of minor importance, the chief distinctions being in the skull and dentition. There are on each side three incisors in the upper jaw, and two in the lower. The middle ones are smallest, the upper outer ones more often very large. The canines are still larger, and recurved; but though powerful, not to be compared with the great tusks of the Morse. There are more commonly five teeth of the molar series, of which the crowns are bluntly conical, and the roots simple. The milk-teeth are mostly shed before birth. The dental formula of the Otariidæ may be represented thus:--Incisors, (3-3)/(2-2); canines, (1-1)/(1-1); premolars, (4-4)/(4-4); molars, (2-2)/(1-1) = 36. The fore part of the skull is not so swollen out and abrupt as in the Walrus, the smaller size of the canines not requiring such space. In youth the skull is long, low, and flat, but in the old males there arise bony crests and processes, altering the shape, especially behind, so that recognition of the species is even difficult. [Illustration: TEETH OF OTARIA. (_After De Blainville._)] As the habits of the family of the Eared Seals are in the main very similar, and seeing how difficult it is from mere outward inspection to tell one species from the other, it seems advisable to follow Mr. J. W. Clark’s mode of treatment, and consider all under the single genus _Otaria_, though incidentally allusion will be made to such forms as are indicative of generic distinction. We have in passing mentioned two kinds, namely, Fur and Hair Seals, and we have also stated that these Eared Seals are not confined to one hemisphere, but equally inhabit northern and southern regions. Taking these facts into account we submit the following table as a kind of provisional arrangement for the reader, that he may carry away a notion of what may be termed a combination of commercial and geographical divisions. _Northern._ _Southern._ } { THE FALKLAND ISLAND FUR SEAL. } { THE SOUTH AFRICAN, OR CAPE THE NORTHERN FUR SEAL.} FUR SEALS. { FUR SEAL. } { THE NEW ZEALAND FUR SEAL. } { THE ASH-COLOURED OTARY. STELLER’S SEA LION. } { HOOKER’S SEA BEAR. GILLIESPIE’S HAIR SEAL.} HAIR SEALS. { WHITE-NECKED OTARY. { THE PATAGONIAN SEA LION.