Cauloramphus spiniferum (Johnston, 1832)

General description: 

Cauloramphus spiniferum is an encrusting bryozoan species, common to most British rocky shores in the south and west of the country. The colonies form thin, irregular sheets spreading over the substrate. Cauloramphus spiniferum is able to encrust various substrates including stones, shells and kelp holdfasts. It ranges from the mid-shore to shallow subtidal waters, where it can occur in abundance. It does not appear to extend below the kelp bed.
The species is widely distributed in the cool temperate waters of the Atlantic, from the Shetland Isles to the northern coasts of France. It has also been recorded from the Atlantic and Pacific coasts of North America.