west. Birds of the same species actually crossed paths, travelling in contrary directions (16).
The above grouping applies to the British avifauna, but a somewhat similar arrangement might be made of the birds of any particular area, large or small. The grouping of birds for the study of Geographical Distribution is of little consequence in connection With migration, but the mapping of the world into various ornithological rather than zoogeographical regions is of considerable importance, both for convenience in tracing the ranges of migrants, and in the discussion of the history of migration, which almost certainly began in the form of short wanderings from the centres of distribution. It is of comparatively small importance what boundaries we take for the various regions; these depend largely upon the view of certain ornithologists as to which groups of birds shall be considered as typical of the regions in question. Sclater's six regions are perhaps the most universally used. They are as follows:—
1. Palæarctic, embracing the whole of Europe and northern Asia.
2. Ethiopian—Africa, Arabia, Madagascar and roughly half of the Atlantic and Indian Oceans.
3. Indian, including India, Further India, Southern China, the western portion of the Malay Archipelago and the Chinese Seas.
