412 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



The typo of C. dissimilis has the bead 3f ; depth 4f ; eye 4 ; snout 3| ; inter- 

 orbital 3; scales 12-66-9, 38 before dorsal. Of 21 specimens of Couesius from 

 Rapid Creek all but one are infested more or less with a parasitic trematodo 

 embedded under the scales and showing as small black spots. All of those 

 from Hill City and many from Custer and Sheridan are similarly aifected. 



85. Platygobio gracilis (Richardson). Flat-headed Chub. Fort Pierre, Fort Union, 



above Fort Union, Milk River, Yellowstone River, and Sweetwater River (as 

 Pogonichthys communis type, Girard, 1856 and 1858) ; Milk River (as Pogonich- 

 thys communis, Suckley, 1860) ; near Bridger Pass (as Pogonichthys (Platygobio) 

 gulonellus type, Cope, 1864a) ; Kansas River near Fort Riley (as P. gulonellus, 

 Cope, 1865) ; Platte A^alley (as P. communis, Gill, 1876) ; Fort Benton and 

 Judith River (as Pogonichthys communis, Cope, 1879) ; Missouri River, St. 

 Joseph, Mo. (Jordan &, Meek, 1885); Kansas River (Graham, 1885); Missouri 

 River at Sioux Falls (Meek, 1892) ; Poplar River at Poplar, and Missouri River 

 at Craig, Mont. (Eigenmann, 1894); Platte River at Fremont (Meek, 1894). 



This abundant minnow was found by us at the following places: White 

 River near Chamberlain ; Redwater Creek near Spearfish ; canal at Nio- 

 brara ; Bone Creek and Niobrara River near Long Pine ; Middle Loup River at 

 Dunning; Chadron Creek, Lone Tree Creek, and White River nearChadron; 

 Platte River at Grand Island; Niobrara River near Valentine; Mud Creek 

 and South Loup River at Ravenna; Clear Creek, Clermont; North Platte 

 River at Glenrock, Casper, and Douglas; Cheyenne River at Edgemont and 

 Cheyenne Falls ; Powder River at Arvada ; Deer Creek at Glenrock. 



The fiat-headed chub is preeminently the characteristic fish of the shallow 

 alkaline streams of the middle Missouri Basin / and shows better than any 

 other the peculiar bleaching effect of the alkaline waters of that region. 

 The fishes are all reduced to a nearly uniform pale or faded appearance. 

 Except those found in the headwaters above the alkali, they are almost 

 wholly without pigment cells of any kind. Perhaps the most extreme case 

 of bleaching is that of P. gracilis, which, of all American fishes, seems to bo 

 the one most perfectly adapted to life in these alkaline streams. 



86. Anguilla chrysypa Raiinesque. Common Eel. "Believed to be common 



throughout the State" of Kansas (as A. rostrata, Graham, 1885); Kansas 

 River at Lawrence and Topoka (Cragin, 1885a). The eel probably occurs 

 abundantly in the lower portion of the Missouri Basin, but no definite records 

 are known. 



87. Hiodon alosoides (Rafinesquo). Toothed Herring. Quaking Asp River (as 



Hyodon chrysopsis, Jordan, 1878); Missouri River, St. Joseph, Mo.; Tabo 

 Creek, Lexington, Mo. (Jordan & Meek, 1885) ; Silver Lake (Cragin, 1885a) ; 

 Republican River, Concordia, Kans. ; Saline River, Wakeeney, Kans. (Hay, 

 1887) ; Missouri and Big Sioux rivers, Sioux City (Meek, 1892) ; Poplar River, 

 Poplar, Mont. (Eigenmann, 1894) ; Floyd River at Sioux City, and Platte 

 River at Fremont (Meek, 1894). 



Young examples of this species were obtained as follows: Crow Creek, 

 Chamberlain; Choteau Creek, Springfield; Bazile Creek and Ponca Creek, 

 Niobrara ; Loup River, Ravenna ; White River, Chadron ; Wood and Platte 

 rivers, Grand Island ; Platte River, Casper; and Clear Creek, Clermont. Th6 

 largest specimens obtained do not exceed 6 inches in length. Though it was 

 not secured in many of the streams examined by us, this species is no doubt 

 generally distributed throughout the lower and middle Missouri River basin 

 in all suitable waters. It is a fish of the open stream, being found where there 

 is some current and Avhere the depth is not great. It reaches a length of a 

 foot or more, and is a handsome fish possessing some game qualities, though 

 not of much food value. At Hot Springs we were told that this fish is found 

 at Cheyenne Falls in considerable numbers in the spring, that it is locally 

 known as the " whitefish," and that it affords some sport for the local anglers. 



