es appeared to direct this movement: for
both kept swimming alongside the zygaena, one of them opposite each of
its huge eyeballs.

The negro seemed slightly perplexed by this unexpected manoeuvre. He
had anticipated an instantaneous attack, and had made every preparation
to receive and repel it. He had even taken the knife from his teeth,
and was holding it tightly clutched in his right hand, ready to deal his
deadly blow.

The shyness of the shark produced a disappointment.

Something besides: for it now occurred to Snowball that the cunning
zygaena was trying to pass him, with the design of making a _razzia_
towards the helpless party in his rear.

The moment this suspicion arose to him he turned short in the water, and
struck out in a direction that would enable him to head the shark, and,
if possible, intercept it.

Whether the creature intended to pursue his original plan of attacking
the sailor and his charge, or whether he was manoeuvring to _turn_ the
Coromantee, it mattered not. In either case Snowball was pursuing the
correct strategy. He knew that if his supple antagonist could once get
round to his rear, his chances of safety for himself or the others would
be sadly diminished. Should the zygaena once get past him and continue
on towards the sailor, swift swimmer as Snowball was, he could have no
chance of overtaking a fish.

At this crisis a thought occurred to him which promised to avert the
calamity he most dreaded,--that is, the shark getting past him, and
continuing on to the others. The thought found expression in speech.

"Ho! Massa Brace!" he cried, once more taking the steel from between
his teeth. "Swim roun' to de right. Keep a-gwine in de circle. For de
Lord sake, keep ahind me, or you loss fo' sartin!"

The sailor scarcely needed the counsel. He saw the danger before
Snowball had spoken, and had already commenced the movement which the
Coromantee was requesting him to make.

Once more the tableau changed. The _dramatis persona_ in their relative
positions first formed an isosceles triangle, then a scalene, afterwards
a right line. Now all were moving in a circle, or rather in three
circles concentric to one another; the sailor, with his charge,
revolving round the centre, Snowball in mid radius, while the shark,
flanked by his satellites, went gliding along the outer circumference,
his lurid eyes glaring continually inward, as if watching for an
opportunity to break the