APRIL, 1910. FISHES OF CHICAGO MEEK AND HILDEBRAND. 317 



Length 15 to 18 inches. 



This fish inhabits the larger streams and lakes from the Great 

 Lake Region to Florida and northeastern Mexico. 



Fox River, McHenry, Illinois; Dead River, Beach, Illinois; Des 

 Plaines River, Berwyn, Illinois; Wolf Lake, Roby, Indiana; Lagoon, 

 Buffington, Indiana; Lagoon, Pine, Indiana; Deep River, Liverpool, 

 Indiana. 



Family Percidse. 

 THE PERCHES AND DARTERS. 



Body more or less elongate, terete or compressed, covered more or 

 less completely with rather small ctenoid scales; mouth large or small, 

 terminal or inferior; teeth usually villiform in bands on jaws, occa- 

 sionally with few canine-like teeth; vomer and palatines usually 

 with teeth; pseudo-branchiae small, glandular or concealed; opercle 

 usually ending in a single flat spine; preopercle entire or serrate; 

 dorsal fins 2, the first of 6 to 15 spines; gill rakers slender, toothed; 

 gill membranes separate or joined, not connected with the isthmus; 

 lower pharyngeals separate, with sharp teeth; pyloric caeca few; anal 

 papillae usually more or less developed; air bladder small and ad- 

 herent, often wanting. 



a. Preopercle distinctly serrate below and behind angle; pseudo- 

 branchiae well developed; branchiostegals 7; no anal papillae, 

 fishes of large size. 



b. Canine teeth on jaws and palatines; body subterte. 



Stizostedion, 318 



bb. No canine teeth present ; body compressed. Perca, 320 



aa. Preopercle entire or nearly so ; pseudo branchiae small or want- 

 ing; anal papillae usually present; fishes less than 6 to 9 inches 

 in length. 



c. Cranium broad between the eyes; interorbital space 4.0 to 4.7 

 in head; snout long, pig-like, and projecting beyond the 

 inferior mouth ; gill membranes separate. Percina, 320 



cc. Cranium narrow between the eyes; interorbital space nar- 

 rower 5 to 9 in head; snout pointed or blunt, projecting very 

 little or none beyond the terminal or nearly terminal mouth. 



d. Median line of belly with enlarged scales or plates, these falling 

 off leaving a naked strip; separation of ventrals equal to or 

 greater than their width at base. 



e. Premaxillaries not protractile. H adropterus , 321 



