8 
in reality, a mere shell, with the substance entirely destroyed, save 
where the clever miners have left the thinnest of thin partitions 
between their galleries. I have a piece of wood taken from a 
vessel recently placed on the stocks for some trifling repairs, no 
suspicion being entertained that the hull was infested with Teredo ; 
but the shipwrights discovered that much of the timber, which 
appeared sound and solid, was riddled by the ‘‘ ship-worm,” and a 
transverse section of a piece of wood from this vessel, now in my 
possession, shews, on a surface 6 inches long by 3 inches broad, 180 
perforations varying from one-eighth to one-quarter of an inch in 
diameter. ’ 
As illustrating the rapidity of the destruction, it may be 
mentioned that planks of soft wood known to have been submerged 
for less than two months have been found completely riddled by 
the Teredo; and in the British Museum may be seen sections of 
Quebec Elm and English Oak which formed part of Yarmouth 
Pier, and, after being in the sea four years, were found to be 
perforated in all directions. 
Some of the performances of these self-immured agents of 
destruction have become historical. 
In or about the year 1731 fears were entertained for the safety 
of Holland, it having been discovered that the piles which form 
the artificial barrier against the inroads of the sea were being 
destroyed by Teredo. 
When divers went down to inspect the Russian vessels which, 
during the bombardment of Sebastopol, were sunk off the mouth 
of the harbour, they found that the work of removing the 
obstruction had already been undertaken by a large body of these 
‘submarine engineers”’ ; and in the museum of the Royal United 
Service Institution there is (among other specimens of ‘‘ worm- 
eaten’’ ship’s timber) a piece of one of these Russian vessels. 
Various materials have been tried with the view of rendering 
wood safe from the attacks of boring marine animals, but the most 
reliable plan appears to be that of covering the surface with 
metal ; copper sheathing being used for vessels, and broad-headed 
iron nails for piles, harbour walls, &c. 
There are at least four distinct species of Teredo now natural- 
ized in British waters; and in tropical seas there are many others 
ready to attack any vessel not properly protected. 
In colder latitudes the Teredo becomes more rare, and in the 
arctic seas it is unknown. 
There is another genus of Pholades, named Xylophaga nearly 
allied to Teredo, which bores across the grain, and penetrates the 
wood less deeply than the ‘ ship-worm.” 
Fossil wood obtained from London Clay, Oolite, and Green- 
