A genus established for the reception of the _Procellaria Capensis_ of Linnæus, a species abounding in all the temperate latitudes of the southern seas. 601. Daption Capensis Vol. VII. Pl. 53. Genus PRION, _Lacep._ A genus of fairy-like Petrels confined to the southern hemisphere: much confusion exists respecting these birds, and they are so puzzling that I regret to say I have not been able to throw any light upon the subject. Of the following species two only have been figured:— 602. Prion Turtur Vol. VII. Pl. 54. 603. Prion vittatus Vol. VII. Pl. 55. 604. Prion Banksii. _Pachyptila Banksii_, Smith, Zool. of South Africa, Aves, pl. 55. _Prion Banksii_, Gould in Ann. and Mag. of Nat. Hist., vol. xiii. p. 366. Found in the temperate latitudes of the Atlantic and Pacific, and I believe in similar latitudes all round the globe. 605. Prion Ariel, _Gould_. _Prion Ariel_, Gould in Ann. and Mag. of Nat. Hist., vol. xiii. p. 366. I killed this species in Bass’s Straits, where it was rather numerous. Genus PUFFINUS, _Briss._ The members of this genus inhabit the seas of both the northern and southern hemisphere, but are nowhere more abundant than round Australia, the fauna of which country comprises four species, which make one or other of the groups of islands lying off the coast their great nurseries or breeding-places. 606. Puffinus brevicaudus, _Brandt_ Vol. VII. Pl. 56. It will be seen that I have alluded in forcible terms to the great abundance of this species in Bass’s Straits, in confirmation of which I annex the following extract from Flinders’ Voyage, vol. i. p. 170:— “A large flock of Gannets was observed at daylight, and they were followed by such a number of the sooty petrels as we had never seen equalled. There was a stream of from fifty to eighty yards in depth, and of three hundred yards or more in breadth; the birds were not scattered, but were flying as compactly as a free movement of their wings seemed to allow; and during a full _hour and a half_ this stream of Petrels continued to pass without interruption, at a rate little inferior to the swiftness of the Pigeon. On the lowest computation I think the number could not have been less than a hundred millions. Taking the stream to have been fifty yards deep by three hundred in width, and that it moved at the rate of thirty miles an hour, and allowing nine cubic yards of space to each bird, the number would amount to 151,500,000. The burrows required to lodge this quantity of birds would be 75,750,000; and allowing a square yard to each burrow, they would cover something more than 18½ geographic square miles of ground.”