764 BIRDS OF SOUTH AFRICA, 
In habits they resemble Oceanitis lewcogaster, with which they 
freely consort, flitting over the waves and picking up odd bits 
flung over the ships’ sides. When taken in hand they disgorge 
large quantities of an oily matter, which quickly congeals, and 
assumes the appearance of dirty lard. Mr. Rickard records it from 
the neighbourhood of East London, and Mr, Andersson gives the 
following note:—“ This bird is not unfrequently met with off the 
the south-west coast of Africa, as well as in many of the bays and 
inlets. I have occasionally seen it very abundant about the 
fisheries at Walwich Bay and Sandwich Harbour, where these birds 
would approach within a few feet of the fishermen, eagerly picking 
up the smaller particles of refuse thrown away by them whilst 
cleaning their fish on the shore.” 
General colour throughout, brownish-black ; rump and thighs 
white ; legs and feet black; webs between the toes yellow, edged 
with black ; irides black. Length, 7’; wing, 6”; tail, 24’. 
Fig. Dresser, B. Eur. viii, pl. 614, fig. 1. 
738. Oceantris Tropica (Gould). Black-bellied Petrel. 
Thalassidroma melanogaster, Layard, B.S. Afr. p. 538. 
Not uncommon off Cape L’Agullas and on the south-eastern 
coast. While cruising with Admiral Trotter in the old “ Castor ” 
frigate, the boats being always at our disposal, we obtained many 
specimens of this and other species of birds inhabiting the Cape 
seas. Indeed, most of our knowledge of our oceanic birds is due 
to the opportunities so kindly afforded us by our kind and noble 
old friend, now, alas! no more. 
General colour throughout, brownish-black ; belly white, divided 
down the centre by a black stripe; rump and sides behind the 
thighs, pure white; legs, feet, and webs between the toe, black. 
Length, 84” ; wing, 6” 5’”’; tail, 3”. 
Fig. Gould, B. Austr. vii, pl. 62. 
739. OckANITIS LEUCcOGASTER (Gould). White-bellied Petrel. 
Thalassidroma leucogaster, Layard, B. 8. Afr. p. 358. 
Obtained by His Excellency Sir George Grey in the Cape seas. 
The only specimen that has fallen under our notice was kindly 
presented to the South African Museum by Lieutenant-Commander 
L. A. Bearsdslee, of U.S. Navy, and captured on board his ship, the 
