Evening star., 1952-03-21
Gun I Totin' Worms
Thot Shoot Their Prey
y. Of Virginia Scientist Reports
On Low Sc0le Of Life Studies
By Thomos 4. Henry

There are gun-toting worms that
shoot their prey.
Such is the contention of DR.. william
working with some Of the loWliest forms
Of animal life.
The particular arms bearing worms
are members Of the flatworm family.
not true worms at all but closely related
to the nematodes which prey on roots.
These are minute. soft bodied, leaf.
shaped creatures found in still, fresh
water.
In the same waters dwell hydras.
closely related to jellyfish. Around their
mouths are stinging organs, so-called
nematocysts. with which they paralyze
their prey minute water organisms
before engulfing them. These are much
the same organs as those found In the
sea nettles. which are capable of in
fiicting painful stings to bathers.
Now. DR.. Kepner says in letter to
Science. oficial organ OF the American
Association for the Advancement Of
Science. the little f1atworms pursue the
jeliyfishes partly for the reason, it ap-
pears. Of securing these nematbcysts
both to paralyze the minute creatures
they themselves use for food and to de-
stroy their own enemies. Among these
are closely related fresh-water creatures,
the SO-called arrow worms. Ordinarily
the arrow worms feed on the fiatworms.
Have Turned the Tables.
DR.. Kepner says he has found evidence
Of the reverse -flatworms armed with
the stingers Of the jellyfsh feeding
freely on the arrow worms. There is q
strong implication that they have turned
the tables by securing gums"
Dr. Kepner first described this phe-
nomenon in technical journal some
years ago and his communication to Sci
ence is in reply to criticisms of his OBJ
ServationS by other biologists.
1T was not our argument" he says.
"that these flatworms need nematocysts
to capture prey. They obviously do not
need these guns ordinarily to obtain food
any more than soldier ordinarily needs
his gun to capture food"
But he continues, I'VE have actually
recorded two examples in which micro
stomum (fiatworm) has immobilized q
stenoStomum (arrow worm) by means OF
nematocyst wounds and then ingested
the wounded prey.
I'm the face Of this evidence the bur-
den Of proof seems to Lie on the shoul-
ders Of those who deny that the micro
stomum sometimes uses alien guns to
capture food. just as soldier may some-
times use captured enemy gun to cap
ture the enemy's cali"
Very far down in the scale Of life ex-
kAva Il la - &1~~ ~.
ner finds In studies Of the microscopic,
one-celled animal. the amoeba, which is
about the simplest form of animal. Some
OF its hunting behavior seems to border
on intelligence. or foresight.
Factor in Their Conduct.
"Amoebas," DR.. Kepner says, "circum-
vent contingencies as they are presented
and the future constitutes q factor in
their conduct as it does In that of men"
Observation shows, he says, two ways
In which these micro-organisms obtain
food, circumfluence and decentralization.
In the first. he says. food is engulfed
by the amoeba's body flowing intimately
about 1t. as drop Of oil flows about q
bit Of sand. In decentralization the amoe-
ba surrounds motile object Of food in
wide embrace, but at no time In con-
tact with the food.
In my recent studies have observed
that some moving objects Of food present
q peculiar feature. They move at uni
form rate, like marble down q slight
incline. Their projected paths are pre-
dictable. Amoebas INCEST such food OBJ
jects. diatoms and algae, by circumfiu-
ence, just as o man lays hold Of rolling
marble directly. without being concerned
about probable lines Of escape"
On the other hand, he holds. circum-
vallation II used for capture of moving
prey that present possibility Of escape.
Thus the amoeba Ia able to trap an un-
practicable moving object however it
may change It's path. And 1t must know
something Of the habits Of its prey be-
fore deciding which method to use.