THE TORFEBO. 



147 



Our native species^, found mostly in winter, especially on 

 the low sandy shores of Cape Cod is Torpedo occidentalis. 

 Its batteries and nerves are substantially as in the Euro- 

 pean species. The electrical organs arc constructed on the 

 principle of a Voltaic pile, consisting of two series or layers 



Fig. \W.—Baja eglanteria, male. Mouth and gill-slits, jaws and teeth of Mylio 

 batis fremenvillii 



of six-sided cells, the space between the numerous fine 

 transverse plates in the cells filled with a trembling jelly- 

 like mass, each cell representing, so to speak, a Leyden jar. 

 There are about 470 cells in each battery, each provided 

 with nerves sent off from the fifth and eighth pairs of 

 nerves. The dorsal side of the apparatus is positively elec- 

 trical, the ventral side negatively so. The electrical cur- 

 rent passes from the dorsal to the ventral side. When the 



