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Show 262 PISCES. before the pectorals; the anus very far forwards; anal fin occupying the greater part of the inferior surface of the body, and most frequently extending to the end of the tail; no dorsal fin whatever. GYMNOTUS, Lacep. No fin at the end of the tail, under which extends the anal. 'fhe TRuE GYMNOTI have no sensible scales; their intestines which have several flexures occupy but a moderate space; the creca are numerous, and the stomach resembles a short obtuse sac strongly plaited within. One of their air vessels, cylindrical and elongated, extends very far behind in a sinus of the abdominal cavity, the other, oval and bilobate, composed of a thick substance, occupies the upper part of the abdomen, and is placed on the resophagus. The species known inhabit the rivers of South America. The most highly celebrated is G. electricus, L.; Bl., 156 (The Electrical 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 there· with, so situated. It is, however, dissipated by use, and to renew it, the Gymnotus requires rest and nourishing food.( 1) The or· gan 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. Each bundle is composed of numerous parallel, mem· branous laminre, 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 verticallamince. The little cells, or rather the little prismatic and transverse canals formed by these two kinds of laminre, are filled with a gelatinous matter, and the whole apparatus receives a propor· tionably large number of nerves.(2) (1) See Humboldt, Zool. Obs., I, p. 49, et seq. . . (2) See Hunter, Phil. Trans. vol. LXV, p. 395. Add the Gymnotm requt~· biat~s, llumb., Zool. Obs., I, pl. x, No. 2, according to whose observations thiS spec1es has no posterior natatory bladder. MALACOPTERYGII APODES. 263 CARAPus, Cuv.(1) A compressed and scaly body; the tail much narrowed behind. From the rivers of South America.(2) We might, perhaps, distinguish from the common species those with an elongated snout only open at the end.(3) STERNAROI-IUs, Schn.( 4)-APTERONOTus, Lacep. The anal terminated before it reaches the end of the tail which is furnished with a particular fin; a soft fleshy filament on ~he back lodged in a groove running to the end of the tail and retained ther~ by tendinous threads, which still allow it some degree of liberty, a singular mode of organization, the use of which cannot be divined.( s) The head is oblique, compressed, naked, and the skin prevents both the opercula and the rays from being seen externally; rest of the body scaly; teeth small and crowded, and on the middle of each jaw scarcely perceptible. The Sternarchi like the preceding fishes inhabit the waters of South America.(6) GYMNARCHus, Cuv. " 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 co~ical 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. (~) Oarapo, according to Marcgrave, the name of these fishes at Brazil. ( ) ~mnotm macrourua, Bl., 157, 2; Carapo, Gm.;-G. brachiurus, Bl., 157, l;-fascwtus, Gm.;-G. albua, Seb., III, pl. 32, f. 3. (3) Gymnotus rostratus, Schn., pl. 106. (4) Sternarchus, i. e. anus in the sternum. (S)l 1 rather think the separation is accidental, and that, in fact, it is one of the mtaucshee de.s of the tail ' wh' h th k' . . . lC ' as e s m 1s weak m th1s particular place, is easily de- 14~~) 3~mnotm albifrons, Pall., Spic. Zool., VIII, pl. vi, f. 1; Lacep. JJ, vi, GyNm.B . t The Gym no tu s acus, or fie raafer, belongs to the genus Ophidium, and the no U8notopterus, Pall. and Gm., Notoptcre capirat, Lacep., to the Herrings. \ |
