80 A MANUAL OF THE BIRDS OF AUSTRALIA. 
wing 275, tail 120 mm.; and L. 1. ascensionis Mathews, from the Atlantic Ocean, 
breeding at Ascension Island and Fernando Noronha, also smaller than the typical ; 
average measurements : culmen 51, wing 260-265, tail 110 mm. 
Genus SCEOPHAETHON. 
Scawophaéthon Mathews, Austral Av. Rec., Vol. II., pts. 2 and 3, p. 56, Oct. 23rd, 1913. 
Type (by original designation): Phaéthon rubricauda westralis Mathews. 
Phenicurus Bonaparte, Comptes Rendus Acad. Sci. Paris, Vol. XLI., p. 1115, (end Dec.) 1855. 
Type (by monotypy): P. rubricauda Boddaert. 
Not Forster, Synopt. Cat. Brit. Birds, p. 16, (Dec.) 1817. 
Large Phaéthontid birds, with short deep, laterally compressed, not hooked, 
bills, long wings, short tails with extraordinary elongated central pair of tail-feathers, 
short legs and feet, the four toes connected with a web. 
The bill is longer than the head, not hooked, but the culmen arched, deep, 
much laterally compressed, the edges of both mandibles coarsely serrated. The 
nostrils are open linear slits placed high up near the base of the culmen, the feathering 
running back from the nostrils to the gape at a very acute angle ; the gape is wide ; 
the rami of the lower mandible are thick, placed close together, enclosing a very 
narrow feathered tract, and fusing at two-thirds the length of the mandible; the 
culmen chord is twice the length of the metatarsus. The wing is long with the first 
primary longest. The tail is short, slightly wedge shaped, composed of sixteen 
feathers, the central pair very much elongated, the webs very much diminished : 
this pair are about six times the length of the culmen, while the second pair are less 
than twice its length. The legs are short and thick, the toes short and rough. The 
metatarsus is less than half the length of the culmen and is covered with hexagonal 
roughened scutes, the scutes much smaller at the back. The toes are all connected 
with webs, but are nothing like the feet of any Steganopod. That is, the 
middle toe is longest, the outer toe longer than the inner, while the hind-toe is very 
small and placed posteriorly. The scaling of the toes consists of regular scutes. 
58. Sceophaéthon rubricauda.—RED-TAILED TROPIC BIRD. 
[Phaéton rubricauda Boddaert, Tabl. Planch. Enlum., p. 57, (pref. Dec. 1st) 1783: Mauritius. 
Extra-limital.} 
Gould, Vol. VIL., pl. 73 (pt. xxxv.), Dec. Ist, 1848. Mathews, Vol. IV., pt. 3, pl. 231, June 
23rd, 1915. 
Phaéthon novehollandie Brandt, Mem. 1’Acad. Imp. Sci. St. Petersb., Ser. VI., Vol. V., pt. 11, 
p. 272, 1840: Lord Howe Island. 
Phaéthon rubricauda erubescens Rothschild, Avifauna Laysan, pt. m1., p. 296, Dec. 1900: 
Kermadec Islands. 
Phaéthon rubricauda westralis Mathews, Austral Av. Rec., Vol. I., pt. 4, p. 88, Sept. 18th, 
1912: [Rottnest Island] = Houtman’s Abrolhos, West Australia. 
DIsTRIBUTION.—Queensland, South and West Australia. 
Adult male—General colour both above and below silky-white with a pinky 
hue ; the feathers on the crown and nape have dark bases ; a black patch in front 
and behind the eye; bastard-wing, primary-coverts, greater coverts and quills 
white tinged with pink, all the feathers having conspicuously black shafts ; some 
of the innermost secondaries black broadly margined with white ; the long flank 
feathers white, lead-grey on the inner portion of the outer webs, and those on the 
sides of the rump grey, broadly margined with white ; tail-feathers pinky-white with 
black shafts becoming red on the elongated middle feathers. Bill orange-red, 
nostrils brown; feet and upper part of legs faint blue, rest black. Total length 
520 mm.; culmen 67, wing 348, tail 92, middle feathers 442, tarsus 32. 
