Stalked barnacle

Pedunculata
Pollicipes pollicipes
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Maxillopoda
Infraclass:	Cirripedia
Superorder:	Thoracica
Order:	Pedunculata Lamarck, 1818

Goose barnacles (order Pedunculata), also called stalked barnacles or gooseneck barnacles, are filter-feeding crustaceans that live attached to hard surfaces of rocks and flotsam in the ocean intertidal zone.

Some species of goose barnacles such as Lepas anatifera are pelagic and are most frequently found on on oceanic coasts. Unlike most other types of barnacles, intertidal goose barnacles (e.g. Pollicipes pollicipes and Pollicipes polymerus) depend on water motion rather than the movement of their cirri for feeding, and are therefore found only on exposed or moderately exposed coasts.

In the days before it was realised that birds migrate, it was thought that barnacle geese, Branta leucopsis, developed from this crustacean, since they were never seen to nest in temperate Europe, hence the English names "goose barnacle", "barnacle goose" and the scientific name Lepas anserifera (Latin = "goose"). The confusion was prompted by the similarities in colour and shape. Because they were often found on driftwood, it was assumed that the barnacles were attached to branches before they fell in the water. The Welsh archdeacon of Brecon, Giraldus Cambrensis, made this claim in his Topographia Hiberniae.

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Wikipedia