CLASSIFICATION OF BIRDS. 15 



Each order, it will be seen, possesses a peculiar 

 formation of the bill, wings, or feet; and it is by the 

 close observance of them, as well as of differences in 

 their plumage, that the naturalist is enabled to dis- 

 tinguish between the different species.* 



* With fuller anatomical information upon the subject, 

 later zoologists have regarded the following arrangement as 

 most nearly representing Nature: 



Of the class Aves there are three sub-classes, viz., Nata- 

 tores, (principally aquatic], Cursores, (principally terres- 

 trial), and lusessores, (principally arboreal). 



The sub-class, NATATORES, embraces four orders, viz., 

 the Pygopodes, (containing four families ; grebe, loon, pen- 

 guin, etc.); the Longipennes, (two families; petrel, gull, 

 etc.)j; the Steganopodes, (two families; pelican, etc.); .and 

 the Lamellirnstres, (two families: ducks, mergansers). 



The sub-class, CURSORES, consists of three orders; first, 

 GrallcB, (containing six families, rails, herons, flamingo, 

 snipe, plover, etc.) ; second, Brevipennes, (two families, 

 ostrich, apteryx, etc.); third, Gallince, (four families, 

 grouse, pheasant, turkey, etc.) 



The sub-class, INSKSSORKS, is a union of five orders. 

 First, Pullastrcp, (four families, brush turkey, dodo, pigeon, 

 etc.) ; second, Accipitres, (three families, the birds of prey) ; 

 third, Syndachyli, (seven families, hornbill, kingfisher, 

 humming bird, swift, whip-poor-will, etc.) ; fourth, Zygo- 

 dactyli, (seven families, trogons, cuckoos, "woodpeckers, 

 parrots, etc.); fifth, Passeres, (twenty families, sparrows, 

 thrushes, tanagers, crows, etc.) The third of these orders 

 is of uncertain limits: very good authorities refer it to the 

 fifth, (Passeres), forming from part of it a sub-order, (Stri- 

 sores). In the system here sketched, the Passeres comprise 

 two sub-orders, distinguished partly by the greater or less 

 perfection of the vocal organs. They are the Clamatore* 



