Callopora lineata (Linnaeus, 1767)

General description: 

Callopora lineata is an encrusting bryozoan, which is characteristic of British rocky shore communities. Colonies form irregularly spreading sheets on the holdfasts of Laminaria species, shells, stones and the underside of boulders, predominantly in the intertidal, but extending down to the shallow subtidal waters.
The species is widespread through the boreal and cool temperate zone, south to the Mediterranean.