114 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



eutirel}^ destitute both of papilla3 and plicae. Jaws without cartilagi- 

 nous sheath. Muciferous system of head well de\eloped. Isthmus nar- 

 row. Pharyngeal bones rather weak, the outer surface of the arch 

 standing outwards and presenting a porous outer margin. The pedun- 

 cle of the symphysis is much longer proportionally and more pointed 

 than in Carpiodes and Biihalichtliys. The teeth are very numerous, small, 

 thin, and compressed as in Carpiodes^ but the lower ones are gradually 

 larger than the upper ones. Their inner edge is slanting outwards, 

 and not uniformly arched as in BuhalicMliys^ or truncate as in Ci/deptus, 

 the innermost margin rising somewhat in the shape of a i)rojecting cusp. 

 Gill-rakers of anterior arch long and slender above, becoming shorter 

 downwards. Body heavy, robust, not especially arched above nor 

 greatly compressed, the form somewhat elliptical ; the depth 2i-3i in 

 the length of the body. Scales large, thick, nearly equal over the body, 

 their i^osterior edges somewhat serrate ; the lateral line well develoi)ed, 

 but not as distinct as in Carpiodes, slightly decurved anteriorly; the 

 number of scales in its course 36-42 ; 13-15 in a transverse series from 

 dorsal to ventrals. Dorsal fin with an elongate basis, its number of 

 rays 25-30; anterior rays somewhat elevated, their length about half 

 that of the base of the fin. Caudal not much forked. Anal fin not 

 much elevated, its rays about 9 in number. Pectorals and veiitrals 

 moderate, the latter with about 10 rays. Sexual peculiarities, if any, un- 

 known. Coloration dark, not silvery. Air-bladder with two chambers. 

 Size very large. A shigle species known. {l/Oug, ^»h; ,3our, butiVilo.) 



113. I. huhalus (Rid.) Ag.—Eed-mouth Buffalo-fish. 



Body robust, moderately compressed, the outline somewhat elliptical, 



but the back rather more curved than the belly; depth 2i-3i in length. 



Head very large and thick, 3^ in length of body. Opercular apparatus 



very strong, the operculum itself forming nearly half the length of the 



bead. Scales very large. Develojied rays of the dorsal 27-29 ; anal rays 



9 ; ventrals 10. Scales 7-37 to 41-G. Coloration dull brownish olive, 



not silvery. Fins dusky. Size very large ; reaches a length of nearly 



3 feet and a weight of 20-30 pounds. Mississippi Valley ; generally 



abundant in the larger streams. 



{Amhlodon huhalus Raf. Jonrn. Pliys. 1818, 421 ; Agassiz, Amer. Journ. Sci. Arts, 1854, 

 19G : Sclerof/nathtis cijprinella C &V. Hist. Nat. Poiss. 1844, 477: ^Ichthyohns cijanellus 

 Nelson, Bull. 111. Mus. Nat. Hist, i, 49: Ichthyobus hubalns Jordau, Bull. U. S. Nat. 

 Mus. xii, 214: Sclcrognatlms cyprinclla Giinther, vii, 24.) 



* See Jordau, Bull. U. S. Nat. Mus. xii, 207. There lias beeu perhaps a confusion 

 among Mr. Nelson's types of this species. One sent by him to us is an Ictiobus. 



