t part 0.48 inches.

For a particular description, and figure of a finer specimen, see below.
The mouth and eyes of this fish were placed in a curious manner. Its food
appeared to be the same as that of the other fish taken this day.

Caught two curious little crabs (Nautilograpsus) one pale blue, and the
other of a pale pink colour: also, another little pale blue crab:

Length of antennae 0.15 inches.
Length of body 0.34 inches.
Breadth of ditto 0.12 inches.

Caught a small animal shaped like a wood-louse (Cymothoa) having nine
rings apparent on the back, and I think seven legs on each side, also, a
tail-like fin on each side, which, when closed under its belly, formed a
sort of shield for the lower part of the abdomen. Antennae, transparent
with pale brown tips, and a few pale brown spots in them, colour pale
blue down centre of the back, dark prussian blue on each side. It had the
power of rolling itself up nearly double; in the same manner as a
wood-louse, but not quite so close; eyes distinct and prominent. It lived
a long time out of water, and appeared to me exactly like an animal I
caught on the 21st November 1837, in south latitude 24 degrees 19
minutes; east longitude 107 degrees 8 minutes.

We also this day caught a Janthina. They have a little valve for the
purpose of taking in air, with which to expand their float. These animals
go in company. They emit when touched a brilliant scarlet dye. A similar
animal caught on the 20th November 1837, in south latitude 25 degrees 12
minutes; east longitude 106 degrees 49 minutes, emitted a violet-coloured
dye. The emission of this evidently depends upon their being irritated,
as I found by many experiments.

The method in which this animal fills its float is curious, it throws it
back, and gradually lifts the lip of the valve out of water, until the
valve stands vertical, it then closes the valve tightly round a globule
of air, around which it folds, by means of the most complex and delicate
machinery. The valve is then bent over until it touches the edge of the
float nearest the head, and when it is in this position, the portion of
it which is inflated with air looks like a bladder, the air gradually is
expelled into the float, and as this process takes place the bladder in
the valve diminishes, and the valve becomes by degrees like a lip pushed
forwards until it lies flat on the float. The valve is composed of two
portions, a cup and a lip. The time occupied f