The old plan of putting the birds of prey at the head of the class, is now almost wholly given up; both because they are not {93}the most highly organised, but only one of the most specialised forms of birds, and because their affinities are not with the Passeres, but rather with the cormorants and some other of the aquatic groups. The Passeres therefore are placed first; and the series of families is begun by the thrushes, which are certainly the most typical and generally well-organised form of birds. Instead of the Scansores and Fissirostres of the older authors, the order Picariæ, which includes them both, is adopted, but with some reluctance; as the former are, generally speaking, well marked and strongly contrasted groups, although certain families have been shown to be intermediate. In the Picariæ are included the goat-suckers, swifts, and humming-birds, sometimes separated as a distinct order, Macrochires. The parrots and the pigeons form each a separate order. The old groups of Grallæ and Anseres are preserved, as more convenient than breaking them up into widely separated parts; for though the latter plan may in some cases more strictly represent their affinities, its details are not yet established, nor is it much used by ornithologists. In accordance with these views the following is the series of orders and families of birds adopted in this work: Class--AVES. Orders. 1. Passeres { Including the great mass of the smaller birds--Crows, { Finches, Flycatchers, Creepers, Honeysuckers, &c., &c. 2. Picariæ { Including Woodpeckers, Cuckoos, Toucans, Kingfishers, { Swifts, &c., &c. 3. Psittaci Parrots only. 4. Columbæ Pigeons and the Dodo. 5. Gallinæ Grouse, Pheasants, Curassows, Mound-builders, &c. 6. Opisthocomi The Hoazin only. 7. Accipitres Eagles, Owls, and Vultures. 8. Grallæ Herons, Plovers, Rails, &c. 9. Anseres Gulls, Ducks, Divers, &c. 10. Struthiones Ostrich, Cassowary, Apteryx, &c. The Passeres consist of fifty families, which may be arranged and grouped in series as follows. It must however be remembered that the first family in each series is not always that which is most allied to the last family of the preceding series. All extensive natural groups consist of divergent or branching alliances, which renders it impossible to arrange the whole in one continuous series. {94}A.--TYPICAL OR TURDOID PASSERES.