THE SEALS. 289 



the skull of the seal, and their dentition would have 

 to be fuller ; hence the supposed points of connec- 

 tion would be confined to a superficial resemblance 

 in the crowns of the molars, as there was very 

 probably an essential difference in the formation 

 of the hind limbs. 



As we are absolutely without any clue to the 

 origin of Seals, we may here mention one other 

 circumstance which seems to speak in favour of 

 the great age of this side-branch of the primary 

 Carnivore* What we yet know of the change of 

 teeth in Seals shows that the change takes place at 

 an extraordinarily early stage of life. 1 In most 

 cases the change takes place before birth ; the milk- 

 teeth never come to be of any use whatever, and the 

 permanent teeth are cut when the young animal is 

 but a few weeks old, and while making its first 

 feeble efforts to join its parents in their repasts. 

 Fig. 51 shows the teeth of a probably still unborn 

 Greenland seal (Phoca gronlandica) . The shading 

 shows the limit of the gums. It will be seen 

 that the milk-teeth have already vanished, all but 



a few unimportant remains; d ?. have wholly 



P 



1 J. Steenstrup, ' Maelkestandsaettet hos Eemmesaelen,' 

 Naturhislorick Foreningens Vidensk. Meddeleser. 1880. 



U 



