ave already learned that Professor Brandt held a somewhat
similar view, though he believed in something more than a connection by
mere channels, and Mr. Koeppen, and also the Russian traveller Mr.
Kessler, agreed with him. So much was Professor Boyd Dawkins impressed
with their arguments at the time, that he wrote (_c_, p. 148): "Before
the lowering of the temperature in Central Europe, the sea had already
rolled through the low country of Russia, from the Caspian to the White
Sea and the Baltic, and formed a barrier to western migration to the
Arctic mammals of Asia."

In one particular Professor Dawkins's views differ from those of almost
all the previous writers. His connection between the Caspian and the
Arctic Ocean is placed to the west of the Ural Mountains, while it had
always been assumed by the Russian writers to have lain on the eastern
or Asiatic side of that mountain range. Thus, when Tcherski in recent
years announced that the tract on this eastern side of the mountains was
covered by freshwater deposits, his discovery seemed once for all to
settle the problem of the arctic marine connection in the negative. As
Professor Dawkins's theory has, however, received much additional
affirmative evidence by current faunal researches, a connection between
the Caspian (or Aralo-Caspian) and the Arctic Ocean (White Sea) may have
actually existed within recent geological times.

What _relict lakes_ are, has already been explained (p. 176), and their
fauna will again be referred to in a subsequent chapter. I might perhaps
be allowed to repeat that such lakes are supposed to have been flooded
by, or to have been in close connection with, the sea at some former
period. Many of the Swedish lakes are spoken of as relict lakes
(Reliktenseen), because they contain a number of marine species of
animals which have now become adapted to live in fresh water, but all of
whose nearest relatives inhabit the sea. One of these, the schizopod
crustacean _Mysis relicta_,--a shrimp-like creature,--which was formerly
believed to inhabit also the Caspian, is of particular interest. More
recently, the occurrence of this _Mysis_ in the Caspian was denied, but
though this denial has been confirmed by Professor Sars in his memoir on
the crustaceans of the great Russian inland sea, he has been enabled to
add two new species of _Mysis_ to the list of those already known to
science. These are _M. caspia_ and _M. micropthalma_, and both are
clos