546 PROCELLARIIDA 
of reddish-brown, like those of most other Petrels (Saunders, 
Phil. Trans., clxvii, p. 164). 
Geographical distribution.—Wilson’s Petrel has been 
found breeding on Kerguelen Island, by the Rev. A. E. 
Eaton; and examples of birds “‘ were obtained by the 
‘Challenger’ Expedition, off the Antarctic ice-barrier on 
February 14th, 1874” (Saunders). In summer it is common 
on some of the islands (notably the Azores) off the West 
African coast, from whence it can be traced in the South 
Atlantic down to the Cape, eastward over the Indian 
Ocean to Australia and New Zealand, and across the 
South Pacific to Chile and Peru. In the North Atlantic 
it is common along the American sea-board, visiting the 
West Indies and Mexico, and reaching about as far north 
as the latitude of the British Islands. In the Antarctic 
Ocean the geographical distribution may be said to be cir- 
cumpolar. 
DESCRIPTIVE CHARACTERS. 
PLUMAGE. Adult male nuptial.—General plumage, sooty- 
black ; forehead, breast, and abdomen, of a paler shade ; 
ereater wing-coverts and inner secondaries, edged with 
ereyish- -white ; the primaries and the tail- feathers are more 
inky black than the rest of the plumage, but the bases of 
the outer tail-feathers are thinly edged with white ; upper 
tail-coverts and thigh-patches, white. 
Adult female nuptial.—Similar in plumage to the male. 
Adult winter, male and female.—Similar to the nuptial 
plumage. 
Immature, male and female. — Resembles the adult 
plumage. 
Beak. Black. 
Fret. Black; proximal portions of the webs, yellow. 
TripEs. Dark brown. 
AVERAGE MEASUREMENTS. 
ToTAL LENGTH igh peal 8%: 
WING hae ae ie Gls 
BEAK 4.2 ae a Oniisece 
TARSO-METATARSUS ee Nee 
EGG 1°3 ><0:9iane 
Allied Species and Representative Forms.—O. gracilis, 
smaller, with the middle of the abdomen white, inhabits the 
west coast of South America. 
