er them less than a quarter of an inch in length, and I watched it
almost instantaneously expand them to the length of nine inches. After
having observed the animal closely for an hour I am writing this with it
before me, alive in a large glass bottle of salt water, and measuring
what I put down. The manner in which it expands these organs is by first
uncoiling those folds nearest the body, and afterwards those most remote;
so that when folded up it looks like a corkscrew with the folds pressed
close together, and when expanded, like a long straight thin bit of
flesh-coloured silk, with a little corkscrew of the same material at the
end. The larger tentacula are shaped like the trunk of an elephant, and
their extremity is furnished with a very delicate organ with which they
can catch anything, and, if touched, they instantly turn some of these
tentacula, which they have the power of moving in any direction, to the
point so touched. They are not electrical: the lateral bags have a slight
tinge of a bright amber colour. These animals sustain themselves in the
water by means of the little bag marked (a) in the figure, which floats
on the surface full of air, they there swim in the manner before
described. I afterwards observed very minute globules, or lumps, in the
long silk-like tentacula. When expanded these were very distinct.

Latitude 29 degrees 26 minutes south; longitude 101 degrees 32 minutes
east.

We caught several small shells (Janthina exigua) this afternoon:
Illustration 9 represents one of them, with the string of air bubbles
attached, by means of which they swim on the water. They appear not to be
able to free themselves from this mass of bubbles: every shell I have yet
found floating in the Indian Ocean possesses these bubbles in a greater
or less degree; they were of a purple colour. I have seen the common
garden snail in England emit a nearly similar consistency: they also emit
a blue or purple liquid, which colours anything it touches.

The animals of the barnacles (Pentalasmis) attached to these shells
assume their purple colours, while the shell remains nearly pure white.

This afternoon we caught an animal (Glaucus, Illustration 10) I had not
before seen. It seemed to represent the order reptilia in the Mollusca,
being sluggish in movement, its eyes distinct, sensitive to the touch,
its head much resembling a lizard in appearance, and having a very strong
unpleasant smell when taken out of the water