The Sea-lion of Steller has been one of the zoological paradoxes. Professor Nilsson, like most preceding authors, regarded it as a variety of the _Otaria jubata_; and therefore I supposed it might be a second species of the restricted genus _Otaria_. Dr. Peters has solved the enigma by uniting it and the Seal which I described from California, observing that the skull in the Berlin Museum, figured by D’Alton under the name of “Steller’s Sea-lion” (_Phoca jubata_), was received from Kamtschatka, and a second skull of an old male in the Berlin Museum was received from Mr. Brandt as coming from Behring’s Straits. The figure of Pander and D’Alton is so imperfect that it would have been impossible to determine the species it represents without the examination of the original skull; and then one sees that it may have been intended for the species to which it is referred. The same observation is applicable to the figure of the skull of Steller’s Sea-bear. It is to be regretted that these skulls escaped the researches of Professor Nilsson, who visited most museums in Europe to examine the typical specimens. The specimen of _Callorhinus ursinus_ now in the Museum was received from St. Petersburg as _Otaria leonina_, or _Leo marinus_ of Steller, from Behring’s Straits; so they evidently confound two species under that name. 8. ARCTOPHOCA. Arctophoca, _Peters_. Dr. Peters described this subgenus from a specimen sent from Chili by Dr. Philippi. It chiefly differs from _Zalophus_ in the palate being much narrower, but rather wider behind, and the teeth rather far apart. I have not seen any skull agreeing with these characters. “With abundant under-fur.” According to figures, the form of the skull and the large size of the orbit are very similar to those of _Phocarctos Hookeri_, but the number and form of the teeth are different. In the ‘Monatsbericht,’ May 1866, p. 276, t. 2. _a_, _b_, _c_, Dr. Peters described and figured with considerable detail a skull of a Sea-bear (sent to the Berlin Museum by Dr. Philippi, who obtained it at Juan Fernandez Island) under the name of _Otaria Philippi_, forming for it a subgenus which he calls _Arctophoca_. In his revision of that paper, published in the same work for November 1866, p. 671, he places it as a synonym or subspecies of what he calls _Otaria falklandica_, which is my _Arctocephalus nigrescens_, and not the _Otaria falklandica_ of Shaw nor the _O. falklandica_ of Burmeister as Dr. Peters supposes, as I have shown above. In this paper he removes _Otaria falklandica_ (that is, _nigrescens_) from the subgenus _Phocarctos_, to which he referred it in his first paper, and places it in his subgenus _Arctophoca_. 1. Arctophoca Philippii. _Chilian Fur-Seal._ Otaria (Arctophoca) Philippii, _Peters_, _Monatsbericht_, May 1866, p. 276, t. 2 (skull), September 1866, p. 671. Otaria Hookeri, var., _Murie_, _P. Z. S._ 1869, p. 108! Inhab. Juan Fernandez Island (_Philippi_; in Mus. Berl.).