110 FISHES OF ILLINOIS 



Of the third charge little can be said. While it is admitted 

 by all competent to judge that carp do uproot vegetation in 

 large quantities, no means are at hand for comparing the effect of 

 this destruction on the decrease of water-birds with the effects of 

 the operations of the hunters themselves. Since 1900 the prob- 

 lem has been complicated in the case of the Illinois River by the 

 effect of the increased flow from Lake Michigan, which has 

 diminished vegetation in many areas. 



Genus CAMPOSTOMA Agassiz 



STONE-ROLLERS 



Body elongate, little compressed; jaws with thick lips; premaxillaries 

 protractile; no barbel; teeth 4-4 or 1, 4-4, 0, with oblique grinding surface 

 and a slight hook on one or two teeth; intestine 6 to 9 times length of body, 

 wound in mariy coils about the air-bladder, which is suspended in the ab- 

 dominal cavity, this condition being unique in Campostoma among all known 

 fishes; peritoneum black; dorsal rays 8; anal rays 7 or 8; scales 46 to 75; 

 lateral line present. Size moderate, not over 6 or 8 inches. Four species 

 known. 



CAMPOSTOMA ANOMALUM (Rafinesque) 



stone-roller; dough-belly; greased chub 



(Map XXIII) 



Rafinesque, 1820, Ichth. Oh., 52 (Rutilus). 



G., VII, 183 (dubium); J. & G., 149, 150 (prolixum) ; M. V, 52; J. & E., I, 205; N. 

 44; J., 55; F, 79; F. F., I. 6, 77; L., 14. 



Distinguishable from all other^Ulinois Cyprinidce by the peculiar dis- 

 position of the very long intestine, which is wound many times in a trans- 

 verse spiral about the air-bladder in the species of this genus, in which alone 

 of all fishes this arrangement is known to, occur. Length 6 inches; body 

 stoutish, subfusiform, only moderately compressed; depth 3.9 to 4.8 in 

 length, usually more than 4.3 in adults; caudal peduncle as a rule somewhat 

 longer than head, its depth 2 to 2.5 in its length; old males heavy forward, 

 the predorsal region swollen and the back more or less elevated. Color 

 brownish olive, the upper parts with brassy luster; sides and caudal peduncle 

 irregularly blotched or mottled with blackish; belly satiny whitish; a dusky 

 vertical bar behind opercle; males with a dark cross-bar through middle of 

 dorsal and anal and a vertical bar at base of caudal, especially conspicuous 

 in spring, when the rest of each fin is fiery red and the snout and sometimes 

 almost the entire body covered with tubercles; females sometimes with a 

 faint dusky cross-bar on dorsal, the anal and caudal plain; young with more 

 or less pinkish to purplish on body. Head subconic, little compressed, 4 to 

 4.6 in length, its width in its length 1.7 to 2; interorbital space very little 

 convex, 2.5 to 3.3 in head, usually less than 3; eye small, circular, 4.2 to 5.2 

 in head, situated forward of middle of head and nearer its upper than under 



