CHAPTER XVIII. 

 THE TRUE SEALS. 



THE COMMON SEALS — THEIR WIDE DISTRIBUTION — THEIR HABITS — THEIR LOVE OF MUSIC — ROBBIN's 

 REEF — THE CASPIAN SEAL — THE HOE-RAT — THE HARP-SEAL — RICHARD'S SEAL — THE BEARDED 

 SEAL — THE GRAY SEAL — THE WHITE-BELLIED SEAL — THE SEA LEOPARD — THE CRAB-EATING 

 SEAL — THE FALSE SEA LEOPARD — THE LARGE-EYED SEAL — THE SEA ELEPHANT — THE CRESTED 

 SEAL — THE WEST INDIAN SEAL. 



THE family, Phocid^, or True Seals, is pretty equaiiy divided 

 between the Northern and Southern Hemispheres, frequent- 

 ing almost exclusively the cold and temperate regions. The 

 absence of an external ear, the short limbs which seem stuck into the 

 body, the hairy flippers, and the teeth, distinguish the animals of this 

 family from the Eared Seals already described. 



They are usually divided into thirteen genera, and Gray groups these 

 genera into five sub-families, the first of which (the sub-family of the 

 Phocin.€j, contains five genera. 



I.— GENUS CALLOCEPHALUS. 



The three species of this genus are distributed over the coasts of 

 Greenland, the North Sea, and the Caspian Sea, and also in Lakes Aral 

 and Baikal, and the occurrence of seals in these inland waters is a fact 

 of peculiar interest. In the case of the Caspian and Lake Aral, it is 

 remarked by Wallace, that as they are connected with the Northern 

 Seas by extensive plains of low elevation, a depression of less than five 

 hundred feet would open a communication with the ocean. At a com- 

 paratively recent epoch, a gulf of the Arctic Sea must have extended to 

 the Caspian till the elevation of the Kirghiz steppes cut off the passage. 



Lake Baikal offers greater difficulties, for it is a fresh-water lake 

 situated in a mountain district two thousand feet above the sea-levfii, 

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