288 BRITISH BIRDS' EGGS. 



bogs. In Orkney, their nests have been met with in a lake 

 near Nunse Castle, and in another in the Isle of Sanda, and 

 in Shetland they are most numerous in a lake at the back 

 of Rona's Hill. The species is represented as common on 

 the coasts of temperate Europe during the winter, retiring, 

 as with us, to lakes and marshes in the spring. In winter 

 the head of the bird is white, the black head, by which it is 

 distinguished during the breeding-season, being assumed in 

 the course of a week. (PL XYI. fig. 98.) 



THE MASKED GULL. Lams capistratus. This appears 

 to be everywhere a rare species, but examples of it have oc- 

 casionally occurred in the British Islands. "The first spe- 

 cimens were those in the collection of Mr. Bullock, sold to 

 Dr. Leach at the dispersion of his collection, and said to be 

 taken with the young and eggs in Orkney; and a third 

 specimen has since that time been procured from Shetland. 

 It has occurred in Wales, and to Mr. Thompson in Ireland. 

 On the Continent a few instances are also recorded, but we 

 have no information of its breeding-places. It may pro- 

 bably be a northern species : Temmincl^ states that it is 

 found in Baffin's Bay and Davis' s Straits" (' Naturalists' 

 Library/ vol. iv. p. 296). Some eggs are figured in a work 

 by the Kev. I\ 0. Morris as those of this species; they are 



