116 SIZE OF THE GYMITOTUa. 



they have lost.* The mules and horses appear less fright- 

 ened; their manes are no longer bristled, and their eyes 

 express less dread. The gymnoti approach timidly the edge 

 of the marsh, where they are taken by means of small 

 harpoons fastened to long cords. When the cords are very 

 dry the Indians feel no shock in raising the fish into the 

 air. In a few minutes we had five large eels, most of which 

 were but slightly wounded. Some others were taken, by 

 the same means, towards evening. 



The temperature of the waters in which the gymnoti 

 habitually Hve, is from 26 to 27. Their electric force 

 diminishes it is said, in colder waters ; and it is remarkable 

 that, in general, animals endowed with electromotive organs, 

 the effects of which are sensible to man, are not found in 

 the air, but in a fluid that is a conductor of electricity. The 

 gymnotus is the largest of electrical fishes. I measured 

 some that were from five feet to five feet three inches long ; 

 and the Indians assert that they have seen them still larger. 

 We found that a fish of three feet ten inches long weighed 

 twelve pounds. The transverse diameter of the body, with- 

 out reckoning the anal fin, which is elongated in the form 

 of a keel, was three inches and a half. The gymnoti of the 

 Cano de Bera are of a fine olive-green. The under part of 

 the head is yellow mingled with red. Two rows of small 

 yellow spots are placed symmetrically along the back, from 

 the head to the end of the tail. Every spot contains an 

 excretory aperture. In consequence, the skin of the animal 

 is constantly covered with a mucous matter, which, as Volta 

 has proved, conducts electricity twenty or thirty times 

 better than pure water. It is in general somewhat remark- 

 able, that no electric fish yet discovered in the different 

 parts of the world, is covered with scales.f 



* The Indiana assured us that when the horses are made to run two 

 days successively into the same pool, none are killed the secoud day. 

 See, on the fishing for gymnoti, " Views of Nature." (Bohn's ed., p. 18.) 



f We yet know with certainty only seven electrir fishes ; Torpedo 

 narke, Risso, T. unimaculata, T. marmorata, T. gaivanii, Silurus elec- 

 tricus, Tetraodon electricus, Gymnotus electricus. It appears uncertain 

 whether the Trichiurus indicus has electrical properties or not. (See 

 Cuvier's Regne Animal, vol. ii.) But the genus Torpedo, very different 

 from that of the rays properly so called, has numerous species in the 

 equatorial seas; and it is probable that there exist several gyu.noti 



