398 REPOET OF COMMISSIONER OP FISH AND FISHERIES. 



Numerous specimens obtained by us at the follovviug places: Enemy 

 Creek, Mitchell; Rock Creek, Mitchell; Dakota River, Mitchell; Choteau 

 Creek, Springfield ; Emanuel Creek, Springfield ; Prairie Creek, Scotland ; 

 Crow Creek, Chamberlain; Rapid Creek, Rapid City; Hat Creek, Ardmore; 

 Cottonwood Creek, Edgemont ; Middle Creek, Belle Fourche ; French Creek 

 at Custer; Bazile Creek, Niobrara; pond at Niobrara; pond at Creighton; 

 Elkhorn River, Fremont; Elkhorn River, Norfolk Junction; Elkhorn River, 

 Ewing; Spring Creek, Bazile Mills; Salt Creek, Havelock; Mud Creek, 

 Ravenna; Long Pine Creek and ponds, Long Pine; Bone Creek, Long Pine; 

 Ingalls Lake, Long Pine; Chadron Creek, Chadron; South Loup River, 

 Ravenna; Dismal River, Dunning; Platte River, Fremont; Beaver Creek, 

 York ; Niobrara River, Marsland ; Blue River, Seward ; Lincoln and Beaver 

 creeks, York ; Minnechaduza Creek, Valentine ; Clear Creek, Clermont. 



In all the warmer, sluggish creeks with muddy bottom, and in all the 

 warmer ponds and stagnant pools of the prairie region from Illinois to AVyo- 

 ming, this, the fat-head or black-head minnow, is one of the most abundant 

 species. During the dry season many of the small streams are reduced to 

 isolated pools, mere mudholes, which are kept stirred up and rendered filthy 

 by the cattle which visit them to slake their thirst. In these pools, however 

 shallow and filthy they might be, we never failed to find this hardy, little 

 fish. There is no doubt that all the nominal species cited in the above 

 synonymy belong to a single species. There is considerable variation in the 

 development of the lateral line, the position of the dorsal, the shape of 

 the head, and the color; all of these, except the variation in the lateral line, 

 are accessory sexual characters. In breeding males the head is short, the 

 snout very blunt, and the origin of dorsal fin nearer tip of snout than base 

 of caudal ; the males are very dark, sometimes the upper parts and entire 

 head being blue-black, while the females are much paler. The females are 

 more elongate, head larger, snout less bluut, and correlated with this is the 

 more posterior portion of the dorsal. Among two dozen examples studied, 

 all the females have the dorsal midway between the snout and base of caudal, 

 while in all the males the dorsal was nearer snout than base of caudal. 

 The lateral line is usually better developed on the females than on the males. 



On a number of male examples we find from 9 to 28 pores and these are 

 often scattered {parietaUs.) In several females we find the number of pores 

 varying from 20 to 46, or complete. A female 2% inches long, from Ingalls 

 Lake, is described as follows: Head 3*; depth 3*; eye 4; snout 4|; D. I, 8; 

 A. 7 ; scales 9-47-3, lateral line developed on 9 scales on one side and 2 on the 

 other. Body short and stout; snout blunt; caudal peduncle compressed, 

 deep, its least depth 2 in head. Origin of dorsal nearer snout than base of 

 anal, directly opposite ventrals. Entire head, except preopercle and free 

 edge of opercle, and upper parts blue-black, middle of side with a broad 

 plumbeous band; lower parts pale; fins all more or less thickly dusted with 

 fine dark spots ; a long dark blotch on anterior rays of dorsal ; snout with 

 about 25 large tubercles, about 7 on tip of lower jaw. A female about 3 

 inches long from Lincoln Creek has the following characters : Head 4 1- ; 

 depth 4*; eye 4f ; snout 3f ; D. i, 8; A. 7; scales 9^16-4, the lateral line 

 nearly complete, 2 or 3 isolated scales without pores. Body more slender; 

 snout and head less blunt; caudal peduncle more slender, its least depth 

 more than 2 in head. Color pale ; back and upper part of sides dusted with 

 fine dark specks; plumbeous lateral band faint; under parts pale; few fine 

 punctulations on fins; dorsal with a long black blotch on anterior rays. 



The specimens from Hat Creek, 11 to 2 inches long, present the following 

 characters: Head 3|, — depth; eye 3£, = snout; dorsal I, 8; anal i, 7; 

 scales 10-55-5; lateral line decurved and incomplete; scales small and 

 crowded anteriorly, about 30 before the dorsal; origin of dorsal in front of 



