I/O 



Shell Life 



Holland have more than once had their welfare — 

 perhaps their existence — threatened by the ravages 

 of the Ship-worms among the piles of their embank- 

 ments. In the days of "the wooden walls of England," 

 prior to the use of copper-sheathing, we also suffered 

 greatly ; but now that so many of our vessels are of 

 iron or steel, the Ship-worm's sphere of activity must 

 be greatly curtailed. The " infallible " remedies in 

 the shape of washes and paints that have been put 

 forward to check the ravages of this little sea-monster 

 must number several hundreds. This, perhaps, is a 

 matter that, could it be known to the Ship-worm, 



Ship-worm 



might cause it to feel proud, that it had instigated 

 so much enterprise in others. Most of this, however, 

 must have been misdirected zeal; but there is one 

 case on record of its having inspired a great piece 

 of enofineerinof. The elder Brunei is said to have 

 declared that the method adopted in the construction 

 of the Thames Tunnel was suggested to him by the 

 Teredo. 



The Ship- worms are very like Wood Piddocks, with 

 an enormous development of the siphons, which may 

 exceed a couple of feet in length. The shell is even 

 more gaping than that of the Piddocks, for the valves 

 touch only at the beaks and at a point on the opposite 

 margin : it is helmet-shaped, marked as in Xylophaga, 



