th a fine muddy sandy bottom. The eastern
extremity of the large island bearing South by East 1/2 East led into the
harbour. As we threaded our way among the patches of coral, the view from
the masthead of the submarine forests through the still pellucid water
was very striking. The dark blue of the deep portions of the lagoon
contrasted beautifully with the various patches of light colours
interspersed.

We found to our surprise that the group into which we had penetrated was
entirely distinct from that under which we had first anchored to the
southward, so that we had already discovered the Abrolhos to form three
separate groups.

RAT ISLAND.

The centre island we named Rat Island, from the quantity of that vermin
with which it was infested. We also saw here a few seals, and numbers of
a very pretty lizard (figured in the appendix) with its tail covered with
spines. Several of these were brought away alive. I had two myself for
nine months on board, and afterwards presented them to Lady Gipps. Of
those taken by Lieutenant Emery, he was so fortunate as to bring one
alive to England, in 1841. It is still in his possession, and thrives
remarkably well. In one of his last letters he writes to me as follows on
the subject: "The Abrolhos lizard is very docile, and knows Mrs. Emery
quite well, and will eat and drink out of her hand; but is timid with
strangers. Its habits are rather torpid, but it becomes active when in
the sun or before the fire. It eats so very little that a piece of sponge
cake about the size of a small bean will satisfy it for three or four
weeks. It changes its skin twice a year."

The formation of Rat Island resembles that already noticed in Pelsart
Group; there were the same low overhanging cream-coloured limestone
cliffs, to the height of half the island; the greatest elevation of which
was 13 feet, with a similar soil, mixed with guano, and filled with
burrows of the sooty petrel, or mutton bird. Surrounding it is a low
coral reef, trending northward to the outer edge of the group.

CORAL FORMATION.

This reef afforded me an opportunity of examining the coral formation of
the Abrolhos, which, with the exception of Bermuda, is the place farthest
removed from the equator where coral formation is found. The reef on
which Rat Island rests extends off four hundred yards on the inner side,
and has 12 fathoms just off it, on a grey sandy mud. The greater portion
is composed of a variety of corals in