rom the raft the distances each would have to traverse were not
very unequal, Snowball knew that his scaly competitor far excelled him
in the quality of speed.

It was this thought that was causing him anxiety,--amounting almost to
anguish,--that caused him to plunge wildly through the water,--to utter
loud cries, and make other noisy demonstrations,--with a view of
distracting the attention of the zygaena from the victims it had
fore-chosen, and drawing its attack upon himself.

His shouts and gesticulations proved equally unavailing. The cunning
zygaena took no heed of either; but with its dark dorsal fin, set like a
well-bent sail, it kept straight on towards the easier victims.

The sides of the isosceles triangle were gradually growing unequal,--
gradually and slowly, but, alas! surely. Already was it an irregular
_scalene_. Snowball perceived the change,--each moment becoming more
perceptible, each moment augmenting his fears.

"Poor lilly Lally!" cried he, in a voice that betrayed his anxiety. "O
Mass' Ben! fo' de lub o' Gorramity, swum to de right,--round dat away,
an' let me git 'tween you an de ravenin' beast. To de right!--da's de
way. Do yer bess, Mass' Brace, an' gi' me time get up. I take care o'
de lubber ef I once get im widin reach o' dis chile's arm."

The injunction thus uttered had the desired effect. Up to that time the
sailor, sunk low in the water by reason of the extra weight, had not
become fully cognisant of the peril of his position. Hitherto his mind
had been more occupied with the idea of overtaking the raft, than any
danger to be dreaded from sharks. He was not even aware of the
zygaena's approach; for the fin, which had betrayed the monster's
presence to those on the _Catamaran_,--from being seen _en profile_,--
could not so easily be distinguished when viewed in "front-face." No
wonder, therefore, that the victims which the zygaena had selected for
its attack remained unconscious of its approach; and it was only on
seeing Snowball spring out from the _Catamaran_, and swim towards him,
that the sailor suspected the proximity of a shark. At the same
instant, also, he remembered the interrogatory that had been addressed
to him by little William, and his own laconic reply designating the
individual as a _hammer-head_. From these various circumstances he
could tell that there was a shark bearing down upon him; but in what
direction he could not conjecture, until the hurried wo