e was no thinning of the crowd.

As he drifted on with the inharmonious throng, he noticed what seemed
the objective of the war. This was the caves which lined the tunnel.
Some were apparently rigid, others were mobile. A large red-and-gray
animal was pushed into the mouth of one of the latter, and the walls
instantly closed; then they opened, and the creature drifted out, limp
and colorless, but alive; and with him came fragments of the wall,
broken off by the pressure. This happened again and again, but the
large creature was never quite killed--merely squeezed. The tentacled
non-combatants and the large white fighters seemed to know the danger
of these tunnel mouths, possibly from bitter experiences, for they
avoided the walls; but the dog-faced invaders sought this death, and
only fought on their way to the caves. Sometimes two, often four or
more, would launch themselves together into a hollow, but to no avail;
their united strength could not prevent the closing in of the
mechanical maw, and they were crushed and flung out, to drift on with
other debris.

Soon the walls could not be seen for the pushing, jostling crowd, but
everywhere the terrible, silent war went on until there came a time
when fighting ceased; for each must look out for himself. They seemed
to be in an immense cave, and the tide was broken into cross-currents
rushing violently to the accompaniment of rhythmical thunder. They were
shaken, jostled, pushed about and pushed together, hundreds of the
smaller creatures dying from the pressure. Then there was a moment of
comparative quiet, during which fighting was resumed, and there could
be seen the swiftly flying walls of a large tunnel. Next they were
rushed through a labyrinth of small caves with walls of curious,
branching formation, sponge-like and intricate. It required energetic
effort to prevent being caught in the meshes, and the large
red-and-gray creatures were sadly torn and crushed, while the white
ones fought their way through by main strength. Again the flying walls
of a tunnel, again a mighty cave, and the cross-currents, and the
rhythmical thunder, and now a wild charge down an immense tunnel, the
wall of which surged outward and inward, in unison with the roaring of
the thunder.

The thunder died away in the distance, though the walls still
surged--even those of a smaller tunnel which divided the current and
received them. Down-stream the tunnel branched again and again, and
with