Rahida insignis (Richardson) Mad Tom 

 Schilheodes viarginatus (Baird) 



35. Rays of anal tin less than sixteen; lower jaw longer than upper; band 



of premaxillary teeth with a narrow backwards extension on each 

 side; Mississippi Valley and Gulf States 



OpJadelus olivans (Raf.) Mudcat, Yellow Cat 

 Pilodictis olivaris (Raf.) 

 (Leptops olivaris (Raf.) ) 

 Rays of anal fin sixteen or more; jaws equal or with the upper longer 

 than the lower; band of premaxillary teeth without narrow backwards 

 extensions 36. 



36. Tail well forked; color bluish or silvery; bony bridge from head to dorsal 



fin complete (except in H. lacustris and H. catus, which have a small 

 gap) 37. 



Tail fin rounded or only slightly forked; color brownish or yellowish; 

 with a gap in the bony bridge between the head and the dorsal fin 

 (may be felt through the skin) 4 1 . 



37. Anal fin long, usually with 30 to 35 rays; eye low, below the middle of 



the side of the head; Mississippi Valley and Gulf States 



Ictalurus furcatus (C. 6? V.) Blue Cat, Fork-tail Cat 

 Anal fin shorter, usually with less rays; eye above the middle of the side 

 of the head 38. 



38. Anal fin with nineteen or twenty rays, with its base much shorter than 



the head; N. Y. to Texas, in coastal streams 



Haustor catus (Linn.) White Cat 



Ictalurus catus (Linn.) 

 Anal fin with twenty-three to thirty rays, with its base about as long as 

 the head 39. 



39. Area between the eyes concave, with a groove running back to the dorsal 



fin; Mississippi Valley 



Ictalurus anguilla E. &'K. Eel Cat 

 Area between the eyes flattened or slightly convex 40. 



40. Bony bridge from head to dorsal fin complete; length of head about one 



and one-half times the width; body with irregular dark spots; tail fin 

 deeply forked, with the upper lobe smaller and more pointed than 

 the lower; Great Lakes to the Gulf 



Ictalurus punctatus (Raf.) Channel Cat 



Ictalurus lacustris punctatus (Raf.) 

 Usually with a gap in the bony bridge from head to dorsal fin; head 

 wider; body spotted or plain colored; tail fin less deeply and more 

 regularly forked; Great Lakes area 



Haustor lacustris (Walbaum) Lake Cat 



Ictalurus lacustris lacustris (Walbaum) 



4L Eyes rudimentary, covered by skin; cave streams of eastern Pennsyl- 

 vania 



Gronias nignlabris Cope BHnd Cat 

 Eyes normal 42. 



263 



