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Show 156 PROF. W. H. FLOWER ON THE ELEPHANT SEAL. [Jan. 4, resemblance consists: the bones are constructed upon quite a different type; and though the similarity is masked by this curious overgrowth or hypertrophy of bone in certain parts, it can be shown, by the existence of intermediate forms, that their resemblance is, on the whole, to those of the land Carnivora. As might be expected, the intermediate forms are found in the Otariidse ; and nothing can display so strikingly the importance of the characters derived from these bones than to see the retention in Otaria, with the external pinna and scrotum, and power of use of the hind limbs, an incus and stapes far more resembling the corresponding bones in the Ursidse than in the Seals. Macrorhinus, on the other hand, has extremely modified ossicula. The stapes isa simple subcylindrical mass, and, being thicker and more rounded towards the incudal than at the attached end, has almost a bell- or bottle-shape, with scarcely a trace of division into crura. In this respect it resembles that of the Walrus alone among the Pinnipedia. The incus is a very remarkable bone, its ordinary characters being quite masked by the imnieuse globular development of the posterior and outer part of the body, or that which lies over the processus brevis, and which throws the articular surface quite away from its normal upward aspect. Owing to this bulky form of the body, the bone is larger than that of any other known mammal, except Manatus. A deep elongated pit or groove, running in the internal face from the middle of the articular surface, is another characteristic. A similar, though less extreme, dilatation of the body is found in all the true Seals, but the peculiar pit only in the Stenorhynchince ; indeed, as Mr. Doran has pointed out, it is to the incus of these, rather than to the (in so many respects more nearly allied) Cystophora, that this bone of Macrorhinus bears most resemblance. After remarking that this bone is " only a caricature," so to speak, of that of Phoca, as its posterior part assumes and exaggerates the Phocine type, the form of the long crus induces Mr. Doran to believe that the incus of Macrorhinus is a truly central form. But the form of this crus is obviously very variable, even in the series of closely allied Seals figured at the top line of plate lx, of the memoir ; and it may be doubted whether the peculiar long slender and subcylindrical limb of the incus in Macrorhinus should be regarded as retention of a generalized form, as it certainly is not exactly paralleled in any other. The malleus also more resembles that of Stenorhynchus than that of any of the other Seals. Systematic Position and Affinities.-In any natural arrangement of the existing Pinnipeds, the Elephant Seal appears to me to form the extreme term of the series, as it is the one which combines in itself in the fullest degree all the characters by which the Seals are distinguished from the terrestrial Carnivora. It is, if I may so say, the most " seal-like " of all the Seals. The Walrus as regards its dentition is more highly specialized, but in a direction peculiar to itself; and in other characters, as those of the limbs, it retains a more generalized form. The Elephant Seal and, though perhaps to a slightly less degree, the Bladdernose have kept nearer to the |