acorn barnacle: any of various barnacles, such as Balanus balanoides, that live attached to rocks and have a volcano-shaped shell from the top of which protrude feathery food-catching appendages ( cirri )
barnacle goose: a N European goose, Branta leucopsis, that has a black-and-white head and body and grey wings
goose barnacle: any barnacle of the genus Lepas, living attached by a stalk to pieces of wood, having long feathery appendages ( cirri ) and flattened shells
gooseneck barnacle: → goose barnacle