164 Bulletin 47, United States National Museum. 



Sclerognathus cyprinella, CUVIER & VALENCIENNES, xvii, 477, 1844, Lake Pontchartrain. 



Ichlhyobus bubalus, AGASSIZ, Amer. Jour. Sci. Arts, 1854, 196, not of "Rafinesque. 



Ichthyobus cyanellus, NELSON, Bull. 111. Mus. Nat. Hist., I, 49, 1876, Illinois River. 



LMiyobus bubalus, Jordan, Bull. U. S. Nat. Mus., xn, 214, 1878. 



Sclerognathus cyprinella, GUNTHER, Cat., vn, 24, 1868; JORDAN & GILBERT, Synopsis, 883, 1883. 



Subgenus ICTIOBUS. 



262. ICTIOBUS UBUS, (Agassiz). 



(MONGREL BUFFALO.) 



Scales 8-41-7. D. 30; A. 10. Body much less elevated and less com- 

 pressed than in 7. bubalus, the back not at all carinated ; axis of body 

 above ventrals about at the lateral line, and but very little farther from 

 the dorsal outline than from the ventral ; depth 3 to 3 in length. Head 

 very stout, strongly transversely convex, thicker, larger, and less pointed 

 than in 7. bubalus, about 4 in length. Eye about equal to snout, 5 in head, 

 much smaller than in I. bubalus. Mouth large, considerably oblique, 

 opening well forward, approaching that of 7. cyprinella. Mandible longer 

 than eye. Premaxillary somewhat below suborbital. Dorsal fin lower 

 and less rapidly depressed than in the next, the longest ray scarcely i the 

 length of the base of the fin. Anal fin rounded; its rays not rapidly 

 shortened ; the middle ones not much shorter than the longest. Colors 

 very dark; fins all black. Mississippi Valley; in the larger streams, 

 less common than the others ; certainly distinct from 7. bubalus, but we can 

 not always separate it from 7. cyprinella, and perhaps it is not really dif- 

 ferent, (urus, a wild bull.) 



Carpiodes urns, AGASSIZ, Amer. Jour. Sci. Arts, 1854, 355, Tennessee River, Huntsville, Ala. 

 BubalichtJtys urus, niger, Ohio River, andbonasus, Osage River, AGASSIZ, Amer. Jour. Sci. Arts, 



1855, 193, 195. 

 Bubalichthys unis, JORDAN, 1. c., 209; JORDAN & GILBERT, Synopsis, 883, 1883. 



263. ICTIOBUS MEBIDIONALIS, (Gimther). 



Scales 7-38-7. D. 29 ; A. 10. Mouth small, inferior, slightly corrugated. 

 Depth 3i to 3 in length. Head 4 to 4|, not much longer than high. Eye 

 rather small, of the length of the head and f that of the snout. Subor- 

 bitals narrow. Anterior dorsal rays not much produced, shorter than the 

 head; caudal forked; origin of ventral vertically below the fourth dorsal 

 ray; pectoral not extending to ventrals. Coloration uniform. RioUsuma- 

 cinta, Guatemala. (Giinther.) (meridionalis, southern.) 



Sclerognathus meridionalis, GUNTHER, Cat., vn, 23, 1868, Rio Usumacinta, Guatemala. 



264. ICTIOBUS BUBALUS, (Rafinesque). 

 (SMALL-MOUTHED BUFFALO ; RAZOR-BACKED BUFFALO ; SUCKER-MOUTHED BUFFALO.) 



Scales 8-39-6. D. 29; A. 10; V. 10. Body considerably elevated and 

 compressed above; the dorsal rion subcarinate; belly thicker; depth 

 2 to 2f in length ; axis of body above the ventrals, below the lateral line, 

 and nearly twice as far from the back as from the belly. Head moderate, 

 triangular in outline when viewed from the side, 4 in length. Eye equal 



