In August 1830, being becalmed on the banks of Newfoundland, I obtained several individuals of this species from a flock composed chiefly of _Thalassidroma Leachii_, and _Th. Wilsoni_. Their smaller size, and the more rapid motions of their wings, rendered them quite conspicuous, and suggested the idea of their being a new species, although a closer inspection shewed them to belong to the present. In their general manners, while feeding, floating on the water, or rambling round the boat in which I went in pursuit of them, they did not differ materially from the other species. Their flight, however, was more hurried and irregular, and none of them uttered any note or cry, even when wounded and captured. I have been assured that this bird breeds on the sandy beaches of Sable Island on the coast of Nova Scotia; but not having had an opportunity of visiting it, or any other breeding place, I here present you with Mr HEWITSON’s observations on this subject. “In an excursion,” says this amiable and enterprising naturalist, “through the Shetland Islands during the present summer, in search of rarities for this work (the British Oology), I had the very great satisfaction of seeing and taking many of these most interesting birds alive; they breed in great numbers on several of the islands, principally upon Foula, the north of Hunst, and upon Papa, and Oxna, two small islands in the Bay of Scalloway; the last of these I visited on the 31st of May in hopes of procuring their eggs (it being the season in which most of the sea-birds begin to lay); but in this I was disappointed; the fishermen who knew them well by the name of Swallows, assured me that my search would be quite useless, that they had not yet “come up from sea,” and so it proved. Sixteen days after this (June 16th and three following days) I was at Foula, but was alike unsuccessful, the birds had arrived at their breeding places, but had not yet begun laying their eggs; numbers of them were sitting in their holes, and were easily caught; one man brought me about a dozen tied up in an old stocking, two of which I kept alive in my room for nearly three days, and derived very great pleasure from their company; during the day they were mostly inactive, and after pacing about the floor for a short time, poking their head into every hole, they hid themselves between the feet of the table and the wall; I could not prevail upon them to eat any thing, though I tried to tempt them with fish and oil; their manner of walking is very light and pleasing, and differing from that of every other bird which I have seen; they carry their body so far forward and so nearly horizontal, as to give them the appearance of being out of equilibrium. In the evening, toward sun-set, they left their hiding places, and for hours afterwards, never ceased in their endeavours to regain their liberty; flying round and round the room, or fluttering against the windows; when flying, their length of wing,