Species details: Porcellana platycheles

These are from Lulworth Cove in Dorset. I have three, but I never see them, they are always hidden between the rocks, and don't even come out after dark. Occasionally I get a glimpse of them when I shine a torch between the rocks, which they don't seem to mind. They seem quite hardy, but they are so secretive that its like they aren't there at all. I guess they make themselves useful by feeding on detritus between the rocks.