282. Mouth almost hori2;ontal 



Lepidomeda jarrovii Cope 

 Mouth obhque 



Lepidomeda vittata Cope 



283. With a small barbel at each corner of the mouth 



Plagopterus argentissimus Cope 

 No maxillary barbels 



Meda fulgida Girard 



284. Body scaleless or with bony plates; Family Cottidae Sculpins 285. 

 Body scaled 295. 



285. Gill membranes almost free from the isthmus (fleshy part between the 



gill openings), making a fold across it; spinous portion of dorsal fin 

 well in advance of soft portion; in deep water of some of the Great 

 Lakes 



Triglopsis thompsoni Girard Lake Sculpin 

 With a wide isthmus between the gill membranes, with no fold across 

 it; spinous and soft dorsal fins adjacent 286. 



286. In the eastern and central states, northwestward through Minnesota 287. 

 In the western states 289. 



287. Lateral line complete; Great Lakes area 



Cottus ricei (Nelson) 

 Lateral line incomplete; northeastern and north-central states 288. 



288. No teeth on the palatine bones (in roof of mouth) ; usually evenly 



mottled 



Cottus gracilis Heckel Miller's Thumb, Rock Cusk 



Cottus cognatus gracilis Heckel 

 With teeth on the palatines; with dark mottlings, often forming vertical 

 bars on the sides 



Cottus ictalops (Raf.) Miller's Thumb, Toe-biter 



Cottus hairdii Girard 



289. With teeth on the palatine bones (in roof of mouth) ; preopercle with 



one large spine turned upwards and two or three smaller spines turned 



downwards below it 290. 



No teeth on the palatines; preopercle with one large spine at its tip 292. 



290. With 12 to 14 rays in the anal fin; Rocky Mountain region 



Cottus semiscaber (Cope) Rocky Mountain Bullhead 

 With 15 to 18 rays in the anal fin; Pacific coastal streams 291. 



291. Anus more than halfway back from end of snout to base of tail fin; seven 



inches long in the adult 



Cottus gulosus (Girard) Rifflefish 

 Anus halfway between end of snout and base of tail fin; getting to be a 

 foot long 



Cottus asper Richardson Prickly Bullhead 



292. Posterior nostrils with tubes; dorsal fins connected 293. 

 No tubes in posterior nostrils; dorsal fins not connected 294. 



293. Lateral line incomplete; Klamath Lakes, Oregon 



292 



