Arizona republican., 1893-02-04

Endowed by Nature with the Means of
Finding Their Way About in the Dark.
How They Use Their Ocean Lamps.
Government biological laboratories
ut Woods Holl and elsewhere along the
coast have been very busy studying
fishes and other creatures that live in
the sea. Sculpins engaged much Of
heir attention. One species, known as
the "sea robin" has pectoral fins re-
~mbling hands, They are discovered
10 be actually organs of touch, and the
Rsh walks on them over the bottom,
feeling for its food as it goes. The slime
Of these "toad fishes" as fishermen call
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 be trans
formed into phosphorescent spots, the
slime being luminous. Thus the finny
dweller in the dark, unfathomed caves
of ocean carries a light about with it to
see by,
One species recently discovered is
called the midshipman. 1t has luminous
disks along its sides and belly, on it's
head and at the base of its back fin. In
fact it is rs profusely decorated with
lights as a midshipman is with but
Conscience the name. Each of these
luminous disks is a complete bullseye
lantern on a small scale, having a lens
for concentrating the rays and reflect
or behind it composed of siliceous spic-
uies. 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 a good many species which
have reflectors without lenses, while
others have lenses without reflectors 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.
II is a veritable animated assemblage of
hnterns. There is wide variation
among deep sea fishes as to their manner
Of carrying their lights. One kind has
q. barbel hanging to its chin, on the end
Of which is suspended what might be
hkened to an electric bulb, while an
sther sort upholds its light over its
Mead ON the highest point of its back
6p. In certain species it is believed that
the luminous mucus from the modified
SHINE 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 midshipman may
have his power, on approach Of an enc
my, to suddenly extinguish his torches;
whereas, when seeking prey, he can
throw out search lights and brilliantly
illuminate his neighborhood. This phos-
phorescent light is similar to that Of
6refies, which Professor Langley, of
the Smithsonian institution, declares to
be the most economical and 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
mystery, all efforts to find it out having
thus far proved unavailing.
Sharks have lately been affording con-
tributions to science. The biologists
have been vivisecting them for the pur-
pose of finding out about the functions
of the ear, which in fishes is made to
some extent on the same pattern as 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 Labyrinth" 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-
eording to the theory of evolution human
beings, as well as all other land animals,
are descended from them. 1t 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 seaworms, but the scientific
men insist that such is the fact. Sharks
are selected for certain experiments be-
cause they are the most ancient of all
surviving types of fishes Washington
Cor. New York World.
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