X INTRODUCTIOxV. 



(wreck), sea-weed, &c. from which I 

 have collected many rare small shells. — 

 Whales have frequently barnacles ad- 

 hering to their heads and jaws; and the 

 ^^ cod is often penetrated by the destruc- 

 tive worm, (teredo navalis)*; which is 

 extremely interesting to examine. 



• The Teredo Navalis is a mucilaginous sub- 

 stance, in the head of which are strong muscles, 

 terminated with hard shell-like substances, one 

 of which is not unlike the cutting part of a car- 

 penter's auger : this the animal works so as to 

 bore holes in almost every sort of wood. It is 

 supposed that the animal, when extremely 



