CLASS PISCES. 523 



in the skin, which opens only very far back, by a hole 

 or sort of funnel, which, sheltering the gills better, 

 allows these fishes to remain some time out of the 

 water without perishing. Their body is long and 

 slender ; their scales, as it were encrusted in a fat and 

 thick skin, are not clearly visible until they are dried 

 up. They are all destitute of ventrals and cceca, and 

 have the anus pretty far back. 



They have been successively dismembered into five 

 or six genera, which we are of opinion should be still 

 subdivided. 



Anguilla, Tliunberg and Shaw. Mur^na, Block, 



Are distinguished by the double character of pectoral 

 fins and of gills opening on each side under those 

 fins. Their stomach is a long cul-de-sac ; their in- 

 testine pretty nearly straight ; their air-bladder elon- 

 gated, has towards its middle a peculiar gland. 



Mur.t.na, Lacep. (Eels, properly so called), 



Have the dorsal and caudal sensibly prolonged around 

 the end of the tail, and forming there by their union 

 a pointed caudal. 



operculum is otherwise complete, andfoimed of all the pieces which 

 commonly helong to it. 



N.B. The Echelus, Rafinesque, Nov. Gen. p. 03. pi. xv. 1. 3. 

 pi. xvi. f. 2. and 3. should he some of them eels, others congers, 

 without opercula to the gills, hut we douht the reality of this cha- 

 racter. 



