ALLIED PETREL. 
stouter, the wing slightly shorter, the general coloration lighter, especially 
noticeable on the mantle and head ; the axillaries more or less splashed with grey, 
and the tarsus slightly longer. The average measurements are: culmen (exp.) 
27 mm., wing 180-186, tarsus 39-41. 
The West Australian breeding bird is slightly smaller than the Kermadec 
form, and is generally of a lighter coloration above, the white advancing more 
on the forehead than in that form, and the young is conspicuously lighter. 
These last four forms are very close, and easily separable at sight from the 
Pacific brown-black birds. 
The difficulty in dealing with these birds does not show itself until the 
Atlantic and Indian Ocean forms are investigated, and it seems due to these that 
Rothschild and Hartert amalgamated all under the specific Puffimis obscums. 
The birds from Seychelles are brown-black above, and agree very closely 
with the Pelew Islands form, but are smaller ; the longer under tail-coverts are 
fuliginous, while some of the shorter are white ; the average measurements of 
eleven specimens give: culmen (exp.) 27.5 mm., wing 185-192, tarsus 36 mm. 
I have seen only two specimens from Reunion, and these both agree in 
having the under tail-coverts white, and apparently the coloration would be 
more blue than the Seychelles bird, but neither of the specimens is in perfect 
plumage. 
Through the courtesy of Mr. Eagle Clarke, I have been allowed to examine 
two birds obtained by the Scottish. Antarctic Expedition on Gough Island. 
These are very light blue-black birds, much lighter than any of the Australian 
forms except the Chatham one, which apparently has a shorter wing and tarsus. 
The measurements are : culmen (exp.) 27 mm., wing 190, tarsus 41. 
Breeding at the Cape Verde Islands is a puzzling race which seems almost 
to be related to both the blue-black and the brown-black birds ; but although 
it has been generally associated with the former, I would consider it better 
placed with the latter. 
They have brown-black backs ; the upper part of the lores all dark, the 
under side of the primary-quills duskjq and the under tail-coverts smoky-brown ; 
the average measurements of a good series are: culmen (exp.) 26.5 mm., wing 
181-183, tarsus 35-36. I have only seen two specimens from the Canary group, 
and these are of the blue-black bird, whose measurements are : culmen (exp.) 
26-27 mm., wing 182-186, tarsus 37-38. It is quite possible that race 
inhabiting this group is separable from the Madeira breeding birds, but longer 
series from the Canaries are necessary. 
A good number have been examined from Madeira and the Great Salvages, 
and these may be compared with the Gough Island bird. They are distinctly 
blue-black above, darker than the Gough Island form ; the lores are almost 
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