About Lottia digitalis (Rathke, 1833)
This species of limpet, Lottia digitalis, can grow up to thirty millimetres in length. It has a low cone-shaped shell, with the apex positioned close to its anterior edge. The anterior slope of the shell is concave, and sometimes overhangs. The posterior slope is convex and marked with heavy radial ribbing, and the shell margin is somewhat lobed and irregular. Shell characteristics of this species are very variable. Its shell is usually brown or dark olive with white patches.
The distribution range of Lottia digitalis stretches from northern Alaska to northern Mexico. It is a common species, found among acorn barnacles on vertical rock faces in high to mid-intertidal zones, on both exposed and sheltered coasts. In California, young limpets that are up to ten millimetres in diameter often live on the opercular plates of gooseneck barnacles (Pollicipes polymerus), and also on mussel shells. In both of these habitats, the limpets' colouring differs from that of individuals living on rocks, and provides camouflage.
