OSSEOUS FISHES. 541 



times by one, sometimes by the other wand, though their extremities 

 are close together. 



The experiments already related in connection with the torpedo were 

 repeated here. If we place ourselves upon an isolated support, and 

 take hold of a metallic rod, a shock is received; but no shock is 

 received, on the other hand, if the fish is touched with a glass rod, 

 or one coverecj, with wax. Humboldt and Bonpland repeated this 

 experiment many times, with decisive results. The electric organ 

 has been carefully described by these observers. The organs extend 

 from under the tail, occupying nearly one-half of the thickness. It 

 is divided into four longitudinal bundles of muscles, the upper ones 

 large, the two smaller below, and against the base of the anal fin. 

 Each bundle consists of many parallel membranous plates, placed 

 closely together and very nearly horizontal. These plates abut in one 

 part on the skin, in another, on the mean vertical plane of the fish. 

 They are united to each other by an infinity of smaller plates, placed 

 either vertically or transversely. The smaller prismatic and trans- 

 versal canal, intercepted by these two orders of plates, are filled with 

 gelatinous matter. All this organic apparatus receives many nerves, 

 and presents, in many respects, an arrangement nearly analogous to 

 that of the torpedoes. 



The Sea-Eels (Mursena Helena) are serpent-like fishes, of cylin- 

 drical form and delicate proportions, but strong, flexible, and active, 

 swimming in waving, undulating movements in the water, just as 

 a serpent creeps on dry land. The muraenas have no pectoral fin ; the 

 dorsal and anal fin are reunited in the tail fin. A branchial opening 

 is observable on each side of the body. The sea-eels are numerous in 

 species. Mur&na Helena (Fig. 365), which is an inhabitant of the 

 Mediterranean, has only a single row of teeth upon each jaw. It 

 attains the length of forty to fifty inches. It loves to bask in the 

 hollows of rocks, approaching the coast in spring-time. It feeds on 

 crabs and small fishes, seeking eagerly for polyps. The voracity of 

 these fishes is such that when other food fails they begin to nibble at 

 each other's tails. 



The sea-eels are caught with rod and line, or by lines and ground- 

 bait, but their instinct is such that they often escape. When they 

 have swallowed a hook they often cut the line with their teeth, or 

 they turn upon it and try, by winding it round some object, to strain 



