1881.3 PROF. W. H. FLOWER ON THE ELEPHANT SEAL. 157 



direct line of modification, only carrying it out to a more complete 

 extent tlian have the ordinary Seals. 



As far as our imperfect knowledge of its osteology allows us to 

 judge, in all points in the anatomy of the limbs in which the Pho- 

 cidae differ from the land Carnivores, such as the general proportions 

 of the bones, especially the shortness of the femur, the want of 

 development of the calcaneal process, the articulation of the fifth 

 metacarpal with the proximal row of carpal bones, the Elephant 

 Seal presents the extreme of modification. The true Seals {Phocince) 

 have well developed claws on both the fore and hind feet ; and the 

 toes of tlie posterior limbs are subequal, the first and fifth being only 

 slightly longer than the others ; and the interdigital menbrane does 

 not extend beyond the toes. In the Elephant Seal the claws of the 

 fore limb are reduced, and in the hind limb are absent or excessively 

 rudimentary ; the first and fifth toes of this limb are greatly enlarged 

 beyond the others, and the skin prolonged in lobes beyond the true 

 end of the digit, producing a much greater modification of the whole 

 foot from the terrestrial type, and causing a considerable superficial 

 resemblance to the forked caudal appendage of a Cetacean or Fish. 

 This character of the pedal extremity is possessed also by the Ste~ 

 norhynchince, which are in many respects intermediate between the 

 PhocincB and the Ci/stophorina. Another and still more important 

 character in the structure of the limbs, in which the Seals resemble 

 the Cetacea and differ from all other known mammals, is most 

 strongly marked in the Elephant Seals, as is well seen in the young 

 skeleton mounted in the Museum of the College of Surgeons. It is 

 that all the phalanges of both limbs (except the ungual phalanges) 

 are ossified from three centres, an epiphysis being developed for 

 each extremity, instead of a single epiphysis at the proximal 

 extremity, as is the rule throughout the class. How far this 

 occurs in other Pinnipeds is not certainly known. Stenorhynchtis 

 leptonyx, as shown in the not quite adult skeleton from New Zealand, 

 presented to the Museum of the College of Surgeons by Mr. W. L. 

 Crowther, F.R.C.S., resembles the Elephant Seal in this respect. In 

 tlie true Seals of our hemisphere (P/ioc«M«), if it occurs, it is as a much 

 less obvious and more transient condition, as I have not been able to 

 detect the double epiphysis in any of the young skeletons in the 

 Museum', 



The modifications of the ossiculu auditiis have been already referred 

 to as showing that the Elephant Seal presents an extreme form, 

 though here also Stenorhij7ichus is its nearest congener. 



In the dentition also it has been shown that the characters by which 

 Seals differ from other mammals are carried to their fullest extent 

 in the Elephant Seal. The Leopard Seals {Stenorhynchus) may be 

 regarded as showing the greatest perfection of the type, in the even 

 row of exactly similar, finely developed, and sharply cusped, two- 

 rooted molars; while in the Elephant Seal the same type has under- 



' In the pes of a young Phoca vittdina in the Oxford Museum there are traces 

 of epiphyses on the "distal as well as the proximal end of the metaciirpal of the 

 hallux. 



