RARER BRITISH BIRDS. 
57 
OF 
THE GULLS IN GENERAL. 
Genus Larus. Linnaeus. 
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, X 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, icpoucog, coloured, and KscpaXrj, 
head ; signifying, that the birds classed under that name have coloured 
heads. 
$ 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. 
I 
