170 



NORTHERN FISHES 



tectiou from predaceous enemies. . . . Their habit of leading and guard- 

 ing their young greatly increases their chances of survival." 



Key to Common Species of F'amily AMEIURIDAE 



1 . Caudal fin deeply forked 2 



Caudal fin not deeply forked, generally rounded 3 



2. Anal fin of 24-29 rays including rudiments 



Channel Catfish, Ictalurus lacustris jmnctattis (Rafinesque) 



Anal fin of 30-35 rays 



Blue Catfish, Ictalurius jurcatus furcatus (Valenciennes) 



3. Adipose fin free, not connected with caudal fin 4 



Adipose fin connected wholly or partly to caudal fin 7 



4. Anal rays less than 16, usually 13 



Shovelhead Catfish, Pilodictis oUvaris (Rafinesque) 



Anal rays more than 16 5 



• 



5. Anal rays 17-24; barbels under jaw gray to black 6 



Anal rays 23-27, usually 23-25; barbels under jaw whitish 



Northern Yellow Bullhead, Ameiurus natalis natalis (LeSueur) 



Diagram 7. Arrangement of teeth in upper jaws of the five genera of Ameiuridae. 

 (A) Ictalurus lacustris punctatu^, no backward extensions. (B) Ameiurus 

 nehulosus nehulosus, no backward extensions. (C) Pilodictus olivaris. with 

 backward lateral extensions. (D) Noturus flavtis, with backward lateral exten- 

 sions. (E) Schilbeodes mollis, no backward extensions. 



6. Pectoral spines strongly barbed (except in very old individuals) ; no light 

 bar across base of tail; fins seldom with jet-black membranes; body often 

 mottled • • 



Northern Brown Bullhead, Ameiurus nebidosus 7iebidosus (LeSueur) 



Pectoral spines not strongly barbed; light bar usually across base of tail; 

 fins with jet-black membranes; body not mottled 



Northern Black Bullhead, Ameiurus melas m^las (Rafinesque) 



7. Band of teeth on premaxillary without any backward lateral extensions 



(Diagram 7) • • 8 



Band of teeth on premaxillary with distinctly backward lateral extensions 

 (Diagram 7) Stonecat, Notxints flaviis Rafinesque 



