Evening star., 1930-06-17
National Museum Receives
Danish Ships Data on Some
of Worlds Queerest Life.
FISH USE LIGHTS
IN SEAS DARKNESS
Some Swallow Food Three Times
Their Own Weight, British
Zoologist Declares.
BY THOMAS r. HENRY.

DA AnONAAS NJ nENhEs
In the dark depths of the North At
lantic dwell some of the worlds queerest
creatures.
DR.. Austin H. Clark of the National
Museum has just received the scientific
reports on the great mass of material
garnered from the ocean deeps by the
Danish ship Dana In 1922, which was
distributed to geological laboratories in
several countries for study
Weirdest of all are the ceratoids, de-
scrloed by G.. Tate Regan, zoologist OF
the British Museum. These are fishes
which live in the deeper ocean, provided
with luminous bulbs by which they
probably communicate with each other,
see their way about and possibly attract
their prey. DR.. Regan found three spe-
cleS In which the males are all dwarfs
attached to and growing as part of the
bodies of females four to six times their
own size, each an individual animal, vet
nVlng as one animal. 1t is a condi-
tlon hitherto unknown to science.
Apparently, says the report, both are
born as individuals. Early in life the
male bites loose flap of skin of the
female, usually near the head, and
holds 1t tightly between his lips until
the flap and his tongue grow together.
Thenceforth the male is entirely para
site on the female, stops growing and
receives all his sustenance through the
arterial system connected with his part
ner by way Of the graft. This graft
between the two fishes is almost as per-
feet as is produced artif1cially with
trees.
Outer Skin Continuous.
"The outer skin of the two fishes"
says Regan, "is continuous, so that u
is impossible to say exactly where one
begins and the other ends. Microscopic
examination of sections of strip of the
tissue connecting the male and female
ceratiaS shows that the male and female
are completely blended, the highly vas
cular f1brous tissue Of the outgrowths
OF the male being continuous with the
skin of the female. In both the general
direction of the fibers and of the small
blood vessels Is longitudinal-that is
Leading from one fish to the other-and
1t seems almost certain that the blood
vessels OF the two fishes are continuous
and that the male is nourished by the
female. The male has a well developed
heart and gtlls, so that 1t does not de-
pend on the blood of the female for
| oxygen. but only for nutritive materials.
The small, capillary-like vessels of the
tissue connecting the two fishes receive
arterlal blood from both and the veins
from them run 10 both fishes.
EThe reason why the ceratoids, alone
among vertebrates have males of this
kind Is evident. They are necessarily
Few in number in comparison with this
more active fishes on which they prey
and they lead a solitary life, fioatina
about in the darkness of the middle
depths OF the ocean. Under such cir
cumstances 1t would be very dificult
Tor mature fish to find a mate, but
tnlS dlfnculty appears. to have been got.
ten over to some extent by the males
after they are Matched and when they
are relatively numerous by attaching
themselves to the females If they are
fortunate enough to meet them, and
remaining attached throughout life.
In all probability the males are In
capable Of free development and the
great majority of them fail to find A
female and perish Another suggested
possibility is that the post-larval FISH
that find and become attached to fe-
males develop into males and those that
do not into females"
Living In a region of almost complete
darkness, these fishes are obliged TO
furnish their own light This is pro.
vided by transparent bulb into which
is secreted luminous substance of
some kind. In some species this bulb
is attached to cord growing out of the
head four or five times the length of
the f1sh and which 1t can control freely
In the water. In one species the light
cord was attached to a protruding bone
and with the bulb on the end was a
bone hook. "It might we'll be termed"
ne said, "a complete angler" The the
ory is that the light serves as q bait for
other fishes, who, when they dart at 10
are caught on the hook and drawn 10
the mouth by means of the cord.
Some fishes of this family found tn
the Dana collection have distensible
jaws and stomachS, so that they can
swallow fishes three times their oya,
length and many times as heavy. THY
Is necessary provision, because tn:
teeth are so arranged that once q lar.%t
fish is caught in the mouth it is i$-
possible to release it and the ceratt@I
must swallow it, whether or no. Az
other variety was found with teeth oil
the top of its head.
The Dana material. DIR. Clark sa3R
Is proving one of the greatest contribu+
lions ever made to the knowledge of life
forms In the ocean deeps, where hiphlv
specialized equipment is necessary for
any creature to live. and shows adapt.
ability of organisms to their environ.
ment In extreme forms.