Washington standard. [volume] (Olympia, Wash. Territory) 1860-1921, 1898-07-22

the Globe.
Scientific American.
The teredO naudlis is a mOllusk be-
longing to the tubiferous bivalves.
1t has been from time immemorial,
in all quarters of the globe, subject
of comment on account of its ravage
in timber exposed to its attacks
There are twenty-fOur species of the
teredo, but the ship worm is the best
known of these. Along the Gulf
coast of the United States the worm
has been carefully studied by the
builders of railroads, and the students
have been rewarded here more
abundantly than those who have ex-
amined the subject elsewhere. In
reality, the teredo is like the flexible
shaft boring machine. The teredo
mavalis is natural reproduction of
this instrument and is something
more. Its long and flexible body
terminates in cutting shells or bits,
and is inclosed, for the sake of its pro-
lection, in a hoselike shell, which
reaches from the inferior extremity to
within very short distance of what
is known as the head. At that point
the muscles come into play and work
the cutters or bit edges and drive
them into the timber, cutting as small
and as round a hole as any boring
machine yet devised. 1t can change
its course at any point, and has this
advantage over the flexible shaft
auger.
The teredo first appears in the egg,
which is round, like a mustard seed,
which comes from a whitish looking
mass, just below the stomach OF the
teredo, about q quarter of the distance
from the head to the tail, and the
eggs are in number from one to three
millions.
These eggs are laid at the beginning
of the warm season in the spring, and
are deposited from time to time until
cold weather sets in. The eggs hatch
in tine water, and give out worms
about 1-25 of an inch long, and so
small as to be almost invisible to the
inexperienced observer. They swim
about for a day or SO in the water, ap-
parently enjoying their brief time of
adolescence, and then search for TIM
Der. They enter the timber by boring
and cutting with the shells or cutters
with which they are provided, and
the enteance they make is 80 small
that it can scarcely be seen.
The worm grows at the rate Of
two inches per month, under favorable
circumstances, and bores hole to &C.
its increasing size. The
length of the hole is an indication of
the length OF the teredo, for it attaches
its smaller end to the entrance of its
burrow, and pushes forward with the
growth of its body. AS it progresses it
deposits a coating of lime upon the
sides of its cell, the deposits being
thinner as the animal advances. The
deposit, which is thick at the entrance,
is merely a film at the head, where is
collected a whitish fluid, which con-
tains the lime secreted for making the
lining of the cell and perhaps, ALSO
for repairing the wear of the cutters.
The worm continues its progress for
one and half years and propagates
and dies. 1t is said it reaches the
length of ten or twelve inches. The
largest automatically observed speci-
men was twenth-three inches long and
five-eighths of an inch thick at the
large end. When grown, the teredo
seems to be a gelatinous worm, at
tenuated in shape, extremely delicate
to the touch and tapering to a very
small point. The anterior or large
end has two bifurcations provided
with horny stiles which close up
against each other like shells.
These cutters are attached to q
pair of strong muscles which operate
very much like forceps or scrapers.
The edges of the shells carry away
little chips or fibers of the wood. The
continued scraping makes the walls of
the shell regular, and, in time, with
the action of the water, polishes them
smooth. The bore hole made by the
teredo is generally straight, as the
inclination Of the worm is in the line
of the grain of the wood, and is
changed only when the course will
project the teredo into the tunnel OF
some other borer or when the path
leads through some knots or twists in
the wood. The teredo avoids the bur-
row of its neighbor with great accur-
acy. There may be hundreds Of
worms living in the same cubic foot of
timber, but they never cut across or
into the cavities of their neighbors.
Coming in contact during its boring
with wood having obnoxious qualities
the worm avoids it by going around it,