REPORT OF AMERIC'AN COMMISSIONERS. 321 



tlie fur-seals, owing to the greater length and Distinction be- 

 mobility 01 their liippers and to then- structural '^i^i Lair seals, 

 peculiarities, travel on land with considerable 

 facility and speed, the body being lifted high 

 above the ground and the gait suggesting the 

 ambling pace of the bear. The true hair seals 

 (family Phocidce) on the contrary are wholly 

 unfitted for progression on land. From the 

 natural history standpoint they represent the 

 extreme of differentiation or departure from the 

 ancestral stock among the terrestrial carnivorous 

 mammals. In accordance with their aquatic 

 habits the fore legs have been so modified that 

 they are little more than stiff paddles, like 

 those of the whale; the hind flippers stick out 

 behind and can not be turned forward for use in 

 terrestrial locomotion or in climbing over rocks, 

 and their bodies drag heavily over the ground. 

 Their movements on land or ice are awkward 

 and laborious, and consist of a series of vertical 

 curvatures and extensions of the spine, suggest- 

 ing the method of locomotion of the measure 

 worm. 



The amphibious fur-seals are not only inter- Fm-seais. 

 mediate between the hair seals and terrestrial 

 carnivorous mammals in structure and means of 

 locomotion, but also in habits, for they spend 

 2716 41 



