A sound behind him brought him to an abrupt halt. He peered cautiously back through the branch-roofed tunnel. He was being trailed. Something, bestial or human, lurked back there in the forest shadows. He saw it — or them — dimly, as formless as darker shades in the shifting array that marked the wind-stirred leaves.

For the first time, the successive mysteries began to induce a sense of menace. He increased his pace. The shadows slid and skittered behind him, and, lest he ascribe the thing to fancy, a low cry of some sort, a subdued howl, rose in the dusk of the forest at his left, and was answered at his right.

He dared not run, knowing that the appearance of fear too often brought a charge from both beasts and primitive humans. He moved as quickly as he could without the effect of flight from danger, and at last saw the beach. There in the opening he would at least distinguish his pursuers, if they chose to attack.

But they didn't. He backed away from the wall of vegetation, but no forms followed him. Yet they were there. All the way back to the box and the remains of his fire, he knew that just within the cover of the leaves lurked wild forms.

The situation began to prey on his mind. He couldn't simply remain on the beach indefinitely, waiting for an attack. Sooner or later he'd have to sleep, and then — Better to provoke the attack at once, see what sort of creatures he faced, and try to drive them off or exterminate them. He had, after all, plenty of ammunition.

He raised his gun, aimed at the skittering shadow, and fired. There was a howl that was indubitably bestial; before it had quivered into silence, others answered. Then Carver started violently backward, as the bushes quivered to the passage of bodies, and he saw what sort of beings had lurked there.

A line of perhaps a dozen forms leaped from the fringe of underbrush to the sand. For the space of a breath they were motionless, and Carver knew that he was in the grip of a zoologist's nightmare, for no other explanation was at all adequate.