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Comparative Morphology of Chordates 



Phocidae: "Earless seals'" —no pinnae; pelvic flippers, directed 

 backward, serve in place of a caudal fin and cannot be rotated forward 

 useless on land. Common "harbor seals." 



Odobkmdae: No pinnae: upper canines become enormous tusks 

 projecting downward. Walrus (Fig. 562). 



Distribution of Carnivora: World-wide except in Australia, New 

 Zealand, Polynesia, and islands adjacent to them. The "native dog" 

 or "dingo" of Australia is a true carnivore (not marsupial), but its 

 presence there as the only member of Carnivora in that part of the 

 world is probably due to its import at ion by early man (Fig. 563). 



The hoofed mammals, "ungulates," have commonly been re- 

 garded as constituting an Order, Ungulata, including several sub- 

 orders. Such scanty knowledge as is available concerning the origin of 

 ungulates indicates that probably they have not had common origin 

 in some primitive hoofed ancestors, it is more likely that the common 



Fig. 562. Walrus. Odobenus. (Courtesy, American Museum of Natural History, New 



' York.) 



