FISHES OF MINNESOTA 11 



FF. Upper jaw protractile; formed entirely 

 by the premaxillaries. 



(Killifishes) Poeciliidse, 50 

 EE. Head without scales. 



F. Gill membranes united with the isth- 

 mus; ordinary teeth absent. 

 G. Dorsal fin with less than ten rays; 

 pharyngeal teeth in one or more 

 rows, less than eight in the main 

 row. (Minnows) Cyprinidse, 26 



GG. Dorsal fin with ten or more rays; 

 pharyngeal teeth in one row and 

 numerous. (Suckers) Gatostomidse, 20 

 FF. Gill membranes free from isthmus. 



G. Lateral line present; tongue with 

 sharp teeth. 



(Moon-eyes) Hiodontidse, 42 

 GG. Lateral line absent; mouth small 

 and toothless; stomach gizzard- 

 like. (Gizzard Shads) Dorosomidse, 42 

 A A. Ventral fins present, throacic or jugular. 



B. Body covered with scales or bony plates. 

 C. Eays of the ventral fins I, 5. 

 D. Vomer with teeth. 



E. Anal spines, one or two. 



F. Anal rays, less than twenty. (Perch) Percidse, 62 

 EE. Anal spines, three. 



F. False gills (pseudobranchia) on the 

 under side of the opercles small and 

 covered by skin. 



(Sunfishes) GentrarcUdse, 54 

 FF. Pseudobranchia well developed. 



(Sea Bass) SerranidEe, 72 

 EEE. Anal spines 4 to 10. (Sunfishes) Centrarchidse, 54 

 DD. Vomer without teeth. 



E. Anal spines, one or two; a large slit behind 

 the' fourth gill. 

 F. Lateral line extending on the caudal 



fin; snout scaly. (Drums) Sciaenldae, 73 



FF. Lateral line not extending on the cau- 

 dal; snout not scaly. (Perch) Percidse, 62 

 CC. Rays in ventral fins not I, 5. 



D. Dorsal fin of spines anteriorly; soft rays pos- 

 teriorly. 

 E. Vent far forward; ventral rays 7; dorsal 

 spines 3 or 4. 



(Pirate Perches.) Aphredoderidae, 53 

 EE. Vent normal; ventral rays I, 1; dorsal spines 



unconnected. (Sticklebacks) Gasterosteidae, 51 

 DD. Dorsal fin of soft rays only; dorsal and anal 



free from the caudal. . (Cod-fishes.) Gadidae, 75 



