THE THORNBACK SKATE. 461 
The object of this strange power seems to be twofold, namely, to defend 
itself from the attacks of foes, and to benumb the swift and active fish on 
which it feeds, and which its slow movements would not permit it to catch 
in fair chase. . It does not always deliver the electric shock when touched, 
though it is generally rather prodigal of exercising its potent though invisible 
arms, but will allow itself to be touched, and even hanuled, without inflicting 
a shock. But if the creature be continually annoyed, the shock is sure to 
come at last, and in such cases with double violence. It has been observed, 
moreover, that the fish depresses its eyes just before giving its shock. 
That the stroke of the Torpedo is veritable electricity is a fact which was 
once much disputed, but is now conclusively proved bya host of experiments. 
Needles have been magnetized by it just as if the shock had been that of a 
galvanic battery, the electrometer showed decided proofs of the nature of 
the fluid that had been sent through it, and even the electric spark has been 
obtained from the Torpedo-—very small, it is true, but still recognizably 
apparent. It is rather curious, that in the course of the experiments it was 
discovered that the upper surface of the Torpedo corresponded with the 
copper plate of a battery, and the lower surface with the zinc plate. 
The structure of the electrical organ is far too complex to be fully de- 
scribed in this work, as it would require at least forty or fifty pages, and a 
large number of illustrations. Any of my readers who would like to examine 
it in detail will find ample information in an article on the subject by Dr. 
Coldstream, in the “ Cyclopedia of Anatomy and Physiology,” and from a 
valuable series of wax models in the museum of the College of Surgeons. 
This fish is found in the Mediterranean and-the In dian and Pacific Oceans, 
and occasionally off the Cape, and has now and then been captured on our 
coasts. Happily, the oer 
Torpedo does not attain : = : 
a very great size, one of 
the largest specimens 
being about four feet 
long, and weighing sixty 
or seventy pounds. 
THE Rays are well 
represented in England 
by several large and 
curious species. One of 
the commonest exam- 
ples is the THORNBACK 
SKATE, or Ray, so called 
from the lurge number 
of thorny projections 
which are scattered over 
its back, and especially 
along the spine. 
The Thornback is one THORNBACK SKATE.—(Raza clavata.) 
of our common Rays, ‘ 
and is taken plentifully on the shores of England, Scotland, and Ireland. 
As is the case with many of the same genus, the flesh is considered rather 
good, and is eaten both when fresh and when salted for consumption during 
stormy weather. Autumn and winter are the best seasons for procuring this 
fish, as the flesh is then firm and white, while during the rest of the year 
it is rather liable to become flabby. Thornbacks taken in November are 
thought to be the best. 
This species, like the rest of the Rays, feeds on crustacea, flat-fish, and 
