30. CATOSTOMID^: QUASSILABIA. 143 



in Moxostoma, and the lips arc thicker. Size large. (~/r, a broad sur- 

 i'ace ; (pa^o-f^, pharynx.) 



16. P. esis'iaaatws Cope. 



Body oblong, moderately compressed, heavy at the shoulders. Head 

 very large, 3-f in length of the body. Eye small, behind the middle of 

 the head. Mouth extremely large, the lower jaw oblique when the 

 mouth is closed, the mouth, therefore, protractile forwards as well as 

 downwards. Lips very thick, coarsely plicate, the lower lip full and 

 heavy, truncate behind. Head above evenly rounded or somewhat cari- 

 nated. Scales 6-45-G. Dorsal rays 13 ; ventral 9. Color brassy green 

 above; lower fins red. Great Lakes and Mississippi Valley; abundant 

 in inaiiy streams. 



(Cope, Proc. Amor. Phil. Soc. Puila. 1870, 467 ; Jordan, Man. Vert. 311 ; Jordan, 

 Bull. U. S. Nat. Mus. xii, 108.) 



7O. QUASSILABIA Jordan & Braytou. 



Hare-lip Suckers. 



(Lagocliila Jordan & Braytou, preoccupied.) 



(Jordan & Braytou, Man. Vert. E. U. S. ed. 2, 1878, 401: type Lagoddla lacera Jordan 

 & Braytou. ) 



Suckers like Moxostoma in every respect excepting the structure of 

 the mouth. Head shortish, conical, with lengthened snout; its length 

 4^-5 times in that of the body, the opercular region being reduced, 

 so that the eye is well backwards. Suborbital bones narrow. Fon- 

 tanelle large, widely open. Mouth large, singular in structure, in- 

 ferior, the upper lip not protractile, greatly prolonged, closely plicate. 

 Lower lip much reduced, divided into two distinct elongate lobes, which 

 are weakly papillose. The split between these lobes extends backwards 

 to the edge of the deutary bones, which are provided with a rather hard, 

 horny plate, as in Pantosteus. The lower lip is entirely separated from 

 the upper at the angles by a deep fissure. The skin of the cheeks forms 

 a sort of cloak over this fissure, the crease separating this skin from the 

 mouth extending up on the sides of the muzzle. The crease between 

 the lips extends down on the under side of the head. System of mucif- 

 erous tubes well developed. Pharyngeal bones not dissimilar from the 

 usual type in Moxostoma^ rather weak, with numerous small teeth. 

 Body elongate, not much compressed, not elevated. Fins moderate, 

 formed as in Moxostoma. Scales large, as in Moxostomctj the lateral line 

 well developed and nearly straight, with about 45 scales in its course. 

 Air-bladder in three parts. Sexual peculiarities unknown ; probably 

 little marked. (Quassus, broken or torn; labia, lip.) 



