52 A MANUAL OF THE BIRDS OF AUSTRALIA, 
Immature—When the young flies it has a dark grey head which extends on 
to the throat ; the ocular patch distinctly blackish ; the grey is a dirty-brown grey, 
while the bill is practically all black, but the lower edges of the under mandible 
show pale brownish. The grey head and neck lose their brownish tinge while the 
culmen takes on a light yellowish-brown shade, the strip on the lower edges of the 
lower mandible becoming paler. The fully-adult has a beautiful pearl-grey head, 
neck and throat, while the culmen is pale clear yellow and the lower edge of the 
lower mandible is also clear light horn or yellowish. Some birds, however, in the 
change, as shown by the coloration of the bill, have the head white and the back 
of the neck inclining to white. 
Nest, Egg, and Breeding-season—Unknown. 
Distribution and forms.—Sub-antarctic as far as is known. Four forms can be 
recorded, but more material is necessary before finality can be suggested. These 
are: 7’. c. chrysostoma Forster, from Cape Seas (of which D. culminata Gould may 
be a synonym); 7’. c. mathewst (Rothschild) from Campbell Island, New Zealand, 
as having the cheeks and throat pure white, and top of head white, not grey ; back 
browner ; 7’. c. harterti Mathews, from South Indian Ocean (Kerguelen Island 
breeding) in its deeper, heavier bill, coloration as in preceding ; 7’. c. alexanderi 
Mathews, from West Australian seas, with smaller and paler bill. 
40. Thalassarche chlororhynchus.—-YELLOW-NOSED MOLL YMAWK. 
[Diomedea chlororhynchos Gmelin, Syst. Nat., Vol. I., pt. m., p. 568, April 20th, 1789: Cape 
Seas. Extra-limital.] 
Gould, Vol. VII., pl. 42 (pt. xv.), June Ist, 1844. Mathews, Vol. II., pt. 3, pls. 98 and 99, 
Sept. 20th, 1912. 
Thalaseogeron cartert Rothschild, Bull. Brit. Ornith. Club, Vol. XIV., p. 6, Oct. 30th, 1903: 
Point Cloates, mid-West Australia. 
Diomedea basst Mathews, Nov. Zool., Vol. XVIII., p. 206, Jan. 31st, 1912: ‘“‘ New South 
Wales.” 
DistTRIBUTION.—Southern Australian Seas. 
Adult male—Back, scapulars and wings slaty-brown, tail-feathers hoary-grey, 
lesser, median, and greater wing-coverts dark brown with white bases, like the 
bastard-wing and primary-coyerts ; primary-quills black on the outer webs, hoary- 
grey on the inner ones, with white shafts at the basal portion ; secondaries dark 
brown, white on the inner webs ; some of the feathers of the olecranal region dark 
brown while others are white with brown tips ; humeral feathers also dark brown ; 
rump and upper tai]-coverts white ; a patch on each side of the breast grey, like the 
back ; a pale grey line in front and over the eye ; head and neck all round, mantle 
and entire under-surface white, as also the axillaries ; under wing-coverts white, 
those around the margin dark brown ; bill black, culmen yellow, passing into orange 
at the tip; a line at the base of the mandible yellow; legs flesh colour. Total 
length 710 mm, ; culmen 118, wing 464, tail 190, tarsus 75. 
Adult female.—Similar to the adult male. 
Immature.—Agrees in general coloration with the adult, but differs from that. 
in the colour of the bill, which is in this wholly black (due to immaturity) ; irides 
black ; feet and legs yellowish-white. Culmen (exp.) 114 mm. long, depth at base 36, 
wing 462, tail 165, tarsus 75. (TZ. carteri Rothsch.) 
Nestling, Eggs, and Nesting-place——Unknown. 
Distribution and forms —Apparently Sub-antarctic but not well known. Races 
not yet determined. Thus the West Australian bird was named from an immature 
specimen and the Tristan d’Acunha bird described as D. eximia Verrill, owing to a 
misunderstanding of the species. When breeding places are discovered forms may 
be accurately circumscribed, 
