Fig, 2. Acorn Barnacles 



BARNACLES 



In many waters, Barnacles are the predominant 

 form of fouling. Two general types are found. 

 Acorn Barnacles (figs. 2 and 18) have a hard, 

 conical shell -which is made up of several dis- 

 tinct plates, and varies from a fraction of an 

 inch to several inches in diameter at the base. 

 The top of this cone is covered by four movable 

 plates which may become detached when the animal 

 dies. When the whole cone drops off or is re- 



12 



