25 



phlsm is exhibited by this species. The males have oran (re-colored spots on the sides in- 

 stead of dark brown, as in the females; measurements of males and females by Mr. W. E. 

 Howard of Ottawa, 111., have shown also that in the former the profile is steeper, with fore- 

 head concave, and that the ventrals are longer, reaching: past the vent. 



Found very generally distributed in the State, except in the upper Rock River basin. 

 Fox River and tributaries, and the DaPage, Desplaines, and Kankakee basins. Not common 

 in the sluggish portions of creeks. 



Lepomis pallidus (Mitchill). — Blue-gfill. 



The most important of the sunflshes as a food fish. The name blue-gill refers to the 

 blue color usually found on the lower portion of the cheeks. Form of the body orbicular; a 

 black spot usually present on the dorsal posteriorly. 



Generally distributed and quite common in the larger streams; apparently not found In 

 the upper portion of the Wabash basin; not very common southward. 



Eupomotis heros (Baird & Girard). (318b) 



In appearance like the preceding, but with a blood-red margin on the opercular flap in 

 the male. 



Taken from two ponds near St. Francisvllle, and from a pond opposite Mt. Carmel; a 

 specimen also recorded from Onion Creek, at Topeka, 111. 



Eupomotis gibbosus (Linneeus). — Pumpkin-seed; Common Sunfish. (319) 



Wavy blue lines on the cheeks and opercles; colors very bright, with much yellow; 

 opercular flap with red on the posterior margin. 



Abundant in the Illinois basin; especially so in the lakes of northeastern Illinois. 

 Otherwise widely distributed, but not abundant. Not found in collections from the Wabash 

 or its tributaries. 



Micropterus dolomieu Lacep^de. — Small-mouth Bass; Green Bass; Red-eye 

 Bass. 



The gamiest of Illinois fishes. Often confounded with the large-mouth bass by the In- 

 experienced, although the separation on a basis of the finer scales in this species (17 rows 

 on cheek and 72 to 80 in the lateral line) is quite easy. The young may be readily recog- 

 nized by the white margin of the caudal fin. 



Found in large clear streams. Not taken from the Wabash or Kaskaskia basins. 

 Otherwise generally distributed in favorable situations. 



Micropterus salmoides Lac^pfede. — Large-mouth Bass; Black Bass; Green 

 Bass, 



Scales on the cheeks in about 10 rows; 65 to 70 in the lateral line. The young have a very 

 marked black stripe on the sides and around the snout. This stripe breaks up later into 

 spots, which gradually disappear with age, but are usually noticeable until the third year, 

 and sometimes later. 



Common throughout the State in the sluggish portions of streams. 



Family Percid^ (The Perches). 



KEY TO ILLINOIS GENERA OF THE FAMILY PERCID.?:, 



a. Pj'eudobranchia well developed; branchiostegals 7; Jno anal papilla; mouth large, 

 terminal; fishes growing to a weight of 1 lb. or more. 



b. Canine teeth on jaws and palatines; body cylindrical, elongate; ventrals sepa- 



rated by a space equal to width of base Stizostedion. 



bb. No canine teeth; body oblong, slightly compressed Pkkca. 



aa. Paendobranchia small! or wanting; branchiostegals 6; anal papilla usually 

 present; small fishes, never exceeding 10 inches in length, usually much 

 smaller. 



c. Lateral line developed, at least anteriorly. 



d. Body usually almost cylindrical; nuchal region never much compressed; skull 



immediately behind eyes, '"^•shaped in cross section. 



e. Breadth of cranium between eyes about equal to diameter of orbit; snout pig-like, 



projecting much beyond mouth Peboina. 



