HABITS or THE NOEWEGIAN LEMMIKG. 33 



a more genial climate and more abundant food, but return to us 

 as surely as summer itself ; nor do tbey ever, so far as I know, 

 breed during their passage. Even the Locusts present no such 

 problem as the lemmings, since it is generally the wind rather 

 than any migratory instinct which brings their dreaded hosts to 

 the shores of Europe. Perhaps the most noticeable parallel is 

 afforded by the migration of Pallas' s Sand-grouse in 1863*, when a 

 species, whose home is in the Tartar steppes, journeyed in consi- 

 derable numbers to the most western shores of Europe, and very 

 probably many individuals perished, like the lemmings, in the 

 waves of the Atlantic. 



There is, however, a solution of this difficulty, involving a 

 subject that has always seemed to me of the deepest interest, 

 and which led me to spend two years among the Canaries and ad- 

 jacent islands. I allude to the island or continent of Atlantis. 



Now without going so far as to assert that the Canary and 

 other Atlantic groups are but the uppiled volcanic summits of a 

 submerged land, it yet is evident that land did exist in the North 

 Atlantic Ocean at no very distant date ; and the depth of water 

 on the so-called telegraph-plateau disposes of one of the difficul- 

 ties felt by many with, regard to more southern latitudes. Is it not 

 then conceivable, and even probable, that when a great part of 

 Europe was submerged and dry land connected Norway with 

 Grreenland, the Lemmings acquired the habit of migrating west- 

 ward for the same reasons which govern more familiar migrations ? 



To make this clearer, let me put a hypothetical case. Suppose 

 the Swallows were partial migrants from Grreat Britain, and sup- 

 pose that Africa were to become submerged, would not many 

 generations of Swallows stiU follow their inherited migratory in- 

 stincts, and seek the land of their ancestors through the new waste 

 of waters ? whilst the remaining stock, unimpeded by competition, 

 would soon recruit the ranks for a new exodus. It appears 

 quite as likely that the impetus of migration towards this conti- 

 nent should be retained as that a dog should turn round before 

 lying down on a rug, merely because his ancestors found it neces- 

 sary thus to hollow out a couch in the long grass. 



InjQuenced, I feel bound to admit, by this idea, I should 

 willingly have found lemmings in Iceland; but the only indi- 

 genous mammal there, I believe, is the Mus islandicus (? sylva- 



* Vide ' Ibis,' 1864, pp. 185-222. 



