The opercular aperture is diamond shaped and protected by two further plates which can slide across when the animal is not feeding.

Individuals in a group fertilise each other and, after a period of maturation, nauplii are liberated into the water.

After a number of moults, the larvae settle out of the zooplankton in about April and attach themselves to rocks and stones on the sea floor.

B. crenatus is a fast-growing barnacle and can grow from a length of 3 millimetres (0.12 in) to 9 mm (0.35 in) in the month of May after settling.

It seems to favour habitats with strong currents and when overcrowding occurs, may be distorted to fit the space available.