Fissurella crassaFissurella crassa, common name the thick keyhole limpet, is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets and slit limpets.DescriptionThe size of the shell varies between 34 mm and 90 mm.DistributionThis species occurs in the Central Pacific to Peru and Chile; but not off the Galápagos Islands.