Balanus (balanus)

[L., ripeds of the family Bala nid a; the acorn-shells or sea-acorns, called barn a cles, except in Great Britain, where the peduncu Balanus percatus. lated Lepadidæ have that name. B. tintinnabulum is the representative species. The shell consists of 6 plates, with an operculum of 4 valves. Colonies are to be found on rocks left dry at low water, on ships, on timber, on lobsters and other crustaceans, and on the shells of conch if ers and other mollusks. They differ from the members of the genus Lepas in having a symmetrical shell and in being destitute of a flexible stalk. They pa through a larval stage of exis IMG:content-1582.png:[merged small][merged small][subsumed][ocr errors][subsumed][ocr errors][subsumed][ocr errors][subsumed][merged small][subsumed][merged small][merged small][merged small][merged small][merged small] ton.