Marine molluscs (6)
(Other definitions for scallops that I've seen before include "Molluscs with wavy-edged shells" , "Semi-circular curves used as ornamental edging - or shellfish" , "Tasty shellfish or ornamental curved edgings" , "Curves forming a wavy edge" , "Edible molluscs" .)
(Other definitions for whelks that I've seen before include "Marine snails" , "Kind of sea snails used as food" , "Seasnails" .)