Valves white, thick, furrowed and placed close together. Scutum quadrangular, radially furrowed; umbonal area smooth; secondary area ventral to umbo-apical ridge broad, and occludent margin protuberant. Internal umbonal tooth present on right-hand scutum; that on left scutum often reduced. Tergum trapezoid and generally more striated than scutum. Carina rather broad, placed close to scuta and terga. Prongs of fork diverging at an angle of 90° or more. Peduncle orange.
Mouth parts and cirri lacking any specific characters; caudal appendages smooth and curved, typical for the species. Filamentary appendages generally five, sometimes six, on each side of body, one situated on prosome, the rest beneath basis of cirrus 1.
L. anserifera is variable in external characters, but is distinguished by the presence of five, occasionally six, filamentary appendages and the curved, pointed, caudal appendage.
Capitulum up to 40 mm in length. Peduncle generally as long as capitulum, sometimes contracted.
Pelagic. L. anserifera is a rare visitor in northern waters attached to driftwood, ships' hulls and other floating objects, often with other species of Lepas. It enters the Norwegian Sea through the Faeroe Channel in summer and autumn.
Distribution in the North Sea:
Occasionally carried by ships to the North Sea, Shetland Islands, and Denmark (Copenhagen).
Almost cosmopolitan, chiefly in tropical and temperate seas.