Fingered or ribbed limpets (Lottia digitalis) attached to rocks above the low tide line. The 3 small black snails in the center of the frame are checkered periwinkles, (Littorina scutulata). Groups of acorn barnacles (Balanus glandula) can be seen at upper left and lower right. All 3 of these species are abundant intertidal species from Alaska south to CA. Photo Ruby Beach, Olympic Peninsula, Oregon.