this snail has a solid, smooth shell, which is a uniform black colour. However, older or eroded individuals may be white at the peak of the shell. The opening (aperture) is thick and white, except for a black line around the outer edge. The door (operculum) is solid, semi circular and covered with small lumps. The colour is orange-tan with black lines.

This species is found on open rocky surfaces or boulders at mid to high tide. They are found in a range of places from very exposed to moderately sheltered.Juveniles usually cluster in crevices and under boulders.

These are algal grazers.

May occur as widely scattered individuals or in tightly bunched clumps often numbering in the hundreds of individuals. Egg capsules are white and slightly oval in shape. These are laid in shallow depressions and in small holes in the rock or on the sides and underneath cobbles.

Coastal Marine Invertebrates Vol 1 Photo Credit: Egg case pictures Karen Taylor