CARAPUS. FISHES. 435 



Hunter and Humboldt. It is able to give shocks so violent as to stun men and 

 even horses, and seems to have the power of directing these shocks at will. The or- 

 gan which produces such singular effects runs along the under part of the tail, of 

 which it occupies nearly half the thickness ; is divided into four longitudinal bundles, 

 two larger above and two smaller below. Each bundle is composed of a great num- 

 ber of membranous parallel laminae nearly horizontal, united to one another by an 

 infinite number of vertical laminae directed transversely. The small cells or pris- 

 matic transverse canals intercepted by these laminae are filled with a gelatinous 

 matter, and the whole apparatus is abundantly provided with nerves. The electrical 

 shock given by the Gymnotus is readily communicated through a circle formed by 

 eight or ten persons ; and its use to the animal seems to be to procure its prey, by 

 stunning the fishes, which it is said to do through the medium of the water at some 

 distance. 



Gen. 10. CARAPUS, Cuv. Gymnotus, Bloch. 

 Body compressed, scaly, the tail tapering suddenly behind. 



C. brachiurus, Cuv. Head small and compressed ; under jaw longer 

 than the upper, and both furnished with small teeth ; body yel- 

 lowish, with brown undulations ; tail short, pointed. Inhabits 

 rivers of Brazil Bloch, pi. 157j, fig- 1. 



C. macrourus, Cuv. Head compressed, upper jaw projecting be- 

 yond the lower ; body brown, with a few irregular spots of a 

 deeper colour ; tail long, slender. 2 to 3 feet long. Inhabits 

 rivers of Brazil. Block, pi. 157, ng. 2. 



C. rostratus, Cuv. Snout elongated, the opening at the point ; anal 

 fin extending to the extremity of the tail. Inhabits S. American 

 rivers Shaw, iv. 63. 



Gen. 11. STERNARCHCS, Schn. Gymnotus, Gmel. 

 Anal fin terminating before arriving at the point of the tail ; 

 caudal fin distinct ; head oblong, depressed, naked ; a soft 

 fleshy filament on the middle of the back retained in a fur- 

 row ; body scaly. 



S. albifrons, Cuv. Snout obtuse; head naked, with numerous aper- 

 tures from which a viscid fluid exudes; body white above, black- 

 ish on the sides and belly ; tail compressed. 1 foot long. Inha- 

 bits fresh waters in Surinam Shaw, iv. 64. 



The curious structure on the back of this fish, Cuvier conjectures, maybe an acci- 

 dental separation of some of the muscles of the tail, from the weakness of the skin 

 on this part. 



Gen. 12. LEPTOCEPHALUS, Penn. 



Head small ; body laterally compressed like a riband ; dorsal, 

 caudal, and anal fins united ; branchial aperture small, trans- 

 verse. 



L. Morrisii, Gmel. Body semipellucid, pale ; margin of the back 

 and belly with minute black spots ; lateral line nearly in the 

 middle, and straight ; pectoral fins extremely small. 6 inches 

 long. Inhabits coasts of England Wern. Mem. ii. pi. 22, fig. 1. 



Gen. 13. OPHIDIUM, Lin. 

 Dorsal, anal, and caudal fins united ; tail pointed ; body elon- 



