ORNITHOLOGICAL EXPLORATIONS 21? 



ably were obtained during the latter i^art of the summer, bleaching may 

 account for their lighter color. (Cf. that Schrenck's very dark birds 

 were obtained in January and February.) As to the differences pointed 

 out by Pallas (Z. R. A., I, p 3 17), who seems chiefly to refer to the form 

 of the tail, I can only state, that I am unable to see them. 



A glance at the subjoined dimensions will convince us that the speci- 

 men is very small, not exceeding the average of the smaller Central 

 European form. This fact is particularly interesting when we consider 

 that it is in this very region that H. leucocephalns obtains its greatest 

 development. The H. albicilla from Bering Island looks like a pygmy 

 alongside its gigantic white-headed cousins. 



"<?" ad. — U. S. Nat. Mus. No. 101199; Grebnitski No. 61. Bering Island, November, 



1883. 



Wing, 608"""; tail-feathers, 258'"™; cultneu from cere, .51"""; radius of curvature 

 from cere to tip, 27™™ ; height of upper mandible at fore border of cere, 26™™ ; external 

 chord of hind claw, 39™™. 



97. Thalassoaetus pelagicus (Pall.). 



1H26. — Aquila pelagica Pall., Zoogr. Ross. As., I, p. 343, pl.l. — Kittl., Kupfcrt., I, 

 p. 3, tab. ii, fig. 1 (1832).— /(?., in Liitke,Voy. aut. Monde, Atlas, Part. hist. 

 pi. xiii. — Id., Denkw., I, p. 330; II, pi. ad p. 364 (1858). — Middend., Sibir. 

 Reis., II, 2 (p. 125) (18.53). — Haliatus p. Temm. & Schleg., Faun. Jap. Av. 

 (p. 11, pi. iv) (1847).— Cassin, lUustr. Birds, p. 31, pi. vi (1854).— Schrenck, 

 Reis. Amurl. , I, p. 222 (I860).— Schlkg., Mus. P. B. Aquila?, p. 14 (1862).— 

 SwiNHOE, P. Z. S., 1863, p. 260.— Id. ibid., 1871, p.339.— /(Z., Ibis, 1874, p. 

 150.— HoMEYER, Journ f. Oru., 1868, p.248.— Pkzkwalski, Putesch. Us- 

 suri, Suppl. (p. 52) (1870).— Finscii, Abh. Brem., Ver., Ill,' 1872, p.24.— 

 Dall, Avif. Aleut. Isl. west Unal., p. 4 (1874). — David & Oust., Ois. Chine 

 (p. 13).— Taczan., Journ. f. Orn., 1876, p. 190.— Id., Bull. Soc. Zool. France, 

 1876, p. 120.— 7rf., ibid., 1883, p. 329.— /d., Orn. Faun. Vost. Sibir., p. 8 

 (1877).— Blakist. &. Pryeh, Tr.As. Soc. Jap.,VIII, 1880, p. 238.— lid., ibid., 

 X, 1882, p. 180.— Blakist., Chrysanthemum, April, 16-^3.— Id., Amend, 

 List B. Jap., p. 66 (1884).— Seebohm, P. Z. S., 1884, p. ■i09.—Thalassoaetus p. 

 Stejneger, Pr. U. S. Nat. Mus. 1883, p. 65 ; Auk, 1884, p. 82. -Id., Naturen. 

 1884, p. 7, fig.— DvBOWSKi, Bull. Soc. Zool. France, 1883, p. 351. 



1830. — Falco leucopierus Temminck, PI. Color., I, pi. 489. 



1832. —Falco imperator Kittlitz, Kupfert., I, p. 3. 



1858. — Aquila osaifraga Kittlitz, Denkwiird., II, pp.366, 406 {nee But)NN., 1764). 



As I have shown elsewhere (Pr. U. S. Nat. Mus., VI, 1883, p. 66, and 

 this work under Halkcetus leucucephalus), Pallas was very much mis- 

 taken in giving Bering Island as the true habitat of this bird. This 

 mistake arose from his having misunderstood Steller's description of 

 the bald eagle as referable to Th. pelagians. The habitat is especially 

 the mainland of Kamtschatka, where it is abundant^ but also all the 

 countries bordering the Okotsk Sea. 



