164 BACKBONED ANIMALS. 
ing four filaments that twine about the sea-weed, prevent- 
ing them from washing ashore. 
Torpedoes ( 7orpedinida).—The fishes of this family 
are electricians, and are common on the New England 
coast. The electric ap- 
paratus (Fig. 201) is situ- 
ated between the head 
and the bases of the pec- 
toral fins, and is composed 
of numerous hexagonal 
membranous tubes placed 
side by side at right an- 
gles with the surface of 
the body, and so close to 
it that their ends are 
often visible above and 
below. The cells contain 
mucus, and are traversed 
by nerves that proceed 
from the eighth pair. So 
powerful is this battery 
that fishermen have been 
knocked over as if with 
Fic, 201.—The torpedo, with its ele- @0 ax€, the shocks also 
trical apparatus displayed. 4, bran- passing up the harpoon- 
chiz ; 6 brain; ¢, electric organ ; rope, or the knife used in 
& cranium; me, spinal cord; 2, . : 
nerves to the pectoral fins; x Z, cutting them. Allied are 
nerves going to the electric organ;  sting-rays ( Z7ygon), cow- 
Mi€YEs nosed rays, etc. The 
great devil-fish (Fig. 
202), that has curious prolongations or claspers at 
the head, attains a width of twenty-seven feet. They 
have been known to tow large vessels against the wind 
for long distances by fouling the anchor. The Japanese 
use the skeletons of rays in the imitation of tortoise- 
shell. 
