_Birds._--Although the Canadian sub-region possesses very few resident birds, the numbers which breed in it are perhaps greater than in the other sub-regions, because a large number of circumpolar species are found here exclusively. From a comparison of Mr. Allen's tables it appears, that more than 200 species are regular migrants to Canada in the breeding season, and nearly half of these are land-birds. Among them are to be found a considerable number of genera of the American families Tyrannidæ and Mniotiltidæ, as well as the American genera _Sialia_, _Progne_, _Vireo_, _Cistothorus_, _Junco_, _Pipilo_, _Zonotrichia_, _Spizella_, _Melospiza_, _Molothrus_, _Agelæus_, _Cyanura_, _Sphyrapicus_, and many others; so that the ornithology of these northern regions is still mainly Nearctic in character. Besides these, it has such specially northern forms as _Surnia_ (Strigidæ); _Picoides_ (Picidæ); _Pinicola_ (Fringillidæ); as well as _Leucosticte_, _Plectrophanes_, _Perisoreus_, and _Lagopus_, which extend further south, especially in the middle sub-region. No less than 212 species of birds have been collected in the new United States territory of Alaska (formerly Russian America), where a humming-bird (_Selasphorus rufus_) breeds. The great majority of these are typically American, including such forms as _Colaptes_, _Helminthophaga_, _Siurus_, _Dendræca_, _Myiodioctes_, _Passerculus_, _Zonotrichia_, _Junco_, _Spizella_, _Melospizpa_, _Passerella_, _Scoleophagas_, _Pediocetes_, and _Bonasa_; together with many northern birds common to both continents. Yet a few Palæarctic forms, not known in other parts of the sub-region, appear here. These are _Budytes flava_, _Phylloscopus kennicottii_, and _Pyrrhula coccinea_, all belonging to genera not occurring elsewhere in North America. Considering the proximity of the district to North-east Asia, and the high probability that there was an actual land connection at, and south of, Behring's Straits, in late Tertiary times, it is somewhat remarkable that the admixture of Palæarctic and Nearctic groups is not greater than it is. The Palæarctic element, however, forms so small apportion of the whole fauna, that it may be satisfactorily accounted for by the establishment of immigrants since the Glacial period. The great interest felt by ornithologists in the discovery of the three genera above-named, with a wren allied to a European species, is an indication that the faunas even of the northern parts of the Nearctic and Palæarctic regions are, as regards birds, radically distinct. It may be mentioned that the birds of the Aleutian Isles are also, so far as known, almost wholly Nearctic. The number of land-birds known from Alaska is 77; and from the Aleutian Isles 16 species, all of which, except one, are North American. Plate XX. [Illustration] A CANADIAN FOREST, WITH CHARACTERISTIC MAMMALIA.