..The fishes of Illinois . as a rule on a level with the upper margin of the pupil; cleft of mouthmaking an angle of 40° to 60° with the vertical; maxillary scarcelyreaching front of orbit, its length about f the diameter of the very largeeye; jaws subequal, the isthmus less than pupil. Teeth as a rule 1, 4-4, 1,in occasional instances 1, 4-4, 0, 0, 4-4, 1, or 4-4; the first three teethof the outer row usually strongly hooked and with a well-developedgroove whose edges are somewhat crenate; intestine shorter than bodyand head; peritoneum silvery. Dorsal fin with 8 rays, slightly nearersnout th
..The fishes of Illinois . as a rule on a level with the upper margin of the pupil; cleft of mouthmaking an angle of 40° to 60° with the vertical; maxillary scarcelyreaching front of orbit, its length about f the diameter of the very largeeye; jaws subequal, the isthmus less than pupil. Teeth as a rule 1, 4-4, 1,in occasional instances 1, 4-4, 0, 0, 4-4, 1, or 4-4; the first three teethof the outer row usually strongly hooked and with a well-developedgroove whose edges are somewhat crenate; intestine shorter than bodyand head; peritoneum silvery. Dorsal fin with 8 rays, slightly nearersnout than base of caudal, set almost directly over ventrals; longestdorsal ray somewhat less than head (1-1); anal rays 8, occasionally 7;pectorals short, less than § to ventrals, to in head; ventralsreaching vent. Scales 5, 35-38, 3; 12 to 14 scales before dorsal; lateralline as a rule developed only anteriorly; some specimens met with,however, in which not more than 2 or 3 pores were lacking on posteriorhalf of Fig. 30 The typical form of this species appears to be confined,with us, to the northern part of Illinois, being most abun-dant in the small glacial lakes of Lake and McHenry coun-ties, where it is found in clear, cool water among weeds andover sand along shore. Specimens taken from the headwatersof the Fox, Des Plaines, and Du Page fivers, and some fromthe upper Rock and its tributaries (Yellow creek, Stephensoncounty, Kishwaukee River at Sycamore, Rock River at Oregon,and Green River at Geneseo) have the teeth 0, 4-4, 1, or , 1, though the body is somewhat slender and the eye ishardly so large as in the lake form. From farther southward we 136 FISHES OF ILLINOIS have about 80 collections, chiefly from the sluggish waters of theIllinois River and tributary lakes at Havana and Meredosia, inwhich the dentition is more usually 2, 4-4, 2, and the lateral line isnearly always complete. Collections of the same form, which maybe identical with the unnamed* va
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Keywords: ., bookcentury1900, bookdecade1900, bookidcu31924, booksubjectfishes
