LARINyE. GAVIA. 239 



tacea, insects, and worms. They are of vagrant habits, 

 shifting from place to place according to the abundance 

 of food. They walk well, wade into shallows, swim with 

 ease, floating most buoyantly ; have a light, wavering, mo- 

 derately rapid flight, hover over the water, pat it with their 

 feet in stooping, and with up-stretched quivering wings, 

 pick up their food. They nestle, often in multitudes, on 

 islands and headlands, form a bulky nest, and lay from 

 two to five oval large eggs, of a dull colour, spotted with 

 dusky. The young are clothed with close variegated 

 down, and can soon walk, but generally remain near the 

 nest until fledged, when they always differ in colour from 

 the adult birds. The species are all closely allied, but 

 may be divided into several genera. The number found 

 in Britain is thirteen. 



GENUS CXLIX. GAVIA. MEW. 



The " Sea-Mews, " or " Smaller Gulls, " have a consider- 

 able affinity to the Terns. They are birds of rather small 

 size, with the body rather light ; the neck moderate, the head 

 rather large, broadly ovate. Bill rather long or moderate, 

 slender, much compressed, slightly decurved at the end, 

 acute ; upper mandible with the nasal sinus rather long, 

 narrow, and feathered, the edges very thin ; inclinate, the 

 tip narow, rather acute, slightly prolonged, with a faint sinus 

 on the margins ; lower mandible very much compressed, with 

 the intercrural space very long and extremely narrow, the 

 commissure forming a slight angle with the dorsal line, 

 which is nearly straight, the edges very thin, the tip rather 

 acute. Mouth of moderate width ; tongue fleshy, slender, 

 tapering ; oesophagus very wide, its walls extremely thin ; 

 stomach rather small, oblong, moderately muscular, with 

 large tendons, and thick horny epithelium, with very pro- 

 minent longitudinal rugae ; intestine of moderate length, and 

 very narrow ; coeca extremely small, cylindrical. Nostrils 

 linear-oblong. Eyes rather small; eyelids feathered, with 

 bare crenulate margins. Aperture of ear of moderate size. 

 Legs of moderate length, rather slender ; tibia bare for one - 



