yet been described according to Linnæus's system, so called it Larus crepidatus. Its food here seems to be chiefly Helices, on account of its dung being of a lively red colour, much like that which was procured from the shells.
12th. A shark, Squalus carcharias, Linn., taken this morning, and with it two pilot fish. I went out in the boat and took several blubbers. The pilot fish, Gasterosteus ductor, Linn., is certainly as beautiful a fish as can be imagined; it is of a light blue, with cross streaks of darker colour. It is wonderful to see them about a shark, swimming round it without expressing the least signs of fear; what their motive for doing so is, I cannot guess, as I cannot find that they get any provision by it, or any other emolument, except possibly that the company of the shark keeps them free from the attacks of dolphins or other large fish of prey, who would otherwise devour them.
The blubbers taken to-day were Beroe labiata and marsupialis, Mss., the first of which made a pretty appearance in the water by reason of its swimmers, which line its side like fringes, and are of a fine changeable colour; and Callirrhoe bivia, Mss., the most lifeless lump of jelly I have seen; it scarcely seems to be possessed of life, but for one or two motions we saw it make.
13th. A shark taken, but not one pilot fish attended it, which is rather uncommon, as they are seldom without a shoal of from ten to twenty. At noon I went in the boat, and took the Sallee man, Phyllodoce velella, Linn., which is a sailor, but inferior in size to the Portuguese man-of-war, yet not without its beauty, chiefly from the charming blue of the lower side. Its sail is transparent, but not movable, so it trusts itself to the mercy of the winds, without being able to turn to windward, as the Portuguese man-of-war perhaps can. We saw several of these latter to-day, and observed many small fish under their tentacula, which seemed to shelter there, as if with its stings it could defend them from large enemies.
15th. I had the good fortune to see a bird of the shearwater kind, which I shot; it proved not to have been
