lassed with
the "genus ostrea," or the "genus mytilus."

After watching the swimmers a little longer, I strolled along the reef,
in the direction which Johnny had taken in pursuit of Arthur, stopping
occasionally to watch the bursting of a wave of uncommon magnitude, or
to examine some of the interesting objects that were strewn with such
profusion in every direction, and which rendered that barren ledge so
choice a spot for the studies of the naturalist. Some ten or fifteen
minutes had been thus employed, and it was beginning to grow dark, so
that Arthur and Johnny, whom I had not yet overtaken, could be but just
distinguished, like two specks in the distance, when I heard the
powerful voice of Browne, raised in a loud and prolonged halloo.
Pausing to listen, I soon heard the cry repeated, in a manner that
showed as I thought, that something unusual had taken place. Hastening
back, I found that Max and Browne had swum off to a coral knoll, in the
lagoon, a stone's throw from the reef, and dared not venture back, being
closely blockaded by a large fish swimming about near the spot, which
they supposed to be a shark. They called loudly for me to come after
them in the boat, and to lose no time about it, as there was water
enough on the knoll, to enable a shark, if tolerably enterprising, to
reach them where they stood. Though it was rapidly getting dark, there
was still sufficient light to enable me to distinguish an enormous fish
of some kind, cruising back and forth, with the regularity of a sentinel
on duty, between the reef, and the shallow where Max and Browne were
standing up to their knees in water. The case appeared to admit of no
delay, and jumping into the boat, I pulled over to the coral patch with
all possible speed, passing the fish close enough to see that it was in
fact a large shark, and he proved also to be an exceedingly fierce and
ravenous one. It almost seemed as though he understood my errand, for
he followed, or rather attended me, closely, keeping so near the bow of
the boat that it was with great difficulty and some danger, that I at
length got the blockaded swimmers aboard. When this was effected, his
disappointment and consequent bad temper were quite apparent; he swam
round and round the boat in the most disturbed and agitated manner as we
returned, making a variety of savage demonstrations, and finally going
so far as to snap spitefully at the oars, which he did not discontinue,
until B