118 ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 



Genus— MESITES. Jen. 



Corpus elongatum, gracile, antice subcylindricum, postice compressum, nudum, squamis 

 nullis. Caput depression. Rostrum breve, obtusum : os terminate, rictu modico. 

 Maxilla debiles ; superior margins ex ossibus inter max illaribus omnino formato, 

 maxillaribus retroductis et a labia partim celatis. Denies minuti, acuti, in maxilla 

 utrdque uniseriati ; in lingua et vomere biseriati ; in ossibus palatinis et pharijn- 

 gahbus nulli. Apertura branchialis amplissima, membrand sex-radiatd, subter 

 gulam prqfunde emarginatd, hand ist/imo annexd. Pinna dorsalis U analis valde 

 retropositce, opposite. Pinna pectorales et ventrales parvce. Pinna caudalis 

 leviter emarginata. 



There can be no doubt, I imagine, as to this being an entirely new form, 

 and a very interesting one, from the circumstance of its being at the 

 extreme end of the family to which it belongs, and its very much departing from 

 the usual characters of that family. I have referred it to the Cyprinidce, taking 

 that group in the enlarged view in which Cuvier accepts it ; though by those who 

 divide it into subfamilies it would probably be associated with the Cobitidce, or 

 made to constitute a distinct one by itself. It agrees with the Cyprinida in 

 general in the form of its mouth, in the upper jaw having its margin entirely 

 formed by the intermaxillary, the maxillary being present, but placed behind and 

 partly concealed in the thickness of the lip, and in the want of an adipose ; but 

 it altogether departs from that family in the entire want of scales, of which there 

 is not even a vestige in the dried skin, and in which respect it would seem to 

 shew an affinity to the Siluridce. Yet it has none of the other characters of the 

 family just mentioned. On the other hand, in the backward position of the 

 dorsal and anal fins, which are opposite to each other, it agrees with the Esocidce. 

 The pharyngeal bones are unarmed, but this deficiency is made up for by the 

 strong curved teeth on the tongue, independently of the minuter ones in the jaws. 



The intestine is extremely short and quite straight, measuring only fourteen 

 lines in length from the pylorus to the anus, in a specimen two inches and a half 

 long. The stomach is of an oval form, of considerable capacity, very mem- 

 branaceous, with the cardiac and pyloric openings near together at the upper 

 extremity, from the latter of which the intestine is immediately reflexed to pass 

 off to the anus. In the specimen dissected, the stomach was much distended by 

 a nearly perfect individual of the genus Colymbetes, which appeared to have been 

 recently swallowed, and was scarcely at all altered. There are no ccecal append- 

 ages. The air-bladder is of an elongated oval form, and of considerable de- 

 velopment. 



