30. CATOSTOMID^E CARPIODES. 117 



D. 29 ; A. 10 ; Y. 10. Coloration paler ; the lower fins slightly dusky. 

 Mississippi Valley and southward ; generally abundant. 



(Calostomus biibalns Kirtland, Rep. Zool. Ohio, 1838, 168, not of Rafinesque: Buba- 

 liclitlti/s bubal us Agassiz, Amer. Jouru. Sci. Arts, 1855, 195 : BubalichtJiys bubalus Jordan, 

 1. c. 20(5: Sclerognathm wus Glinther, vii,22; B. altus Nelson MSS. in Jordan, Proc. 

 Acad. Nat. Sci. Pliila. 1677, 73; apparently the oldest tenable name, certainly belong- 

 ing to the species.) 



61. CAKPEODES Rafinesque. 



Carp Suckers. 



(Sclcrognathus Valenciennes.) 

 (Rafinesque, Ichth. Oh. 1820, 56: type Catostomus cyprinus Le Sueur.) 



Head comparatively short and deep, sometimes conic, sometimes 

 blunt; its length ranging from 3 to 5 in that of the body; its upper 

 surface always rounded. Eye moderate, median or anterior in posi- 

 tion. Suborbital bones well developed, their depth about half that of the 

 fleshy portion of the cheek below. Fontanelle always present, well de- 

 veloped. Mouth always small, horizontal and inferior; the mandible 

 less than one-third the length of the head ; the lips thin, the upper pro- 

 tractile, narrow, the lower quite narrow, /y-shaped, or rather fi -shaped, 

 behind ; both lips feebly plicate or nearly smooth, the plicaB often more 

 or less broken up. Jaws without cartilaginous sheath. Muciferous 

 system moderately developed. Opercular apparatus well developed; 

 the subopercle broad; the operculuin in the adult more or less rugose. 

 Isthmus moderate. Pharyugeal bones remarkably thin and laterally 

 compressed, with a shallow furrow along the anterior margin on the in- 

 side, and another more central one on the outline of the enlarged sur- 

 faces. Teeth very small, compressed, nearly equally thin along the 

 whole inner edge of the bone, forming a fine, comb-like crest of minute 

 serratures; their cutting edge rises above the inner margin into a 

 prominent point. Gill-rakers of anterior arch slender and stiff above, 

 becoming reduced downwards. Body ovate or oblong; the dorsal outline 

 more or less arched; the ventral outline more nearly straight; the depth 

 from half to one- third the length ; the sides compressed, the back nota- 

 bly so, forming a sort of carina. Caudal peduncle short and deep. 

 Scales large, about equal over the body, their posterior margins slightly 

 serrate ; lateral line well developed, nearly straight, with 34-41 scales j 

 12-15 scales in a cross-row from dorsal to veutrals. Dorsal fin begin- 

 ning near the middle of the body, somewhat in advance of ventrals, 

 falcate ; its anterior rays elevated and often filamentous, their height 

 ranging from to 1 the length of the base of the fin ; the number of 



