THALASSIDROMA NEREIS, Gould. 
Grey-backed Storm-Petrel. 
Thalassidroma Nereis, Gould in Proc. of Zool. Soc., Part VIII. p. 178. 
During a calm which occurred on my passage from Hobart Town to Sydney in May 1839, I obtained four 
examples of this new species of Petrel, and I subsequently observed it flying about in considerable numbers 
near the eastern entrance of Bass’s Straits; I also met with it on my passage home in April 1840, between 
New South Wales and the northernmost point of New Zealand; further than this I have little to commu- 
nicate respecting it. 
The Thalassidroma Nereis is a species readily distinguishable from its congeners by the total absence of any 
white mark on the rump, the want of which first drew my attention and induced me to suspect it, as it sub- 
sequently proved to be, a different species from any 1 had before seen ; my readers will therefore easily 
imagine with what pleasure I descended the ship’s side and sallied forth in a little ‘ dingy’ to procure speci- 
mens as they came fluttering around me. This is not the only instance in which science has been benefited 
through the kindness of the captains I have sailed with allowing me the use of a boat whenever the weather 
permitted such a favour to be granted me without retarding the progress of the ship. Through the 
liberality of the owner of the ‘ Parsee’, Robert Gordon, Esq., and the ready assistance of the late Captain 
McKellar who commanded that vessel, nearly thirty species of oceanic birds were obtained in this way 
during my voyage to Australia ; whence some idea may be formed of the numbers of birds encountered in 
the open sea, and of the employment the naturalist may find during a voyage round the globe. 
In the habits and mode of flight of this species I could observe no difference whatever from those of the 
other Storm-Petrels ; and as a matter of course, its food is also similar ; any oily substance, together with 
mollusks, being equally partaken of by all the members of the genus. 
The sexes are alike in plumage, and are not materially different in size. 
In conclusion I may state, that I did not observe this species in any other parts of the ocean than those 
mentioned above ; at the same time it is not improbable that it may possess a much wider range. 
Head, neck and chest sooty grey ; lower part of the wing-coverts, back, rump and upper tail-coverts grey, 
each feather very slightly margined with white ; wings greyish black ; tail grey, broadly tipped with black ; 
under surface pure white ; irides, bill and feet black. 
The Plate represents a male and a female of the natural size. 
