50 
LOWER MAMMAL GALLERr. 
forming a single posterior swimming-paddle. Their action is 
similar to that of a person propelling a boat with a single oar 
worked from the stern. 
This description applies fully only to the true Seals or 
Phocidce ; the Otariid(8, or Eared Seals, resembling ordinary 
Carnivores far more, especially in the position of their hind- 
limbs, as explained below. 
The skull (see fig. 27) has no processes behind the sockets of 
the eyes, and the posterior teeth are different from those of the 
Land-(;arnivora, there being no specialized sectorial tooth nor 
any flat tubercular teeth at the back of the mouth. All the 
teeth are long and sharj), with the points directed towards the 
Fig 27. 
Skull of the Leopard-Seal [Of/mor/miKs leptomjx'). 
i, incisors ; c, canine j pm, premolars ; m, molar. 
throat, thus forming admirable instruments for catching and 
holding such slippery prey as the fishes on which Seals feed ; 
but they are useless for biting the prey into small pieces, each 
fish being invariably swallowed whole. Some of the Seals have 
their teeth provided with additional sharp-pointed cusps along 
their edges, as in the Leopard-Seal, Ogmorldnus leptonyx ( 646 ), 
fig. 27. _ _ . _ 
In the Walruses, which are in many ways intermediate 
between these two families, the dentition is very remarkable, 
the canine teeth being enormously developed, while all the 
other teeth are small and rudimentary, with flattened crowns. 
