12. Mouth points downward (inferior), is sucker-like with thick, 



papillose lips; dorsal fin with 10 or more rays 



^^ J Suckers 

 ®. \ ^( Catostomidae 



Mouth opening toward the front (terminal or subterminal); dorsal 

 fin with less than 10 rays 



^^^.^..^^^^ ^ Minnows 



® ^ \ ^ / Cyprinidae 



13. Dorsal fin preceded by free dorsal spines 

 ^ -^L^UL^^r^^^^^ Sticklebacks 



^•»^ ^ ">^~ •■ ^ — ^^^^^\ Gasterosteidae 



"^ p. 91 



Dorsal fin not preceded by free dorsal spines 14 



14. Body scaleless, but may be covered with spines or prickles; head 



large; eyes in top of head; pectoral fins large 



Sculpin 

 g/-l ^ ^^^^^^ -— -^^^-^.^A cottidae 



■^^ J 



Body with scales 15 



15. Single median barbel on chin 



^ ^^^^~~~~^^^^^^^^^^:Z:^^)^^^ Burbot 



^^^^^^^3 ^_i:5 ) Gadidae 

 \ " ^- ^^^-"^ p. 71 



No barbel on chin 16 



14 



