506 GULL TRIBE. 
figured species (Attagis latredlle:) inhabits the Falkland Islands and the higher 
mountains of the southern part of South America. In both genera the beak is 
rather short and compressed, with the aperture of the nostrils in most cases closed 
by a horny membrane covered with short feathers. Generally these birds are met 
with in pairs or small coveys of five or six, which frequent the same spots for long 
periods. . Although they frequent desert regions, the nest is placed near a lake; 
the number of eggs being four or five. 
THE GULL TRIBE. 
Order GAVLE. 
Formerly associated with the petrels, the terns, skimmers, gulls, and skuas, 
are now generally regarded as nearly allied to the Linvcole, with which they agree 
in the arrangement of thei plumage. 
Externally these birds are characterised 
by the prevalence of pure grey and white 
in their adult plumage, and by the com- 
plete webbing of the three front toes, as 
well as by their long wings, in which the 
fifth secondary quill is wanting. Their 
skulls differ from those of the typical 
Innvicole in the absence of basipterygoid 
processes on the inferior surface of the 
rostrum; while the hinder extremity of 
the lower jaw is abruptly truncated; and 
in the wing the flat bone, corresponding 
to the first joint of the human forefinger, 
has two circular perforations—a feature 
distinguishing the skeleton from that of any of the plover tribe and their allies. 
Throughout the group there are deep grooves on the upper surface of the skull for 
glands; the development of these being very variable among the Limicolw. Except 
in the skimmers, the beak is simple, and may be either straight or hooked. In 
the wing there are ten large primaries, and one minute and concealed; the whole 
plumage is remarkably compact, the contour-feathers having after-shafts; there 
are twelve tail-feathers; the spinal feather-tract is well defined by bare lateral 
areas on the neck, and forked on the upper-back; and the oil-gland is tufted. In 
their down-clad and active young, these birds resemble the plovers, but the down 
is of a more complex type. The first toe is raised above the level of the others, 
with which it is not connected by membrane; and the nasal apertures in the skull 
are schizorhinal, while the external nostrils are elongated, and placed rather low 
down on the sides of the base of the beak. In the general structure of the palate, 
as well as in the presence of a process on the outer side of the humerus (see figure 
in Vol. III. p. 295), the gulls resemble the plovers. Rarely, if ever, exceeding 
three in number, the eggs are spotted or scrolled with dark markings on the light- 



YOUNG GULLS COVERED WITH DOWN. 
coloured ground, 
