Robert Thompson / Keyhole limpet {Diodora graeca} in tidepool, Strangford Lough, County Down, Northern Ireland, September

Robert Thompson / Sea gherkin {Pawsonia saxicola} and Keyhole limpets {Diodora graeca} Ballyhenry Point, Strangford Lough, County Down, Northern Ireland, UK, September

Tim Laman / Giant Keyhole Limpet (Megathura crenulata) in Purple Hydrocoral (Stylaster venustus) Farnsworth Bank, California, USA. July 2001.