Jordan and Evermann. — Fishes of A^orl/i America. 163 



88. ICTIOBUS, Kafinesque. 

 (Buffalo Fisuks.) 



Icliolms, JtAFlNESQUK, Ichtli. Oh., 55, 1820, (bubabts). 

 Sdeioijmtllms, CuviBii anil Valenciennes, xvii, 477, 1814, {ryprinella). 

 BiibalichlhiiK, AoASSiz, Aiiier. Jour. Sci. Arts, 192, 1850, (urns). 

 IchOiyobm, Agassiz, (corrected ortliography). 



Body robust ; head very large and strong. Eye moderate, anterior. 

 Fontanelle large, well open. Opercular apparatus largely developed ; the 

 suboperculuni broad ; the operculum strongly furrowed. Mouth large 

 for a sucker, terminal, protractile forward, or downward and forward. 

 Mandible strong, obli(iue. Lips little developed ; the upper narrow and 

 smooth; the lower rather full on the sides, but reduced to a narrow rim 

 in front. Jaws without cartilaginous sheath. Muciferous system of head 

 well developed. Isthmus narrow. Pharyngeal bones rather weak ; the 

 teeth numerous, moderate or small ; the lower ones gradually larger than 

 the upper ones. Gill rakers long and slender above, becoming shorter 

 downward. Scales large, thick, nearly equal over the body ; lateral line 

 well developed, slightly decurved anteriorly. Dorsal fin elongate, its 

 rays 25 to 30; anterior rays somewhat elevated, their length about i that 

 of the base of the iin ; caudal not much forked ; anal fin not much ele- 

 vated, its rays about (• ; pectorals and ventrals moderate, the latter with 

 about 10 rays. Sexual differences slight. Coloration dark, not silvery. 

 Air bladder with 2 chambers. Fishes of very large size, inhabiting deep 

 rivers, chiefly in the Mississippi basin. (/A,'0if, fish; (iovc, bull.) 



ScLEROGNATHUS, (aK\Tqp6<;, liivrd; yi'aSos, jaw): 

 «. Mouth large, terminal, protractile forward; lips very thin; lower pharyngeals and teeth 



weak. CVPltlNELLA, 2111. 



ICTIOBl'S: 



aa. Mouth smaller, more or less inferior, protractile downward, and with thicker lips; lower 

 pharyngeal bones stronger; the teeth comparatively coarse and large, increa.sing in 

 size downward. 

 6. Back scarcely elevated, the depth 3 to3J4 •'i length. 



c. Mouth rather large and oblique, approaching that of /. aipriiiella, more obIi<iue 



than in the next. vrus, 2t)2. 



cc. Mouth small, inferior. mehidionalis, 203. 



bh. Back elevated and compressed, the depth 2)^ to 2% in length; mouth small, inferior. 



liUDALl'S, 264. 



Subgenus SCLEROGNATHUS, Cuvier & Valenciennes. 



261. ICTIOBUS CYPRINELLA, (Cuvier & Valenciennes). 



(Red Mouth Buffalo Kish; Common Buffalo Fish.) 



Head very large and thick, 3^^ in length; depth 2i to 3i in length. 

 Developed rays of the dorsal 27 to 29; anal rays 9; ventrals 10. Scales 

 7-37 to 41-6. Body robust, moderately compressed, the outline somewhat 

 elliptical, but the back rather more curved than the belly. Opercular 

 apparatus very strong, the operculum itself forming nearly i the length 

 of the head. Coloration dull brownish olive, not silvery; fins dusky. 

 Size very large ; reaches a length of nearly 3 feet and a weight of 20 to 

 30 pounds. Mississippi Valley ; generally abundant in the larger streams. 

 (Diminutive of cypriniis, carp.) 



