could emit, at will, a certain portion of the water, and it
appears, therefore, probable that this fluid is taken in partly
for the sake of regulating its specific gravity. This Diodon
possessed several means of defence. It could give a severe
bite, and could eject water from its mouth to some distance,
at the same time making a curious noise by the movement
of its jaws. By the inflation of its body, the papillae, with
which the skin is covered, become erect and pointed. But
the most curious circumstance is, that it secretes from the
skin of its belly, when handled, a most beautiful carmine-red
fibrous matter, which stains ivory and paper in so permanent
a manner that the tint is retained with all its brightness
to the present day: I am quite ignorant of the nature
and use of this secretion. I have heard from Dr. Allan of
Forres, that he has frequently found a Diodon, floating alive
and distended, in the stomach of the shark, and that on
several occasions he has known it eat its way, not only
through the coats of the stomach, but through the sides of
the monster, which has thus been killed. Who would ever
have imagined that a little soft fish could have destroyed
the great and savage shark?

March 18th. -- We sailed from Bahia. A few days afterwards,
when not far distant from the Abrolhos Islets, my;
attention was called to a reddish-brown appearance in the
sea. The whole surface of the water, as it appeared under a
weak lens, seemed as if covered by chopped bits of hay, with
their ends jagged. These are minute cylindrical confervae,
in bundles or rafts of from twenty to sixty in each. Mr.
Berkeley informs me that they are the same species