Possible Clues:

• Serve 'em on the halfshell
• 'But four young - hurried up,/All eager for the treat' (Lewis Carroll)
• Chesapeake Bay products
• Succulent bivalves, perhaps with pearls
• Rosy set of odd shellfish
• Secretive people often found in bed
• Molluscs
• From them you get the pearls that are Shelley's, perhaps
• Marine mollusks ...
• Dish sometimes served 'on the half-shell'