New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1847-11-01

81 a. ssivalves Order Of Succession; The various
yely ft,ie ,ortanee Changes in the Classification
Of fae aOlnscs and other Animals Tribute 10 the La
b0rs Of Culver
LApIFsANp GENrLENES: After having giyon
general outline Of the characteristcs Of mousca in
the last &c a- proceeded to Illustrate the peculi-
ties % Il. isf Jlass OF that group called acepha'
In. T~un having entered into as many details as
possible with regard to their structure alluded to
the different groups which belong TO that class :
bu. as perhaps many or some Of this audience may
wish 70 know how these facts are ascerlained.
have brought here some Of these animals in order
to demonstrate on them the peculiarities Of their
organization For. let me remind you that the OBJ
ecis ia nature arc not you see them define
ated IN the diagrams. 10 the diagrams the objects
must be represented Of larger size than natural,
and in strong outlines Things not so easily
seen in nature and therefore wish to show you
ia whst manner we must proceed in ordor to see
lor ourselves the objects in nature, and how we are
able 20 proceed IN making new observations and
comparing the types not yet understood.
have thus taken for example the oyster as it s
the most COMMON Of this order Of animals ! have
been told that there was some misunderstanding in
the minds Of some ofmy auditors, when explained
the difference between the oyster and the common
bivaye shells. The misunderstanding was With
respect 70 the shell which is concave, and arose from
not attending to the manner ia which the shells
were beld in the hand when demonstrating them.
The two valves are united ut one end by what Is
called the gament IL is elastic substance,
which contracts when the muscular power oil the
animal which closes the valve is relaxed In order
70 open an oyster particularly for anatomical IN.
vcstigation, il is only necessary to pass KNIFE be-
tween the valves on the back near the projecting
portion, where the two valves are united so that
The strong muscular portion OF the animal, and
which passc across the whole body and hxes u
selfto the valve be divided. You this dark
spot In tie centre Of the valve. Here IS the mus
cuar portion tough like meat and the hDres OF this
part Of the animal are transverse, running from one
valve TO the other Now after the valve is
moved IN such manner--it IS not much matter
what valve il removed. only perhaps It is more
convenient 10 allow the animal 20 remain in the
deep valve which retains the water-you see at
once the animal in its natural position. Here you
have This muscular portion, which Is tne toughest
mart Of the animal aud then skin which runs all
around the shell This skin which lines the whole
inside Of the valve and which can be upheld very
easily il attached 10 the muscle and runs all round
the shell o. the margin. II II appears now not 10
cover entirely the surface OF the she'll 1t is owing to
the contraction of the ibres which are In this mem
brane. The margin OF the membrane ltseli mas
verv complicated structure There are irnges
sometimes most beautiful and of very elegant color
IN the different species of clans and bvalve shells
and v hen YOU remove this portion OF the shell,
which is called the "mautle. you have another
membrane quite similar to that, which is situated
uansversely. This is the gill There is another
inside-a second one so that there are two lobes Of
the raj on one side and above that two long tenta
cles, which are placed here above the mouth. Ga
the other side we have the same structure. Now
the mouth is here on this upper portion of the she'll
A a.. 40, han tIkr "a
the whole animal in water as then, with brush or
pencil YOU can elevate the one above the other
and examine their beautiful structure
In this upper portion Of the animal is the stom-
sch. large cavity surrounded by dark brown
eoiOred liver which forms the sOitest part OF the
OYSTER Around the liver is the ovary. The eggs
tr an minute as not to be perccptIble to the naked
eve bat are readily seen under the microscope
The intestinal tube, which begins here between
the tcutacles, AZ the anterior portion OF the body
tarns twice between the liver and the ovary and
then passes through the upper region, in which we
see the heart OF the Oy ster. The Intestinal canal
does not pass through the heart of the oyster as in
\ other animals, which shall demonstrate immedi-
etey. What is peculiar to the oyster IS that the
mantle is open all round There is no slphon,
but the water as often the shell opens, can reach
Immediately the whole surface OF the gill-the food
eau Immediately reach the mouth, so that the ami
NAL has no need Of tube which could be eionS ated
and protruded between the valves IN order to 40
sorb the surrounding water
You see that the position OF the mouth indicates.
without any doubt that this is the anterior edge OF
the oyster and this the superior this tho inferior
side and this the p0steriOr. As have remarked
the animal rests forever on the deep valve so that
when examining an oyster anatomcally, IN order 70
compare /; with other shells, we must put 1t Ia a
position different from that il used TO have in nature
Bat this is the with many other animals.
Amonr the water Asccts. for instance, there are
many " no constantly swim with the feet upw ard
bat nobody when comparing them with others
would think at proper 70 compare them IN that re
yers,d position. We must IN these cases bring the
animal into the natural position Of the greatest
humber of animals in order 10 come 10 nget un
dersfarfing of the correspondence between the
parts SO il is with the common hard clam. Ipus
the two valves are precisely Identical IN the shape
Bpt nfer having removed one of them you see here
agrest difference in the structure OF the animal
There are two muscular bundles uniting the TWO
valves one on the anterior and the other IN Tue
postellOr portion Of the animal, so that inc i've
valves arc shut by two sets OF muscular horss, aru
Iot by central set as In the oyster ANA thts sc
Two sets Of muscles are placed one on the anterior
Il M the other on the posteriOr end OF the animal
I60se two muscles act, however, In the same man
Der as toe single mascle IN the oyster. The mantle
here surrounds the shell precisely in the same way
uin the oyst, ut il Is not open all around mere
boat two thirds backward the mantle unites from
II twOsdes IL is open only on Tie anterior ridge
4 Nih,t the water can enter either between the
ssnie ohes or through the hole which is formed By
T. junction Of the two portions OF the mantle.
la, have done here, you remove the mantle you
o. s,oiior ast membranes which are the gills $
hey are so collapsed IN this animal that cannot
sow them They should becovered with water an'
bose who wsh to see their structure may remain
Ter the lecture and shall pat the animal IN
ssicr and demonstrate those membranes. lne',
~ considerable muscular mass, underneath ~hic'
sthe muscle OF foot by which the auimai welAs
his foot they protrude between the valves ana ~
acons 81 II FIX themselves on the sand or stones ah'
reep along by successive contractions and expan
cons Of theirbody In the same way as IN 'h'
ss,er, We hsve here the mouth surrounded by ten
eles. The liver is above and OF a brownish color
ain me oyster. Then We have the heart here De
feen the gils. and the intestinal cavity, and the All
en'ery canal which passes through the centre o
heart TIL beating Of the heart can DC
an Tor long I aI.sr you open the waves o
oyster. ltb seyen or eight times during
~note. In the q Stems the pulsations are e.
ast the sane i-ascency. When contracted
shesrt Is 20 srat size-when expanded