Physical 

This genus includes many of the barnacles on the eastern seaboard. Average size is 2 inches in diameter.

Habitat

Acorn Barnacles grow in partially brackish estuaries on rocks, jetties, and boat bottoms. They are found from high intertidal areas to 1,000 feet in depth.

Feeding 

Acorn barnacles are filter feeders that use their cirri to catch plankton and detritus floating in the water column.