THE GENUS LAIIUS. 
249 
Feet rather slender, moderately long, bare above the 
knee : tarsi squarish, plates anteriorly, covered behind and 
at the knee with hexagonal scales ; toes, three before, the 
middle one of moderate length, all palmate to the end, hind 
toe (sometimes wanting) very small, elevated ; claws slightly 
arcuate, shortish, bluntish, increased interiorly into an edge. 
Wings long, the first quill longest, the second nearly 
equal; scapulars longish. 
Tail equal or slightly rounded, of twelve feathers. 
Note. — In the larger species the beak is very deep, and 
the knob or protuberance of the lower mandible very dis- 
tinct; the beak becomes shallower and more attenuated, 
and the knob nearly disappears in the smaller species. 
With regard to the tail, there are two remarkable and op- 
posite exceptions ; the one existing in the Larus Sabini, 
which has the tail furcate, like that of a Tern ; the other 
in L. roseus *, in which it is subcuneate, the middle feathers 
being considerably longer, the rest graduated. 
Physiognomy. — In their general appearance, the Gulls 
are intermediate between the diving aquatic birds and the 
Grallse, and their manners correspond with this character. 
The head is large, the beak moderately long, the neck 
shortish, the body deeper than broad, the wings long, the 
tail moderate, the feet somewhat slender, and bare a little 
above the knee. They are clothed with a very fine elastic 
plumage, plentifully supplied with down. The predominat- 
ing colours are pure white, pale greyish-blue tinged with 
purple, deep slate-purple, and various tints of brown. 
There is no difference between the sexes in point of colour : 
the females are somewhat smaller. 
* The name given pro tempore to a new species of gull, discovered by the 
last Arctic expedition, but which is to receive its proper designation from 
Dr Richardson. 
