FAMILY AMEIURIDAE 171 



8. Pectoral spine smooth on posterior edge, but with longitudinal groove; no 



acute notch between caudal and adipose fins 



Tadpole Madtom, Schilbeodes tnollis (Hermann) 



Pectoral spine with fine teeth, or serrae, on posterior edge; notch between 

 caudal and adipose fins more or less acute 9 



9. Pectoral spine short, 3 in head; the length of jwsterior serrae not one-half 

 diameter of spine; color light brown, sometimes faintly mottled 



Slender Madtom, Schilbeodes insignis (LeSueur) 



Pectoral spine long; less than 2 in head; the posterior serrae strong and length 

 nearly equal to diameter of spine; color grayish with specks and large blotches. 

 Brindled Madtom, Schilbeodes miurtis (Jordan) 



GENUS Ictalitrus Rafinesque 



The species of this genus are characterized by their large size, deeply 

 forked tail fins, and silvery or plumbeous coloration. The bony bridge 

 between the dorsal fin and the head is sometimes complete. These 

 species prefer the deeper river channels and the clear lakes, and in 

 general avoid muddy waters. They are distributed in the Mississippi, 

 Great Lakes, and Gulf of Mexico drainages and southward to Guate- 

 mala. 



NORTHERN CHANNEL CATFISH (Great Lakes Catfish) 

 Ictalurus lacustris lacustris (Walbaum) 



This catfish is the large one found in the Great Lakes and connected 

 waters. The separation of this subspecies from the following subspecies, 

 Ictalurus lacustris punctatus, is difficult and questionable. It is said to 

 differ in sometimes having the supraoccipital processes unjoined so 

 that they do not form a continuous bony bridge between the head and 

 the dorsal fin. The tail is forked, but somewhat less so than that of the 

 following subspecies. The head is heavier and broader. The body is a 

 dark, slaty blue and may or may not be spotted. 



Hubbs and Lagler (1941) gave the range of this catfish as from the 

 Prairie Provinces of Canada and the Hudson Bay region through the 

 Great Lakes drainage. This subspecies was listed for Minnesota by Cox 

 (1897), but no records were reported. It is possible that it occurs in 

 Lake Superior or the Lake Superior drainage. In the summer of 1941 

 catfishes, apparently of the following subspecies, were collected from 

 the St. Louis River by the Minnesota Department of Conservation. 

 Greene (1935) did not find it in Lake Superior, but reported it from 

 Lake Michigan. 



CHANNEL CATFISH (Speckled Catfish, Fiddler) 

 Ictalurus lacustris punctatus (Rafinesque) 



The channel catfish has a rather slender body and a very large, 

 deeply forked caudal fin, or tail, fitting it eminently well for life in the 



