322 THE OCEAN WORLD. 



are often riddled and perforated. They appear to all outward examina- 

 tion as solid and perfect as at the moment they were first driven ; 

 but they yield to the least effort, bringing ruin and destruction on 

 the edifices they support. Ships have been thus silently and secretly 

 mined, until the planks crumbled into dust under the feet of the 

 sailors. Others have gone down with their crews, entirely caused by 

 the ravages of these relentless enemies, which are terrible from their 

 unapproachable littleness. 



M. Quatrefages, who has minutely studied the organization and 

 habits of the Teredos in the Port of Saint Sebastian, reports the fol- 

 lowing fact, which will give the reader some idea of the rapidity with 

 which these dangerous molluscs pursue their ravages : 



" A boat, which served as a passage-boat between two villages on the 

 coast, went down in consequence of an accident at the commencement 

 of spring. Four months after some fishermen, hoping to turn her 

 materials to advantage, raised the boat. But in that short space of 

 time the Teredos had committed such ravages that the planks and 

 timbers were riddled and worm-eaten so as to be totally useless." 



At the beginning of the eighteenth century, half the coast of 

 Holland was threatened with annihilation because the piles which 

 support its dikes and sea-walls were attacked by the Teredo ; and it 

 proved no contemptible foe. Many hundreds of thousands of pounds 

 were expended in order to avert the threatened danger. Fortunately, a 

 closer attention to the habits of the mollusc has brought a remedy to 

 a most formidable evil ; the mollusc has an inveterate antipathy to 

 rust, and timber impregnated by the oxide of iron is safe from its 

 ravages. This taste of the Teredo being known, it is only necessary, in 

 order to scatter this dangerous host, to sink the timber which is to be 

 submerged in a tank of prepared oxide of iron clothed, in short, in a 

 thick cuirass of that antipathy of the Teredo, iron rust. Ships' timbers 

 are also served with the same protecting coating ; but the copper in 

 which ships' bottoms are usually sheathed serves the same purpose. 



The singular Acephalous Mollusc known to naturalists as the 

 Teredo navcdis, and popularly as the Ship Worm (Fig. 129), has the 

 appearance of a long worm without articulations. Between the valves 

 of a little shell, with which it is provided anteriorly, may be seen a 

 sort of smooth truncature, which surrounds a swelling projecting pad 

 or cushion. This cushion is the only part of the body of the animal 



