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  • José H. Leal

Shell of the Week: The Beaded Periwinkle

Cenchritis muricatus (Linnaeus, 1758) is a marine snail of the periwinkle family Littorinidae. The species may reach 30 mm (about 1.2 inches), and,as the common name implies, the shell surface is covered with a sculpture of tiny beads. The snails basically live above the high tide line on rocky coasts, exposed coral rock, and other hard substrates. Beaded Periwinkles are capable of climbing vertical rocky cliffs to heights of over 14 meters (about 46 feet). When away from the water, it avoids desiccation and overheating by hiding in moist crevices. As with other periwinkles, Beaded Periwinkles graze on microalgae and possibly microfungi that grow on hard substrates on the so-called “splash zone” above and between tide lines.


The Beaded Periwinkle, Cenchritis muricatus, from Coral Cove, Florida. Photos by James F. Kelly.