44. The file shell, Lima, has a lasplike covering of spiny 

 ribs. The briglitly colored sensory tentacles are contrac- 

 tile but cannot be withdrawn completely into the shell. 

 (Marineland, Florida) 



4.5. File shells are able tn 

 swim about slowly, clap 

 ping their valves, which 

 are held verticallv. (West 

 Indies. Fritz Goro: Life 

 Magazine) 



46. File shell (West In- 

 dies. Fritz Goro: Life 

 Magazine) 



