220 CATHARTIDA, AMERICAN VULTURES.—GEN. 165. 
. 
Oxs. The Greenland Sea Eagle, 7. albicilla; and the Northern Sea Eagle, H. 
pelagicus (Cass., Ill. 31, pl. 6, and in Bp., 42,43; Extioz, pl. 34, 35), both usually 
attributed to our fauna, remain to be detected, the former in N. E., the latter 
in N. W., portions. H. pelagicus has 14 rectrices, and is otherwise distinct. 
hic. 143. Bald Bagle. 
165. Genus POLYBORUS Vieillot. 
Caracara Buzzard. Bill long, high, compressed, little hooked, commis- 
sure nearly straight to the deflected end; nostrils linear, oblique, in the front 
upper corner of the cere, which is truncate and bristly; sides of head. 
extensively denuded ; occipital feathers lengthened ; 3d and 4th quill longest, 
Ist shorter than 7th; outer 4-5 emarginate; tarsus almost naked, longer 
than middle toe. Brownish-black, barred on the neck, breast and most of 
the upper parts, with yellowish-white; auriculars whitish; tail whitish, 
narrowly black-barred and with broad black terminal zone; primaries like- 
wise barred with whitish; feet yellow; bill greenish-white. Length 23; 
wing 15-17; tail about 10. Southern border, Florida to California; a 
remarkable form, allied in some respects to the vultures. AvD., i, 21, pl. 
4; Nurr., i, 52; Cass. in Bo., 45; Coor., 492. THARUS var. AUDUBONII. 
Family CATHARTIDA. American Vultures. 
Head, and part of the neck, more or less completely bare of feathers ; eyes flush 
with the side of the head, not overshadowed by a superciliary shield; ears small 
and simple. Bill lengthened, contracted toward the base, moderately hooked and 
comparatively weak. Nostrils very large, completely perforated, through lack of a 
bony septum. Wings very long, ample and strong; tail moderate. Anterior toes 
long for the order, webbed at base; hind toe elevated, very short; claws compara- 
tively lengthened, obtuse, little curved and weak. ‘To these external characters, 
which distinguish our vultures, I may add, that there are numerous osteological 
peculiarities. A lower larynx is not developed. The capacious gullet dilates into 
an immense crop. The coeca are extremely small. ‘The feathers lack an aftershaft. 
ev ers 
