GULL. NATATORES. LARUS. 501 



In summer the head and neck are pure white ; the grey Summer 

 streaks disappearing on the approach of spring. p uma S e - 



In the young state the ground colour of the plumage is a Young. 

 greyish-white, with a slight tinge of wood-brown, barred 

 and spotted all over with grey or broccoli-brown. Tail 

 irregularly spotted with pale brown. The shafts of the 

 primaries white, and the whole of the webs greyish- 

 white. Bill livid at the base, and the tip blackish- 

 brown. Legs and feet pale flesh-coloured red. 



After the second moult the ground of the plumage becomes 

 whiter, and the spots and bars decrease in size and hue. 

 The next change produces some of the pearl-grey fea- 

 thers upon the mantle, and the under plumage and tail 

 become white. At the succeeding moult, that is, at the 

 age of three years, the bird is matured, and undergoes 

 no further change, except the periodical one, upon the 

 head and neck. 



ICELAND GULL. 



LARUS ISLANDICUS, Edmonston. 

 PLATE XCVIII. 



Larus islandicus, Edmonston, in Mem. of Wern. Nat. Hist. Soc. 4. 506. 



Flem. Br. Anim. i. 139. No. 224. 

 Larus argentatus, an Arctic var. Sabine, in Trans. Linn. Soc. J2. 546. No. 



20 Temm. Man. d'Ornith. 2. 764. " un variete' qui parait propre aux 



contrees polaires." 

 Larus leucopterus, Buonap. Sjn. No. 301. Faun. Amer. Boreal. 2. 418. 



No. 183. 



Larus arcticus, Macgillivray, Trans. Wern. Soc. 5. 268. 

 Larus glaucoides, Temm. Man. 



White- winged Silvery Gull, Richardson and Swainson. 

 Iceland Gull, Flem. Br. Anim. 1. 139. No. 224. 



IN Mr EDMONSTO^S first notice of the Glaucous Gull, under Periodical 

 the name Larus islandicus, a suspicion is started, from the dif- visitant - 

 ference of size existing between individuals of the newly obser- 

 ved kind, that there might be two species, having such a rela- 



