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ELECTRIC EEL (Gymnotus electricus)
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ELECTRIC See also:EEL (Gymnotus electricus) , a member of the See also:family of fishes known as Gymnotidae. In spite of their See also:external similarity the Gymnotidae have nothing to do with the eels (See also:Anguilla). They resemble the latter in the See also:elongation of the See also:body, the large number of vertebrae (240 in Gymnotus), and the See also:absence of pelvic fins; but they, differ in all the more important characters of See also:internal structure. They are in fact allied to the carps or Cyprinidae and the See also:cat-fishes or Siluridae. In See also:common with these two families and the Characinidae of See also:Africa and See also:South See also:America, the Gymnotidae possess the See also:peculiar structures called ossicula auditus or Weberian ossicles. These are a See also:chain of small bones belonging to the first four vertebrae, which are much modified, and connecting the See also:air-See also:bladder with the auditory See also:organs. Such an agreement in the structure of so complicated and specialized an apparatus can only be the result of a community of descent of the families possessing it. Accordingly these families are now placed together in a distinct sub-See also:order, the Ostariophysi. The Gymnotidae are strongly modified and degraded Characinidae. In then the dorsal and caudal fins are very rudimentary or absent, and the anal is very See also:long, extending from the anus, which is under the See also:head or See also:throat, to the end of the body. Gymnotus is the only genus of the family which possesses electric organs. These extend the whole length of the tail, which is four-fifths of the body. They are modifications of the lateral muscles and are supplied with numerous branches of the See also:spinal nerves. They consist of See also:longitudinal columns, each composed of an immense number of " electric plates." The posterior end of the See also:organ is See also:positive, the anterior negative, and the current passes from the tail to the head. The maximum See also:shock is given when the head and tail of the Gymnotus are in contact with different points in the See also:surface of some other See also:animal. Gymnotus electricus attains a length of 3 ft. and the thickness of a See also:man's thigh, and frequents the marshes of See also:Brazil and the Guianas, where it is regarded with terror, owing to the formidable See also:electrical apparatus with which it is provided. When this natural See also:battery is discharged in a favourable position, it is sufficiently powerful to stun the largest animal; and according to A. von See also:Humboldt, it has been found necessary to See also:change the See also:line of certain roads passing through the pools frequented by the electric eels. These See also:fish are eaten by the See also:Indians, who, before attempting to See also:capture them, seek to exhaust their electrical See also:power by See also:driving horses into the ponds. By repeated discharges upon these they gradually expend this marvellous force; after which, being defenceless, they become timid, and approach the edge for shelter, when they fall an easy See also:prey to the See also:harpoon. It is only after long See also:rest and abundance of See also:food that the fish is able to resume the use of its subtle weapon. Humboldt's description of this method of capturing the fish has not, however, been verified by See also:recent travellers. Additional information and CommentsThere are no comments yet for this article.
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