15. LAEU8. 259 



(1882); Nelson, Cruise ' Cortvin; p. 107 (1883: Plover Bay); 



Blakiston, Atnend. List D. Jai)an, p. 20 (1884) ; Seebohm, B. Japan. 



Emp. p. 291 (1890). 

 Larus pelafjicus [nee IJruch), Taczan. Bull. Soc. Zool. Fr. 1876, p. 263 ; 



id. J.f. 0. 1876, p. 202 (Abrek Bay) ; id. Bull. Soc. Zool. Fr. 1882, 



p. 397 (Kanitschatka). 

 Larus affinis, Seebohm, Ibis, 1879, p. 24 (?) ; Blakiston ^ Fryer, Tr. 



As. Soc. Japan, x. pt. i. p. 104 (1882), 

 Larus borealis [nee Bruch), Seebohm, Ibis, 1884, p. 32 (Kuril Is., sp. 



"no. 2787;" nee Seeb. Ibis, 1882, p. 236, whicli = Z. affinis); 



Blakiston, Ame7id. List B. Japan, pp. 20, 34 (1884). 

 Larus achistisagus, St.ejneg. Auk, 1884, p. 231 (Bering 1., Kamt- 



schatka) ; Baird, Brew., Sr Ridqw. Water-B. N. Amer. ii. p. 229 



(1884 : Alaska) ; Stejneg. Bull. U.S. Nat. Mus. no. 20, p. 67 



(1885 : Commander Is., &c.) ; A. 0. U. Check-l. N. Amer. B. 



p. 88 (1886) ; Stejneg. Pr. U.S. Nat. Mus. x. p. 119, pi. viii.fig. 1 



(1887 : Commander Is.) ; Eidyio. Man. N Amer.B. p. 29 (1887) ; 



Nelson, Rep. N. H. Alaska, p. 53 (1887; Diomede Is.) ; Nikolski, 



Sakhalin Faun. p. 270 (1889) ; Taezan. Mem. Ac. Petersb. (7) xxxix. 



p. 1024(1893: East Siberia) ; ^//m, ^wA;, 1893, p. 123 (distribution). 

 Larus marinus scliistisagus, Seebohm, B. Japan. Emp. p. 291 (1890). 



Adult male in hreeding-plumage. Head, neck, tail, and underparts 

 ■white ; mantle and upper wing-surface dark slate-colour of varying 

 shades, but darker, as a rule, than in L. affinis ; scapulars and 

 secondaries similarly tipped with white ; all the primaries white at 

 their extremities ; shafts of the principal quills dark brown ; the 

 three outer quills dark greyish brown — hardly to be termed black — 

 on their outer webs, paler on the contiguous subterminal portions 

 of their inner webs ; the first white for more than 2 inches apically, 

 or crossed above the tip by a narrow dark bar which fades with 

 the age of the feather ; the 2nd quill with a white subterminal 

 spot on the outer web, and a corresponding patch of white — but 

 not a complete mirror — on the inner web, confluent with the 

 usual grey ' wedge ' which descends from the base of the inner web ; 

 3rd quill transversely barred with blackish brown, with a white 

 termination to the grey wedge of the inner web ; 4th similar, but the 

 white more defined and the upper portion of the outer web lead- 

 colour : 5th and Gth similar, but lead-colour on both webs with 

 merely a dark subterminal bar ; the upper quills grey, tipped with 

 white. In less mature birds there is no spot on the 2nd quiU. 

 Bill rich yellow, with the usual red spot at the genys ; tarsi and 

 toes " dark reddish violet-grey " (Stejneger). Total length 24 to 

 25 inches, culmcn about 2-8, wing 17'5 to 18, tail 7*5 to 8, tarsus 

 2"75, middle toe with claw 2-75. 



The female, as usual, is smaller, and has a less robust bUl. 



Adult in winter. Similar, but streaked about the head and neck. 



Immature. Similar, but remains of dark brown mottlings on the 

 wing-coverts and inner secondaries ; rectrices with an irregular 

 mottled subterminal brownish band ; quills dull brownish, without 

 any mirrors, but otherwise the general disposition of pattern is 

 jnuch as in the adult. 



Yoxuuj. Clove-brown, with darker streaks on the head and neck, 



s2 



