20 PRELIMINARY REPORT 



Upper Mississippi (Nat. Hist. Surv., 1892-3-5); Pomme de Terre 

 River, Appleton, and Chippewa River, Montevideo (Woolman & Cox, 

 1892); Red River of the North and tributaries (Woolman, 1892, 

 Report U. S. Fish Comm., 1893, p. 369); Upper Mississippi (Wool- 

 man & Cox, 1894). 



Schilbeodes exilis (Nelson). 



Adipose fin continuous with the caudal; color dark brown or 

 blackish; pectoral spine roughish in front, serrate on its posterior 

 edge; head rather small and not much depressed; jaws about 

 equal ; dorsal spine not high and inserted midway between the tip 

 of the snout and front of the anal fin. Length four inches. Found 

 in rivers under stones. Either not common or because of its pe- 

 culiar habits has not been observed. One specimen has been taken 

 in the Blue Earth River at Mankato (Cox, 1893). 



Order PLECTOSPONDYLI. 



Family CATOSTOMID^. The Suckers. 

 Body generally elongate, in some species much compressed, 

 while in others heavy and depressed; covered with smooth-edged 

 scales; head scaleless; no barbels; mouth varying in size, but 

 always so constructed that it can be drawn out to a considerable 

 extent, thus enabling the fish to take food from the bottom of the 

 stream or lake. No teeth in the jaws ; pharyngeal bones set with 

 numerous teeth which are somewhat similar to a comb. Gill mem- 

 branes united to the isthmus; dorsal fin contains many soft rays; 

 no spines; caudal fin forked; ventral fins inserted far back on the 

 abdomen ; pectoral fins inserted on the lower part of the body. In- 

 testine long; air-bladder large and in two or three parts. Five 

 genera and eleven species are known at present in Minnesota. 



KEY TO THE GENERA OF CATOSTOMIDJE. 



A. Dorsal fin long, its rays 25 to 50; air-bladder in two parts. 



B. Top of the skull with a soft spot (fontanelle), (determined by- 

 pressing on the part) ; scales rather large, 34 to 42 in the 



lateral line. 



C. Mouth large, terminal, protractile forwards. . Ictiol)llS, 21 

 CC. Mouth small, inferior, protractile downward. Carpiodes, 22 



BB. Top of the skull without a fontanelle, scales rather small, 



about 56 in the lateral line Cycleptus, 23 



AA. Dorsal fins short, its rays 10 to 18. 



B. Scales small (48 to 100 in the lateral line); air-bladder in 

 two parts; pharyngeal teeth small. 



(Fine-scaled Suckers) Catostomus, 24 

 BB. Scales large (less than 48 in the lateral line); air-bladder 

 in three parts; pharyngeal teeth increasing in size down- 

 wards (Red-horse) Moxostonia, 25 



