We caught several sharks, and an immense hammerhead (_Zygaena vulgaris_), that we could not catch, followed us for a very long time. As I looked at him sailing along under the stern of the ship, I was at a loss to imagine for what purpose such a head was given to it; exactly like an immense caulking-hammer, with an eye in each end; in every other detail of shape, and in habits of voracity too, as far as I know, it resembles the ordinary sharks. That it is so constructed to serve some special purpose in its economy there can be no doubt, but what that may be, remains to be discovered. We fished for albatross with marked success, to be devoured by both men and officers, stuffed as a goose; the rag from off the bung of a cask of whale-oil, rubbed with an onion and chewed, would be mildly flavoured as compared to the flesh of this sea-bird. Petrels were ever with us, like flights of martins round the habitations of man; always on the wing, never resting, or roosting either, as far as I could see; watch them in their easy graceful flight, till the last lingering ray of light sank away beneath the watery horizon; and, as night wrapped them in her sable mantle, they were still on the wing. Be on deck as the first blush of early dawn crept drowsily over the sleeping sea, and with the rosy light came the petrels, still flying, as they had vanished in the darkness. We tried to catch them by loosing long threads over the stern, and tangling them, like human spiders; we did trap one, but the sailors were mutinous at such unheard-of barbarity; injuring the chickens of ‘Mother Carey’ was an offence not to be tolerated, even in a zealous naturalist; so, at the captain’s request, the cotton webs were abandoned. The one taken was the black stormy petrel, _Thalassidroma melania_ (C. Buonaparte): upper plumage entirely black (as are the wing-coverts), below ferruginous; tail deeply forked, and very short.