198 U.S. NATIONAL MUSEUM BULLETIN 282 



Variation. — N. miurus shows remarkable uniformity of characters, 

 considering its wide latitudinal range. The chief geographic differences 

 noted are the paler and more emaciated condition of southern speci- 

 mens; those from clear northern streams (Tippecanoe and Huron 

 Rivers) are darker and fatter. The basic color pattern is the same 

 throughout the range. A very slight increase in fin rays from north 

 to south is suggested by certain of the caudal ray counts. Pearl River 

 specimens do not appear to be differentiated. 



The following summarized data lists, in order, the number of 

 counts, the range (in parentheses), and the mean: 



Vertebrae: Homochitto River, Mississippi 15 (34-37) 35.13; Corney 

 Bayou, Louisiana 7 (34-36) 35.14; Hatchie River, Tennessee 31 

 (35-37) 36.03; Poteau River, Oklahoma 9 (34-35) 34.56; southern 

 Illinois and southeastern Missouri 14 (35-36) 35.29; Ohio River, 

 Indiana 4 (34-37) 35.25; Coal River, West Virginia 28 (34-37) 35.79; 

 Huron River, Michigan 103 (32-36) 34.50; all specimens 212 (32-37) 

 35.03. 



The ensuing data are listed in the following sequence: (a) chiefly 

 Mississippi drainage, Louisiana and Mississippi, (b) Arkansas River 

 system of Missouri, Kansas, and Oklahoma, (c) southeastern Missouri, 

 (d) Kentucky and Tennessee, (e) Wabash and Ohio drainages, Indiana, 

 (f) Muskingum River system, Ohio, (g) Huron River, Michigan, and 

 (h) total, all specimens. 



Internasal pores: (a) 228 (1-2) 1.02; (b) 82 (1-2) 1.06; (c) 48 (1-2) 

 1.06; (d) 78 (1-2) 1.05; (e) 52 (1-2) 1.29; (f, including Lake Erie 

 specimens) 66 (1-2) 1.05; (g) 146 (1-2) 1.01; (h) 701 (1-2) 1.05. 



Sojt pectoral rays: (a) 40 (7-9) 7.83; (b) 57 (7-9) 8.12; (c) 34 (8-9) 

 8.24; (d) 30 (7-8) 7.80; (e) 50 (7-9) 7.92; (f) 28 (8-9) 8.07; (g) 144 

 (7-9) 7.92; (h) 383 (7-9) 7.97. 



Anal rays: (a) 21 (14-16) 15.14; (b) 28 (13-16) 14.54; (c, including 

 southern Illinois) 18 (14-16) 15.22; (d) 15 (13-17) 14.67; (e) 25 

 (14-17) 15.28; (f) 13 (14-16) 15.08; (g) 77 (14-17) 15.16; (h) 197 

 (13-17) 15.05. 



Lower-half caudal rays: (a) 21 (24-29) 26.14; (b) 32 (23-29) 26.63; 

 (c) 17 (25-29) 27.47; (d) 14 (24-28) 26.43; (e) 25 (23-29) 26.36; 

 (f) 14 (25-28) 26.57; (g) 71 (24-29) 26.42; (h) 194 (23-29) 26.52. 



Upper-half caudal rays: (a) 21 (32-37) 34.14; (b) 33 (31-34) 32.70; 

 (c) 17 (31-35) 32.82; (d) 15 (31-36) 33.33; (e) 25 (31-35) 33.08; 

 (f) 14 (31-36) 33.29; (g) 72 (30-35) 32.49; (h) 197 (30-37) 32.92. 



Total caudal rays: (a) 21 (57-65) 60.29; (b) 32 (54-62) 59.28; 

 (c) 18 (57-63) 60.33; (d) 14 (56-64) 59.79; (e) 25 (54-63) 59.44; 

 (f) 14 (57-62) 59.86; (g) 80 (55-64) 58.93; (h) 204 (54-65) 59.43. 



Distribution. — Noturus miurus (map 14) is known from the 

 Great Lakes basin, the Mississippi River system, the Pearl River 



