Evening star., 1954-04-26
Tiny Seq Creatures
Flash Rainbow Light
Animals ore Found to Be
As Elusive os Moonlight

Animals are Found to Be
As Elusive as Moonlight
By Thomas R. Henry
There are MINDLESS nights when
Caribbean waters seem like great fielos
of green-flaShing firefies.
These lumineScent animals are the
most delicate creatures on earth, and
also among the most abundant and
least known. They are the ctenophores,
or NEUTRALITY-SUSPICIOUS. which ap-
arently once started out to be worms
but stopped on the way. Specifically
they are little more than animate bags
of water with skins thinner than the
most delicate tissue paper.
The curious light-making mechanism
was described before the National
Academy of Sciences here by Drs. E.
Newton Harvey and Joseph j. Chang
of Princeton University. The carnivo-
rous water bags. they found. have 'lu-
minous tissue" which acts in fashion
quite similar to the muscles of higher
animals, responds to stimulus of elec-
tricity or touch according to its in
tenSity, and shows a measurable rate
of fatigue.
They worked particularly with the
New World mnemiopSiS one amber
green species of which sometimes on
calm summer days covers completely
thousands of square yards of sea-like
a raft formed of millions of millions Of
VI individuals floating just below the sur
face where they are so thick that their
bodies touch each other.
ilpa af e.. hi NJ
phore is like fragment of moonlight
on the sea. 1t is so fragile that the
slightest current Of water in its neigh
borhooo, such as might be caused by
the oar of a passing boat, is sufficient
to tear it to bits. It is about as elusive
as that same moonlight. When gently
grasped the jelly-like substance slides
through the fingers. Taken in a net
and placed in tub Of salt water, it
completely vanishes on the way from
boat to laboratory.
Exist in Abundance.
Yet they exist in imagination stag
gering abundance. Ordinarily they live
at considerable depths in the zone Of
absolute calm where all wave movement
ceases. The great hordes rise to the
surface only on nights when the surface
of the ocean is like q sheet of glass.
They are among the lovelieSt of all sea
creatures. The delicacy Of their color
ing is that Of spring arbutus or
anemone.
Their presence is noted chiefly from
the brilliant flashing Of rainbow colors
as they pass few inches below the
surface The majority are pear-shaped.
These range from inch to nearly a
foot in diameter. Giant of the race,
however, is Venus girdle, best known
in the Mediterranean but found in all
sub-tropical seas and sometimes swept
as far north as the coast OF New
England. It Is an undulating, irri-
descent ribbon as much as five feet long
and two inches wide.
The animal with which the Princeton
scientists carried out their experiments
is ball-shaped with diameter OF about
four inches. There are many luminous
organiSms-flSh, worms, molluSkS-on
the surface of summer seas. Among the
continuously flashing lights of different
colors there will be an occasional green
flash considerably more vivid than any
of the others-probably big mnemi-
opSis.
The ctenophores are most varied in
the Bay of Naples where ID species
have been identified and where most
of the little information available about
them has been obtained. There are IA
species now known from the Carib-
bean. In absolute numbers, however.
the fragile creatures are most abun-
dant in North Atlantic and sub-Arctic
where, because of the rougher seas.
they seldom are seen.
Pincer-Like Tentacles.
Each living water bag has slit
like mouth on top and what apparently
is a sense organ of some kind on the
bottom. Its minute, struggling prey are
seized in two pincer-like tentacles and
pushed into the mouth. They are di-
gested quickly by the juices in the
water sac in which float about what
ever vital organs the ctenophore has.
The ctenophores are by no means
merely aberrant jelly fish which they
resemble only in the extreme tenuous-
ness of their bodies. They have no UNI
brellas and no singing cells. They are
believed to be somewhat higher ami
mails in the evolutionary scale with at
least the beginnings of nervous sys-
tenn. Certain cells lining the water sac
appear to be specialized in the direc-
ton of nerve cells and they send out
filaments which constitute kind Of
network through the fluid. This sys-
tenn presumably activates the comb
like protruberances on the body by
means of which they swim.
The function of the strange green
luminescence is unknown. It would
seem of questionable value in attract
ing prey and it is difficult to imagine
that these most fragile, evanescent Of
earths creatures have any sort OF
love lite Still Matchmaking constitutes
notable part Of their activities apd
appears to be served by q quite COM
plicated organization.
1.-THE response" Drs. Harvey and
Chang have reported to the Acad-
emy, "is remarkably like that Of
muscle. At 81 to 80 degrees centigrade
with a small piece of tissue single
flash appears having a latent period
that varies considerably, a half-rise
time of 35 milliseconds thousandths
of a second). a maximum peak time Of
so milliseconds. 1t has a nine-tenths
decay time of ia milliseconds.
Lowering the temperature prolongs
the time course Of single flashes and
raising it has the opposite effect Light
intensity increases as strength Of the
stimulus increases. Fatigue appears