104 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY III. 



*• Dorsal (in elongate, more or less elcvati-d in front, of about 25 or more dt^veloped 

 rays : air bladder in two parts, 

 t I'ontanolli' obliterated by the union of the parietal bones: head nhort and small : 

 body elongate. {Cyvleptince.) 

 Ii. Mouth small, inferior, with very thick, papillose lips : scales small, ou to 60 iu 



the course of the lateral lino C yclkptus, 9. 



tt Fontanelle well developed : head large : body oblong or ovate : scales large, 35 to 

 45 in the course of the lateral line. (Bubalichthyinw.) 

 i. Dorsal rays in moderate number (24 to 33). 

 j. Mouth comparatively small, inferior, protractile downwards. 



k. Pharyngeal bones narrow, with the teeth comparatively thin and weak. 



Cakpiodes, lU. 

 A-^". Pharyngeal bones strong, the teeth comparatively coarse and large, in- 

 creasing in size downwards Buijalicutiivs, 11- 



jj. Mouth quite large, terminal, protractile forwards : i)haryngoal bones and 



teeth moderate : lips thin, nearly smooth Iciixii yobus, 12. 



ii. Dorsal fin very long, of about 50 developed rays Myx()CYI'i;inl"s, 13 



Genus QUASSILABIA Jordan d Brayton. 



Lagochila Jordan & Brayton, Proc. Ac. Nat. Sc. Phila. 280. 1877. (Preoccupied in 



conchology as Lagochilus.) 

 Quassilabia {JoHT>AS & Brayton) Joudan, Man. Vert. E. U. S. ed. 2d, 401, l'^73. 

 Type, Lagochila laceia Jordan & Brayton. 

 Etymology, qitafmiis, broken or torn; labia, lip. 



Suckers like Myxostoma in every respect exceptiiifj the .structure of 

 the mouth and opercula. Head shorti.sh, conical, with lenjjthened snout; 

 its length 4^ to 5 times in that of the body, the opercuhir region being 

 reduced, so that the eye is well backwards: suborbital bones narrow : fon- 

 tanelle larj;e, widely open. Mouth large, singular in structure, inferior, 

 the ui)per lip not protractile, greatly prolonged, closely plicate. Lower 

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

 weakly papillo.se. The split between these lobes extends backwards to 

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

 horny plate, as in J'antostevs. The lower Hp 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 tiiis lissur*', the crease separating this skin 

 from the mouth extending up on the sides of the muzzle. Tlu' crease 

 between the lips extends down on the under si<le of the head. System 

 of muciferous tubes well developed. 



Pharyngeal bones not dissimilar from the usual ty|>«' in Mi/.rofintmuy 

 rather weak, with numerous .small teeth. 



Body elongate, not much compressetl, not elevated. Fn)s moderate, 

 of precisely the type usual in Alyxontoma. 



