Barbour County index. [volume] (Medicine Lodge, Kan.) 1880-current, 1892-12-07
A BORING IOLLUSK.
It's Life Spent IN Digging It's Way
Into Hard Rock.
The Wonderful Feat Accomplished by
tho Pholss, Soft Sheilflsh
Which Frequents tho South
ern COaStS.

What looks like very commonplace
lump of mud has recently been exposed
to public view in q glass case by itself
at the Smithsonian institution. 1t is
much more of a curiosity than 1t APP
pears at the first glance. Buried in the
mass, which is really drab-colored lime
stone, are about a dozen mollusks that
look somewhat Hike large little neck"
or ''long" CLANS
The question naturally occurs, how
lid these bivalves find their way into
the hard rock, the openings of the
holes they occupy being only small
fraction of the size required to admit
their bulk. In the case OF long clam
there is no difficulty in pcrcciving how
it digs its way down into the sand,
leaving behind it only a little canal
through which to communicate with
the outer world. But here the mate
rial bored into is stone, and for long
time it was q mystery even TO science
how the mollusk got into the rock, be-
ing commonly found where the latter
was between tides"-that is, at times
covered with water and at other times
LETT dry.
Happily the puzzle has been so we'd.
says the Washington Star. Tho bivalve,
which has been named the ''pholas," is
originally lodged on the rock in the
shape Of an egg-the accidental sur
vivOr of myriads lost. Maybe it gets
entangled in seawced, but, at ali events.
as soon as it is Matched out and appears
in its proper shape as baby mollusli
it begins to bore. What it bores with
has been question much discussed.
Some have contended that it does tho
work with the sharp edges Of its shell.
turning round and round for the pur-
pose; but the material of the shell is OBJ
viously too soft for that to be possible.
Others have asserted that it secretes
acids which eat away the stone, as
hchens do in the vegetable world. But
the truth seems to be that the boring is
performed by means of the foot" of
the animal, with which it patiently
screws hole for itself.
Once lodged in hole of its own, the
little mollusk has nothing more to fear.
But it must keep on boring all the time,
SO as to make more room for itself as it
grows. Indeed, inasmuch as it keeps
on growing all of its life, 1t must always
continue to bore. However, 1t has the
great advantage over nearly all other
living creatures that it resides within an
impregnable house, where no foe can
possibly reach it. The hole where it
entered is never enlarged, and this
hermit among bivalves simply occupies
itself in scooping away the rock as fast
as 1t desires more space. 1t lies some
distance, say three or four inches, from
the doorway of its dwelling, filing up
the hallway" as 1t might be termed,
with a sort of cement secreted by itself,
save for small passage through which
it communicates with the water or air
outside.
When 1t wants to feed, 1t extends its
long neck through this passageway and
out of the aperture, spreading from the
extremity of the organ q number of del
icate tentacles, which gather In ami
malcul@ and other microscopic food. In
the ordinary course of nature the pholas
dies, and its decomposed substance is
washed out of the hole which it occupied
while living. It often happens that into
the holes thus left vacant by these BIZ
valves young mollusks of other kinds
are conveyed accidentally by the waves.
They grow, and In so doing, supposing
that they belong to species which attain
considerable size, they are compelled to
take the shape Of the holes. Thus con-
biologists, coming across such tenants
in the pholas' dwellings, used in many
instances to mistake them for new
species as yet undiscovered.
The pholas is very plentiful all along
the Pacific and Gulf coasts, and the
pretty bivalvular shells are sold in great
numbers under the name Of angels
WINGS" ON account of their peculiar
form and MARKINGS