AXHIXGA. — SULA. 201 



short scale, Lut when tliev once reacli a high altitude, ther soar most 

 gracefully with set wings, fir?t in a \YiJej slow circle, then with 

 a sudden straight rush, then a circle and so on, all apparently 

 without a single wing-beat. AYlien thus high up in the air thny 

 have a most peculiar arrow-shaped ajjpearance ; thin sharp beak, 

 slender neck and body, and broad, fan-shaped tail.*' 



Family SULID.E. 



The Ganuets are rather laroe birds with conical bills which 

 taper towards the tip, but no hook, the wings are long and 

 Swallow-like in form, the tail is long and wedge-shaped, the legs 

 short, and the feet fully webbed, all four toes being connected and 

 the outer one the longest. 



Their distribution is chiefly, on the coasts of the temperate and 

 tro};ical seas of both hemispheres. 



About nine species comprise tbe family, five occurring within the 

 confines of South America, one of which is represented in British 

 Guiana. 



Genus SULA Briss. 



Sida Brisson, Ora. vi. p. idi, 1760. Type S. leucogastei' (Bodd.). 



The members of this oenus are distino-uished chieflv by their 

 pointed bills, hidden nostrils, and wedge-shaped tails. 



127. Siila leucogaster. 

 ^Vhite-bellied Boobt. 



PeJeciintis Ieuco//osfer Bodd. Tabl. PI. Enl. p. 57, 17S8 (Cayenne). 



Siila su/a Oi,Mlvi"e-Gi-ant, Cat. B. Brit. Mus. xxvi. p. 430, 1S98. 



Sula leucogaster Brabourne & Chubb, B. S. Amer. i. p. GO, no. oo9, 1912. 



Immature. General colour above and below smoky-brown, some- 

 what paler on tlie axillaries and abdomen. 



Total length G20 mm., culmen 97, wing 395, tail 158, 

 tarsus 4n. 



Wc do not know tlie exact locality of tlie bird descrilied. 



Adult male. Back, wings, and tail smoke-brown ; iiead, tliroat. 

 and neck all round darker and more chocolate-brown ; iindor 

 wing-covorts, sides of brea>t, lower flanks, and lateral under tail- 

 coverts like the back ; breast, abdomen, sides of body, axillaries. 



