Ynghylch

This large sea snail is found on rocks and amongst seaweeds around the middle to lower parts of the shore. Known as the edible periwinkle, common periwinkle or winkle, it looks pretty similar to a land snail, with a dark brown or grey banded shell and little eye stalks poking out. The edible periwinkle feeds by grazing on algae on the rocks using its rasping tongue, called a radula. They don't like dry areas, so will often be spotted clumped together in a crevice or rockpool at low tide.