PISCES. 



It is from five to six feet long, and communicates such violent shocks that 

 men and horses are struck down by them. This power is dependent on the 

 will of the animal, which gives it what direction it pleases, and renders it 

 effective, even at a distance, killing fishes therewith, so situated. It is, how- 

 ever, dissipated by use, and to renew it, the Gymnotus requires rest and 

 nourishing food. The organ which is the seat of this singular faculty, extends 

 along the whole under side of the tail, occupying about half its thickness ; it 

 is divided into four longitudinal fasciculi, two large ones above, and two 

 smaller ones below, and against the base of the anal fin. The little cells, or 

 rather the little prismatic and transverse canals formed by the two kinds of 

 laminae that unite the bundles, are filled with a gelatinous matter, and the 

 whole apparatus receives a proportionably large number of nerves. 



GYMNAIICHUS, Cuvier. 



The body scaly and elongated, and the gills slightly open before the pectorals 

 as in Gymnotus ; but a fin, with soft rays, occupies the whole length of the 

 back ; and there is none behind the anus, nor under the tail, which terminates 

 in a point. The head is conical and naked, the mouth small, and furnished 

 with a single row of small trenchant teeth. 



G. niloticus. The only species known; discovered in the Nile by M. 

 Riffault 



LEPTOCEPHALUS, Pennant, 



The branchial aperture before the pectorals; body compressed like a riband; 

 head extremely small, with a short and somewhat pointed snout ; pectorals 

 almost imperceptible, or totally wanting ; the dorsal and anal hardly visible, 

 and uniting at the point of the tail. The intestines occupy but an extremely 

 narrow line along the inferior edge. 



L. morisii, Gm., inhabits the coast of France and England. Several other 

 species, however, are found in the seas of hot climates, all of them as thin as 

 paper, and transparent as glass, so that even the skeleton is not visible. The 

 study of their organisation is one of the most profound, and interesting, to 

 which travellers can devote themselves. 



OPHIDIUM, Linnaeus. 



Dorsal and anal fins united with that of the tail, and terminating the body 

 in a point ; the body so elongated and compressed that it has been compared 

 to a sword, and invested like that of an eel with small scales planted in the 

 thickness of the skin. The Ophidii, however, differ from eels in their well 

 cleft branchiae, which are furnished with a very apparent operculum and a 

 membrane with short rays. Their dorsal rays are articulated, but not 

 branched. 



AMMODYTES, Linnceus. 



An elongated body like that of the preceding fishes, provided with a fin, 

 having articulated but simple rays, occupying a great part of the back, with 



