10 POPULAR BRITISH CONCHOLOGY. 



many enemies^ but not his destiny. As it was in the days 

 of Ovid, when he compared the shipworm in the wood to 

 grief gnawing at his heart, so it is now ; with a very slight 

 accommodation of the words of a living poet, we may still 



say— 



" The stoutest bulwark maa can raise, 

 Is the ship-worm's food at last." 



But it will be asked. What have we to do with a worm 

 in a book about shells ? We shall see, on examination, it 

 turns out that this destructive creature is a true mollusc ; 

 that in the ^^ round head" is contained the greater part of 

 the body, and that the dreadful "jaws" are nothing but 

 the two valves of a fragile shell. 



Pieces of wood are found pierced like the piece repre- 

 sented (Plate 11. fig. 3), with a number of long tubular 

 holes ; some of these holes will be lined with a shelly tube, 

 which being taken out resembles, and has been taken for, 

 a Serpula (the shell of a true worm). Within this tube, 

 occupying its whole length, is a soft worm-like lining, 

 containing the alimentary canals; at the smaller, which 

 is generally the upper end, is a gristly ring, in which are 

 inserted two shelly or horny pieces, in some species like a 

 pair of paddles (Plate II. fig. 4) in others like pens (Plate II. 



