trout will not thrive where the tem- 

 perature of the water at any time exceeds 60 degrees. 



Family Umbrid^ (The Mud-minnows). 



Umbra limi (Kirtland). — Mud-minnow. 



This little fl h has a form very much like that of the common dogfish (Amia calva). It 

 can; however, ho at once distinguished from the latter by its small dorsal fin, which has but 

 14 rays, while the number is 42 to 53 in Amia. 



Usually taken from grassy ponds or muddy creeks, which it apparently prefers to 

 larger open waters. Taken in 29 localities throughout the State. 



Family Luciid^ (The Pikes). 



Lucius vermiculatus (La Sueur).— The Little Pickerel. (214) 



The Little Pickerel seldom exceeds 12 Inches in length. It differs from our other species 

 {L. lueius) in this respect, and in having the cheeks and opercles fully scaled, 



Found in grassy prairie creeks and along weedy margins of larger streams throughout 

 the State. 



Lucius lueius (Linn sens). — Common Pike; Pickerel. (216) 



A voracious feeder, takiner fishes of considerable size; the jaws provided with strong 

 backward-pointing teeth. Differs from the preceding in having the lower portion of the 

 opercle bare. 



No longer common, but found in all sections of the State. 



Lueius masquinongy (Mitchill). — Muskallunge. (217) 



Differs from the preceding two species in having the lower portion of both cheeks and 

 opercles bare. 



Taken in Lake Michigan; has been said to occur in the lakes of northern Illinois (Nel- 

 son). 



Family Pceciliid.^ (The Ktllifishes). 



Fundulus diaphanug menona (Jordan & Copeland). — Top-minnow. 



Found in Illinois only in the lakes of the northeastern part and in Rook River. 



Fundulus dispar (Agassiz). — Top -minnow. (208) 



The body marked with several narrow vertical bars of dark color. 



Found throughout the State in the quiet weedy pools of smaller streams, or along the 

 margins of larger streams. Quite rare northward. 



