138 FISHES OF ILLINOIS 



pectorals about § to ventrals, 1.2 to 1 .4 in head; ventrals reaching vent 

 or front of anal. Scales 5, 32-36, 4; 12 or 14 before dorsal; lateral line 

 complete, generally noticeably decurved on anterior half of body. 



This abundant but rather insignificant and indefinite species 

 belongs to the group which apparently avoid the streams of the 

 southern Illinoisan glaciation. Although distributed throughout 

 the state from the Ohio and Saline rivers on the south to the extreme 

 northern boundary, and represented in our records by 128 collec- 

 tion localities, but five of these are within that area, and these are 

 on its northern borders where its peculiarities are least pronounced. 

 It is consistent with this limitation to its distribution in this state 

 that it should show a decided preference, according to our collec- 

 tion records, for clean swift waters over muddy and stagnant ones. 

 Its frequency coefficient for waters over a bottom of rock or sand 

 is 2.00, and the corresponding frequency ratio for a swift current 

 is 1.18. It is essentially a species of small rivers and creeks, our 

 frequencies for these two classes of streams being 2.65 and 2.23 

 respectively, while that for the larger rivers is only .41 and that for 

 lakes and ponds but .17. In general distribution it is limited to a 

 region extending from the Great Lake basin. Lake Champlain, and 

 the streams of the St. LawTence system, by wa}^ of the Missouri 

 River to Wyoming, northward to the Lake of the Woods and the 

 Red River of the North, and southward through the Ohio and the 

 Mississippi basins to the San Antonio River in Texas. 



From the little that is known of its feeding habits, its food is no 

 more peculiar than its general appearance, consisting of a mixture 

 of aquatic insects, crustaceans, and chance vegetation. 



NOTROPIS PHENACOBIUS Forbes 



Forbes, 1885, Bull. 111. State Lab. Nat. Hist., II. 2, 137. 



This fish unites with a strong general resemblance to Phenacobius 

 the chararcters of Notropis. The body of the adult is short and deep, the 



head square, the nose long, and the eye unusually 

 large. Length 2\ inches; depth 3.5 to 4; caudal 

 peduncle 4 to 4. 75. Color in alcohol indefinite; sides 

 somewhat silver\^ scales along and above the lateral 

 line slightly specked with black. The head is quad- 

 rate in transverse section, flat above, 3.75 to 4; 

 Pj^. 2,^ nose decurved, 3 .4 to 3.5; interorbital space 2.9 to 



3.1. The mouth is inferior, horizontal, rather small, 

 lips fleshy, not lobed, lower jaw much the shorter, 2.75 to 3.1 in head, 

 upper lip opposite the lower margin of the pupil, upper jaw to posterior 



