EIGHTH ANNUAL MEETING. 29 
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auger, file, and gouge. The best invention of the kind was 
patented a short time since—a Massachusetts mechanic copying 
exactly the tuol of the teredo. 
They enter the wood perpendicular to the surface, and they 
usually turn and follow the fibre upward. They grow rapidly, 
and their galleries increase in diameter. As they progress they 
deposit a white, calcareous coating on the interior. The sawdust 
enters the abdominal cavity, and is ejected by one of the two 
siphons that remain extended from the opening in the wood. 
Some naturalists have stated that the teredo feeds upon the 
wood. The best authorities claim, and undoubtedly with truth, 
that they enter the wood simply to create a home, but procure 
their food from the water, using the second of the two siphons. 
In the Gulf of Mexico they grow to the length of a foot 
in one year. Their galleries are then about one-fifth of an inch 
in diameter. They rigidly respect each other’s rights cf occu- 
pancy. They never cut into each other’s openings. They have 
the power of retraction to the extent of an inch. When they 
approach within the thickness of a sheet of paper to a fellow- 
traveller’s path, they withdraw, and go around him or start in 
another direction. So thoroughly do they excavate the interior 
of massive timber, that the piles break off by their own weight. 
During the year 1875, twenty-one heavy oaken piles, driven on 
the outer end of one of the new coal docks of the Delaware, 
Lackawanna and Western Railroad Co., Hoboken, N. J., were 
attacked by the teredo. In six months they were actually eaten 
completely off at a point about ten feet below mean low water 
I have a section of one of these piles given me by the foreman 
of the dock-builders who constructed it. 
The teredo requires clear, pure salt water. They are never 
found in timber situated near the outlets of sewers or gas- 
works. Fresh, or even brackish water kills them. Hence the 
number of uncoppered steamers, sailing vessels, and barges that 
are seen in the summer-time moored at Rondout and other 
points on the Hudson River, sent there to insure the destruc- 
tion of the marine worms that have lodged in their planking. 
The teredo cannot exist except in his woody chamber. With- 
drawn from it he dies in twenty-four hours. It will live for 
