62 STRANGE DWELLINGS. 



however, retain this form for more than six and thirty hours, but 

 undergoes a further process of development, and is then fur- 

 nished with a distinct apparatus for swimming and crawhng. 

 It also possesses rudimentary eyes, and in that portion of the 

 body which may be considered the head, there are organs of 

 hearing resembling those of certain molluscs. When it has 

 passed its full time in this stage of development, it fixes upon 

 some favourable locality, and then undergoes its last change, 

 which transforms it into the worm-like mollusc with which 

 naturalists are so familiar. 



The ravages committed by this creature are almost incredible. 

 Wood of every description is devoured by the Ship worm, whose 

 tunnels are frequently placed so closely together that the parti- 

 tion between them is not thicker than the paper on which this 

 account is printed. As the Teredo bores, it lines the tunnel with 

 a thin shell of calcareous matter, thus presenting a remarkable 

 resemblance to the habits of the white ant. When the Teredos 

 have taken entire possession of a piece of timber, they destroy 

 it so completely, that if the shelly lining were removed from the 

 wood, and each weighed separately, the mineral substance would 

 equal the vegetable in weight. 



The Shipworm has been the cause of numerous wrecks, for it 

 silently and unsuspectedly reduces the plankings and timbers 

 to such a state of fragility, that when struck by the side of a 

 vessel, or even by an ordinary boat, large fragments will be 

 broken off. I iiave now before me two specimens of * worm- 

 eaten ' timber, one of which is so honey-combed by this destruc- 

 tive mollusc, that a rough grasp of the hand would easily crush 

 it. Yet this fragment formed part of a pier on which might have 

 depended a hundred lives, and which was so stealthily sapped 

 by the submarine miners, that its unsound state was only dis- 

 covered by an accident. 



Another species of the same genus. Teredo coriiiformis, is 

 remarkable for the locaUty in which it is found. This curious 

 mollusc burrows into the husks of cocoa-nuts, and other thick 

 woody fruits which may be found floating in the tropical seas. 

 In consequence of the locality which it selects for its habitation, 



