southerly route, which is by no means the case. On the contrary, westward at Heimdal means across a rapid river, over a wide lake, and up a steep, rocky, and snowy mountain, and this is the course which is followed. Now this ends eventually in the ocean, and thus we are again landed at the question from which we set out. After all, it is not the power of direction which is so remarkable: this is a faculty possessed by many animals, and by man himself in a savage state. A young dog which I took from England, and then from my home in Vaage by a path to Heimdalen, a distance of forty-six miles, ran back the next morning by a direct route of his own, crossing three rapid rivers and much snow, and accomplishing the distance in six hours, without the vestige of a path. This same dog afterwards repeated the feat, but followed the path, and took two days in reaching his destination, hindered and not aided, as I believe, by his experience. Herr Palmén, indeed, says "experience guides migration, and the older migrants guide the younger," like one of Mr. Cook's personally conducted tours. This obviously cannot be the case with the lemmings.
It is now generally admitted that instinct is merely inherited experience, and is therefore primarily calculated to benefit the species, unless indeed circumstances have changed meanwhile more rapidly than the structures to which the phenomena of instinct are due. Now, the lemmings during their wanderings pass through a land of milk and honey, where, if their instincts could be appeased, they might well take up a permanent abode, and yet they pass on, whilst their congener, the field-vole, remains in quiet possession of the quarters from which he was temporarily ousted. It is indeed almost as strange a sight to see the holes, the deeply-grooved runs, and the heaps of refuse of these restless creatures, which have passed away but yesterday, as it is to see the fjelds suddenly become alive with a new and boisterous tenant, who, like another Ishmael, has the hand of all men against him.
Now, if we compare the migration of the lemmings with that of our more familiar swallows, we find that the latter obviously seek a more genial climate and more abundant food, returning to us as surely as summer itself; nor do they ever, so far as I know, breed on their passage. The swifts, which stay but a short time with us, remain in Norway barely long enough to rear their young before returning to Africa. It is difficult, in fact, to find a parallel case to that of the lemmings: the nearest approach, perhaps, is afforded by the strange immigration of Pallas's sand-grouse in 1863, when a species whose home is on the Tartar steppes journeyed on in considerable numbers to the most western shores of Europe, and very probably many perished, like the lemmings, in the waves of the Atlantic. But to revert to the swallows, which annually desert Europe to visit Africa. Let us suppose that these birds were partial migrants only — that is, that a remnant remained with us after the departure of the main body — and further suppose that the continent of Africa were to become submerged, would not many generations of swallows still follow their inherited migratory instincts, and seek the land of their ancestors through the new waste of waters, whilst the remaning stock, unimpeded by competition, would sooner or later, according to the seasons, recruit the ranks for a new exodus? It appears quite as probable that the impetus of migration towards this lost continent should be retained as that a dog should turn round before lying down on a rug merely because his ancestors found it necessary thus to hollow out a couch in the long grass.
Well, then, is it probable that land could have existed where now the broad Atlantic rolls? All tradition says so: old Egyptian records speak of Atlantis, as Strabo and others have told us. The Sahara itself is the sand of an ancient sea, and the shells which are found upon its surface prove that no longer ago than the miocene period a sea rolled over what now is desert. The voyage of the "Challenger" has proved the existence of three long ridges in the Atlantic Ocean, one extending for more than three thousand miles; and lateral spurs may, by connecting these ridges, account for the marvellous similarity in the fauna of all the Atlantic islands. However, I do not suppose that the lemmings ever went so far south, though they are found as fossils in England; but it is a remarkable fact that whilst the soundings off Norway are comparatively shallow for many miles, we find a narrow but deep channel near Iceland, which probably has prevented the lemming from becoming indigenous there, although an American species was found in Greenland during the late Arctic Expedition. If, as is probable, the Gulf Stream formerly followed this deep channel, its beneficent influence would only extend a few miles from
