C4 

 Genus 20. Centrarchus, C. Sc V. 



43. Centrarchus macropterus, Lac. 



(BqI. II, 47; Centrarchus iridcus.) 



This is also a species confined in Illinois to the southern part of 

 the State, where we have taken it in Cache Pdver, in Clear and 

 Drury Creeks, in Great House Creek, near Mt. Carmel, and in various 

 ponds and sloughs in the river bottoms of that region. 



Family VI. ELASSOMATID.E. 

 Genus 21. Elassoma, Jordan. 



44. Elassoma zonatum, Jordan. 



A southern species, not collected by us north of St. Francisville, 

 in Lawrence county. Not uncommon in small, muddy pools. 



Family VII. APHREDODEEID.E. 



Genus 22. Aphredoderus, Le Sueur. 



K 45. Aphredoderus sayanus, Gilliams. — Pirate Perch. 



(Bui. II, 48; Aphododerus isolepis.) 



Throughout the State from the Calumet to Union county and the 

 Wabash but far the most abundant southward. Occurs almost in- 

 variably in small streams only, but occasionally taken in the Illinois. 

 One of the commonest species in mud holes in the Mississippi bot- 

 toms, in Southern Illinois. Very rare in the central prairie region. 



Family VIII. ATHERINID.E. (The Silversides.) 

 Genus 23. Labidesthes, Cope. 



46. Labidesthes sicculus, Cope. — Brook Silverside. 



A very abundant minnow in small streams and lakes in Central 

 and Northern Illinois ; also occurs rarely in the Wabash Valley, 

 commonly in Kock River, and occasionally in the Ilhnois. 



Order II. HEMIBRANCHII. 

 Family IX. GASTEROSTEID.E. (The Sticklebacks.) 



Genus 24. Gasterosteus, L. 



47. Gasterosteus inconstans, Kirt. — Brook Stickleback. 



Locally common in rivers and small streams in the northern part 

 of the State only. We have not taken it south of Rock River. 



