Marine gastropod (7)
(Other definitions for abalone that I've seen before include "Seafood" , "Source of mother-of-pearl" , "Ormer, ear shell" , "Mollusc, the sea-ear" , "marine creature" .)
(Other definitions for limpet that I've seen before include "Shellfish; type of mine" , "Mollusc adhering to rocks" , "A shellfish that sticks to rocks or ships" , "Rockpool clinger?" , "he's not easily got rid of" .)