134 Proceedings of the Royal Physical Society. 



are each credited with an example; and again, Degland 

 mentions an adult shot at Eouen. 



The true home of this bird is on the borders of the Arctic 

 Circle ; and, since its eggs were first taken by Sabine, on the 

 west coast of Greenland, it has been found breeding on 

 Melville Peninsular by Sir Edward Parry ; on Cape Dal- 

 housie by Sir John Eichardson ; on Prince Albert's Land (c/. 

 Captain Feilden, Zoologist, 1879, p. 8) in Franklin Bay, and 

 Alaska. Middendorf found it breeding on the tundras of the 

 Taimyr; and the remains of an Qgg taken by him were 

 exhibited by Professor Newton, at a meeting of the Zoological 

 Society, on December 10, 1861. 



The few eggs that are to be found in collections were 

 procured by the Arctic Expedition sent out at the instance of 

 the Government of the United States, and were taken by Mr 

 E. Macfarlane in Franklin Bay in 1865. Your Museum of 

 Science and Art is indebted to the Smithsonian Institute at 

 Washington, for one of these oological treasures. 



In early autumn these birds migrate southwards, especially 

 following the coast lines of North America. It has occurred 

 once on the Bermudas, and lately as far south as Peru, in 

 12° S. latitude. 



Through the kindness of Mr Howard Saunders, I am 

 enabled to place before you skins of Sabine's Gull in three 

 stages of plumage. The first is a bird of the year, the same 

 as the bird obtained on the Forth. It was killed on the 

 Thames in 1862 (c/. Harting's "Birds of Middlesex," p. 251). 

 The second in breeding plumage is like the Loch Spelve 

 specimen. The third in winter dress, was killed in December 

 at Callao. You will notice that it has lost its hood, the 

 forehead especially being white, whilst the nape has assumed 

 black feathers, where white in summer. 



In this stage, until a very few years ago, the bird was 

 unknown. It is even now excessively rare, Mr Howard 

 Saunders possessing the only two specimens in Europe — this 

 being one of them; a third being in America. 



The genus Xema, which was founded by Leach, contains 

 only one other species besides X. Sdbinii, namely, the Fork- 

 tailed Gull (X furcatum^ Neboux), a bird which, were it 



