NOTROPIS 



135 



depth 2.3 to 3 in its length. Color oliyaceguSjjather dusky above, 

 the dark^pjmctulations on the scales confined mostly to the edges; 

 sides lej : d eniilvery 7^wrthr a black stripe extending forward through eye 

 to encVofsnout ; belly with an""OTange_tint ; fins plain. Head small, conic, 

 3.9 to 4.2 in length; width~bT~head 1.'8 to 2 in its length; interorbital 

 space 2 . 6 to 3 . 1 ; eye quite large, 2.7 to 3 in head, being usually about 

 J longer than the snout ; the distance from the tip of which to the anterior 

 rim of the pupil is about equal to the diameter of the orbit; nose short 

 and rather sharp, 3 . S to 3 . 8 in head ; mouth moderate, oblique, the upper 

 lip as a rule on a level with the upper margin of the pupil ; cleft of mouth 

 making an angle of 40° to 60° with the vertical; maxillary scarcely 

 reaching front of orbit, its length about f the diameter of the very large 

 eye ; 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 teeth 

 of the outer row usually strongly hooked and with a well-developed 

 groove whose edges are somewhat crenate; intestine shorter than body 

 and head; peritoneum silvery. Dorsal fin with 8 rays, slightly nearer 

 snout than base of caudal, set almost directly over ventrals; longest 

 dorsal ray somewhat less than head (1-1); anal rays 8, occasionally 7; 

 pectorals short, less than § to ventrals, 1.3 to 1.6 in head; ventrals 

 reaching vent. Scales 5, 35-38, 3; 12 to 14 scales before dorsal; lateral 

 line as a rule developed only anteriorly ; some specimens met with, 

 however, in which not more than 2 or 3 pores were lacking on posterior 

 half of body. 



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 and 

 over sand along shore. Specimens taken from the headwaters 

 of the Fox, Des Plaines, and Du Page fivers, and some from 

 the upper Rock and its tributaries (Yellow creek, Stephenson 

 county, Kishwaukee River at Sycamore, Rock River at Oregon, 

 and Green River at Geneseo) have the teeth 0, 4-4, 1, or 1. 

 4-4, 1, though the body is somewhat slender and the eye is 

 hardly so large as in the lake form. From farther southward we 



