214 FISHES OF ILLINOIS 



length. Color (females) brownish olive with a purplish black lateral band 

 continued forward across cheek and opercle and through eye to end of 

 snout; belly pinkish white; median fins more or less specked with dusky, 

 anal faintly so and only near base; males with sides crossed by 16 or 17 

 rather obscure bars of dusky, and with edges of lateral band somewhat 

 serrate; anal with two or three rows of prominent dark specks. Head 

 much depressed and rather elongate, 3.5 to 3.9 in length; width of 

 head 1.6 to 2 ; interorbital space 2.2 to 2.5; eye 3.3 to 3.9; nose 2 . 8 

 to 3.4, noticeably longer than eye; maxillary 2". 8 to 3.3 in head, man- 

 dible greater than eye; jaws subequal, the lower scarcely so long as 

 upper; "teeth in a broad band, the outer series considerably enlarged, 

 canine-like" (J. & E.). Dorsal inserted behind ventrals, its rays 9; anal 

 rays 11, the fin noticeably longer in males (longer than head) than in 

 females (about % head) ; ventrals to vent ; pectorals almost or quite to 

 ventrals, 1.4 to 1.9 in head. Scales 33 to 34; transverse series 11; 

 cheeks and opercles and top of head covered with large scales. 



This is much the most abundant Illinois species of its family, and is 

 the one to which the name of top-minnow has been most generally at- 

 tached. It occurs in great abundance throughout the state in waters 

 of all descriptions, most frequently, however, in the smaller streams 

 and headwaters of southern and eastern Illinois. Its condensation 

 southward is illustrated by our frequency coefficients for the three 

 sections of the state — 2.13 for southern Illinois and 42 and .44 

 for central and northern Illinois respectively. By far the greater 

 part of our collections have been taken from the basins of the Kas- 

 kaskia and the Wabash, and the ponds and creeks of the extreme 

 southern part of the state. 



Outside Illinois it occurs from Michigan, and Wisconsin south- 

 ward throughout the entire lower Mississippi Valley to Louisiana and 

 the rivers of Texas. It is reported by collectors to be most abundant 

 in ponds, creeks, and canals, and along the margins of sluggish 

 streams. It is a surface swimmer, as its common name implies, and, 

 like Funduhis dispar, it is easily distinguished in the water by a sil- 

 very occipital spot. 



Nearly the whole food of the species consists of insects, as illus- 

 trated by our examination of 1 7 specimens taken from various places 

 in central and southern Illinois. The 10 per cent, of vegetation 

 eaten by these fishes was almost wholly filamentous algse, taken in 

 such quantities by some as to make it certain that their presence in 

 the food was not a matter of accident. In one fish, for example, the 

 entire intestine was crammed with these algas, and in three others 

 they made more than half the food. Insects were the major part 

 of the remainder, although Entomostraca and amphipod Crustacea 

 (Crangonyx) were likewise common. 



