Origin of the name [edit]
In 13th-century England the word "barnacle" was used for a species of waterfowl, the barnacle goose (Branta leucopsis). This bird breeds in the Arctic but winters in the British Isles so its nests and eggs were never seen by the British. It was thought at the time that the gooseneck barnacles that wash up occasionally on the shore had spontaneously generated from the rotting wood to which they were attached, and that the geese might be generated similarly. Credence to the idea was provided by the tuft of brown cirri that protruded from the capitulum of the crustaceans which resembled the down of an unhatched gosling. Popular belief linked the two species and a writer in 1678 wrote "multitudes of little Shells; having within them little Birds perfectly shap'd, supposed to be Barnacles [by which he meant barnacle geese]."[5]

Wikipedia entry on Lepas anatifera.