Fissurella barbadensis:

Barbados Keyhole Limpet is 3-5 cm in length. Solid, conical, and highly elevated, with round or oval orifice at top. The surface is rough, with a heavy assortment of radiating ribs that project at the margins and give the shell a scalloped edge. Variable in colour and generally some shade of green, gray, or pink with brown blotches. The interior usually has alternating rings of dull green and white. Occurs in intertidal regions, on rocks near low tide level.