INTRODUCTION. XXXVll 



Subfamily Larin.«. 

 Xema, Zcw/i. —HiU rather shorter than the head, moderately stout; the upper 

 mandible decurved from beyond the nostrils to the tip, the gonys angulated 

 and advancing upwards. Nostrils basal, lateral, linear. Wings long, the 

 first quill the longest. Tail distimlly forked. Legs moderately long; the 

 lower part of the tibia bare for some distance; tarsi tolerably strong; three 

 toes in front entirely webbed, hind toe small, elevated (p. 641). 



Rhodostethia, MacgiUhn-ay.—V^\\\ very short, rather slender; the upper man- 

 dible decurved towards the tip, the lower mandible with the intercrural space 

 narrow, the knob slight, the dorsal line concave, and the tip narrow. Wings 

 long, pointed, the first quill the longest. Tail cuneate, the central feathers 

 much longer than the lateral ones. Legs rather short, the tibia bare for a 

 short distance ; tarsus anteriorly scutellate, rough posteriorly ; hind toe very 

 distinct, with a large curved claw; the three anterior toes entirely webbed ; 

 claws rather large, and curved (p. 643) 



Larus, Limicviis. — Bill of moderate length, strong, hard, compressed, cutting, 

 slightly decurved towards the point, lower mandible shorter than the upper, 

 the symphisis angular, prominent. Nostrils lateral, near the middle of the 

 beak, pierced longitudinally, pervious. Wings long, the first and second 

 quills varying slightly in their relative length, but nearly equal. Tail square 

 at the end. Legs moderately slender, lower part of the tibice naked, the 

 tarsus long, three toes in front entirely palmated, the hind toe free, short, 

 but not rudimentary, articulated high up on the tarsus above the line of the 

 other toes (p. 645). 



RiSSA, Stephens.— ^\\\ rather short and stout, the upper mandible considerably de- 

 curved to the tip, the lower mandible compressed, with the intercrural space 

 long and narrow. Nostrils median, linear, oblong. Wings long, pointed, 

 the first primary slightly exceeding the second. Tail slightly but perceptibly 

 forked in the young, nearly square in the adult ; tarsus very short in propor- 

 tion to the foot ; hind toe minute and usually obsolete ; claws rather small, 

 slightly curved (p. 667). 



Pacophila, Kaup.—^\\\ shorter than the head, robust, compressed, straight, the 

 upper mandible decurved towards the tip, lower mandible narrower. Nostrils 

 basal, linear, oblong, wider in front, covered above and behind with a sloping 

 thin-edged plate. Wings long, pointed, the first quill longest. Tail rather 

 lono, slightly graduated. Legs short, bare for a short distance above the 

 tibia; tarsi broadly scutellate in front, and minutely at the sides and l)ack ; 

 interdigital membranes emarginated and serrated ; claws strong and curved ; 

 hind toe furnished with a large claw, and connected on the inside with the 

 tarsus by a well-defined zveb (p. 669). 



Subfamily Stercorariin.e. 

 StercoraRIUS, Brisson. — Bill strong, hard, cylindrical, formed for cutting ; 

 compressed, curved, and hooked at the point ; base of the upper mandible 

 covered with a cere. Nostrils situated towards the point of the beak, 

 diagonal, narrow, closed behind, pervious. Tail slightly rounded, the two 

 middle feathers elongated, sometimes considerably. Wings moderate, the 

 first quill the longest. Legs strong, naked above the tarsi, which are rather 

 long ; three toes in front, palmated; the hind toe small; claws large, strong, 

 very much curved (p. 671). 



