24 PKELIMINAKY KEPOET 



Genus CATOSTOMUS Le Sueur. 

 KEF TO THE SPECIES OF CATOSTOMUS. 



A. Scales very small, about 100 Id lateral line. . . catostomus, 24 



AA. Scales about 65 in the lateral line. . . . commersouii, 24 



AAA. Scales 48 to 55 in the lateral line nigricans, 25 



Catostomus catostomus (Forster). Northern Sucker. Long-nosed Sucker. 



Body long and slender; head also long and slender, flat above; 

 a long and tapering snout which overhangs the large mouth; upper 

 lip thin with two to four rows of papillae; anterior edge of lower 

 jaw rather hard; eye small and inserted back of the middle of the 

 head. Scales small, 95 to 114 in the lateral line. Dorsal with 10 

 01 11 rays. Head contained 4^ to 4f times in the length. Depth 

 4i to 4f in the length. 



T!he spring males have the head and anal fln covered with tuber- 

 cles and a rosy lateral band. 



This is probably a common fish in the streams and lakes of the 

 uoirthem part of the state, but at present it is known only from the 

 mouth of Rapid River, a southern tributary of the Rainy River 

 from the Red Lake Indian Reservation, where it is quite common 

 (Woolman & Cox, 1894). 



Catostomus commersonii (Lac^p^de). Black Sucker. Ck>mmon Sucker. Fine 

 Scaled Sucker. 



Color very variable, being sometimes quite dark, hence giving 

 rise to the name, black sucker, and again specimens will be found 

 that are quite light, and in certain localities these are termed white 

 suckers; generally dark olivaceous on the back, lighter below, 

 males rose tinted on the sides in spring. Head large; snout coni- 

 cal, extending but little beyond the mouth; mouth large, the lips 

 covered with papillae ; scales small, smaller forward, 10-64 to 70-9. 

 Head contained 4 to 4^ times in the length. Depth' 4J. Dorsal 

 with 12 rays. Length when mature 18 inches. 



Common in all our lakes and streams. Specimens have been 

 recorded from Vermillion Lake, St. Louis Co. (Nat. Hist. Surv., 

 1891); the stream and lakes in the vicinity of Mankato and South- 

 western Minnesota (Cox, 1891-5); Big Stone Lake, Upper Minnesota 

 River and tributaries (Woolman & Cox, 1892); Mantrap Lake, Up- 

 per Mississippi River from its source to Grand Rapids, with its 

 tributaries; Gull Lake and tributaries; Mille Lacs and tributaries 

 (Nat. Hist. Surv., 1892-3-5) ; Lake of the Woods, Lake Superior, St. 

 Louis Rivers and Upper Mississippi, in the region of the Deer River 

 and Grand Rapids (Woolman & Cox, 1894). 



