ICTIOBUS 



69 



median axis a pale green ; ventral region white dulled with bluish ; pre- 

 dorsal region and upper part of caudal peduncle slate; dorsal and caudal 

 fins drab-gray; anal dusky olive; ventrals lighter; pectorals dull white 

 under olive. Head large and heavy, its length from 3.3 to 3.7, depth 

 3.9 to 4.2, width 4.8 to 5.2 in 

 length of body ; snout blunt and 

 broadly rounded; interorbital 

 space convex, 2 to 2.4 in head; 

 snout separated from frontal 

 region of head by a slight trans- 

 verse depression in front of 

 orbits, giving it a turned-up 

 appearance; mouth large and 

 wide, terminal, protractile for- 

 ward, very oblique, upper edge 

 of mandible about reaching level 

 of median axis, upper lip almost 

 on a level with lower margin 

 pf orbit; mandibles strong and 

 broad, forming a wide protrud- 

 ing angle at their union with 

 the quadrate; lips thinner and 

 smoother than in other species 

 of Ictiobus, upper very thin and nearly smooth, lower thicker and some- 

 what lobed at corners, rather faintly and finely striate; eye 5.6 to 7 in 

 head, situated well forward ; opercle strongly striated and very broad 

 Dorsal rays 24 to 28, longest ray a little more than half the base of fin 

 caudal not deeply forked; anal short, inserted under last rays of dorsal 

 ventrals falling about as short of vent as pectorals do of ventrals. Scales 

 large, uniform in size and evenly distributed, rather loosely imbricated, 

 their number 7 or 8, 37 to 40, 6 or 7 ; lateral line-complete, rather flexuose 

 posteriorly and somewhat abruptly elevated in front of dorsal fin. 



Sexual differences slight, the males averaging a little smaller in size 

 and darker in color than the females; spring males without tubercles. 



Distributed throughout the Mississippi Valley, in rivers, lakes, 

 ponds, and larger creeks; also in the Red. 'River of the North to 

 Winnipeg. It does not occur east of the Alleghanies, nor in the 

 Great Lakes. 



This is a very abundant fish in our larger streams and in the 

 lakes of the river bottoms, being one of the three species most 

 commonly shipped from the Illinois and the Mississippi under the 

 name of "buffalo-fish." It is taken abundantly in the latter river 

 at Cairo, Grafton, and Quincy, and is one of the important com- 

 mercial species of the Illinois, from which it is caught in large 

 numbers as far north as Henry. It is much less abundant now, 

 however, than some years ago. It is the common "buffalo-fish" 

 of the fishermen, and generally receives no more distinctive name. 



