468 BULLETIN 50, UNITED STATES NATIONAL MUSEUM 



the chord of cuhnen. Wing large and pointed, the longest primary 

 exceeding distal secondary by about one-third the length of mng; 

 third primary (from outside) slightly longest, the second and fourth 

 about equal, the first (outermost) mtermediate between sixth and 

 seventh; five outer primaries with inner webs abruptly emarginated, 

 the sixth sinuated, the second to sixth, inclusive, sinuated on outer 

 webs; secondaries broad, their tips subtruncate, reaching in closed 

 wing, beyond seventh primary. Tail about two-thirds as long as 

 wing, strongly cuneate (the graduation equal to nearly, sometimes 

 quite, one-third the total length of middle rectrices), composed of 14 

 broad, rigid subacuminate rectrices. Tarsus slightly less than one- 

 sixth as long as wing, moderately stout, the upper half (approximately) 

 of acrotarsium densely feathered, elsewhere covered with small 

 hexagonal and roundish scales, except on acrotarsium immediately 

 below the feathered portion, where there are a few transverse scutella ; 

 middle toe, without claw, about three-fourths as long as tarsus; 

 outer toe slightly longer than inner, reaching (without claw) to about 

 the proximal thu'd of the subterminal phalanx of the middle toe; 

 hallux shorter than inner toe; claws large, strongly curved, moderately 

 acute, conspicuously graduated in size, that of outer toe only about as 

 long as that of hallux, the latter about as long as that of inner toe, but 

 stouter; upper surface of toes with a nearly continuous series of trans- 

 verse scutella, the under surface roughly papillose or almost spiculate; 

 no trace of web between basal phalanges of outer and middle toes. 



Plumage and coloration. — Plumage in general full and compact, 

 the feathers of pileum, hindneck, and foreneck lanceolate, forming a 

 distinct "hackle," those of the chest, breast, and abdomen also lanceo- 

 late, but less distinctly so; plumage of thighs, and under tail coverts 

 full, soft, and rather loose webbed; tail coverts long and broad, cov- 

 ering considerably more than basal half of tail; loral region nearly 

 bare, with only scant, short bristles. General color dusky grayish 

 brown; adults with tail and tail coverts (in one species the forehead, 

 lesser wing-coverts, and thighs also white), the bill, cere, and feet 

 orange-yellow; young with tail, etc., only partly white, the bill and 

 cere dusky. 



Range. — Northeastern Asia, one species accidental in Aleutian and 

 Pribilof Islands, Alaska. (Two species ^^) 



Type. — Thallasoaetus pelagicus (Pallas). 



'5 Thallasoaetus niger Heude (Haliaetiis niger Heude, Naturaliste, 1887, July 

 1, 95: Mer de Tartaris= Korea) is sometimes considered a subspecies of T. pela- 

 gicus. I have seen uo specimens, however, and therefore follow Peters (Check- 

 list Birds of World, i, 1931, 258) in using a binomial for pelagicus. The form 

 niger is said to differ from pelagicus in having a deeper bill, and in having the white 

 color restricted to the tail and under tail coverts; the rest of the plumage is black. 



