these stung the person who touched them in the same manner as nettles, only much more severely. On the top of this bladder was a membrane which he turned either one way or the other to receive the wind; this was veined with pink, in an uncommonly beautiful manner; in short, the whole was one of the most beautiful sights I have seen among the mollusca, though many of them are beautiful.
The floating shells, Helix ianthina[1] and violacea, from their particularity, also deserve mention. They are to be found floating on the top of the water by means of a small cluster of bubbles filled with air, composed of a tenacious slimy substance, not easily parting with its contents; these keep them suspended on the surface of the water, and serve as a nidus for their eggs: it is probable that they never go down to the bottom, or willingly come near any shore, as the shell is of so brittle a construction that few sea-water snails are so thin.
Every shell contains within it about a teaspoonful of liquid, which it freely discharges on being touched; this is of a most beautiful red purple colour, and easily dyes linen clothes; it may be well worth inquiry whether or not this is the purpura[2] of the ancients, as the shell is certainly found in the Mediterranean. We have not yet taken a sufficient quantity of the shells to try the experiment, perhaps we shall soon.
Procellaria oceanica differs very little from P. pelagica, Linn., but from his place of abode so far south, and some small difference in plumage, it is more than likely that he is different in species.
9th. Found two new species of Lepas (vittata and midas) on the stern of the ship; they were both sticking to the bottom, in company with L. anatifera, of which there was great abundance.
10th. Took plenty of Helix ianthina and some few of violacea. Shot the black-toed gull of Pennant; it had not
