WHALES AND SEALS 89 



Now as to external features in which the seal tribe 

 differ from the whales. In the first place the former 

 have completely retained their hairy covering. There 

 is no hint of a commencing baldness whatever. 

 Moreover, there is not here a case of the substitu- 

 tion of one organ for another that plays a similar 

 part ; for the seals have an abundant layer of fat, and 

 are pursued for purposes of oil as much as are whales. 

 They have fur and blubber. Again, the extra length 

 of digit required is not brought about in the Cetacean 

 fashion by the increase in the separate phalanges of 

 the fingers, but by the formation of cartilaginous 

 extensions of the fingers beyond the nails. That 

 these are beyond the nails shows that they are not 

 comparable to the extra phalanges of the whales ; for 

 the rudiments of nails, which have been discovered in 

 whales, are terminally placed upon the hand. 



A peculiarity which the sea-lion shares with the 

 whales is the great breadth of the scapula ; for 

 some reason or other this seems to be useful to 

 an aquatic animal, for it is in these two types 

 that the scapula seems to attain to its greatest 

 diameter. It is true that in Edentates the same 

 bone is also very broad, and that it is relatively 

 narrow in the Manatee ; but the breadth is most 

 striking in the sea-lion and in the whale. But on 

 a close comparison of the blade-bones of the two 

 it is to be noticed that, in spite of superficial like- 

 ness, there are fundamental differences. In the 

 sea-lion it is the front part of the bone, that which 

 lies headwards of the spine, that is expanded most ; 



