The two skulls of this species in the British Museum agree in most particulars; but they differ considerably in the form of the hinder nostrils. The larger one is without its upper teeth, but the forms of the roots are well exhibited by their sockets; the front edge of the hinder nasal opening is produced rather further forward, and is acutely angular. The other skull, which is rather smaller and has the teeth in good condition, has the hinder nasal opening with a slightly arched, nearly truncated, front edge. Dr. Peters refers _Phoca falklandica_ (Shaw, Zool. i. p. 256) and _Otaria falklandica_. (Hamilton, Ann. & Mag. N. H. 1839, p. 81, t. 4; Jardine, Nat. Lib. vi. p. 271, t. 25) to this species. But as neither Dr. Shaw nor Dr. Hamilton describes the number or position of the teeth, it is not possible to determine if this is the _Fur-Seal_ of the sealers, collected at the Falkland Islands, more especially as the fact of the skull coming from the Falkland Islands is not well ascertained. See the other synonyma which have been established on the sealers’ descriptions and figures or the skins collected for the furriers at the Falkland Islands (Gray, Cat. Seals and Whales, pp. 55, 56). Dr. Hamilton, who prides himself on his figure, represents the hind legs as extended behind: but they look very awkward in that position, the stuffer having evidently had a difficulty in extending them. The hair of _A. nigrescens_ is considerably longer than that of _A. cinereus_, but not so harsh, the fur of the half-grown _A. nigrescens_ being longer, sparse, flat, rather curled at the end, giving it a crispness to the feel; while the hairs of the very young specimens are abundant, nearly of equal length, forming an even coat that is soft and smooth to the touch. Capt. Abbott’s young specimen in the British Museum chiefly differs from the adult specimen in the same collection in the hairs being longer, more erect, and with minute white tips, and in the face, throat, and chest being rufous brown; but this reddish colour is common to the young of several Sea-bears. The skulls from Desolation Island, on the south-west coast of Patagonia, presented to the Anatomical Museum of the University of Edinburgh by the late Professor Goodsir, evidently belong to _Euotaria nigrescens_, the usual Fur-Seal of the Falkland Islands and other parts of the coast of South-west America. Two of the skulls are from adult animals, are without the lower jaws, and have only a few worn and broken teeth, having been rolled on the beach. The other skull is of a young animal, exactly similar to the skull of a young _Euotaria nigrescens_, n. 1013_e_, in the British-Museum collection. The front edge of the hinder nostrils is as arched as in that specimen; the teeth are rather more developed than in our skull; they have a well-marked central lobe and a distinct small acute tubercle on the front edge of the cingulum.