538 



THE TORPEDO. 



mouth is ou the under surface of the head, and is furnished with a 

 crushing apparatus made exactly ou the principle of the stone-crushing 

 machines of the present day. 



In the true Rays, or Raidse, the fore-part of the body is flattened 

 and formed into a disc-like shape by the conjunction of the breast-fins 

 with the iuout. 



Our first example of tl^e Rays is the Torpedo, a fish long celebrated 

 for its power of emitting at will electrical shocks of considerable 

 intensity. In consequence of this property it is sometimes called 

 the Cramp-fish, Cramp Ray, Electric Ray, or Numb-fish. 



The object of this strange power seems to be twofold — namely, to de- 

 feud itself from the attacks of foes, and to benumb the swift and active 

 • » fish on which it 



feeds, and which 

 its slow move- 

 ments would not 

 permit it to catch 

 in fair chase. It 

 does not always 

 deliver the elec- 

 tric shock when 

 touched, though 

 it is generally 

 rather prodigal 

 of exercising its 

 potent though in- 

 visible arms, but 



The Eyed Torpedo {Torpedo oculata). 



will allow itself to be touched, and even handled, without inflicting a 

 shock. But if the creature be continually annoyed, the shock is sure 

 to come at last, and in such cases with double violence. It has been 

 observed, moreover, that the fish depresses its eyes just before giving 

 its shock. 



That the stroke of the Torpedo is veritable electricity is a fact which 

 was once much disputed, but is now conclusively proved by a host of 

 experiments. Needles have been magnetized by it just as if the shock 

 had been that of a galvanic battery ; the electrometer showed decided 

 proofs of the nature of the fluid that had been sent through it ; and 

 even the electric spark has been obtained from the Torpedo— very 

 small, it is true, but still recognizably apparent. It is rather curious 

 that in the course of the experiments it was discovered that the upper 

 surface of the Torpedo corresponded with the copper plate of a battery, 

 and the lower surface with the zinc plate. 



The structure of the electrical organ is far too complex to be fully 

 described in this woik, as it would require at least forty or fifty pages 



