30. CATOSTOMIDiE QUASSILABIA. 143 



in Moxostoma, and the lips are tliiclicr. Size large, {-ka^, a broad sur- 

 face; (fdjwy^^ I)harynx.) 



16S. P. cariBintUiii Copo. 



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



very large, 85 in length of the body. Eye small, behind the middle of 



the head. jMouth 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; abundtint 



in many streams. 



(Cope, Proc. Amer. Pliil. Soc. Pliila. 1870,407; Jordan, Man. Viit. oil; Jordan, 

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



70.— QUASSILABIA Jordan & Braytou. 



Rare-lip Suclcers. 



{Lagocliila Jordan & Brayton, preoccupied.) 



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

 & Brayton.) 



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- 

 tanelh; large, widely open. Mouth large, singular in structure, in- 

 ferior, the ui^per 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 dentary bones, which are provided with a rather hard, 

 hornj" plate, as in Pantosteus. The lower liji is entirely sei)arated 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 separathig 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 Moxostoma^ the lateral line 

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

 Air-bladder in three i)arts. Sexual peculiarities unknown ; probably 

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



