Electric Eel. Gymnotus Electricus. 475 



ELECTRIC EEL. GYMNOTUS ELECTRICUS. 



Frequents marshes and fresh waters in Brazil and Tropical America. Be- 

 numbs domestic animals ; 5 to 6 feet long. Structure of electric organs. 

 Discharges exhausted by repetition, thus the eels can be killed. Bridging 

 of streams ; wearing tall rubber boots and clothes. 



The electric eel of marshes and fresh waters in Brazil, Guiana 

 and other tropical American countries, the most powerful of 

 electric fishes, is especially liable to come in contact with domestic 

 animals which it benumbs or kills by its discharges. It attains 

 to a length of 5 or 6 feet and is distinguished by the entire ab- 

 sence of caudal and dorsal fins, and by the extraordinary develop- 

 ment of the anal fin, which extends as a long fringe along the 

 lower aspect of the body from throat to tail. Its electric ap- 

 paratus consists of two pairs of natural batteries, extended from 

 before backward, directly under the skin, one in the line of the 

 anal fin, and the other in the back of the tail. These are divided 

 up by fine septa, arranged vertically and transversely into a 

 myriad of cells, each -^ inch in diameter, and filled with a 

 gelatinoid cellular structure. These batteries are most abundantly 

 supplied with over 200 trunks from the anterior branches of the 

 spinal nerves. In their course the electric nerves supply twigs 

 also to the skin and muscles. The nerves furnished to the elec- 

 tric organs are much larger than those supplied to organs of 

 motion, sensation or special sense. 



The discharges are under the control of the fish, and by fre- 

 quent repetition the power of the batteries is temporarily exhaust- 

 ed so that the eels can be caught by harpoons and de.stroyed. 

 The power of the shock further bears a direct relation to the size 

 and vigor of the eel, in this agreeing with the potency of the 

 snake venom. In a well developed, vigorous gymnotus, a favor- 

 ably directed shock is capable of killing the largest animal. In 

 the fording of infested streams and marshes large numbers of 

 horses are destroyed, and it has been found needful to change the 

 course of highways to avoid the danger. Bridging of streams 

 would be an obvious precaution, also the use of rubber boots or 

 bandages by those that must enter the water. 



The Indians who eat the eels, take the precaution to drive 

 horses into the infested pools or rivers, on which the fish may 



