d through a
microscope, appear to be minutely reticulated.

The animal may be considered as consisting of four portions: the head;
the upper part of the body, 0.18 inch in length, and divided into five
rings; the lower part, consisting of one shield-like portion, 0.12 inch
in length, the body at the lower portions of this decreases almost to the
thickness of a thread; the tail, 0.3 inch in length, and divided into
three shield-like pieces, laid one over the other as in the shrimp
(imbricated); at the lower extremity of each of these scales there is on
each side a fin-like leg, in addition to those above-mentioned. Breadth
of the animal across its head, 0.2 inch, and this was the broadest part
of it. It lived for some time out of water, and even when put into
spirits, it swam in an extraordinary manner, falling head over heels
every time, which motion it accomplished by swimming on its back and
making rapid strokes with the fin-like legs with which it is provided
behind.

We also caught today several little crabs and barnacles. I kept one
specimen, to show old and young barnacles attached to the same Velella.

The sea was, this morning, covered in places with fleets of the Velella
of Lamarck; also with great numbers of the species of Janthina which I
described yesterday; to both of these kinds of animals large clusters of
barnacles were frequently attached. These barnacles preyed on the
different gelatinous animals which were swimming about. It was curious to
see them seize on these with their hooked tentaculae and draw them in,
whilst the acalepha, or gelatinous animal, contracted and dilated itself
with all its might and main, endeavouring to escape. We saw two or three
times very large shoals of porpoises ahead of us, and when we reached the
spot where they had been we found the sea quite cleared of the animals
with which it was covered in other places, so that we imagined the
porpoises must have been feeding on them. We saw also a whale and a shark
today.

Although these little floating animals were so numerous there were but
very few of the gelatinous species to be seen, and they were chiefly of
the larger sorts. I saw one of the species (Glaucus) of which I have
given a sketch, on the 17th of June. Like all the animals of this species
which we caught to the westward of the Cape it had a red intestinal spot
in it; but excepting in its great size it differed in no respect from the
others which I had seen: this on