PEKCA — RIVER PERCH 275 



gill-rakers slender, pyloric caeca 5 to 8, 4 of them of moderate length, but shorter 

 than stomach, the others mostly rudimentary. Dorsal X to XIII (usually 

 XII or XIII), 17-19; longest dorsal spine about 2}/q 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 specimens 

 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 or eighteen inches in length, and a weight of one or two 

 pounds. It has also occurred much less frequently in our collec- 

 tions, 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 whollj^, 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 {Aplodi- 

 notus), 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, wii^ its dorsal and pectoral poison-spines stiiT-set 

 and unbroken, was a striking illustration 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) Linnjeus 



river perch • 



Body oblong, considerably compressed, back elevated; mouth moderate; 

 premaxillary protractile; preopercle serrate, the serrae on lower margin 

 antrorse, closely set; opercle with a single spine; teeth in villiform bands on 

 jaws, vomer, and palatines; no canines; pseudobranchige small, but perfect; 



