152 FISHES OF ILLINOIS 



pure silvery, having the sheen of fine silver-leaf; iris almost pure silvery; 

 fins all pale, transparent; well called "shiner" or "silvery minnow". Head 

 short and very bluntly conic, 4.1 to 4.8 in length, usually about 4.5; width 

 of head 2.1 to 2.4 in its length; interorbital space 2.9 to 3.3; eye about 

 equal to snout (larger in younger specimens), 3 to 3.4 in head; nose 3.3 to 

 3.6; mouth moderate, terminal, oblique, tip of upper lip even with middle 

 of pupil; maxillary 3 to 3.4 in head, scarcely longer than eye, nearly reaching 

 front of orbit; jaws subequal; isthmus less than pupil. Teeth 2, 4-4, 2, 

 occasionally 1, 4—4, 2 or 2, 4-4, 1; the masticatory surface a very narrow 

 groove; intestine commonly less than length of head and body; peritoneum 

 rather densely specked with black. Dorsal fin with 8 rays, set well behind 

 ventrals, the distance from dorsal to caudal not more than 78 to 85 per 

 cent, of that from snout to dorsal; longest dorsal ray 1.1 to 1.2 in head; anal 

 rays 9, 10, or 11, usually 10; pectorals short, about % to ventrals, 1.2 to 1.4 

 in head; ventrals not reaching vent. Scales rather large and very thin, 

 6, 36-40,3, rows before dorsal 18 to 21; lateral line decurved. 



Extremely variable, having been described under various names even 

 from our own state. No attempt is made here to separate the forms 

 atherinoides, arge, and diledus, the two latter of which should probably be 

 regarded as synonyms of the present species. It appears to be distinct in 

 our collections from N. ruhrifrons, from which it differs in its shorter head, 

 shorter maxillary, larger eye, and blunter snout, as well as in its coloration 

 and faintly developed secondary sexual characters. 



This graceful and attractive species, distinguished by a 

 golden lateral stripe on a clear green ground, is an excessively 

 abundant and active minnow, occurring throughout the state, 

 but almost strictly confined everywhere to the larger lakes and 

 rivers. Among our collections from the smaller lakes of north- 

 eastern Illinois we have not obtained a single specimen of this 

 species, while the waters of Lake Michigan, but a few miles 

 away, were swarming with them along the shore, and especially 

 about the wharfs. There they are captured in great numbers, 

 together with the most abundant of the lake species, the spot- 

 tailed minnow, and sold for bait. Of our 206 collections, the 

 greater part are from rivers, 2.14 being the coefficient for rivers 

 of the second class, and 1.21 for those of the first class. The 

 coefficient for creeks is .93, and that for lowland lakes is .66, our 

 Lake Michigan collections not being represented in this series. 

 The distribution map of the state, for this species, shows a 

 curious difference between southern Illinois, where this minnow 

 occurs mainly in the creeks and smaller rivers, and the remainder 

 of the state, in which the larger streams are its principal resort. 

 It appears to have a moderate preference for a good current (1.19) 

 and for a clean bottom (1.22). but it is nevertheless one of the 

 species which enters the lower Illinoisan glaciation freely. It is 



