Balanus: Balanoides

The opening at the top is diamond-shaped and protected by four plates that form a "door" to prevent drying out (desiccation) during low tide.

It uses long, feathery appendages called cirri to filter plankton from the water. Habitat and Ecology balanus balanoides

Adults generally reach up to 15 mm in diameter , though some records suggest they can range up to 7.5 cm in certain conditions. The opening at the top is diamond-shaped and