The common slipper shell, Crepidula fornicata, has many other common names, including common Atlantic slippersnail, boat shell, quarterdeck shell, fornicating slipper snail, Atlantic Slipper Limpet and it is known in Britain as the "common slipper limpet". This is a species of medium-sized sea snail, a marine gastropod mollusc in the family Calyptraeidae, the slipper snails and cup and saucer snails.