The Republican. [volume] (Oakland, Md.) 1877-current, 1878-11-23
Star-Fishes.

On previous occasion we described
those curious creatures, the sea eggs
the Ecbi1ei of the zoologist. In the
present paper we intend to say some
thing about the star-fshes, which are
not merely common denizens of Our
rock-pools and coasts, but also boast of
being very near relations of the sea
eggs themselves. The name star-tish
in some parts of the country is super
seeded by the terms cross-fsh and five
fingers. Each name applies distinct
lively to the commonest species of these
animals found on our coasts, the COM
mon star-fish (JrdSter rubenSJ This
animal is so familiar that any descrip-
ton of its outward appearance is al
most unnecessary. We see a body
which appears to consist almost entire
ly of five rays. There is very little
body or disc to be noticed in the com
mon star-ish-the name disc applying
to the central portion from which the
rays may be supposed TO spring. The
surface of the body is rough and stud
ded with a great many little promi-
nences and miniature spines, and the
skin itself is not only of tough, leath-
cry consistency, but. contains living par
ticles which, in their own humble way,
represent the more perfect Development
of that mineral we see in the shell of
the sea-egg.
AS we observe star-fish cast up by
! the unkindly waves on the beach, it
certainly appears to be one of the most
helpless and forlorn of Creatures. Drop
it into the nearest rock-pool, however,
and the aspect of matters will soon APP
pear changed. The star-fish will then
be seen to move slowly and circum-
specify over the bed of the pool, and
to present the appearance of an animal
thoroughly at home. The under sur
face of the star-tish certainly offers for
observation a greater abundance of
features than the upper surface. Be-
low and in the center of the body we
see the mouth which, however, is I'M
provided with teeth or jaws, that form
so marked a feature of the sea-eggs.
Stretching like five avenues from this
central mouth we find the rays, and on
their underestimate, packed, one would
think to an extreme degree, are to be
seen the numerous curious little struct-
ures called tube feet, by means of which
the star-ish walks. Each tube foot
consists of little muscular pipe, pro-
vided at its tip with sucker, enabling
the animal to hold on firmly to any sur
face to which the foot may be applied.
We are, therefore, not surprised at the
ready fashion in which the star-tish
crawl about. With hundreds of tube
feet in each ray, the body is slowly but
surely borne over all the inequalities of
rock-pool or sea-bed. The mechanism
that through which the similar feet of
the sea-eggs are put in operation.
But the subject is so interesting that
recapitulation of the locomotive az
rangements in these animals may be
briefly given. The entire system of
tube feet in the star-fish is set in opera
ton, so to speak, through the agency of
water, The tube feet of each ray are
attached to main pipe which runs
, along the groove of the ray in which the
feet are placed. And this main pipe,
} in its turn, takes its origin from cir
cular vessel surrounding the mouth in
ternally. At the base of each tube foot
that is, where the foot is attached to
, the main pipe-a little muscular bag
exists; and we may lastly note that the
, whole system of pipes-main pipe, Cir
cular vessel, tube feet and their sacks
, or bags-is placed in communication
| with the outer world by another tube,
the function of which is to admit water
, to the system. Suppose now, that the
star-tish intends to make tour of its
, abode. Water will first be admitted to
: the circular vessel, and from that YES
sci will run through the main pipe in
each ray, ultimately filing the bags OF
, sacs at the bases of the tube feet. These
bags, like the feet, are muscular, and
{ hence, by their contraction the fluid is
, forced into the feet The latter ara
, thus distended and rendered tense, and
the suckers can therefore be firmly ap-
piled to the surface over which the star
fish is proceeding. When, on the Other
hand, the star-tish comes to rest, OF
, when it is tossed up on the beach by
the waves and we find its tube feet
empty and flaccid, we see the effects Of
: the escape of the water which formerly
? filled them, and without which the
creature is unable to seek 90 fresh fields
!, and pastures new. - Chambers JOurncl
Paving for His Whistle