362 Synopsis of the Birds 
ash • tarsus three inches ; tail reaching two inches beyond 
the wings. 
Summer plumage, head and neck pure white : winter, head 
and neck with brown streaks. 
Young dingy, mottled. 
Glaucous Gull , Lath . Naum . Vog. pi. 35 . 
Inhabits the Arctic regions of both continents : exceeding- 
ly rare in the United States. 
303. Larus marinus, L. Back and wings slate-black 5 quills 
black at the point, tipped with white ; shafts black ; wings 
not reaching beyond the tail ; tarsus three inches. 
Summer plumage, head and neck pure white : winter, head 
and neck with brownish streaks. 
Young dingy, mottled. 
Black-backed Gull, Lath. Wilson's list. Buff.pl. enl. 990. 
and 266 . young. 
Inhabits both continents : not uncommon during winter 
In the middle states. 
B. 
Bill of several pieces. Nostrils immarginate. Feet 4-toed. 
Longipennes , 111. Pclagii, Vieill . Ranz . Lari , Boie. 
66. LESTRIS. 
* 
Larus , L. Gm. Lath. Buphaga , Moehring. Catharracta , 
Brunn. Stercorarius, Briss. Vieill. Lestris , III. Cuv . Temm . 
Labbes , Buff. 
Bill moderate, robust, hard, cylindrical, compressed, 
hooked at tip, edges sharp ; upper mandible with the ridge 
and tip distinct, covered beyond the nostrils by a cere ; lower 
of one piece, shorter, angular beneath, obtuse at tip : nostrils 
subterminal, lateral, oblique, linear, wider before, pervious, 
