GREY-HEADED MOLLYMAWE. 51 
wing-coverts white, more or less shaded with grey, the smaller coverts round the 
margin black, like the upper wing-coverts ; quills below brown with white shafts, 
which are blackish towards the tips; bill uniform, gamboge-yellow, shaded with 
orange on tbe hook and with a very fine line of black round the base of the mandibles ; 
iris light brown; feet delicate blue-grey, darker on the joints and interdigital 
webs ; claws white-horn colour. Culmen (exp.) 115 mm., depth at base 45, wing 
510, tail 200, tarsus 78.5, middle toe 115. 
Adult female.——Similar to the adult male. 
Young.—Difiers from the adult in having the head and neck ash-grey, and 
the upper-surface of wings and interscapular region brownish-black, the smaller 
wing-coverts with paler margins, the bill blue-black, and the legs and feet 
bluish-grey. 
Nestling—Covered with long, thick woolly down, of a pale grey colour; bill 
brownish-black with yellowish-horr coloured tip ; legs and feet yellowish-white. 
Nest.—A conical mound from 8 in. to 18 in. in height constructed of mud mixed 
with vegetable substances, the cup-shaped depression is lined with finer materials. 
Eggs.—Clutch, one ; surface dull, and having a ring round the larger end of 
reddish-brown specks and blotches ; axis 97 to 114 mm., diameter 54 to 69. 
Incubation-period —Sixty days. 
Breeding-season November to January. 
Distribution and forms.—Round the Sub-antarctic Circle. Four forms have been 
separated : 7’. m. melanophrys (Temm. and Laugier) from the Cape Seas, probably 
breeding at Gough Island, Tristan d’Acunha and the Falkland Islands; 7. m. 
belcheri Mathews, with longer bills of paler coloration, from Kerguelen Island ; 
T.m. impavida Mathews, with shorter bills, grey lores, and more black in front and 
above the eyes; and 7’. m. richmondi Mathews from the west coast of South 
America with long bills, deeper than that those of the Kerguelen form, no grey 
on the lores and the biack about the eye reduced to a very faint marking. 
39. Thalassarche chrysostoma.—GREY-HEADED MOLLYMAWkK. 
[Diomedea chrysostoma Forster, Mém. Math. Phys. (Paris), Vol. X., p. 571, 1785: Cape Seas. 
Extra-limital.] 
Gould, Vol. VII., pl. 41 (pt. xxx), Sept. Ist, 1848. Mathews, Vol. IT., pt. 3, pl. 97, Sept. 
20th, 1912. 
Diomedea culminata Gould, Proc. Zool. Soe. (Lond.), 1843, p. 107, Dee. : ‘‘ Southern, Indian 
and South Pacific Oceans ’’ = Cape Seas. 
Thalassogeron chrysostoma alexanderi Mathews, Austral Av. Rec., Vol. III., pt. 3, p. 55, 
April 7th, 1916: West Australia. 
DisTRIBUTION.—Southern Australian Seas. One specimen preserved in Mathews'’s collection 
and another in Perth Museum. C/. Alexander, Emu, Vol. XIX., pt.1., p. 59, July Ist, 1919. 
Adult male-—Head, hind-neck and mantle grey with white base to the feathers, 
becoming dark brown or black on the middle of the back, scapulars and wing-coverts ; 
lesser, median, and greater wing-coverts dark brown, with whitish bases like the 
bastard-wing, primary-coverts and quills, the latter with white shafts and pale brown 
inner webs ; secondaries dark brown with white on the basal portion ; olecranal 
feathers dark brown with pale inner webs which become white at the base ; rump 
and upper tail-coverts pure white ; tail dark hoary-grey with white shafts ; feathers 
above and in front of the eye black; sides of throat, face, and fore-neck white, 
more or less washed with grey ; remainder of the under-surface white ; axillaries 
pale grey with whitish tips ; feathers round the margin of the under-wing blackish ; 
bill black, the culmen yellow, divided from the tip, which is horn colour, by a black 
patch, base and lower edges of mandible yellow ; feet and legs grey, webs fleshy-pink. 
Total length 910 mm.; culmen 111, wing 518, tail 213, tarsus 86. 
Adult female—Similar to the adult male. 
