238 FISHES OF ILLINOIS 



KEY TO SPECIES OF POMOXIS FOUND IN ILLINOIS 



a. Dorsal spines typically VI, rarely V or VII; dorsal distance 1.7 to 1.9 in 

 length, a line drawn from back tip of maxillary at right angles with an- 

 terior margin of premaxillary crossing back in front of first dorsal spine; 

 body more slender and profile more strongly S-shaped than in P. sparoides; 



color light, the dark markings tending to form rings annularis. 



aa. Dorsal spines typically VII or VIII, rarely VI, or IX, or X; dorsal dis- 

 tance 1.8 to 2, the line from back of maxillary crossing behind third or 

 fourth, or even fifth or sixth, to last dorsal spine; color dark, spotted, the 

 dark markings not forming rings sparoides. 



POMOXIS ANNULARIS RAFINESQUE 



WHITE CHAPPIE 



(MAP LXX) 



Rafinesque, 1818, Amer. Month. Mag., 41. 



J. & G., 464; M. V., 115; B., I. 7 (sparoides, part); J. & E., I, 987; N., 37; J., 47; 

 P., 69; F. F., I. 3, 56; L,., 23. 



Length 12 inches; body elongate, compressed, and back elevated; the 

 profile long and quite strongly S-shaped; depth 2.2 to 2.6 in length; greatest 

 width about 2.75 in greatest depth; depth caudal peduncle 1.1 to 1.3 in its 

 length. ' Color silvery olive, mottled with dark green, the dark marks chiefly 

 on the upper part of the body and having a tendency to form narrow vertical 

 bars; gen ral color much lighter than in the next species; dorsal and caudal 

 fins mark i d with green (rather than blackish, as in the next species) ; anal pale, 

 nearly phin; a dusky opercular spot' (J. & E. with emendations). Head 

 long, 2.8 to 2.9; width of head 2.5 to 2.8 in its length; interorbital space 4.3 to 

 5.6, convex; eye 4.5 to 5 in head; nose 3.2 to 4.2, noticeably longer than in 

 the next species and also visibly longer than eye; mouth large, oblique, 

 maxillary past middle of orbit, 2.1 to 2.3 in head. Dorsal typically* VI, 15, 

 the fin inserted further from muzzle than in the next species, the dorsal dis- 

 tance f in the present species being 1.68 to 1.88 in the length; caudal lunate; 

 anal VI (occasionally V), 17-19; ventrals past first anal spine; pectorals 1.3 

 to 1.7 in head. Scales 6, 43-48, 12; lateral line developed on most or all scales. 



The white crappie and the species following are commonly 

 regarded in this state as the best for food of the sunfish family, 

 with the exception of the black bass. The present species occurs 

 in all parts of the state, most abundantly in lakes, ponds, and 

 bayous, but commonly also in the smaller rivers and in creeks. 

 It seems to have no marked local or ecological preferences to 

 embarrass its entrance upon any waters containing its means 

 of subsistence. It enters freely, for example, upon the lower 

 Illinoisan glaciation, is found in the clean glacial lakes of the 



* Of 337 specimens of the present species examined, 318 had VI dorsal spines. 15 had V, 

 and 4 had VII; of 315 specimens of Pomoxis sparoides, 266 had VII spines, 46 had VIII, 2 had 

 VI, 1 had IX, and 2 had X. 



t In two typical specimens of exactly the same length (6 inches), one annularis and one 

 sparoides, the dorsal distance differed 8 tenths of one centimeter. This difference may be said 

 to be due to difference in lenqth of fins, the dorsals in both species terminating at the same dis- 

 tance from the end of the last vertebra. 



