The News-Herald. [volume] (Hillsboro, Highland Co., Ohio) 1886-1973, 1892-08-18
A BORING MOLLUSK.
IT'S Fife Spent In Digging Its Way
Into Hard Rock.
Ths wonderful Feat Accomplished By
the Pholss, q Soft Shellfah
which Frequents the South
ern Coasta.

What hooks like very commonplace
lump of mud has recently been exposed
TO public view in glass case by itself
at the Smithsonian institution. It is
much more Of curiosity than II ap-
pears at the first glance. Buried In the
mass, which is really drab-colored lime
stone, are about o dozen mollusks that
look somewhat like 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 perceivin9 how
II digs It's way down into the sand,
leaving behind II only little canal
through which TO communicebs with
the outer world But here the mate
rial bored Into Is stone, and for a long
time It was mystery even to science
how the mollusk got into the rock, be-
ing commonly found where the latter
was "between tdes1-that Is, at times
covered with water and at other times
left dry.
Happily the puzzle has been so we'd,
says the Washington Star. The bivalve,
which has been named the ''pholas,r is
originally lodged on the rock in the
shape of an egg-the accidental SUR
vivor of myriads lost Maybe it gets
entangled In seaweed. but, at all events,
as soon as it is hatched out and appears
In its proper shape as baby mollusk
It begins to bore. What it bores with
has been q question much discussed.
Some have contended that II does the
work with the sharp edges Of its shell,
turning round and round for the pur-
pose; but the material Of the shell is OBJ
i viously too soft for that to be possible
! Others have asserted that it secretes
acids which eat away the stone, as
/ ichens 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 It's 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 It's life, 1t must always
continue to bore. However, it 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 II
entered is never enlarged, and this
hermit among bivalves simply occupies
itself in scooping away the rock as fast
as it desires more space It lies some
distance. say three OF four inches, from
the doorway Of its dwelling, filling UP
the hallway" as, it might be termed
with sort of cement secreted by itself
save for small passage through which
1t communicates with the water or all
; outside.
, When It wants TO feed, it extends its
} long neck through this passageway and
out of the aperture, spreading from the
: extremity of the organ a number of del
; icate tentacles, which gather in ami
} malcule and other microscopic food. Ir
the ordinary course of nature the phola.
| dies, and its decomposed substance l.
washed ont OF the hole which it occupied
while living. It often happens that int
the holes thus left vacant by these bi
, valves young molluslzs Of other kinds
are conveyed accidentally by the waves
They grow, and in SO doing. supposine
that they belong to species which affair
| considerable size, they are compelled t.
, take the shape Of the holes Thus con
} biologists, coming across such tenant,
} In the pholas' dwellings, used in many
instances to mistake them for new
, species as yet undiscovered
, The pholas Is very plentiful all alont
the Pacific and Gulf coasts, and tn,
pretty bivalvular shells are sold In grea
numbers under the name of "angels
wings" on account of their peculial
, form and markings.