GEOGRAPHICAL DISTRIBUTION OF SEALS. 411 



round Cape Horn, remains to be settled by reference to tbe 

 affinities of tbe different species. 



How Seals came in tbe Caspian Sea and Lake Baikal are 

 two distinct problems. That they exist in both is beyond doubt. 

 On the Caspian is a regular " fishery," where some 100,000 

 are annually taken ; and various trustworthy travellers and 

 missionaries give details of the native "fishery" for Seals on 

 Lake Baikal. As to Seals reported to exist in the Sea of Aral, 

 or Lake Oron in Siberia, I can find no authentic account. The 

 Caspian being below the general ocean-level, and the species 

 being similar to Arctic species, points to some former connection 

 between these oceans. Lake Baikal, however, is several thousand 

 feet above tbe sea-level, tbe Biver Yenisei running down some 

 1200 miles from it into the Arctic Ocean. If Seals have ascended 

 this distance from the coast, the case is unique ; for nowhere 

 else are they found much above the tidal part of a river. This 

 case therefore remains a mystery. 



Behring Sea is also the head-quarters of the Sea Otter, 

 Enhydris lutris, which occurs from Behring Island down the 

 N.W. coast of North America as far as Upper California. In 

 many respects this animal forms a sufficiently good link between 

 Kiver Otters and Seals to emphasize the locality as the centre of 

 distribution and evolution of the group of Pinnipeds. Its fur, 

 the most costly of any, has more affinity to that of an Eared 

 Seal than that of any other Otter. In size it approaches many 

 Seals. Its feet are more webbed and its tail shorter than in 

 Biver Otters ; and, lastly, its pelagic habits make it a very good 

 forerunner of Otariidce. If we assume that one branch of tbe 

 Otter family acquired pelagic habits and a beautiful fur, its 

 exclusively piscine food gradually tending to the differentiation 

 of its molars and premolars into a series of tridents, — whilst 

 another branch of tbe family, preferring crustacea and mollusca, 

 developed its hind teeth into sufficient shell-crackers, and, 

 requiring more prehensile power in its paws to search for its prey 

 under stones, &c, did not develop these so completely into fins 

 as its congener, — the relative geographical distribution of the 

 different species seems sufficiently plain. 



