1S6 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 is a simple subcylindrical mass, and, being thicker and more 

 rounded towards the iucadal 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 cha- 

 racters being quite masked by the immense 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. JJoran to believe that the incus of 2Iacrorhinus 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 Ix. 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 Stenorhynehus than that 

 of any of the other Seals. 



Systematic Position and Affinities. — In any natural arrange- 

 ment 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 ihe limbs, it retains a 

 more generalized form. The Elephant Seal and, though perhaps to 

 a slightly less degree, the Biaddernose have kept nearer to the 



