200 BIRDS — OEDEES OF BIEDS. 



a. Cypseli. Palate fflgithognathous. Wings lengthened in tlieir terminal 

 portions, abbreviated basally, with the first primary not reduced. 

 Tail of ten retrices. Bill fissirostral or tenuirostral. Feet never zygo- 

 dactyle nor syndaotyle, small, weak, scarcely fitted for locomotion ; 

 hallux often elevated or lateral or reversed, front toes usually webbed 

 at base, or with abnormal ratio of phalanges in length and number, or 

 both. Sternum deep-keeled, usually entire or else doubly notched or 

 perforate. Syringeal muscles not more than one pair. 



i. CucuLi. Palate desmognathus. Wings not peculiar in brevity of prox- 

 imal or length of distal portions, and with first primary not reduced. 

 Tail of eight to twelve retrices. Bill of indeterminate form, never 

 cered ; tongue not extensile. Feet variously modified by versatility or 

 reversion of either first, second, or fourth toes, or by cohesion for a 

 great distance of third and fourth, or by absence or rudimentary con- 

 dition of first or second ; often highly soansorial, rarely ambulatorial. 

 Syringeal muscles two pairs at most. 



o. Pici. Palate ' ' exhibiti og a simplification and degradation of the segithog- 

 natbous structure" (Huxley) ; wings bearing out this passerine sflinity 

 in the common reduction of the first primary and tlie restriction of the 

 greater coverts. Tail of ten perfect retrices and usually a supplement- 

 ary pair. Rostrum hard, straight, narrow, sub-equal to head, with 

 commonly extensile and vermiform but not furcate tongue. Feet 

 highly scausorial. Fourth toe permanently reversed ; basal phalanges 

 of toes abbreviated. Sternum doubly notched. Salivary glands highly 

 developed. Hyoidean apparatus peculiar. 



C. PSITTACI. Bill enormously thick, short, high, much arched from the base, 



the upper mandible strongly hooked at the end, cered at the base, and freely 

 movable by complete articulation with the forehead, the under mandible 

 with short, broad truncate Symphysis. Feet permanently zygodactyle by re- 

 version of the fourth toe, which articulates by a double facet. Tarsi reticu- 

 late. Syrinx peculiarly constructed of three pairs of intrinsic muscles. 

 Tongue short, thick, fleshy. Sternum entire or fenestrate. Clavicles weak, 

 defective, or wanting. Orbit more or less completed by approach or union of 

 postorbital process and lachrymal. Altricial, psilopsedio. 



D. EA.PTORES. Bill usually powerful, adapted for tearing flesh, strongly de- 



curved and hooked at the end, furnished with a cere in which the nostrils 

 open. Feet strongly flexible, with large, sharp, much carved claws gradu- 

 ally narrowed from base to tip, convex on the sides, that of the second toe 

 larger than that of the fourth toe, and the hinder not smaller than the second 

 one. Feet never permanently zygodactyle, though fourth toe often versa- 

 tile ; anterior toes commonly with one basal web ; hallux considerable and 

 completely incumbent (except Cathartidw). Legs feathered to the suffrago or 

 beyond. Retrices twelve (with. rare exceptions) ; primaries sinuate or emar- 

 ginate (with rare exceptions). Sternum singly or doubly notched or fenes- 

 trate. Palate desmognathous. Carotids double. Syrinx wanting or devel- 

 oped with only one pair of muscles. Altricial; the young being weak and 

 helpless, yet ptilopsedic, being downy at birth. 

 a. .COLUMBiE. Bill straight, compressed, horny at the vaulted tip, which is sep- 



