612 



webs for a long way up each feather. This is one charac- 

 teristic which serves to distinguish the young of this species 

 from immature examples of the Siberian Herring Gull, 

 Larus affinls, which is found to some extent over the same 

 area ; another mark of distinction exists in the tail, which 

 presents a broad uniform dark band (only the outer feathers 

 being edged with white), whereas in L. affinis the tail is 

 mottled with dark markings, and the band is completely 

 broken up. 



The nestling differs from the young of all other Gulls of 

 the same size, in being of a uniform greyish-white above, 

 and clearer white below ; the bill, black with yellowish-white 

 tip ; legs and feet, dark brown. 



This species concludes the group of the Gulls with hoods 

 which inhabit or visit the British Islands. The hooded 

 species have been separated from the other Gulls under 

 several generic names, but the only one which has been 

 properly restricted to this group is Chro'icocephalus, Eyton 

 (Brit. Birds, p. 53). This genus was based upon " the 

 coloured hood, small size, and more naked tibia"; but 

 the latter characteristic only holds good with regard to a 

 limited number of the hooded Gulls, and is by no means 

 confined to them ; whilst the question of small size is at 

 once disposed of by the giant just described. Kaup saw this 

 inconsistency, and promptly remedied it by creating a fresh 

 genus, Ichthyaettis, for the above species ! The hood is 

 certainly not a structural distinction, nor does it even exist 

 throughout the whole year ; and for these and other reasons 

 which it is unnecessary to mention in detail, it seems advisable 

 to place these Gulls with the rest in the genus Larus. 



