5GS LARUS LEUCOPTERUS. 



iris pale yellow. The head, neck, lower parts, rump, and 

 tail are pure white ; but the head and neck are longitudinally 

 streaked with very pale greyish-brown. The back and wings 

 are pearl-grey tinged with blue, or light bluish-grey, of a 

 paler tint than in Larus glaucus ; the edge of the wing, a 

 large portion of the outer primaries toward the end, the tips 

 of all the other quills, white, as are their shafts. 



Length to end of tail 24 inches ; extent of wings 50 ; 

 wing from flexure 17-L ; tail 6^ ; bill along the ridge If, along 

 the edge of lower mandible 2^ ; tarsus 2^ ; first toe -^, its 

 claw -j3j ; third toe 2^, its claw ^. 



Female in Winter. — Similar to the male, but smaller. 



Variations. — Great differences in size are observed in 

 adult individuals of this species ; the largest that I have seen 

 measuring 26 inches in length, the smallest 20 ; but as they 

 were merely skins, these dimensions cainiot be much depended 

 upon. The bill and tarsi, however, a ary in the same propor- 

 tion. The colours exhibit no remarkable change. 



Male in Summer. — Bill gamboge-yellow, with an orange- 

 red spot on the lower mandible ; iris pale yellow, maigins of 

 eyelids orange-red; feet pale flesh-coloured. The plumage 

 coloured as in winter, but the head and neck pure white. 



Female in Winter. — Similar to the male in colour. 



Habits. — This species has been found in sunmier on the 

 coasts of Greenland, Labrador, and other arctic regions ; 

 whence it migrates southward in autumn, advancing as far as 

 Boston along the eastern shores of America, Avhilc in Europe 

 it appears along the continental shores as far southward as 

 Holland and Belgium. Li Britain, it has been found in 

 Shetland by Dr. Edmondston, from whom I have a specimen. 

 According to Messrs. Baikie and Heddle, " one or two 

 examples have been obtained in Orkney, one of which is now 

 preserved in the College Museum, Edinburgh." I have seen 

 two individuals shot in the neighbourhood of Banff" by Mr. 



