FORKED-TAILED GULL. 563 



long and narrow ; nostrils in its fore part, longitudinal, submedial, linear, 

 pervious. Lower mandible with a slight prominence at the end of the 

 angle, which is long and narrow, the dorsal line then straight or slightly 

 concave, the ridge convex, the sides nearly flat. 



Head of moderate size. Neck short. Body rather slender. Wings 

 very long. Feet of moderate length, rather strong ; tibia bare below for 

 a short space, covered behind with narrow scutella ; tarsus compressed, 

 anteriorly covered with numerous scutella and three inferior series of 

 transverse scales, laterally with rounded scales, posteriorly with oblique 

 scutella. Toes slender, scutellate above ; first extremely small, se- 

 cond much shorter than fourth, third longest, anterior toes connected by 

 reticulated webs, the outer and inner slightly marginate ; claws small, 

 compressed, obtuse, that of middle toe with an expanded inner edge. 



Plumage close, soft, blended. Wings very long and pointed ; pri- 

 maries tapering and rounded, first longest, second almost equal, the rest 

 rapidly graduated ; secondaries obliquely pointed, the rounded extremity 

 extending beyond the tip of the shaft, which is exterior to it. the inner 

 feathers more elongated. Tail of moderate length, forked, of twelve fea- 

 thers. 



Bill black at the base for more than half its length, the rest pure yel- 

 low. Edges of eyelids vermilion, as is the inside of the mouth. Feet 

 black. Head and upper part of neck all round blackish-grey, that colour 

 terminated below by a ring of pure black encircling the neck. Lower 

 neck all round, the whole lower surface, the upper tail-coverts and the 

 tail, pure white. The back and wings are bluish-grey, excepting a large 

 terminal portion of the secondaries, and the tips of the primaries, which 

 are white, the primaries themselves being black, with their shafts brown- 

 ish-black. The first quill of the specimen figured had no white on the 

 tip, but some individuals differ in this respect. 



Length to end of tail 13 inches, to end of wings 14| ; extent of wings 

 33 ; wing from flexure 10| ; tail 5 ; bill along the ridge 1, along the 

 edges 1| ; tarsus li% ; middle toe 1, its claw j%. Weight 7 oz. 



The Female is rather less than the male, but in other respects similar. 



