28. Band of premaxillary teeth with a narrow backwards extension on each 



side; adipose fin separated from the tail fin by a distinct notch; spine 

 in the pectoral fin almost smooth behind; about nine inches long; 

 Great Lakes to Texas 



Tsloturus flavus Raf . Stone Cat 

 Band of premaxillary teeth sharply truncated on each side; not with the 

 combination of other characters as above; not over five inches, except 

 R. ins}gnis The Mad Toms 29. 



29. Pectoral spine smooth behind or with a few weak serrations near base 30. 

 Pectoral spine serrate, the serrations being about one-third or more the 



diameter of the spine 32. 



30. Jaws equal; eastern and central U. S. 



Schilheodes gyrinus (Mitchill) Tadpole Cat 

 Schilbeodes mollis (Hermann) 

 Lovv'er jaw definitely shorter than the upper 31. 



31. Head wide; color dark, sprinkled with black spots; fins with pale edges; 



Mississippi Valley 



Rahida nocturna (J. & G.) Freckled Stonecat 

 Schilheodes nocturnus (J. &' G.) 

 Head longer than wide; color yellowish; Gulf States 



Rahida leptacantha (Jordan) Yellow Madtom 

 Schilheodes leptacanthus (Jordan) 



32. Pectoral spine strongly serrate behind, the serrations being almost as 



long as the diameter of the spine; with a distinctly mottled color pat- 

 tern 33. 

 Pectoral spine less strongly serrate behind, the serrations being shorter 

 than onc'half the diameter of the spine; color more even 34. 



33. Distance from end of snout to the base of the dorsal fin less than one and 



onC'half times the distance from the notch between the adipose and the 

 tail fin and the end of the tail fin; with a dark blotch extending to the 

 edge of the adipose fin; Mississippi Valley and streams flowing into 

 Lake Michigan 



Rah-ida miura (Jordan) Brindled Stonecat 



Schilheodes miurus (Jordan) 

 Distance from end of snout to the base of the dorsal fin more than one 

 and one-half times the distance from the notch between the adipose 

 and the tail fin to the end of the tail fin; with a dark blotch on the 

 base of the adipose fin; southeastern and south-central states, north 

 to Indiana 



Rahida eleuthera (Jordan) Furious Mad Tom 



Schilbeodes eleutherus (Jordan) 

 (Includes R. furiosa (J. & M.) ) 



34. With a dark blotch around the front of the dorsal fin; jaws nearly equal; 



Wisconsin to Kansas 



Rabida exilis (Nelson) Slender Stonecat 



Schilheodes insignis (Richardson) 

 Anterior part of back uniformly colored; upper jaw projecting; N. Y. to 

 S. C; common east of the Alleghenies 



262 



