PISCES. 



95 



(very minute and crowded), while the side of the eye is de- 

 prived of teeth ; dorsal commencing at the mouth and ex- 

 tending, as well as the anal, to the caudal. 



ORDER IV. MA L ACOPTERYGII APODES. 



Form elongated ; skin thick and soft, presenting but little 

 appearance of scales ; few bones ; no ventral fins. Two re- 

 markable genera. 



Genus Mur-ena, Lin. 



Small opercula concentrically surrounded by rays, and en- 

 veloped, as well as these latter, in the skin, which only opens 

 at a considerable distance back by a species of tube. Two 

 remarkable subgenera. 



Subgenus Anguilla, Cuv. Eel. 



Gills opening on each side under the pectoral fins ; the 

 dorsal and caudal forming by their union a pointed caudal ; 

 dorsal commencing at a considerable distance behind the 

 pectorals. 



Subgenus Conger, Cuv. 



Dorsal commencing near the pectorals ; upper jaw longest ; 

 same characteristics as in the Eel. 



Genus Gymnotus, Lin. 



Gills partially closed by a membrane, but which opens 

 before the pectorals ; anal extending generally to the end of 

 the tail ; no dorsal. 



ORDER V. LOPHOBRANCHII. 



Jaws complete and free ; branchiae, instead of having the 

 form of a comb, are divided into small round tufts arranged in 

 pairs along the branchial arches, and concealed under a large 

 operculum tied down on all sides by a membrane, which 

 leaves only a small orifice for the escape of the water ; bran- 



