THALASSIDROMA LEUCOGASTER, Gould. 
White-bellied Storm Petrel. 
Thalassidroma leucogaster, Gould in Ann. and Mag. of Nat. Hist., vol. xiii. p. 367. 
This bird is about tbe same size as the Thalassidroma melanogaster , but possesses two characters by which it 
may at all times be distinguished from it : these are, the total absence of black down the centre of tbe abdo- 
men, and tbe shortness of its toes. I encountered it very generally over the South Indian Ocean, where I have 
reason to believe that it ranges over all the temperate latitudes between the Cape of Good Hope and Cape 
Horn, and it is not unlikely that it may inhabit similar latitudes in the South Atlantic. It was also noticed 
bv His Excellency Governor Grey, who procured and transmitted specimens to the British Museum. I 
killed specimens of a nearly allied species within tbe tropics of tbe South Atlantic, which differed in being 
of a larger size and in having a patch of greyish white on the throat ; these differences will doubtless prove 
it to be a distinct species, and I mention this in order that the two birds might not be confounded by sub- 
sequent voyagers or writers on the subject. I have presented a specimen of the larger species, killed by 
myself at tbe Equator, to tbe British Museum, where it is always accessible for comparison and other scien- 
tific purposes. 
Like the T. melanogaster , the White-bellied Storm Petrel is a fine and powerful species, fluttering over 
tbe glassy surface of tbe ocean during calms with an easy butterfly-like motion of tbe wings, and buffeting 
and breasting with equal vigour the crests of the loftiest waves of the storm ; at one moment descending 
into their deep troughs, and at tbe next rising with tbe utmost alertness to their highest points, apparently 
from an impulse communicated as much by striking tbe surface of tbe -water with its webbed feet as by the 
action of tbe wings. Like the other members of tbe genus, it feeds on mollusca, tbe spawn of fish, and any 
kind of fatty matter that may he floating on the surface of the ocean. 
Head and neck deep sooty black ; back greyish black, each feather margined with white ; wings and tail 
black ; chest, all the under surface and the upper tail-coverts white ; bill and feet jet-black. 
Some slight variation appears to exist in the extent of the sooty colouring of the neck ; in some specimens 
it merely descends to the base of tbe throat, while in others it spreads over tbe chest, but never down the 
centre of the abdomen. 
The figures represent the birds of the natural size fluttering over the surface of the waves in a calm. 
