GENUS QUASSILABIA. 105 



Scales large, precisely as iu Myxostoma^ the lateral line well developed 

 and nearly straight, with about 45 scales iu its course. 



Air-bladder iu three parts. 



Sexual peculiarities unknown ; probably little marked. 



But a single species of this genus is known. It is a sort of offshoot 

 Irom the genus Myxostoma, but its non-protractile mouth and singular 

 lower lip would seem to indicate some real affinity with the genus Exo- 

 glossum. 



The name Lagochilus had been previously applied to a genus of Gas- 

 teropods by Blanford, and toagenusof Insects by Loew. As Lagochila is 

 substantially the same word, with the same etymology, and as, if written 

 in strict correctness, it would be Lagochilus also, its authors have seen 

 fit to substitute the name Quassilabia, and thus to forestall all discus- 

 sion as to whether the name Lagochila should be retained. As this sub- 

 stitution was made soon after the original description of the genus, and 

 before the name Lagochila' had come into any general use, it is to be 

 hoped that it will be accepted by succeeding ichthyologists. 



Generic Characterizations. 



LxVGOCHiLA Jordan & Braytou, 1877. — "Similar to Myxostoma (Ptychosfomus Agassiz) 

 except in the structure of the mouth parts. Dorsal fin short ; lateral Hue well devel- 

 oped ; scales large, subequa.] ; air-bladder in three paits ; foutanelle between parietal 

 bones well developed ; pharyngeal bones weak, with numerous small teeth ; upper lip 

 not all protractile, greatly enlarged, but atttuuated, and sirgular iu form. It consists 

 of two elongated and narrow lobes, separated by a n.arrow, deep fissure, which extends 

 inward to the edge of the mandible proper, which seems to be armed with a rather 

 hard or almost horny plate, about as iu the genus Pantosle^is. The two lobes of the 

 lip are weakly papillose. The lower lip is entirely separated from the upper at the 

 angles by a deep fissure. Over this fissure the skin of the cheek lies as a sort of cloak; 

 the crease separating this skin from the mouth, extending up on the sides of the muzzle. 

 The fissure between the lips extends down on the skin of the under side of the head. 

 The opercle is extiemely short and the eye is entirely lu the posterior part of the head." — 

 (Jordan & Braytox, Proc. Ac. Nat. Sc. Phila. p. 280, 1877.) 



QUASSILABIA Jordan & Brayton, 1878. — "When the name Lagochila was fiist pro- 

 posed for this genus, its authoie were not aware that the masculine form, Lagochilua, 

 had been already given to two difieren*; genera, tooneof Gasteropods by Blaufoid a^d 

 to one of Insects by Loew. The words Lagochila and Lagochilus are identical in ety- 

 mology and in all except terminations, and many writers would consider them insuffi- 

 ciently distinct, and would hold that the name Lagochila should be changed. At 

 present, lam inclined to the contraiy opinion; nevertheless, as the matter stands, and 

 as the name Lagochila has not yet come into general use, less confusion perhaps will 

 result from renaming the genus, than from any other course. The name Qaassilabia 

 (Jordan & Brayton} is accordingly suggested as a substitute for Lagochila, considered 

 to be preoccupied in concbology. The etymology is quassus, broken or torn ; labia, lip. 



