I obtained this bird at Maldonado, near the mouth of the Plata, where it was blown on shore by a gale of wind. These birds, although seeming to prefer on most occasions the open ocean, and to be most active, walking with their wings expanded on the crest of the waves, when the gale is heaviest, yet sometimes visit quiet harbours, in considerable numbers. At Bahia Blanca I saw many, when there was nothing in the weather to explain their appearance. I was informed by a sealer, that they build in holes on the sea cliffs of Georgia, where they arrive very regularly in the month of September. No other place is known to be frequented by them for the purpose of breeding. PRION VITTATUS. _Cuv._ Procellaria Vittata, _Gmelin._ Syst. i. 560. I did not procure a specimen of this bird, although I saw numbers on both sides of the Continent from about lat. 35° S. to Cape Horn. It is a wild solitary bird, appears always to be on the wing: flight extremely rapid. Mr. Stokes (Assistant surveyor of the Beagle) informs me that they build in great numbers on Landfall Island, on the west coast of Tierra del Fuego. Their burrows are about a yard deep: they are excavated on the hill-sides, at a distance even of half a mile from the sea shore. If a person stamps on the ground over their nests, many fly out of the same hole. Mr. Stokes says the eggs are white, elongated, and of the size of those of a pigeon. 1. LARUS FULIGINOSUS. _Gould._ _L. Mas. corpore toto obscurè plumbeo-griseo, tegminibus caudæ superioribus inferioribusque pallidioribus; rostro basi rubro, apice nigro; pedibus nigris._ Long. tot. 16½ unc.; _alæ_, 13½: _caudæ_, 6; _tarsi_, 2⅛; _rostri_ 2⅜. The whole of the plumage deep leaden grey; the upper and under tail coverts being lightest; bill red at the base, black at the tip; feet black. Habitat, Galapagos Archipelago (_October_). This species of gull has many characters in common with the _Larus hæmatorhynchus_ of King, from the continent of S. America; but may at once be distinguished from it by the general extreme duskiness of its plumage, feet, tarsi, and bill; and by the more elongated form of the latter. My specimen was killed at James Island. I observed nothing particular in its habits. It is the only species of gull frequenting this Archipelago. 2. LARUS HÆMATORHYNCHUS. _King._ Larus hæmatorhynchus, _King_, Zool. Journ. iv. 103. —— _Jard. & Selb._ Ill. Orn. p. 106. This bird was killed at Port St. Julian on the coast of Patagonia. Beak (when fresh killed) of a pale “arterial blood red,” legs “vermilion red.” 3. LARUS DOMINICANUS. _Licht._ Larus dominicanus, _Licht._ Cat. 82. sp. 846. Grande Mouette, _Azara_, No. 409.