THE GIANT TEREDO. 127 



stices of the wood. This is done in a curiously simple manner, 

 namely, by laying the logs of timber on the ground, introducing 

 a tube into one end, carrying the tube to a height of forty or fifty 

 feet, and then connecting it with a tank filled with the solution. 

 It is, of course, necessary that the timber should be thoroughly 

 seasoned before it is thus treated. M. de Quatrefages suggests 

 that the prepared wood might be sawn into thin planks, which 

 could then be used in the same manner as the copper sheathing 

 now in use. 



Another species of the same genus. Teredo corniformis, is re- 

 markable for the locality in which it is found. This curious mol- 

 lusk burrows into the husks of cocoa-nuts and other thick woody 

 fruits which may be found floating in the tropical seas. In con- 

 sequence of the locality which it selects for its habitation, it can 

 not proceed in one direction for any great distance, and is obliged 

 to make its burrows in a crooked form, which has earned for the 

 creature the specific title of corniformis, or horn-shaped. Fossil 

 woods are often found perforated with these burrows. 



Destructive as it may be, the Ship-worm will ever be an ob- 

 ject of interest to Englishmen, inasmuch as its shell-lined bur- 

 row gave to Sir I. Brunei the idea which was afterward so effi- 

 ciently carried out in the Thames Tunnel. And though, from 

 the alteration of surrounding circumstances, that wonderful mon- 

 ument of engineering skill has not been so practically useful as 

 was anticipated, it has proved of incalculable value as pioneer Vo 

 the numerous railway tunnels of this and other countries. 



The largest species of this curious genns is the GtIAnt Teredo 

 '{Tefredo gigantea), which produces a shell more than five feet in 

 length and three inches in diameter. The substance of the shell 

 is of very great strength, being about half an inch in thickness, . 

 radiated in structure, and so hard that when the first specimen 

 was brought to England many naturalists took it for a hollow 

 stalactite. 



This creature is a burrower into mud, and was discovered in 

 a very curious manner. ' In the year 1797, a violent shock of 

 earthquake took place in Sumatra, and caused .great upheavals 

 of eaa-th and corresponding floods of water. When the sea re- 

 ceded from one of the bays, certain unknown objects were seen 

 protruding from its muddy bed, and were pulled out with tolera- 

 ble ease. They projected about eight or ten inches from the 

 mud, and as the projecting portions were beset by serpulse, bi- 



