KEY TO THE ORGANISMS IMPORT AOT 

 IN THE FOULING OF SHIPS' BOTTOMS 



I. Organisms with hard, often limy shells: 



A. Coiled or twisted tubular shells. . . . Annelids 



B. Cone— shaped shells attached di- 

 rectly to the hull, or shells with 



a long muscular stalk. Barnacles 



C. Flat, spreading, granular discs 



or patches. . Bryozoa 



D. Paired skells, such as clams, 



mussels, oysters, etc .^ . . . . Mollusks 



II. Organisms without shells: 



A. Green, brown, or red filaments or 

 leaflike structures, generally near 



water line Algae 



B. Branching tree-shaped gro\\'ths, the 



branches not expanded at the tips Bryozoa 



C. Straight or branching growths, 

 each thread terminating in an ex- 

 panded tip Hydroids 



D. Rounded soft spongy masses Tunicates 



10 



