168 LAEID^, 



Clarke, Handh. Yorks. Vertebr. p. 81 (1881) ; Coues, Check-l. N. 

 Amer. B. p. 122 (1882) ; Nelson, Cruise ' Cortcin; p. 108 (1883 : 

 Alaska) ; B. O. U. List Brit. B. p. 192 (1883) ; Saunders, Ibis, 

 1883, p. 348 (' Vega ' specimen) ; Coues, Key N. Amer. B. 2nd ed. 

 p. 753 (1884) ; Saunders, 4th ed. Yarrelfs Brit. B. iii. p. 572 (1884) ; 

 Baird, Brewer, ^ Ridgway, Water-B. N. Amer. ii. p. 266 (1884) ; 

 Murdoch, Exped. Pt. Barroio, p. 123, pis. i.-ii. (1885) ; A. O. U. 

 Check-l. N. Amer. B. p. 91 (1886) ; Ridgio. Man. N. Amer. B. 

 p. 37 (1887) ; Nelson, Rep. Nat. Hist. Coll. Alaska, p. 55, pi. iii. 

 (1887) ; Palmen, Vega-Exped. p. 352 (1887 : Pitlekaj) ; Saunders, 

 Man. Brit. B. p. 643 (1889) ; R. Gray, Zool. 1889, p. 45 (Green- 

 land Sea, 78° N., 0'' 25' E.) ; M. Chamberl. ed. Hageriip's B. Greenl. 

 p. 47 (1891) ; Alkn, Auk, 1893, p. 123 (distribution) ; Lilford, Col. 

 Figs. Brit. B. pts. xxiii. & xvii. (1893). 



Boss's Gull. Long, Voy. ' JeannetteJ p. 151 (1883 : off Herald I., 

 Bering Sea). 



Rhodestethia rosea, Taczan. Mhn. Ac. St. Petersh. xxxix. p. 1048 

 (1893 : E. Siberia). 



Adult in summer jilumage (Disco). Neck surrounded by a narrow 

 black collar, otherwise the head and entire underparts white (suf- 

 fused with pink in life) ; mantle and quills pearl-grey ; the outer 

 web of the first primary black, nearly to the tip, the other primaries 

 grey like the mantle, paler on the inner margins ; secondaries tipped 

 with rosy white ; rump and tail rosy white, the latter wedge-shaped ; 

 under wing-coverts grey : bill black ; ring round the eye vermilion ; 

 tarsi, toes and their webs bright red. Total length 13'5 inches, 

 culmen 1-1, wing 10'25, tail 5-25, central pair of feathers 0-8 in. 

 longer than the next, and 1'9 longer than the outermost; tarsus 

 1-25, middle toe with claw 1'2. 



Adult in tvinier. Similar, but without the black collar, and less 

 suffused with rose-colour. 



Immature. Head and underparts white ; a few dark streaks 

 round the eye ; collar fairly defined, especially on the nape ; 

 shoulders pale grey, mantle pearl-grey ; inner secondaries and upper 

 wing-coverts smoke-brown, tipped with white, remaining secondaries 

 pearl-grey, passing into white at their edges ; the three outer 

 primaries blackish on the webs on both sides of the shafts down 

 to the tips and a little way up the inner webs, the rest of the webs 

 white ; in the 4th primary the centre is greyish white, with a dark 

 subterminal bar ; on the inner quills the white increases successively 

 until the 9th is wholly white ; tail pure white. 



Young (September 2l8t). Similar, but crown distinctly pearl-grey, 

 with sometimes a dark feather or two indicative of a hood, and also 

 an approach to a greyish collar; more black about the orbits, and a 

 strongly marked patch on the auriculars ; more blackish brown on 

 the wing-coverts and inner secondaries, which are tipped with 

 greyish to huffish white ; rump barred with dark brown ; tail- 

 feathers chiefly white, with blackish-brown terminations to all 

 except the outer pair or two. This dark band decreases rapidly 

 with advancing age in the feather, and by the following spring it 

 is almost confined to the two central pairs of rectrices. Tarsi 

 and toes brown, 



Hab. Arctic regions : — N.W. Greenland (Disco) ; MelviUe Penin- 



