152 FISHES OF ILLINOIS 



no caudal spot; cheeks and opercles 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 sub- 

 equal; 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 com- 

 monly 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 dilecttis, the two latter of which should probably 

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

 in our collections from A^. ruhrijrons, 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 northeastern 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 coeffi- 

 cient 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 



