EELS. 273 



soft and leathery. The intestines are not fur- 

 nished with caeca ; but the air-bladder is generally 

 well-developed. 



About one hundred and fifty species are recog- 

 nised as constituting this Family, some of which 

 are exclusively marine, others exclusively fluvia- 

 tile ; w^hile others, as our own common Eels, are 

 found in both salt and fresh waters. They are 

 widely scattered over most parts of the globe. 



One of the most curious forms of the Family is 

 that of the Gymnotus or Electric Eel, containing 

 a few species peculiar to the rivers of tropical 

 South America. The species best known, which 

 has been exhibited alive in England, attains a 

 length of five or six feet, with a diameter of eight 

 inches. It has the power of communicating elec- 

 tric shocks of such violence, that the largest ani- 

 mals are stunned, and even destroyed by them. 

 The organ which possesses this truly formidable 

 power, consists of two large bundles of tendinous 

 fibres on each side, occupying the hinder regions 

 of the animal's body ; these are crossed at right 

 angles by other plates of the same kind, and thus 

 a wide and deep network of cells is formed, each 

 filled with a tremulous jelly; the whole organ 

 may be likened to a powerful voltaic battery. 

 Contact is not necessary for the exercise of its 

 powers ; it is said that shocks sufficient to kill 

 other fishes are communicated through water to a 

 distance of five or six yards. 



Genus An gu ill a. (Cuv.) 



The pectoral fins are well developed, though 

 small, in this genus ; the dorsal and anal are con- 



T 



