INVESTIGATIONS IN MINNESOTA AND NORTH DAKOTA. 353 



long as head, almost reaching aual flu ; ventrals short, 1^ in pectoral. 

 Color of male in alcohol, dusky, with ten or eleven darker vertical bars extend- 

 ing from median line of back to below lateral line, the anterior ones narrow, 

 those on posterior part of body broader; the spaces between these bars with 

 small, dark puuctulations; top and sides of head profusely punctulate; a 

 dark suborbital spot; spinous dorsal black on membrane connecting first 

 two or three spines, the rest of spinous part punctate, and edged with black; 

 a small black spot on posterior part; soft dorsal more or less mottled; 

 caudal paler, some black on tip and edges ; anal jjrofusely covered with fine 

 dark points, thickest on edge ; ventrals blue-black ; pectorals pale. Length 

 2 inches. Found by us only in the Minnesota River at the outlet of the Big 

 Stone Lake. Though differing somewhat from typical specimens of E. nigrum, 

 our specimen is apparently a breeding male of that species. 



22. Perca flavescens (Mitchill). Yellow Ferch; Ringed Perch. Little Minnesota 



River at Browns Valley, common; Little Minnesota River near Sisseton 

 Indian agency, 2 specimens; Big Stone Lake at Creager's farm, common ; Big 

 Stone Lake at Ortonville, common. Especially numerous in Big Stone Lake. 



23. Stizostedion vitreum (Mitchill). Wall-eyed Pike ; Pike Perch. Big Stone Lake 



at Creager's farm, 6 specimens; Big Stone Lake at Ortonville, 4. An excel- 

 lent food-fish and fretiuently taken. 



24. Aplodinotus griinniens Rafinesqne. Sheepshead; White Perch; Croaker. Little 



Minnesota River at Browns Valley, 2 specimens; Big Stone Lake at Creager's 

 farm, 5; Big Stone Lake at Ortonville, 2. This species reaches a weight of 

 4 to 6 pounds, but is not much prized as food. It is much sought after by 

 the boys for the otolith of the ear — ''luck stones in the head." 



MINNESOTA RIVER. 



The Minnesota River is 255 miles long and occupies a deep, somewhat 

 regular valley from 150 to 250 feet below the level of the surrounding 

 country, and from li to 2^ miles wide. The upper part of this valley 

 extends from Traverse Lake to Mankato in a southeasterly direction 

 for 175 miles. The lower course extends from Mankato in a northeast- 

 erly direction to the Mississippi Eiver, 7 miles below the falls of St. 

 Anthony. The river is subject to great fluctuations, as is shown by 

 the flood-plain, which is frequently more than one hundred times the 

 width of the river. The bed is of sand and mud. Huge sand-banks 

 along the shores and in the middle of the stream are common. 



Ortonville, Minn., July IS, 1893. — The Minnesota River was exam- 

 ined a mile below Big Stone Lake, just below the mill. The river here 

 during the summer season is a mere brook, winding among the knobs 

 of granite that outcrop in the valley. The size of the stream at the 

 outlet of the lake can scarcely be estimated, since half a mile below 

 it receives a western tributary, the Wheatstone, and a mile below the 

 foot of the lake it is dammed, so that the waters of the two streams are 

 collected, forming a marshy mill-pond from the dam to the lake. Below 

 the dam the course of the river is almost straight for half a mile, and 

 here it is fi^om 3 to 5 miles wide and from 12 inches to 2 feet deep, with 

 a current of possibly 1^ to 2 miles per hour. Tlie immediate banks are 

 low and fringed with willows, and the bed is of fine sand and gravel. 

 In addition to the waters from the lake and the Wheatstone the stream 

 F. R. 93 23 



