IV INTRODUCTION. 



WHEN at sea, I have frequently lowered down 

 my boat to take in floating wood, (wreck), sea- 

 weed, &c. which often contained many inter- 

 esting vermicules and small shells. The wood 

 was generally pierced by the Teredo Navalis. 

 This animal first attaches itself in the state of 

 animalcule to the bottoms of ships, if not sheath- 

 ed with copper, where it increases rapidly, and 

 in a short time pierces the planks, growing 

 larger, and forming its shell as it penetrates. 



WHALES, tortoises, &c. have frequently bar- 

 nacles of a rare description adhering to them : 

 indeed the Lepas attaches itself generally to 

 substances of every description. 



THE Author having observed that the bot- 

 toms of ships soon became covered with bar- 

 nacles in tropical climates, made the following 

 experiment while lying at Magadore, on the 



