308 LARIDA, GULLS, TERNS, ETC.—GEN. 279-80. 
cious and distensible ; there is no special crop; the proventriculus is a bulging o 
the gullet; the gizzard is small and little muscular; the coca are variable; the 
cloaca is large. Certain genera offer peculiarities of this general type of alimentary 
canal. According to Nitzsch, the pterylosis of the gulls ‘‘approaches very closely 
that of the Scolopacide, and can hardly be distinguished therefrom with certainty 
by any character.” In the terns, ‘‘in consequence of the slender and elegant form 
of the body, the tracts are very narrow, and perfectly scolopacine.” The jaégers 
differ ‘“‘in having the outer branch of the inferior tract united with the main stem 
in the first part of its course, and all the tracts still broader and stronger than in” 
the gulls ; while in the petrels, ‘‘ the tract formation of the jaégers is elevated into 
the type of a group, undergoing scarcely any change in the form of the inferior 
tract, but showing some little modification of the dorsal tract.” 
As here constituted, the order embraces two families, to be known by the char- 
acter of the nostrils ; both are well represented in this country. 
Family LARIDA. Gulls, Terns, etc. 
Nostrils not tubular (linear, linear-oblong, oval or drop-shaped), sub-basal or 
median, lateral, pervious. The hallux, though very small and elevated, with its tip 
hardly touching the ground, is, except in one instance, better developed than in the 
petrels. The habitat is fluviatile, lacustrine and maritime, rather than pelagic. 
The family contains four leading genera, each of which may be assumed as the 
basis of a subfamily; all four occur in North America, 
Subfamily LESTRIDIN A. Jaégers, or Skua Gulls. 
Covering of bill discontinuous, the upper mandible being saddled with a large 
horny ‘‘ cere,” beneath the edges of which the nostrils open (unique, among water- 
birds) ; bill epignathous. Tail nearly square, but the middle pair of feathers 
abruptly long-exserted. Feet strong, the podotheca granular or otherwise roughened 
behind, scutellate in front; webs full. Certain pterylographic characters have been 
already noted. A leading anatomical peculiarity in the large size of the ceeca, as 
compared with the cases of the other subfamilies. There is but one genus, and only 
four species are well determined. They belong more particularly to the northern 
hemisphere, although some also, inhabit southern seas; they mostly breed in 
boreal regions, but wander extensively at other seasons. ‘They inhabit sea coasts, 
and also large inland waters; the nidification resembles that of the gulls; eggs, 
2-3, dark-colored, variegated. The sexes are alike; the young different, excepting 
one species; there is also a particular melanotic plumage, apparently a normal 
transient condition. At first the central tail feathers do not project, and they grow 
tardily. The skua gulls are eminently rapacious, whence their name of ‘jacger” 
(hunter) ; they habitually attack and harass terns and the smaller gulls, until these 
weaker and less spirited birds are forced to drop or disgorge their prey. Their 
flight is vigorous ; lashing the air with the long tail, they are able to accomplish the 
rapid and varied evolutions required for the successful practice of piracy. Thus 
in their leading traits they are marine Raptores; whilst the cered bill furnishes a 
curious analogy to the true birds of prey. 
279-80. Genus STERCORARIUS Brisson. 
* Bill shorter than middle toe without claw ; tarsus shorter than middle toe and 
claw ; central rectrices little projecting, broad to the tip. (Buphagus.) 
a 
