RARER BRITISH BIRDS. 57 



OF 



THE GULLS IN GENERAL, 



Genus Larus. LINN^US. 



THE genus Larus (thus characterized : bill, moderate, cul- 

 trated, laterally compressed, bent downwards at the tip; nos- 

 trils, longitudinal, oblong ; anterior toes, membrinated ; hind toe, 

 small or wanting; wings, long) has generally been subdivided 

 into two sub genera Xema, Leach, having the tail forked ; 

 Larus, Stephens, having the tail even ; and sometimes is added 

 Rissa, wanting the hind toe.* Under the sub genus Larus, there 

 has generally been placed two distinct forms, which appear to 

 us to require further subdivision. We therefore propose the 

 name of Chroicocephalusf for a new sub genus under Larus, 

 Linn., for the reception of such Gulls as have the tarsi slender ; 

 thighs considerably denuded ; hind toe, very small ; head only, 

 or head and upper part of the neck, dark coloured in the 

 summer state of plumage. Under this sub genus will be in- 

 cluded the British species of L. Capistratus, Temm., L. Ridi- 

 bundus, Linn., and L. Minutus, Pallas, together with the Con- 

 tinental one of L. Albicilla, J Linn. The general contour of 



* The genus Lestris, by Cuvier, is placed as a sub genus under Larus, 

 Linnaeus. See Remarks on Swimming Birds in general. 



t Derived from two Greek words, K|OOIKO, coloured, and Kf^aX?/, 

 head; signifying, that the birds classed under that name have coloured 

 heads. 



t Montagu mentions, having seen some specimens of this Gull on the 

 coast, near Hastings ; but as none are on record, as killed in the British 

 isles, we shall not admit it into the British Fauna on such uncertain 

 evidence. 





