Middletown transcript., 1892-12-15
LUMINOUS FISHES.
IA SEA ANIMAL THAT CARRIES ]
POWERFUL sEARCHLTGHT.
Creatures which Inhabit the Deep
Are Endowed by Nature with the
Means of Finding Their Way
About in the Dark. How
They Use Their Ocean u
Lamps.


Government biological laboratories
at Woods Holl and elsewhere along the.
coast have been very busy studying
fishes and other creatures that live IN
the sea. Sculpins engaged mucn OF
their attention. One species. known as
the .'.sea robin" has pectoral inns re-
sembling hands. They are discovered
TO be actually organs Of touch. and the
fish walks on them over the bottom.
feeling for its food as it goes. ne slime
of these ..toad fishes" as iis}SFinen cal
the family, is secreted'by rows OF glands.
All fishes have slime secreting organs.
In those which live in the depths OF the
ocean, where is inky darkness. the slime
glands are so modified as TO lie trans
formed into phosphorescent spots. the
slime being luminous. Thus the t1nny
dweller in the dark, unfathoined caves
of ocean carries light about with 1t to
see by.
One species recently discovered is
called the midshipman. It has luminous
disks along its sides and belly. on its
head and at the base of its back fin. In
fact it is as profusely decorated with
lights as a midshipman is with but
tons-hence the name. Each OF these
luminous disks is complete bullseye
lantern on small scale. having lens
for concentrating the rays and IL reflect
or behind it composed of siliceous splc-
ules. The light comes from layer of
phosphorescent cells between the re-
fector and the lens.
No other known fish has such an
equipment for Illuminating purposes.
There are good many snecies which
have refectors without lenses, while
others have lenses without refectors to
brighten the glow of their luminous
spots. But the midshipman is the only
marine dweller thus far discovered
which possesses both reflector and lens.
1t is veritable animated assemblase Of
lanterns. There is a wide variation
among deep sea fishes as to their manner
of carrying their lights. One kind has
barbel hanging to its chin, on he end
of which is suspended what might be
likened to an electric bulb, while an
other sort upholds its light over its
head on the highest point of its back
fin. In certain species it is believed that
the luminous mucus from the modified
slime glands keeps running continually
down the sides of the fish. rendering the
whole animal brilliant
1t is considered likely that these Ian
tern bearing fishes of the depths, which
are chiefly head and mouth and highly
carnivorous, are able to turn their lights
on or off at will. This seems probable
on account of the nerves and blood YES
sells communicating with the slime
glands, which have no other apparent
purpose. Thus the nidshipnlan may
have his power. on approach Of an ene-
my, to suddenly extinguish his torches;
whereas, when seeking prey. ne can
throw out search lights and brilliantly
illuminate his neighborhood. This phos-
phorescent light is similar to that of
freflies, which Professor Langley. of
the Smithsonian institution, declares to
be the most economical aid perfect of
all known lights, giving the greatest
illumination with the least waste and
without perceptible heat. 1t would be
of enormous value to mankind if the
secret of this light which the fishes use
for their torchlight professions under
the ocean could be discovered Unfor-
tunately the nature of it is wholly a
mystery, all efforts to find it ont having
thus far proved unavailing.
Sharks have lately been affortling con-
tributions to science. The ,!iolosists
have been vivisecting them for the liur-
pose of finding out about the functions
of the ear, which in fishes is made to
some extent on the same pattern us in
man. The fact has been known for
some time that the ear is not merely an
organ of hearing. 1t has.to do with the
sense of equilibrium. Light has been
thrown on this matter by removing por-
tions of the auditory apparatus Of sharks.
which are thus rendered unable to main
tain their balance in the water. The
part on which this faculty seems to de-
pend is the .slabyrinth," and the same
effect is produced by cutting the nerves
communicating with it.
Science is paying much attention now
to the observation of marine forms, be-
cause the animals that dwell in the
ocean are the Oldest in existence. Ac-
cording to the theory of evolution human
beings, as well as all other land animals,
are descended from them. It is difficult
to realize that our ancestors in the dis
tant past lived under water, and that
they made their first vertebrate appear
ance as seaworlns, but the scientific
men insist l.iat such is the fact. Sharks
are selected for certain experiments be-
cause they are the most ancient of all
surviving types of Washington
Cor. New York World.