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FISHES.
15

the figure of the head bearing no small re-
HEAD OF HAMMER-SHARK.
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 Gymnotus, 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 membranous plates, separated from each other by a glairy fluid. In the Torpedo the prisms are placed vertically, and form two masses, one on each side of the head; in the Gymnotus, they are horizontal, and form four such organs, one pair on each side of the body.

The effects of fear in changing the colour of the human hair are well authenticated; from the statement of a writer in the “New Sporting Magazine,” it would 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