Possible Clues:

• Mollusc sometimes eaten alive
• Mollusk with an irregular shell
• Some teddy boys terrorised native
• It may be rot, yes, but it's all Shelley, by the sound of it
• Little boy's terrified of shellfish
• Would Shelley, perhaps, have shut up like this?
• Greyish pink bit of chicken meat
• Onyx set near every other jewel's origin
• One taken from bed to table
• Tasty bivalve, may carry pearl