New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1847-10-25

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tion OF the egg Now this yolk or rifellus as it is
cared MS the essential portion Of the egg, and
"lthin mat IS another yesicle filed with transpa
rent hquid IN which several other similar vescles
swim Tins constant and uniform structure Of the
egg affords a test whereby We can ascertain whetb-
or ths organized being before us is an animal The
eggs may be as easily perceived in the lower ami
mails as IN the highest as they are so transparent
that they are readily examined under the micros
cope Now these eggs differ entirely from the
seeds OF plants. Even 10 the conJerre these seeds
are filled only with uniform granules and have no
Intricate minor cells; and now, when these eggs
become movable by having the whole surface GOV.
cred with vlbratOry ella have only to put them
under the microscope in order to decide whether
we have before US the seed OF plant or the NOV
able egg OF an animal lApplause)
! will now proceed 20 demonstrate another class
OF these snimsls-the Acoleph9, or nettle
/ skinned
The name of this class is derived from peculiar
tiles in these animals which ! shall Immediately
explain. You have examples Of Meditsa in these
diagrams. They have many relations 10 the poypi,
bat there Ia general characteristic which will
strike you when II is mentioned. The meduss are
all free-ndependent 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
downward while all polyps have the mouth up
ward In tie very position of the animal in the
surrounding element We have one great difference,
which is as constant the most intricate peculiar.
ity Of their structure. There are few moving ami.
mails in which the difference OF internal structure
between them and the polypi is by no means very
apparent; they have not one organ more than we
have seen among the polypi only little compiled.
ton Of the same organs
In the jelly.fsh We have broad disc, and in
that wide cavity, with mouth in the centre.
from which several, sometimes numerous append.
ages hang down. This is the simplest structure Of
the meduse. There the mass of the animal is
stantly gelatlnous The bodies of this class are
exceedingly soft, so much so, that when taken out
OF the water they almost wholly decompose aud
disappear They contain so very little substance
/ that cart load OF them would not, if dried by
evaporation. leave ounce of hard substance-of
dried membrane. single leaf Of paper would
contain as much solid matter a fall cartl load OF
these animals when dried. They are so liquid that
they arc transparentsO much that they are FREE
quently not seen In the water, and would not be
! perceived at ali if it for their beautiful
colOrs. They have, indeed, the most beautiful del
icste colors Of all the lower animals. Again, a
great number of them are phOsphorescent. In the
/ night they appear like brilliant lights aud 10 some
of them is owing the phosphoresccnce OF the sea -
not to them solely, for the phospborescence Of the
sea is produced by great number of animals.
/ Very numerous and different species of animals
produce that peculiar beautiful light that illumes
the sea during the night. Some of these animals
belong to the artculated types others TO the medu
sT some arc polyps aud perhaps the light is in
+ part owing to physical cause.-the decomposition
of animal aud vegetable matter and perhaps also
To- electricity There is some doubt as 10 the rela
tive agency Of these various causes in producing
the phOspbOrescence OF the ocean
The great difference between the meduse and
the pOpys that the anentary cavity is no longer
& single sac with single openings. The cavity has
branches penetrating into the substance OF the
animal so that we have no longer a singl sac
opening INTO the general cavity, but sac with
qualifications. You perceive in this diagram some
Of these rsmilications They SO delicate that
they hardly be shown without exaggeratng
the colOrs Let me illustrate this peculiarly o the
structure Of this class of the radiated animals Let
that represent the central opening, sometimes an
guiar sometimes pentaugular from that, light ap-
pendages extend toward the periphery, but soon
divide like bood.vessels; and these sacs will
sometimes divide with numerous tubes and form
as many canals as the most complicated blood yes
sci in its divisions In that way the food, after 1t
has been digested is carried into the parts. 1t is
no longer In contact with one surface only. IL 10
now carried into the different parts of the animal
IL is AS If the stomach at the time
heart forcing the digcsted food into the cavities
as the heart propels the blood into all portions OF
the body But here this food, after it has arrived
at the periphery, escapes There are as many
outlets ~ there are tubes. And again, there are
from the periphery numerous minute APPENDICES,
I like tentaces 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 amentary canal
branching in all directions and in the extremity of
these branches we have small tubes absorbing wa
ter and mixing 1t with the food. These teDtacles
forms beautiful appendages in a great many OF
these animals. They vary very much in different
animals. In some the appendages are longer than
the body of the animal itself In others they ara
quite short la some they meet regularly and form
triangles In some they are few IN number, but OF
large size. But in all they are hollow, and they alb
sorb ater and also admit the digested food, which
is circulated through these tubes and introduced
into this circular canal The motion OF the fluids is
not in uniform direction Sometimes 1t is one
way, sometimes another. Ii is an irregular circula
/ tion which changes its direction. In some of the
higher animals the heart causes the blood to rush IN
one direction, aud after ltreturns propels 1t In ano
ther direction, so that in one and the same animal
We have the heart acting in different directions,
/ aud we have that singular phenomena In some OF
the meduss. In this respect we have complca-
ton which exists in very few OF the polypi 1t 10
| round these appendsges that the oysres usually
/ hang in large lunches. These cOored punches are
punches OF eggs hanging outside the tentacles
which surround the mouth.
la some of these animals colored specks have
been seen between the tentacles usually red, and
they have been conjectured not without probabili-
ty 10 be eyes.
This is about all that is known of the structure
/ of these animals. There several varieties OF
them Some nave large gelatlnous discs thcy are
the common elly-hsh. Others have q large vesi-
Gle above the tentacles and compact portion OF the
animal which allows them to swim on the surface
of the water. Others have great many OF these
vesices. Others again have vertical series OF sin
gular appendages acting like oars 10y which they
move very rapidly in the water The locomotion
of the first class those having disc, is owing to
the expansion aud contraction OF the disc. The To-
comoton OF the second class is owing 70 the motion
OF the tentscles and the contraction OF the air yes
sells while that Of the third class is owing to those
series OF vertical appendagcs
la their mode Of growth they present most ex-
traordinary phenomena. Not all OF them have been
studied but those which have been examined pre-
sent these phenomena. The Swedish naturalist,
Sars has discovered that the eggs of the common
medusa OF the Baltic Sea were movable. This 4
might appear almost incredible, had not repeated
subsequent observation established the fact
shall endesvor to illustrate the formation of the
egg. In an egg OF this form the enlarged upper |
porton begins to grow with four aPpendages-