Tanks No. 10, 12 and 24. 
71 
giving electric shocks. Its slimy body is almost circular in shape and 
contains two large "electric organs'’. Each of these consists of several 
hundreds of hexagonal columns of a gelatinous substance, which are supplied 
by a number of branching nerves with curious terminations. These organs 
give rise to a short and strong electric current when the animal is irritated., 
its upper surface being positive, the under surface negative; to experience 
the whole shock, the fish must be touched at the same time on both sides. 
Fig. 122 . Raja punctata, V 3 nat. size. Tank 12. 
Fig. 123. Trygon violaceus, Y 5 nat. size. Tank 10. 
The shock is not so strong as that of the South American Electric Eel, but 
is still sufficiently painful in an adult Ray. The shocks become feeblest 
when repeated frequently. The electric organ is used both defensively 
by the Torpedo and also for killing or at least numbing its prey. A young 
specimen is always kept in a small open tank, in front of tank No. 10, 
for visitors to try the electric power of the fish. — The Electric Ray is 
one of the most common fishes of the Bay of Naples and in spite of its 
poor flesh is often brought to market. They bring forth living young 
ones, 8—14 at a time. The very young embryos have still the shape of 
sharks and only later on become flattened and disk-shaped. 
Of the other Rays the Skate, Raja (Fig. 122), and the Sting Ray, 
Trygon (Fig. 123), are found in the Aquarium, but the latter more rarely. 
The former (tanks 12 and 24) have a lozenge-shaped body of brown 
colour, and a tail armed with a number of small spines. They lay their 
eggs in capsules, which are cast ashore on the beach of the North Sea and 
