Signal-Copiahan. (Hazlehurst, Copiah County, Miss.) 1885-1888, 1886-09-02

does indeed ''comprise In itself din.
cult study of no inconsidcrable magni.
tudc." Mechanics and chemistry have
already been touched upon. and we
shall find that several other branches
of science are involved In the life his.
tory of the shrimp.
In mo first place II will be noticed
that the shrimp has its skeleton and
muscles arranged on principles exact
ly opposite To those Of the rcrtcbrated
animals, such. for example, Us man.
We carry our skeletons inside our
bodies, and the muscles are attached
TO the outside Of the bones. But in all
the crustacca an exactly opposite sys.
TEN prevails, the skeleton being out.
side the body and the muscles being ut.
taehed to the interior of the bones, II,
indeed. the parts OF the skeleton can
rightly be called by that name. Here,
then. the science OF physiology is rep.
resented In the shrimp. Next we como
to another detail of physiology. The
entire body of the shrimp consists OF 3
number of separate rings Of the lime.
strengthened material which has al.
ready been mentioned. When carefully
analyzed these rings or 'segments, as
they are often called, are found TO be
twenty in number, the last live consti.
tuting the so.called "tail." On the
under surface of these segments are
certain appendages which take diff
fcrcnt names according to the Office
which they fulfill Sometimes they are
termed legs. Sometimes they are
paddles or "swimmcrets." Sometimes
they are called claws or pinccrs Some
times they arc modified into jaws. and
so forth. But whatever may bc their
office they are all notifications of the
simple appcndagc, thus carrying out
the universal law that there is no
waste in nature. and that no new
organ is ever made when the same OBJ
icct can be obtained by the modiiica-
ton of some organ which already ex.
iS,S.
Take Your shrimp and straighten
it. This Is the natural attitude, the
curved position with which We are 81
familiar being caused by the contrac-
ton of the muscles under the influences
of boiling water. Also when n shrimp
dies natural death the body becomes
bent. 50 that the aquarium keeper can
always know whether. .he creatures be
alive or dead. Bend the tail backwards
and forwards, and note the wonderful
hinges which enable the Successive
segmcnts to work upon each other.
They are far superior To those of plate
armor. inasmuch that they need no
riycts. and even when the outer skin
has been shed, and Is nearly aS
transparent aS glass. the joints will
play upon each other as freely rs they
did when the creature was alive. Now
turn il ON its back aud fastcn 1t down
To piece of Hat cork, or even a soft
deal board. by couple Of pins. Be-
ginning at the end of the body YOU will
see that it is drawn out into sharp
and ilattcned projection called the
.'tclsOn," /. e., the end of the body.
Some anatomists consider that tho
tclson ought to take rank rs a segment,
and that the shrimp really possesses
twcnty-one segments. just above the
tclson are two double appendagcs,
very much heightened and flattencd
and fringed with strong hairs, so rs tc
look like a fan.
This "tail FAM" as 1t may well be
called, is the chief instrument Of loco
motion whea the shrimp is alarmed
| have already mentioned that
the natural attitude of the shrimp
is with its body extended. Now
when it fears an enemy all ii has to do
is TO contract the body suddenly. The
enormous fcXor muscles, of which the
tail H. composed, actwith such force
that the shrimp is driven backwards
through the water with such speed that
the eye can scarcely follow its track.
The lobster. whose tail-fan must
be familiar TO every one, is said to
drive itself through the water for dis
tance of thirty feet at n single stroke,
and to guide its course with such accu-
racy that it can shoot through an apcr-
turc scarcely wider than its body with
out touching the sides.-Rer. j q.
Wood, ia the Argosg.