chap, v.] CLASSIFICATION. 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 Picaria?, 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 Picaria} are included the 

 goat-suckers, swifts, and humming-birds, sometimes separated 

 as a distinct order, Macrochires. The parrots and the rngeons 

 form each a separate order. The old groups of Grallse 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 Avith these views the following is the series of 

 orders and families of birds adopted in this work : 



Class— AVES. 



Orders. 

 1 Passe ps $ Including the great mass of the smaller birds — Crows, 



" ( Finches, Flycatchers, Creepers, Honeysuckers, &c, &c. 

 o p^or-'oa ] Including Woodpeckers, Cuckoos, Toucans, Kingfishers, 



z. ncarue ... j Swifts, &c., &c. 



3. Psittaci ... Parrots only. 



4. Columbae . . . Pigeons and the Dodo. 



5. Gallina? ... Grouse, Pheasants, Curassows, Mound-builders, &c. 



6. Opisthocomi The Hoazin ouly. 



7. Accipitres . . . Eagles, Owls, and Vultures. 



8. Grallre ... 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 remem- 

 bered 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. 



