ne, and
there can be no doubt that the British Grouse belongs to the northern
migration, just like the Arctic Hare. The Ptarmigan (_Lagopus mutus_)
and the Snow Bunting are also migrants from the north. Though as
resident British birds they are quite confined to Scotland, the remains
of the former have been found in a cave in the south of Ireland, showing
that its range in the British Islands was formerly more extensive.
Another bird which probably came to our shores with this same migration,
though it is now unfortunately extinct, is the Great Auk (_Alca
impennis_), of which some specimens have luckily been preserved in our
museums. From the occurrence of its remains in kitchen-middens and other
recent deposits, the Great Auk is known to have inhabited the coasts of
Scotland, Ireland, and Scandinavia, as well as those of Newfoundland.
Mr. Ussher recently found the bones of this bird near Waterford, which,
I believe, is the most southern locality known. The manner of their
occurrence leaves no doubt that the bird had been used as food by the
early races of man. In all probability it originated in the Arctic
Regions, and subsequently spread south on either side of the Atlantic.
We need not here refer to the many winter visitants,--northern birds
which appear regularly, or at more or less long intervals, in these
islands,--although in most of the ornithological works they are included
under the term "British Birds."

All the British reptiles and amphibia appear to have reached us from the
south or east, but among the fishes there are a good many northern
forms. The whole salmon family--the _Salmonidae_--are typical northern
immigrants. The Stickleback (_Gasterosteus aculeatus_), too, has
undoubtedly come to us from the north. The genus _Cottus_, like
_Gasterosteus_, is certainly Arctic in origin. Originally freshwater
forms, many species are now found between tide-marks, and of these a
few have migrated southward along the coasts of the great continents.
Thus we meet with various species of _Cottus_ as far south as California
and Japan, on the American and Asiatic coasts of the Pacific
respectively. In Europe, two species, viz., _C. scorpio_ and _C.
bubalis_, range as far south as the French coast. Our freshwater
_Cottus_, the Miller's thumb (_Cottus gobio_), has migrated to us from
the north with the Arctic species. All the freshwater forms, indeed, of
this genus are typically Arctic.

A large number of land and freshw