HYBOPSIS ■ 167 



inferior and horizontal, tip of upper lip far below level of lower margin of 

 orbit; maxillary 'A.2 to o.T in head, barely reaching front of orbit; barbel 

 evident, though scarcely projecting; isthmus less than pupil. Teeth 1, 

 4-4, 1 or 0, stout and little hooked, with grinding surface usually not much 

 developed; intestine about .<) of length of head and body; peritoneum silvery. 

 Dorsal tin with 8 rays, occasionally 9, more or less falcate, set a little in 

 advance of ventrals, and distinctly closer to muzzle than base of caudal; 

 longest dorsal ray 1 to 1.2 in head; anal rays usually 8, sometimes 7 or 9; 

 pectorals - s or less to ventrals; ventrals to vent in young only. Scales 6, 

 37 to 40, 4; 14 to 16 rows in front of dorsal; upper longitudinal rows with 

 appearance of running out behind dorsal fin, as in Notropis cornutus, this 

 appearance aided by converging longitudinal lines formed by connecting 

 cross-marks of light color on the scales of some of the rows; lateral line 

 gently decurved anteriorly. 



Sexual differences slight; upper surface of pectoral rays in spring males 

 with very fine pectinately disposed tubercles; no sexually mature females 

 in our collections; some rather young females with ovaries just beginning 

 to enlarge taken about May 20. 



A fish of the larger streams and lowland lakes, widely dis- 

 tributed in Illinois, though rare with us throughout its range. 

 Our 28 collections carry it from Cairo to Jo Daviess county and 

 from the Wabash to the Mississippi. None of them, however, 

 are from the lower Illinoisan glaciation. One collection is from 

 the Rock River near Milan, seven come from the Illinois and its 

 larger tributaries, an equal number are from the Mississippi and 

 its neighboring lakes and bayous, five from the Wabash and its 

 tributaries, three from the Saline River, and two from the Ohio. 

 Outside Illinois it is generally distributed from Lakes Erie and 

 Ontario to Wyoming, Nebraska, and Arkansas, ranging south- 

 ward also to Tennessee. 



HYBOPSIS KENTUCKIENSIS (Eafinesque) 

 river chub; horny-head 



(.Map LI) 



Rafinesque, 1820, Ichth. Oh., 48 (Luxilus). 



G., VTI, 178 (Ceratichthys biguttatus and C. cyclotis) and 179 (C. stigmaticus and 

 C. micropogon) ; J. & G., 212 (Ceratichthys biguttatus and C. micropogon) ; 

 M. V., 65; J. & E., I, 322; N., 45 (Ceratichthys biguttatus); J., 62 (Ceratichthys 

 biguttatus); F. F., I. 6, 89 (Ceratichthys biguttatus); F. 75 (Semotilus bigut- 

 tatus); L., 19. 



A large species, with a general resemblance in form to Semotilus, but 

 the snout more pointed, mouth less oblique, and with no caudal spot (except 

 in young). Length 6 to 8 inches; body subfusiform, very little compressed, 

 robust anteriorly, the body deepest in front of the dorsal fin; profile scarcely 

 declined from front of dorsal to occiput in adults, the descent from that 

 point to muzzle rapid; depth 3.9 to 4.5; caudal peduncle less than head, its 



