104 A MANUAL OF THE BIRDS OF AUSTRALIA. 
Procelsterna albivitta Bonaparte, Comptes Rendus Acad. Sci. Paris, Vol. XLII, p. 773, May 
1856. New name for A. cenereus Gould. 
Procelsterna cerulea kermadeci Mathews, Austral Av. Rec., Vol. III., pt. 3, p. 55, April 7th, 
1916: Kermadec Islands. 
DistRiBuTION.—Probably as a straggler to east coast of Australia, 
Adult male.—General colour above ash-grey, paler and inclining to white on 
the head, sides of face and entire under-surface of body, including the under wing- 
coverts ; under tail-coverts ash-grey like the upper-surface ; inner webs of outer 
primary-quills inclining to black near the shaft, the innermost portion becoming 
whitish ; most of the secondaries grey margined with white at the tips; short 
feathers encircling the eye, black in front and white on the hinder portion ; bill 
black ; iris blackish-blue ; tarsi and toes black, webs lemon-yellow. Total length 
279 mm. ; culmen 29, wing 207, tail 120, tarsus 24. 
Adult female.—Similar to the adult male but smaller. 
Immature—Difters from the adult in being dark slate-grey both above and 
below, the wings being somewhat darker than the back and the primary-quills 
inclining to black. 
Nestling—Almost the same colour as the parent bird. 
Nest.—None ; the eggs are laid on the bare rock or sand. - 
Egg.—Clutch, one ; ground-colour stone, with underlying spots of grey sparingly 
distributed, and fewer spots of chestnut-brown ; axis 42 mm., diameter 30. 
Breeding-season.—September to January. (Norfolk Island.) 
Distribution and forms.—Apparently Pacific Ocean only where, however, five 
forms have been distinguished, as follows: P. c. cerulea (Bennett) from Christmas 
Island and Hawaiian Group; P. c. teretirostris (Lafresnaye) from the Paumotus, 
Marquesas and Society Groups; P. c. nebouxi Mathews, from the Ellice and Pheenix 
Groups darker and smaller than preceding which are all darker than the next two ; 
P.c. cinerea (Gould) from Norfolk, Lord Howe, Kermadec Islands, probably Friendly 
Islands, much paler above and below and also larger; the form P. c. imitatrix 
Mathews, from St. Ambrose Group of the coast of South America, agreeing almost 
exactly in coloration but a little larger. 
Genus LEUCANOUS. 
Leucanous Mathews, Birds Austr., Vol. II., pt. 4, p. 432, Nov. lst, 1912. Type (by original 
designation): Gygis microrhyncha Saunders. 
Gygis Wagler, Isis, 1832, heft 11, col. 1223, Nov. Type (by monotypy): Sterna candida 
Gmelin. 
Not Gyges Bory de St. Vincent, Ency. Meth., p. 449, 1825. 
Alphagygis Mathews, Austral Av. Rec., Vol. II., pt. 5, p. 110, Sept. 24th, 1914. New name 
for Gygis Wagler 1832, as above. 
Small Noddies with long stout bills, long wings, medium tails and very short 
legs, and long toes with indented webs. The diagnostic characters of the genus 
are the shape of the bill and the very short legs, and long toes with deeply indented 
webs. The bill is longer than the head with the culmen straight or even slightly 
upturned, while-it is very deep at the base proportionately. The tail is less than 
half the length of the wing and the outer rectrix is shorter than the second which 
is longest. The middle toe is almost twice as long as the metatarsus though not 
much more than half the culmen. 
The bird described as Gygis microrhyncha by Saunders differs from the above 
in having a long slender bill and a proportionately shorter tail of different formation, 
the third rectrix from the outside being the longest, while the first is absolutely 
shortest. In Sterna alba Sparrman the outside rectrix is longer than the two centre 
pairs, the centre feather being the shortest. 
Coloration all white. 
