Littorina [Littoraria] scabra, India. The common name for members of the genus Littorina and its relatives is periwinkle. This is a marine snail, living on hard surfaces in the littoral zone. Periwinkles serve as human food in various places. Note the eyes placed on protuberances next to the tentacles. Also note the snout, characteristic of many prosobranch groups.
John B. Burch (photographer; copyright holder), Mollusk Division, Museum of Zoology, University of Michigan-Ann Arbor