FISHES OF MINNESOTA 63 



KEY TO THE GENERA OF PEUCID^.. 



A. Branch iostegal rays 7; preopercle serrate; pseudoWranchia (false 

 gills on under side of the opercle) well developed; mouth large. 

 B. Canine teeth (large conical teeth) present on the jaws and pal- 

 atine bones Stizostedion, 64 



BB. No canine teeth present Perca, 65 



AA. Branch iostegal rays 6; preopercle very little if at all serrate; 



pseudobrauchia very little developed; all small lishes. 



B. Upper portion of the skull rather depressed, very little convex 



when seen in cross section. 



C. Space between the eyes wide, upper jaw not protractile; 



snout sharp and conical, projecting beyond the mouth. 



Percina, 65 

 CC. Space between the eyes not wide, snout not projecting 

 much beyond the mouth. 

 D. Body not semitransparent in life; not greatly elon- 

 gate; well eovered with scales. 

 E. Upper jaw not protractile, no groove separating 

 the skin which covers the premaxillaries from 

 the skin of the forehead; anal fin large; scales 

 of the middle line of the belly often dropping 

 off, leaving a naked space. . Hadropterus, 66 



EE. Upper jaw protractile, a groove separating the 

 skin which covers the premaxillaries from the 

 skin of the forehead; anal spine one, this very 

 small; anal fin shorter than the soft dorsal. 



Boleosoma, 67 

 DD. Body semitransparent in life; very long and slender; 

 belly naked; upper jaw protractile; a row of black 

 dots along the lateral line. . . Amniocrypta, 68 

 BB. Upper portion of the skull not depressed, convex in cross 

 section; upper jaw not protractile. 

 C. Lateral line developed, at least on the anterior portion of 

 the body; dorsal spines 8 to 14. 

 D. Lateral line straight; body rather heavy. Etlieostonia, 69 



DD. Lateral line slightly curved, running high ante- 

 riorly; dorsal fins well separated; body slender. 



Boleiclitliys, 71 

 CC. Lateralline not at all developed; dorsal spines 6. Microperca, 72 



