The News-Herald. [volume] (Hillsboro, Highland Co., Ohio) 1886-1973, 1914-08-13
EATS ITS OWN TAIL
Queer Feast Of the Tadpole Be-
fore 1t Becomes a Frog.
EVOLUTION OF A P0LLYW0G.
Changes That Mark the Transition Of
This Curious Creature From an
Aquatic to an Air Breathing Animal.
How u Differs From the Toad

How 1t Differs From the Toad
There is no more interesting creature
on earth than a polywOg. or tadpole
for it is fish in the process of trans
formation into land animal The
whole process can be watched IL you
put few polywogs in milk bottle
or jar full of water with some water
plants.
In any of the ponds In the parks in
the cities or in the pools In the suburbs
in the proper season frog spawn can
be found 1t floats on the water like
masses of sago pudding A handful
Of this will furnish entertainment for
several weeks and will at the same
time give a lesson in evolution.
The spawn that floats on the ponds
Is the eggs Of frogs. They lay it in
the first warm days of spring. spread
ing it where the rays of the sun will
warm it. Each egg contains a yolk.
which Is the food Of the living germ
within, and Is coated with black. prob
ably to attract as much heat as pos.
sible and at the same time to protect
the germ from the penetrating ultra
violet rays of the light, which would
destroy it. The black yolk is In the
center of mass of transparent jelly
which is there as protective covering
If small mass of spawn be placed
in a jar of water and watched daily
with an ordinary magnifying glass the
black yolk of each egg will presently
ha H. zko
Gradually this takes the form of a tiny
pollywog. which soon begins to wrig
gle. After few days these little black
bodies wriggle out through the trans
parent jelly and attach themselves to
bits of green sticks or weeds, which
should be placed in the jar with them
For some time they remain attached
to such supports by sucker, waiting
for the opening of the mouth. AS yet
there are no visible eyes, but small
stumps on each side of the head will
be noticed. These are the gills The
whole skin If examined with lens
will be found to be covered with a sort
of animated velvet pile. for its cOmpo
nent threads are in constant motion
ter to carry on the work of breathing
and little later these movements will
be strong enough to bear the body
slowly along. so that locomoton at this
stage is like that of the iowliest of liv
ing creatures. the protozoa.
When the mouth appears the inside
of the great fleshy lips and the jaws
will hn TO ha MT
of horny teeth numbering many hun
dreds. The gills will also have grown
considerably. These. however. soon
give place to internal gills, and the
water taken at the mouth passes out
again by small funnel on the right
side of the head. This fishlike stage
disappears with the appearance of the
forelegs.
The hind legs next appear, and as
these develop the mouth is closed for
alterations No food can be taken. and
during this enforced fast the tadpole
supports life by consuming its tail.
This is slowly digested by process
not yet clearly understood BY the
time this strange feast has ended the
peared-the tadpole has become frog
and leaves the water for the land As
tadpole it fed by rasping off vegeta
BILE and animal matter with its teeth:
as frog it feeds by jerking food into
its capacious mouth by the flick Of
very sticky tongue.
Nevis and toads in their pollywog
stage can scarcely be told from frogs
but nevis remain water animals, wear
ing tails, all their life. Some of then
retain their gills also, but most of then
develop lungs and have to come t. tn,
surface to breathe. There are few spe
cies which have neither gills nor lungs
and therefore do not breathe al all
their blood being oXidiZpd by the skin
alone.
Adult frogs spend most of their nine
In the water. bUt they must rome III
the surface to breathe roads once
they leave the water do not return to
it.-New York World
Insurance and Assurance.