200 BIRDS—ORDERS OF BIRDS. 
a. CYPSELI. Palate egithognathous. Wings lengthened in their terminal 
portions, abbreviated basally, with the first primary not reduced. 
Tail of ten retrices. Bill fissirostral or tenuirostral. Feet never zygo- 
dactyle nor syndactyle, small, weak, scarcely fitted for locomotion ; 
hallux often elevated or lateral or reversed , front toss 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. 
6. CucuLl. 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 scansorial, rarely ambulatorial. 
Syringeal muscles two pairs at most. \ 
ce. Prox. Palate ‘‘exhibiting a simplification and degradation of the egithog- 
nathous structure” (Huxley); wings bearing out this passerine affinity 
in the common reduction of the first primary and the 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 scansorial. 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, psilopzedic. 
D. RAPTORES. Bil 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 curved 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 ptilopedic, being downy at birth. 
EK. COLUMBA:. Bill straight, compressed, horny at the vaulted tip, which is sep- 
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