68 CHAPTERS ON THE NATURAL HISTORY 



si i-on teeth, sharp in front and flat behind, are imbedded in it, 

 in alveolar sockets, on each side. The saw is a most formidable 

 weapon of offense, by means of which the fish tears pieces of 

 flesh off the body of its victim, or rips open its abdomen to feed 

 on the protruding intestines. The teeth proper, with which the 

 mouth is armed, are extremely small and obtuse, and unsuitable 

 for inflicting wounds or seizing animals." 



In the world's ichthyfauna there are certainly five families 

 of Rays and Skates ; of these we have in our own waters some 

 very interesting representatives. For example, there is the fa- 

 mous Torpedo (Torpedo occidentalis) found quite abundantly 

 along our Atlantic coasts, probably as far south as Virginia. I 

 have made a drawing of this large Ray, and it is shown in Fig. 

 8 of this chapter. Physiologists have always taken great interest 

 in this remarkable fish, from the fact that it possesses a peculiar 

 organ upon either side of his body, between the pectoral fin and 

 the, head and gills. This organ is endowed with the power of 

 generating electricity, and is under the control of the animal. 

 An electric shock can be given voluntarily by the Torpedo, and it 

 uses this with great effectiveness, either as a means of defense, 

 or else to stun or kill the creatures on which it feeds. It is of 

 no economic importance whatever, and fishermen, when they 

 get them in their pound-nets, are very careful to let them alone, 

 as the electric shock, even from an average-sized Torpedo, may 

 knock a strong man down or completely paralyze his arms for 

 some little time. These Electric Rays (Torpedinidce) are also 

 very generally known as " Crampfish," as the oil extracted 

 from them is said to be a good remedy for rheumatism and 

 cramps. The oil is obtained from the livers, and it is said, also, 

 to make an admirable lamp oil. Large Torpedoes will yield as 

 much as three gallons of oil, but the average is about a gallon 

 and a half. They are captured with the harpoon. For one to 

 receive a shock from the Electric Ray, the contact must be at two 

 points, as the battery has all the characters of a manufactured 

 one, and the electricity all the known properties of that fluid 

 elsewhere. It will emit the spark; deflect the magnetic needle 

 and decompose chemical compounds. On the upper side of the 

 organ the electricity is positive, while upon the under side it is 

 found to be negative. Many other forms of Electric Rays are 

 found in different parts of the world, usually in tropical or sub- 

 tropical seas; some of the big species attain to a weight of 100 



