CHAPTER V. 
BURROWING MOLLUSCS. 
The Boring Snail of the Bois des Roches— Opinions as to the method of 
burrowing— Shape of the tunnels — Solitary habits of the Snail — The Gaper 
Shell — The Limpe/t — The Piddock, its habits and appearance — Struc- 
ture of the Shell, and its probable use — Method of burrowing — The Date 
Shell — Its extraordinary powers of tunnelling — The Wood-borer and its 
habits— The Razor Shell — Its localities and mode of life — The Shipworm 
— Its appearance when young and adult — Its curious development — Its 
ravages — Its value to engineers. 
Ill fitted as the Molluscs seem to be for the task of burrowing, 
there are several species which are able not only to make their 
way through soft mud, or into the sandy bed of the sea, but to 
bore deep permanent tunnels into stone or wood. Even the 
hard limestone and sound heart-of-oak timber can n not defy 
these indefatigable labourers, and, as the sailor or the dweller 
on the coast knows full well, the rocks and the timber are often 
found reduced to a mere honey-combed or spongy texture by 
the innumerable burrows of these molluscs. 
There is now before me a piece of very hard calcareous rock, 
in which are bored several deep holes, large enough to admit 
a man’s thumb, and remarkably smooth in the interior, the 
extremity being always rounded, Indeed, if a hole were made 
in a large lump of putty by putting the thumb into it and 
turning it until the sides of the hole became smooth, a very 
good imitation of these miniature tunnels would be produced. 
This fragment of stone was taken from a little wood in Picardy, 
called Le Bois des Roches, on account of the rocky masses that 
protrude through its soil, and was brought to England by Mr. 
H. J. B. Hancock, who kindly presented it to me. 
