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CARNIVORES. 



in which it remains so long as they are filled with solid ice ; but when this 

 breaks up the seals betake themselves to the ice-floes, upon which the young are 

 born in the months of March and April. The ringed seal is not a migratory species, 

 and in some localities is found in considerable numbers. It is one of those seals 

 which make a circular " blow-hole " in the ice, through which they can ascend or 

 descend at pleasure ; such apertures being made while the ice is forming. 



Nearly allied to the ringed seal are the Baikal seal (P. sibirica) and the 

 Caspian seal (P. caspica), which are respectively confined to the inland seas from 

 which they take their names. Both these seals are rather larger than the ringed 

 seal, and are very similar to one another. Their especial interest is derived from 



SEALS SWIMMING. 



their habitat ; the Baikal seal inhabiting a fresh- water lake, while the waters in 

 which the Caspian seal dwells are but slightly salt. The curious part of the matter 

 is that neither Lake Baikal nor the Caspian Sea appear to have had any recent 

 connection with the Arctic Ocean ; and if, as is most probably the case with the 

 latter, we have to look to a former connection with the ocean to the southward, it 

 becomes difficult to see whence came the stock from which these two allied species 

 were derived. Mr. Allen has suggested, however, that the ringed, the Baikal, and 

 the Caspian seal may be all descended from an allied extinct species whose remains 

 are found in the Pliocene deposits of Belgium. 



Lastly, we have the bearded seal (P. barbata), which is distinguished from all 

 the other members of the genus by its superior size, its broad muzzle and convex 



