The Buffalo Fishes 



dii. Air bladder in three parts. 



k. Mouth normal, the lower lip entire or merely lobed. 



/. Pharyngeal bones moderate, the teeth compressed, gradually 

 larger downward; Moxostoma, 60 



//. Pharyngeal bones very strong, with tlie lower teeth much en- 

 larged, subcylindrical and truncate; Plaropliarynx, 64 



hk. Mouth singulai', the upper lip not protractile, greatly en- 

 larged, the lower lip developed as two separate lobes.-.. 



Lagochila, 6s 



GENUS ICTIOBUS RAFINESOUE 

 The Buffalo Fishes 



Body robust; head very large and strong; fontanelle large; 

 well-open; opercular apparatus well developed, the subopercle 

 broad, the opercle strongly furrowed; mouth large, terminal, pro- 

 tractile; mandible strongly oblique; lips little developed, the 

 upper narrow and smooth, the lower full on the sides, but 

 narrow in front; pharyngeal bones rather weak, the teeth 

 numerous; scales large, thick, and nearly equal over the body; 

 lateral line well developed, slightly decurved anteriorly; dorsal 

 rays numerous, the anterior somewhat elevated; caudal not much 

 forked. 



Large, coarse fishes, usually dark in colour, inhabiting chiefly 

 the larger rivers and some of the small lakes of the Mississippi 

 Valley. Only four species known, the three following and a 

 fourth from Guatemala. 



a. Mouth large, terminal, protractile forward; lips very thin; 



lower pharyngeals and teeth weak; cyprine'lla, ■ 39 



aa. Mouth smaller, more or less inferior, protractile downward, 

 and with thicker lips; lower pharyngeals stronger, the 

 teeth comparatively coarse and large. 



b. Back scarcely elevated, the depth 3 to 3^ in length. 



c. Mouth rather large and oblique, approaching that of /. cvprinclla, 



more oblique than in the iie.xt; urns, 40 



cc. Mouth small, inferior; nu'ridioualis, 41 



bb. Back elevated and compressed, the depth 2\ to 2f in length; 



bubahis, 41 



3S 



