SEALS. 71 



The accompanying illustration, which is kindly lent 

 by Messrs. Routledge and Sons, shows the remarkable 

 form which both jaws are obliged to assume in order 

 to accommodate those enormous tusks. This jaw, if 

 formed in the usual manner, would be in the way of 

 tusks, so that the mouth could not be closed. It is, 



FKULL OF WALRUS. 



therefore, very much narrowed in front, so that it 

 passes easily between the tusks, and can move with 

 freedom. 



Another strange variation in the structure of these 

 animals is shown in the centre of Plate I., the figures 

 in which represent that extraordinary creature, the 



