APODAL MALACOPTERYGIANS. 225 



The True Gymnoti have no sensible scales; their intestines, which 

 have several flexures, occupy but a moderate space ; the caeca are numer- 

 ous, and the stomach resembles a short obtuse sac strongly plaited within. 

 One of their air-vessels, cylindrical and elongated, extends very far be- 

 hind in a sinus of the abdominal cavity ; the other, oval and bilobate, com- 

 posed of a thick substance, occupies the upper part of the abdomen, and 

 is placed on the oesophagus. The species known inhabit the rivers of 

 South America. The most highly celebrated is 



G. electricus, L.; Bl. 156, (The Gymnotus), which, from its 

 almost uniform shape and obtuse head and tail, has also been 

 called the Electrical Eel. 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, however, 

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

 nourishing food*. The organ which is the seat of this singular fa- 

 culty 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 ana] fin. Each bundle is composed of numerous parallel, 

 membranous lamina?, nearly horizontal, and closely approximated to 

 each other, one end terminating on the skin, and the other on the 

 median vertical plane of the animal : they are united with each other 

 by a multiplicity of small transverse and vertical laminae. The little 

 cells, or rather the little prismatic and transverse canals formed by 

 these two kinds of laminae, are filled with a gelatinous matter, and 

 the whole apparatus receives a proportionably large number of 

 nerves-]-. 



CarapusJ, Car., 



Have a compressed and scaly body ; the tail much narrowed behind. From 

 the rivers of South America§. 



We might, perhaps, distinguish from the common species those with an 

 elongated snout only open at the end ||. 



Stern arches % 'Schn. — Apteronotes, Lacep., 



Have the anal terminated before it reaches the end of the tail, which has 

 a fin of its own ; a soft fleshy filament en the back, lodged in a groove 

 running to the end of the tail, and retained there by tendinous threads, 

 which still allow it some degree of liberty, a very singular mode of orga- 



* See Humboldt, Zool.Obs. I, p. 49, et seq. 



f See Hunter, Phil. Trans. Vol. LXV, p. 395. Add, the Gymnotus aquilabiatus, 

 Hunib. Zool Obs. I, pl.x, No. 2, according to whose observations this species has no 

 posterior natatory bladder. 



% Caropo, the name of these fishes at Brazil, according to Marcgrave. 



§ Gymnotus macrourvs, Bl. 157, 2; — Carapo, Gm.; — O. brachiurus, Bl. 157, 1;— 

 fascialus, Gm.; — G. albus, Seb. Ill, pi. 32, f. 3. 



|| Gymnotus rostratus, Schn., pi. 106. 



Tf Sternarchus, i. e. anus at the sternum. 



vol. ii. a 



