BRANTA AURITA. _Oken._ Lehrbuch der Naturgesch., Th. 11, p. 362, 1815. MALACOTTA BIVALVIS. _Schumacher._ Essai d’un Nouveau Syst., &c., 1817. GYMNOLEPAS CUVIERII. _De Blainville._ Dict. des Sc. Nat., Art. Mollusc., Plate, fig. 1, 1824. [37] Many authors (Poli, Montagu, &c.,) have doubted from the strangely mistaken description, viz., “ore octovalvi dentato,” whether this species could be the _Lepas aurita_ of Linnæus. But in the Linnean Society, there is a proof plate from Ellis’s “Account of several rare Species of Barnacles,” in ‘Phil. Trans.,’ 1758, with an excellent figure of the _C. aurita_, and on the margin in Linnæus’s handwriting is the name _Lepas aurita_. _C. capitulo duobus tubularibus quasi-auribus instructo, pone terga rudimentalia (sæpe nulla) positis: scutis bilobatis: carinâ nullâ, aut omnino rudimentali: pedunculo longo, a capitulo distincte separato._ Capitulum with two tubular ear-like appendages, seated behind the rudimentary and often absent terga; scuta bilobed; carina absent, or quite rudimentary; peduncle long, distinctly separated from the capitulum. Filaments attached to the pedicels of the second cirrus; two upper spines of the maxillæ pectinated. _Hab._--Mundane; extremely common. On ships’ bottoms from all parts of the world. Arctic Sea. Greenland. Pacific Ocean. Often attached to Coronulæ on Whales. On slow-moving fish, according to Dr. A. Gould. Often associated with _C. virgata_, and _Lepas anatifera_, _L. Hillii_, and _L. anserifera_. _General Appearance._--The capitulum (seen from above in Pl. III, fig. 4 _a_) is slightly compressed, almost globular, composed of thick membrane, with two large, ear-like, flexible, tubular, folded appendages, at the upper end, opening into the sack. These appendages are seated behind the rudimentary terga when such are present, or behind the spots which they would have held if not aborted. In a young condition they are tubular, but not folded; and often, according to Prof. Macgillivray, either one or both are at first imperforate. They are formed externally of the outer membrane of the capitulum (rendered thin where folded), and internally of a prolongation of the inner tunic of the sack; between the two, there is, as around the whole sack, a double layer of corium. A section across both appendages, near their bases, is given in Pl. III, fig. 4 _b_, showing how they are folded,--the chief fold being directed from below upwards, with a smaller fold, not always present, from between the two, outwards. The folds sometimes do not exactly correspond on opposite sides of the same individual; they are almost confined to the lower part, the orifice itself being often simply tubular. These appendages are sometimes very nearly as long as the whole capitulum: a section near their bases is sub-triangular. I shall presently make some remarks on their functions and manner of formation.