Genus Xc.
Length sixteen inches, bill one inch and an half long, black, and very hooked at the tip: the head as far as the eyes, the chin and throat, waved, brown and dusky white: the rest of the body on the upper parts of a sooty brown, the under of a deep ash colour; the inner part of the quills, especially next the base, very pale, nearly white, and the wings, when closed, exceed the tail by about an inch: the tail is much rounded in shape, and consists of twelve feathers, of the same colour as the upper parts of the body: the legs are pale yellow, the outer toe black the whole length, the middle one half way from the tip, the webs also correspond, the outer one being black, except just at the base; and the inner one black for about one third from the end: the claws black; the spur, which serves in place of a back toe, is also black.
This inhabits Norfolk Island, and burrows in the sand like a rabbit, lying hid in the holes throughout the day, and coming out of evenings in quest of food.

This bird appears to differ so very little from the dark grey Petrel of Cook's Voyage, vol.i.p.

258.

that it is not improbable it may prove to be the same species.

This is described in the General Synopsis of Birds, vol.vi.p.