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What happens when a Lingula lamp shell is startled?

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lamp shells Lamp shells on the sea floor off the coast of Massachusetts.

When a Lingula lamp shell is startled, it retracts its shell into its burrow. This movement is made possible by the animal's contractile pedicle, a long, fleshy stalk that attaches the organism to the bottom of its burrow in mucus. While the pedicle allows the shell to extend for feeding, its ability to contract provides a vital defense mechanism for the animal when it senses a threat.1