Note 9 — Family STRIGIDÆ.—The Owls.

This case of the restriction of the American representative of a European or Western Palæarctic species to the western half of the continent has parallel instances among other birds. The American form of Falcolanarius (var. polyagrus), of Corvus corax (var. carnivorus), Pica caudata (var. hudsonica and var. nuttalli) and of Ægialitis cantianus (var. nivosus), are either entirely restricted to the western portion, or else are much more abundant there than in the east. The European genera Cinclus, Coccothraustes, Nucifraga, and Columba have representatives only in the western portion of North America.

Instances of a similar relation between the plants of the Western Province of North America and those of Europe, and more striking likeness between the flora of the Eastern Region and that of Eastern Asia, are beautifully explained in Professor Gray’s interesting and instructive paper entitled “Sequoia, and its History,” an address delivered at the meeting of the American Association for the Advancement of Science, at Dubuque, Iowa, August, 1872. The poverty in the species of tortoises, and richness in lizards, and the peculiarities of the ichthyological fauna, as well as absence of forms of Western North America and Europe, compared with Eastern North America and Eastern Asia, afford other examples of parallelism in other classes of the Animal Kingdom.