THE IMPENETRABLE SEA 



The electric rays (family Torpedinidae) are the most 

 curious and mysterious members of the ray group. In 

 common with the electric eel (Gymnotus) and the African 

 catfish [Malapterurus) it has the power of benumbing or 

 even killing its victims by delivering electric shocks. The 

 electric ray is represented by several genera, ranging over 

 the Mediterranean Sea and the Atlantic and Indian 

 Oceans, and is otherwise known as the cramp-fish, the 

 cramp ray, the numb-fish and the torpedo. 



Dr. Albert Giinther (1830-19 14), the German-born 

 zoologist who, as a naturalized British subject was the 

 keeper of the British Museum's zoological department for 

 twenty years, exhaustively investigated the strange power 

 possessed by these fishes. He wrote: "The fish gives the 

 electric shock voluntarily, when it is excited to do so in 

 self-defence, or intends to stun or kill its prey; but to 

 receive the shock the object must complete the galvanic 

 circuit by communicating with the fish at two distinct 

 points, either directly or through the medium of some 

 conducting body. If an insulated frog's leg touches the 

 fish, by the end of the nerve only, no muscular contrac- 

 tions ensue on the discharge of the battery, but a second 

 point of contact immediately produces them. It is said 

 that a painful sensation may be produced by a discharge 

 conveyed through the medium of a stream of water. 

 The electric currents created in these fishes exercise all 

 the known properties of electricity: they render the 

 needle magnetic, decompose chemical compounds, and 

 emit the spark." 



The torpedo is slow in its movements, quite unlike its 

 fellow ray the devil-fish, with its lightning-like lashing 

 movements. Without its power to use electricity as a 

 weapon it could not catch the swift and active fishes on 

 which it feeds. It has its mysterious power completely 

 under control. It does not always deliver the shock. If it is 

 not irritated or angered it may be touched and even 

 handled — contacting it at the two points which would in 



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