Crepidula plana, common name the eastern white slippersnail, is a species of sea snail, a marine gastropod mollusk in the family Calyptraeidae, the slipper snails or slipper limpets, cup-and-saucer snails, and hat snails. This species is characterized by a flat white shell, a white body, and development that includes a planktotrophic larval stage. This species often occurs inside large gastropod shells that are inhabited by hermit crabs. In this case the shells are often extremely flat, and often recurved.

Like all slipper snails, Crepidula plana is a filter feeder. They brood their offspring in clusters of transparent capsules between the substrate, the propodium and the neck.

Crepidula plana is native to the East Coast of North America, where it ranges from Canada to North Carolina. It has also been reported as introduced into San Francisco Bay. Reports of this species in the Gulf of Mexico or south of North Carolina are incorrect, and result from taxonomic confusion with other flat white species of Crepidula, including Crepidula atrasolea, and Crepidula depressa.

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