110 FISHES OF ILLINOIS 



been complicated in the case of the Illinois River by the effect of the 

 increased flow from Lake Michigan, which has diminished vegeta- 

 tion in many areas. 



Genus CAMPOSTOMA Agassiz 



(stone-rollers) 



Bodv 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 bodv, 

 wound in many 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) 



Rafinesque. 1820. Ichth. Oh., 52 (RutilusV 



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

 44; J., 55; F., 70; F. F., I. 6, 77; L., 14. 



Distinguishable from all other Illinois Cyprinidce by the peculiar dis- 

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

 transverse 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, sub fusiform, 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 brassv 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 

 onvex, 2.5 to 3.3 in head, usually less than 3; eve small, circular, 4.2 to 

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

 under surface; nose 2.3 to _».s. the muzzle moderately decurved, over- 

 hanging the rather large and horizontal mouth; maxillary 3.3 to 4.6 in 

 t reaching scarcely back of vertical from posterior nostril; lower jaw 

 wholly included; upper lip quite flesh)-; breadth of isthmus 1.3 to 1.5 



