FISHES. 



15 



HEAD OF HAxMMER-SHARK. 



the figure of the head bearing no small re- 

 semblance to that of the 

 hammer used in caulking 

 ships. 



Besides the senses which 

 we have enumerated, which 

 Fishes possess in common 

 with other Vertebrata, 

 there is another faculty 

 with which some species 

 are endowed, quite peculiar 

 to this Class. It is the power 

 of communicating electric 

 shocks at will to other 

 creatures. The Fishes most 

 noted for this property 

 are the Torpedo, occasionally found on our own 

 shores, and the Gymiiotus, or Electric Eel, of 

 South America. The electric organs consist of 

 numerous six-sided cells, at first sight apparently 

 composed of a clear trembling jelly, but really 

 containing a great number of delicate membran- 

 ous plates, separated from each other by a glairy 

 fluid. In the Torpedo the prisms are placed ver- 

 tically, and form two masses, one on each side of 

 the head ; in th^ Gymnotus, they are horizontal, 

 and form four such organs, one pair on each side 

 of the body. 



The efifects of fear in changing the colour of 

 the human hair are w^ell authenticateid ; from the 

 statement of a writer in the " New Sporting Maga- 

 zine," it w^ould appear that Fishes may be subject 

 to similar phenomena. *' Into a pool of about 

 four acres, partially surrounded with trees and 

 terminating a range of other pools above, through 



