DIVING PETREL. 47 
Adult male——Upper surface glossy blue-black, including the head, back, wings, 
and middle tail-feathers ; some of the scapulars grey with white tips, the small 
coverts round the bend of the wing edged with grey ; primary-quills pale brown on 
the inner webs ; some of the innermost secondaries fringed with white at the tips ; 
outer tail-feathers pale brown, narrowly edged with white at the tips ; fore-head 
sooty-black without any gloss; sides of face dark slate-grey ; sides of neck and 
fore-neck paler slate-grey with white tips to the feathers, which a give minutely 
barred appearance, this is also shown on the sides of the body ; throat, breast, 
abdomen, and under tail-coverts white ; axillaries ash-brown, slightly fringed with 
white ; under wing-coverts ashy-grey, margined with white and having black 
shaft-lines ; bill black, the base of the cutting edge of the upper mandible, and 
line along the lower edge of the lower, blue-grey ; iris very dark greyish-brown ; 
tarsi and toes beautifully light blue. Total length 230 mm. ; culmen 15, wing 118, 
tail 40, tarsus 22. 
Adult female-——Similar to the adult male. 
Immature—As adult, but weaker bill and feet and shorter wing, and with 
whitish tips to back feathers, wing-coverts and secondaries. 
Nestling—Covered with dark ashy-grey down, paler on the under-surface ; 
bill black ; feet and legs blue. 
Nest.—At the end of a crooked burrow. 
Egg—Clutch, one ; white, surface dull; axis 38-42 mm., diameter 32-33. 
Breeding-season.—July and August. (Mokohinou Islands.) November. (North- 
east Island, Bass Strait.) October and November. (Macquarie Island.) 
Distribution and forms.——Round the Sub-antarctic Circle. Forms at present 
under review by Murphy and Harper, but results not yet published. Seven sub- 
species up to now named: P. wu. urinatrix (Gmelin) from Queen Charlotte’s Sound, 
South Island of New Zealand ; P. wu. chathamensis Murphy and Harper from the 
Chatham Islands as being larger and throat more splashed ; P. uw. belcheri Mathews 
in being smaller, the under-surface of the wings white, the grey of the chest separate 
and the nostrils larger ; P. wu. exsul Salvin from Kerguelen Island, larger, with grey 
feathering on side of chest extensive, and flanks mottled with grey as under wing- 
coverts ; P. uw. dacunhe Nicoll, from Tristan d’Acunha and (?) Gough Island, smaller 
and with much less grey on flanks and sides of throat ; P. wu. berard Quoy and Gaimard, 
from the Falkland Islands, with less grey on throat than preceding, but larger, 
though less than P. w. exsul; and P. uw. coppingeri Mathews from Straits of Magellan, 
smaller still and with very little splashing on throat. 
SuperRFAMILY DIOMEDEOIDEA. 
Only one family is at present recognised, consisting of very large birds with 
the nasal openings separated into two distinct tubular orifices opening on each side 
of the bill, very long wings with very numerous secondaries and strong webbed feet 
with no hind-toe, Their distribution is a little curious and worthy of consideration, 
as, mainly Antarctic and Sub-antarctic, a series live in the North Pacific. The groups 
are easily separated by the bill formation, but more detailed research will probably 
allow of still better segregation as we find the following facts ; all the North Pacific 
forms are referable to the genus Phebastria, characterised by the descent of the 
culminicorn basally behind the nasal apertures to overlap the latericorns. The 
species of similar size allotted to Thalassarche are sub-antarctic circumpolar and 
have the culminicorn basally more or less separated from the latericorns by a naked 
strip of skin which also sometimes separates the culminicorn from the frontal feather- 
ing. The largest forms have the same distribution, Diomedea (sensu stricto), and 
have no naked skin between the culminicorn, and latericorn while the base of the 
lower mandible shows no basal bar. An intermediate form, Diomedella, has a 
