AYES. 389 



Sp. Phaeton athtreus L., BUFF. PL enl. 998, LESS. Ornith. PL 114, fig. i ; 

 Phaeton phoenicurus GM., BUFF. PZ. e^L 979, GUER. Iconogr., Ois. PI. 

 65, fig. 3; Phaeton flavirostris BRANDT, Lepturus candidus BBISS. Orniih. 

 vi. Tab. 42, fig. 2, BUFF. PL enl. 369. Compare J. F. BRANDT Tentamen 

 monographic generis Phaeton, Mem. de FAcad. imper. des Sc. de St. Peters- 

 bourg, 6ieme Se"rie, Sc. math, et phys. Tome v. 2, 1839. (These birds recall 

 Sterna and Larus, but must, nevertheless, be referred to the family of the 

 Steganopods.) 



Family IV. Longipennes. Bill with margins entire. Wings 

 elongate. Feet stilted, with tibiae seminude, in some tetradac- 

 tylous, with hallux free, posterior, simple, in some tridactylous, 

 with hallux none. 



A. Nostrils linear, placed at the base of bill, pervious. 



Rhynchops L. Bill long, compressed, straight; lower mandible 

 two-edged towards the tip, longer than upper, with tip truncate. 

 Feet tetradactylous, with palmar membrane excised. Wings very 

 long; first two quills longer than the rest. 



Sp. Hhynchops nigra L., BUFF. PL enl. 357; LESSON Ornith. PI. 113, fig. i, 

 from America ; another species occurs in the eastern hemisphere, Khynchops 

 flavirostris YIEILL., Sh. orientalis RUEPP. Atlas PL 24. The lower man- 

 dible with its sharp upper edge is received in a groove of the upper man- 

 dible like the blade of a pocket-knife in its handle. 



Sterna L. Bill long, straight, compressed, pointed, with man- 

 dibles subequal, the lower shorter. Feet small, tetradactylous, with 

 palmar membrane mostly excised; tarsi scutellate anteriorly. Wings 

 very long, with first quill-feather longer than the rest. 



a) Tail cuneate, longer. Palmar membrane scarcely excised, large. 

 (Sub-genus Anous LEACH, GRAY, Megalopterus BOIE.) 



Sp. Sterna stolida L., BUFF. PL enl. 997, the Noddy; on the Atlantic Ocean 

 between the tropics, Indian Ocean and South Pacific, &c. 



b) Tail forked, or emarginate. Palmar membrane deeply excised between 

 the toes. 



Sub-genus Sterna. (Sterna, GRAY, with addition of sub-genera Hydro- 

 chelidon BOIE, GRAY, Phcetusa and Gygis WAGL. and GRAY.) 



Sp. Sterna hirundo L., BUFF. PL enl. 987, LESSON Ornith. PL 113, fig. 2, 

 the sea-swallow; bill and legs red, head on the top as far as the eyes black, 

 body light-grey above, white below ; the same colours in Sterna minuta L., 

 BUFF. PL enl. 998, NAUMANN, Taf. 254, which, however, is much smaller, 

 and in addition is distinguished by white above the eyes. Similarly 



