THE BIRDS OF AUSTRALIA. 
written upon this mixture only, it necessarily follows that a reconsideration 
of the facts is necessary. 
Vieillot described his bird from Australian seas, and the bird which I have 
described and figured, and which was killed at sea in 35° S. lat. and 158° 5' E. 
long., agrees with the type-specimen and may be regarded as typical. 
Gould’s T. leucogaster is a different species, and with it, as an absolute 
synonym, must be placed F. melanoleuca Salvador! {Bull. Brit. Orn. Club, 
Vol. XXI., pp. 78-79, 1908) from Tristan d’Acunha (?). I will go into this 
later on. 
Philippi and Landbeck {Arch, fur Nat. Wiegmann, 1860, p. 282) introduced 
Thalassidroma segethi for a bird killed off the coast of Chili, South America. 
The original diagnosis is as follows : — 
Thalassidroma Segethi, uropygio, basi caudae abdomineque albis, reliquo corpora omnino 
nigro-fusco. 
Dimensionen : Lange des Fliigels vom Bug bis zur Spitze 5 Zoll 9 lin. 
Pacific Ocean, off Chili. 
Coues’ condensed translation will be more helpful than the two pages 
given by PhiHppi and Landbeck : — 
The bill and feet are glossy black. The head, neck, back, throat and breast, as well as 
the upper wing-coverts, dark blackish-grey, the latter, however, tending towards brownish. 
Wing and tail-feathers deep black. The feathers of the u^per -parts have white borders, which, 
however, are worn away in the course of the summer. The inner-web of the four outer tail- 
feathers is white at the base. The upper tail-coverts, the abdomen, the flanks, and the 
circumanal region are white. Under tail-coverts are black, with white bases and tip. The 
lesser inferior wing-coverts, and the whole border of the wings are black, the rest of the 
inferior coverts white. 
Length 7^ inches (French). Bill 6 lines ; tail 2 inches 11 lines ; wing 5i inches. Tarsus 
1 inch 5 lines ; middle toe 10 lines. Naked portion of the tibiae 7 lines. Wings when folded 
reaching an inch beyond the tail. 
There appears to be a discrepancy in the measurement of the wing given. 
The “Challenger” Expedition obtained five specimens in 37° 29' S. and 
83° 7' W., which were identified as P. grallaria, and have been the cause of most 
of the trouble since. These are the specimens with the white fringes to the 
feathers of the back, about which there has been so much discussion as to whether 
this was a specific character, a sign of age, or what not. If one has examined 
Petrels from breeding-places, one will at once recognise these light tips as signs 
of a newly-moulted bird and no discussion at all is necessary. 
There is a specimen killed off S. Ambrose which, though obviously identical 
with the “ Challenger ” birds, has no white tips, and it was procured towards the 
end of winter, July 20th, while the “Challenger” specimens were all killed 
on the same day at the beginning of summer, viz. November 11th. 
When Forbes was working on the Anato7ny of the Petrels with these very 
birds in front of him, which are unquestionably F. segethi, he wrote, “F. segethi 
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