422 ZOOLOGY. 
two inches) long. Raja eglanteria Lacepéde (Fig. 391} 
ranges from Cape Cod to the Caribbean Sea. The smaller 
figures in Fig. 391 represent respectively the mouth and 
gill-slits, and the jaws of Myliobatis fremenvillii Lesueur. 
In the torpedo the body is somewhat oval and rounded. 
Fig. 392 represents Torpedo marmoratus, of the Mediter-: 
ranean Sea. 
Our native species, found mostly in winter, especially 
on the low sandy 
shores of Cape Cod, 
is Zorpedo, occiden- 
talis Storer. Its bat- 
teries and nerves are 
substantially as in 
the European spe- 
cies. The electrical 
organs are construct- 
ed on the principle. 
of a Voltaic pile, 
consisting of two 
series or layers of 
hexagonal cells, the 
space between the 
numerous fine trans- 
verse plates in the 
cells filled with a 
trembling jelly-like 
mass, each cell 
representing, so to 
ak ad eae Mocha fomeneui's. ©” Speake & Leyden Jar, 
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 electrical, the ventral side nega- 
tively so. The electrical current passes from the dorsal to 
the ventral side. When the electrical ray is disturbed by the 
touch of any object, the impression is conveyed by the sen- 
sory nerves to the brain, exciting there an act of the will. 
which is conveyed along the electric nerves to the batteries,. 
