The daily national Whig. [volume] (Washington, D.C.) 1847-1849, 1847-11-01

The name of this class Is derived from peculiar
titles in these animals which shall Immediately
explain. You have examples of Medilsa In these
diagrams. They have many relations to the polypi,
but there is one general characteristic which will
strike you when il is mentioned The meduse are
all Neutrality-suspicious. of the soil They have no
point OF attachment They cannot fix themselves
upon the soil. They have no means by which they
can become attached and all have the mouth down
ward, while all polyps have the mouth upward In
the very position of the animals in the surrounding
clement we have one great difference, which is as
constant us the most intricate peculiarly of their
structure. There are few moving animals in which
the difference Of internal structure between them and
thepoypi is by no means very apparent: they have
not one organ more than we have seen among the
polyp', only little complication of the same organs
In the jelly-hsh we have broad disc, and in that
wide cavity, with mouth in the centre from
which several, sometimes numerous, appendagcs
hang down. This is the simplest structure of the
medusae There the mass Of the animals constan-
tly gelatnous. The bodies of this class are excee
dinghy soft so much so, that when taken out of the
water they almost wholly decompose and disappear.
They contain SO very little substance that a cart
load Of them would not, If dried by evaporation,
leave ounce Of hard substance-of dried men,
brane. A single leaf Of paper would contain as
much solid matter full cartoad Of these ami
mails when dried They so liquid that they arc
transparent--so much SO that they are frequently
not seen in the water, and would not be perceived
ut all II it were not for their beautiful coors. They
have indeed the most beautiful, delicate coors of
the lower animals. Again, great number of them
are phosphorescent. In the night they appear like
brilliant lights, and to some Of them is owing the
phosphorescence OF the sea mot to them solely
for the phosphorescence of the sea is produced by
great number of animals. Very numerous and dill
erent species of animals produce that peculiar
beautiful light that illumes the during the night
Some of these animals belong to the articulated
types, others TO the meduse some are polyps and
perhaps the light is in part owing physical causes
the decomposition of animal and vegetable matter
and perhaps also electricity There is some doubt
to the relative agency Of these various causes in
producing the phosphorescence Of the ocean.
The great difference between the medusae and the
polpys is, that the almentary cavity is no longer
single sac with single openings. The cavity has
branches penetrating into the substance Of tbs ami
nal, that we have no longer single sac opening
into the general cavity, but sac with notifications.
You perceive in this diagram some of these ramfca-
tons. They so delicate that they hardly be
shown without exaggerating the colors. Let me H.
ustrate this peculiarly of the structure Of this class
Of the radated animals. Let that represent the
gular; from that light appendages extend toward the
periphery, butsoon divide like bood-vesses, and these
sacs will sometimes divide with numerous tubes and
form as many canals of the most complicated blood
vessels In its divisions In that why the food aferit
has been digested is carried into the parts. 1t is
longer in contact with one surface only 1t is now
carried into the different parts of the animal. 1t isas
if the stomach was ut the same time heart, forcing
the digested food into the cavities as the heart pro-
pels the blood into all portions OF the body But here
this food after has arrived at the periphery escapes
There are as many outlets as they are tubes. And
agun there IRE from the periphery numerous minute
appendages, like tentacles with an opening at the
end, which absorb, pump the water and introduce 1t
into canal which runs all round the animal. So
we have no longer the food introduced into cavity
containing water, but we have the aimentary canal
branching in all directions; and in the extremity of
these branches we have small tubes absorbing water
and mixing Il with the food These tentacles forms
beautiful appendages in a great many of these ami
mails They vary very much in different animals
In some the appendages are longer than the body of
the animal ITSELF In others they are quite short In
some they meet regularly and form triangles. In
some they are few in number but of large size. Bat
in all they are hollow, and they absorb water and al
admit the dgesed food which is circulated through
these tubes and introduced into this circular canal
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Sometimes il is one way sometimes another. 1t Is
an irregular circulation which changes Its direction
In some Of the higher animals the heart causes the
blood to rush in one direction and after il returns,
propes 1t in another direction that In and the
same animal we have the heart acting in different d.
rections, and we have that singular phenomena in
some OF the medusp In this respect we have COM
plication which exists in very few of the polyp II
is round these appendages that the ovaries usually
hang in large lunches These colored punches are
punches Of eggs hanging outside the tenaccs which
surround the mouth
In some OF these animals copred specks have been
seen between the tentaces usually red and they have
been conlecured, not without probability, to be eyes.
This Is about a that is known OF the structure Of
lhese ANIMALS ihere are several varieties oil Them
some nave large geiaunous discs; they are the com
mon eliy-fsh others nave large vesiclc above the
tentacies and compact portion OF the animal, which
allows them 70 SWIM on the surface OF the water.
otllers nave grea. many o. 'hese yesices. others
again nave Vel'icd, sc,es u appehaages act
ing ike ours, ny WHICH uey move very rapdiy In the