PERCA RIVER PERCH 275 



3 . 2 to 3 . 7 ; maxillary past back of pupil, 2.1 to 2 . 2 ; gill-rakers slender; 

 pyloric caeca 5 to 8, 4 of them of moderate length, but shorter than stom- 

 ach, the others mostly rudimentary. Dorsal X to XIII (usually XII or 

 XIII), 17-19; longest dorsal spine about 2 J in head; caudal lunate; anal 

 II. 11 or 12; ventrals half way to vent; pectorals 1.7 to 1.8 in head. 

 Scales 9-11, 85-91. 19-24; lateral line usually complete, in some spec- 

 imens extending on caudal; cheeks fully scaled, the scales very strongly 

 ctenoid, rows about 15. 



A much smaller fish than the preceding, seldom exceeding a foot 

 < >r eighteen inches in length, and a weight of one or two pounds. It 

 has also occurred much less frequently in our collections, which 

 have come mainly from the Mississippi and the Illinois rivers, with a 

 few, also, from the Rock, the Wabash, and the Kaskaskia. It seems 

 to be a species of somewhat more limited range than the wall-eyed 

 pike. The distribution area of our variety (griseum) extends from 

 the Red River of the North and the Assiniboin River, through the 

 upper Great Lakes and the upper Mississippi Valley, west to Montana 

 and south to Tennessee and Arkansas. Its habits, so far as known, 

 are similar to those of the preceding species, and it occurs in similar 

 waters, the two having been taken together by us in about the usual 

 ratio for river and lake fishes. 



Judging from the results of an examination of fourteen specimens 

 obtained from the Illinois River at different places and times, it feeds 

 wholly, or almost wholly, on fishes. Four of these specimens had 

 eaten gizzard-shad, two had taken catfishes, one of which was a 

 bullhead, two had eaten sheepshead (Aplodinotus), and one had 

 taken a black bass and a sunfish. The presence of a medium-sized 

 bullhead in the stomach of one of these fishes, with its dorsal and 

 pectoral poison-spines stiff-set and unbroken, was a striking illus- 

 tration of the voracity of this species. 



It is of much less commercial importance than the wall-eye. the 

 catch from the Mississippi River in 1899 reaching a total of only 

 39,000 pounds. 



Genus PERCA (Artedi) Linn.-eus 

 (river perch) 



Body oblong, considerably compressed, back elevated; mouth mod- 

 erate; premaxillary protractile; preopercle serrate, the serrae on lower 

 margin antrorse, closelv set; opercle with a single spine; teeth in villiform 

 bands on jaws, vomer, and palatines; no canines; pseudobranchia small. 

 but perfect; pyloric csei a 3 to 7 ; dorsal spines 12 to 1 u ; anal with 2 slender 



