FISHES OF MINNESOTA 13 



KEY TO THE GENERA OE ACIPENSERID^. 



A. Snout uot Hat but rather conical; spiracles present; bony plates 

 not coming together on the tail; gill-rakers long and not 



fan-shaped (Common sturgeon) Acipeuser. 



AA. Snout Hat, broad and shovel-shaped; no spiracles present; bony 

 shields coming together and completely covering the tail; gill- 

 rakers fan-shaped. . (Shovel-nosed Sturgeon) Schaphirliynchus. 



Genus ACIPENSER Liniiteus. 



Acipeuser rubicundiis Le Sueur. Lake Sturgeon. Rock Sturgeon. 



Young with snout long, somewhat like Scaphirhynchus platoryn- 

 chus; bony shields much keeled with hooked spines; adult snout 

 comparatively much shorter than in the young; shields disappear- 

 ing with age on the lower parts and becoming smooth on the upper 

 surface; dorsal shields 11 to 16; lateral shields 30 to 39; ventral 

 plates 8 to 11; three shields in a single row between the anal fin 

 and vent. Dorsal with 35 rays and anal 26. A large fish which 

 reaches a length of 6 feet and a weight of one hundred pounds. Two 

 mounted specimens are now in the museum of the University of 

 Minnesota which were taken from the Mississippi River at Minne- 

 apolis. They abound in the Lake of the Woods, and are often taken 

 in Lake Superior, On portions of the Lake of the Woods sturgeon 

 fishing is the chief occupation, thousands of large fish being taken 

 annually. 



Genus SCAPHIRHYNCHUS Heckel. 



Scaphirhynchus platorynchiis (Rafinesque). Shovel-nosed Sturgeon. White 

 Sturgeon. 



Body rather long, tapering much toward the heterocercal tail ; 

 tail flattened from above, continued in a long filament; bony shields 

 with a sharp ridge or keel; dorsal shields 15 to 20 in number; those 

 in the lateral line numbering 41 to 46, and those on the belly or 

 ventral surface 11 to 13. Specimens are often taken which are 5 

 feet in length. It has been taken in the Minnesota River at Man- 

 kato (Cox, 1893); in the Mississippi River at Winona (Holzinger, 

 1894); in the Mississippi River at Minneapolis (reported by fisher- 

 men), and further collection of data will, no doubt, show that it is 

 common, especially in the tributaries of the Mississippi. 



