I found that when this colouring matter was mixed with water, it became of a deep blue.

In those which I caught in November 1837, I may have been deceived, and the colouring matter might also possibly have been scarlet directly it was emitted.

It is difficult to conceive what use this liquid can be to the fish against its foes, yet it certainly uses it as a means of defence.
To one of these shells, the fish in which was alive and well, we found attached a number of barnacles, some of which were of large size.
This sort of Janthina was very abundant; today we caught eight, and saw great numbers of them: yesterday we caught a smaller one of a different species.

(Janthina exigua.) This kind of Janthina is attached to its float by a sort of peduncle, which it has the power of elongating, so that the fish itself sinks, with its shell, and yet remains attached to the float, which continues at the surface.

In one instance, I saw this peduncle elongated to a length of 0.9 inches.