Size large, up to 5 inches in total length. Capitulum fleshy, with two large folded ear-like appendages, and with two to five minute valves, remote from each other. Opercular opening surrounded by hood. Two small scuta below the opening visible through transparent outer layer of membrane. Cirri short, much flattened, and leathery. Peduncle cylindrical, expanded at base for attachment.
Faint pink, occasionally with irregular mottled patches of brown or purple on the capitulum; peduncle irregularly striped with brown or purple; cirri, white.
World-wide, attached to shells of Coronula on whales, occasionally on a ship's bottom or on buoys and rocks.
Conchoderma auritum is most often found attached to the shells of Coronula on the humpback whale; sometimes more than fifty are attached to one shell. "Rarely a specimen is found attached to the base of the teeth of an old sperm whale" (Sheffer, 1939). Gordon C. Pike reports finding specimens of C. auritumon sperm and fin whales taken in British Columbia. In each case the barnacles were associated with a deformation or an apathological condition of the jaws, baleen, or teeth. Each barnacle is usually oriented with the opening facing in the direction the whale swims. The food-laden water passes through the opening and over the feeding appendages, then out through the two "ears" which have tubular openings.