Diodora sayiDiodora sayi is a species of sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets.DescriptionThe deep-water specimens of Fissurella alternata var. sayi are generally smaller, of an olivaceous cast, and with the color rays very faint or entirely absent.DistributionThis species occurs in the Atlantic Ocean off Brazil and the Cape Verde.