ves of a cactus,
then lifted his finger to his shoulder and beckoned. Adan turned
mechanically in the opposite direction; but curiosity overcame him, and
he joined Roldan.

Between two plants not three feet apart two rattlesnakes were engaged
in mortal combat. They coiled with incredible rapidity, flew at each
other with burning eyes and darting tongues, burying a fang somewhere
in the tense bristling armours. The lashing tails struck the spiked
surface of the cactus and augmented their fury; occasionally they
whipped about, hissing deliriously, then returning as swiftly to the
only enemy in sight. They had coiled and struck some four or five
times, whipping all over their narrow arena, when as if by common
consent, they retreated to extreme opposite points, coiled as lightning
strikes, and leapt at each other. Even Roldan gave a hoarse cry of
surprise, and as for Adan, he fell into vocabulary: one serpent had
darted straight down the throat of the other. For a moment there was a
fearful lashing. The choking serpent, with protruding eyes, like small
green coals, and jaws distended in agony, strove to dislodge his
suffocating enemy, and the other humped his back and leapt backward in
frantic efforts to reach the air again. But suddenly their struggles
ceased; they flattened to the ground, only the tails moving
automatically. What was left looked like a monster of some unknown
species; a creature with no head, a huge belly, and two tails.

"Caramba!" exclaimed Adan, "I could not eat that even if we had
anything to cook it with. It looks like a mass of poison."

"I should like to know where that poison was last night. It may be a
good sign, however: as they are the first living things we have seen,
we may be near to the edge of the desert."

Adan crossed himself.

"Come," continued Roldan, "let us move on, before hunger tempts us too
far."

Once more they started on their tortuous way. They walked very slowly,
both from necessity and inclination: the excitement of the fight over,
their physical necessities pressed heavily; they kept as close together
as they could, but rarely spoke: they were too hungry. Both were
oppressed by the fear that at any minute they would come upon a solid
wall of cacti and be obliged to retrace their steps, and both knew that
might mean a stunning blow to courage. At times the constant
zig-zagging, the unalterable, smooth, grey-green surface of the cacti,
made them halt dizzily, for both