THE BIRDS OF AUSTRALIA. 
Wing 9 inches 3 lines : bill, length 8 to 8^ lines ; depth 3^ lines ; width 3| lines ; length 
of nasal tubes 1^ lines ; tarsus 14 lines ; midtoe ISJ lines. Glaces du Pole Sud. Mers 
antarctiques. 
The comment in the Monograph on the variation is (p. 256) : “ Dr. Bowdler 
Sharpe, in his report on the collections of the ‘ Southern Cross ’ Expedition 
(p. 149), points out that the extraordinary variation in size exhibited by a 
series of the Snowy Petrels is not due to a difference of sex ; the males 
measured by him having a wing of 10-1 to 11-8 inches, and the females 9-8 
to 11*8 inches. The variation in size of biU, too, is also very marked, and is 
not a sexual distinction.” 
In my experience of measuring Petrels, I have found no variation such as 
expressed above which was not due to the confusion of races, and I therefore 
examined the series of P. nivea in the British Museum. Upon sorting them 
into groups according to locahties, it was apparent that some other conclusion 
must be arrived at, as large and small birds were present from the same place ; 
but it seemed that the large ones were constantly large while the small were 
as regularly small, and that no intermediates were existent. Careful measure- 
ments confirmed this, nine birds giving : Bill 20-22 by 9.5-10.5 ; wing 251-263 ; 
tarsus 30-32 ; middle toe 33-35 ; middle claw 10-11 mm. ; — while four others 
gave : Bill 24-26 by 12-14 ; wing 297-304 ; tarsus 38-40 ; middle toe, 39-42 ; 
middle claw 13 mm. ; the whole of these being from Cape Adare, Victoria Land, 
and thereabouts. 
It wiU be noted that the large birds have every measurement absolutely 
larger, with no intergradation whatever. These were all killed about the 
same time of year, and both male and female were represented in each size, 
and all were fully adult as far as could be ascertained. The biUs of the small kind 
were very small and weak, and agreed with the general description as evidenced 
by Coues’s diagnosis : “ The bill is very short, being less than half as long as the 
skull ; and exceedingly small, weak, slender and compressed throughout, its 
base being much higher than broad.” They also would be referable to P. nivea 
Forster, and here would be attached P. Candida Peale and P. nivea minor 
Schlegel. The bills of the large birds however, though agreeing in compression 
and general form, could not be called “ exceedingly small and weak,” as they 
are comparatively strong and powerful — as a matter of fact, being very deep 
in proportion. 
I can see no other conclusion but that two distinct species are at present 
included under P. nivea. The names hitherto proposed refer to the small 
form, while the large one appears nameless. Both seem to breed all round the 
Antarctic Continent, and much research and large collections must be made 
before the subspecies and species of Pagodro^na are definitely limited. 
176 
