rom first removing the
valve from the float, until the inflation, and the expulsion of air into
the float being completed, so that the valve begins to move again, is 61
seconds, from the mean of several experiments.

These animals have also the power of compressing the valve into a hollow
tube, which they elevate above the water like a funnel, and draw down air
through it.

The colouring matter which they emit has no stinging, electric or
deleterious properties whatever, that I could discover. 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. It may, of course, have the power of sinking itself much
lower than I have seen it do. When it is in this state, the apparatus
with which it fills the float remains behind the peduncle in a state of
perfect quiescence.

The scarlet fluid emitted by this animal is of such a consistency that it
can be drawn away from it out of the water, like a glutinous thread.

A part of the animal requires attention, it is composed of an outer cup,
or circular lip, which it has the power of contracting or expanding in
the same manner as the valve; and when opened out like a cup, an orifice
can be seen at the bottom of it. It can also expand, and make broad the
arm; and it then appears to use them as sails.

This species of Janthina, I afterwards found, has the power of in some
manner taking in by suction a quantity of water, which it can suddenly
expel again with great violence, sending it out as if from a squirt.

We caught, also, an extraordinary fish this day. Its