The outer shell is fused in a ring . It has a door made of four shell pieces which slot together like a jigsaw puzzle but it is less obvious than that of the brown surf barnacle. Large groups can get fused together to form a honeycomb pattern on the shore.

It is found on hard substrates at the mid tide level and can be very densely packed.

Filters plankton from the water using it's hairy "legs".

Collins: Gunson