Nodilittorina pyramidalis
Nodilittorina pyramidalis, commonly known as a pyramid periwinkle, is a species of sea snail, a marine gastropod mollusc in the family Littorinidae, the winkles or periwinkles.
The subspecies Nodilittorina pyramidalis pascua Rosewater, 1970 is a synonym of ''Echinolittorina pascua''
Description
The pyramid periwinkle is small, ranging from 2.5 cm to less than 1 cm in length. It is pale grey in colour, with two rows of nodules on the central whirl of its body which are a pale buff colour.It lives on or above the high tide line, usually clinging to vertical surfaces. Many individuals will cluster together in crevices to maintain moisture.