143 FISHES or ILLINOIS 



with a very broad silvery to plumbeous band; commonly a large black spot 

 at base of caudal fin; scales faintly cross-hatched on upper part of body and 

 for a little distance below lateral line forward; spots above and below pores 

 of lateral line faint or wanting; fins pale. Head short, 4.1 to 4.7 in length of 

 head and body; width of head 1.8 to 2.1; interorbital space 2.5 to 2.9; eye 

 moderate, 2.8 to 3.5 in head, equal to nose or slightly shorter or longer in 

 adults; nose blunt, usually somewhat decurved, 3.2 to 3.5 in head; mouth 

 rather small, nearly horizontal, the tip of upper lip below level of lower 

 margin of pupil; maxillary usually not quite reaching orbit, 3.7 to 4.5 in head; 

 lower jaw shorter than upper; isthmus less than pupil. Teeth variable: 0, 

 4r-4, 1; 1, 4-4, 1; 1, 4-4, 2; or 2, 4-4, 2; teeth of main row more or less hooked, 

 and generally quite compressed, the grinding surface developed as a quite 

 narrow groove whose edges are smooth; intestine .9 to 1.4 times length of 

 head and body; peritoneum silvery, finely but not densely specked with dark. 

 Dorsal fin with 8 rays, set usually a trifle in advance of the ventrals and nearer 

 snout than base of caudal; longest dorsal ray about equal to the length of the 

 short head; anal rays 8; pectorals scarcely % to ventrals; ventrals usually 

 short of vent. Scales 5 or 6, 36 to 39, 4; 15 to 18 before dorsal; longitudinal 

 rows of scales above lateral line with the appearance of "running out" behind 

 dorsal fin, as in N. cornutus; lateral line usually complete, not much decurved 

 anteriorly. 



Fig. 36 



This abundant, graceful, and well-known species, essentially 

 a northern minnow in this state, is much the most abundant in 

 our largest rivers and in lakes, its frequency ratio in the former 

 being 1.8, and in the latter 1.76. In small rivers and in creeks 

 it has been taken only occasionally, the corresponding ratios 

 being .29 and .14. It is abundant in its favorite localities, and 

 appears in 147 of our collections. In Illinois it is limited to the 

 Mississippi and Lake Michigan drainage, and has occurred but 

 twice south of the central part of the state, once in Union county 

 and once from the Ohio at Cairo. We have found it most 

 frequently in the Illinois River and its adjacent waters at Havana 

 and Meredosia, from which two places 119 of our collections 

 have come. It is also one of the commonest longshore minnows 

 in southern Lake Michigan, swarming especially about the piers 

 off Chicago, where it is caught in quantities and sold fbr bait. 



