TEREDO COMMON SHIP WORM. 151 



This singular animal has proved exceedingly 

 destructive to our shipping. It readily enters 

 the stoutest timbers, and ascends the sides of the 

 loftiest ships, which it most insidiously destroys. 

 When the hulk of a ship is any time under water, 

 the Teredines appropriate it to their own use, and 

 soon commence the work of destruction. 



They begin with the softest part, and at first 

 the apertures are so small as scarcely to be per- 

 ceptible. Their manner of carrying on their 

 labour is remarkable ; they are careful never to 

 intrude upon the habitation of a neighbour, and 

 even where a piece of wood has been so exca- 

 vated as to resemble a honey-comb, no commu- 

 nication or passage has been discovered between 

 the perforations, though often separated only by 

 the slightest lamina of wood. They always bore 

 in the direction of the grain of the timber ; if 

 they meet in their course with another shell or 

 a knot, they make a turn ; when the obstacle is 

 small, they wind round it, and then proceed on- 

 wards, but when large, rather than continue any 

 distance across the grain, they make a short turn 

 back in the form a siphon. The attacks of this 

 insidious enemy have not been confined to ship- 

 ping ; our dock yards also bear sad testimony to 

 their work of devastation. In Holland, where 

 the inroads of the sea, and of the great rivers by 

 which that country is intersected, have been re- 

 strained with immense labour by dykes, the Tere- 

 dines have proved very destructive, piercing and 

 even destroying the piles which sustained them. 



Many remarks suggest themselves in reading 



