e,
as he moved along, one of the little quadrupeds approached him, its
teeth bared. With an almost negligent flip of one powerful, superfast
hand, he slammed it against a nearby wall. It dropped and lay still.
Another of its kind approached it cautiously. The Nipe noticed the
approach with approval. The quadrupeds had no real intelligence, but
they had the proper instincts.

At last the Nipe came to another of the many places where the tunnels
met with others of the network. He crossed through several rooms, all
very large and cluttered with the dusty, long-dead bones of hundreds of
the local intelligent life-form--if (and he was not sure in his own mind
of this) they could actually be called intelligent. But he moved
carefully, stepping over the human bones and the empty, staring skulls.
They had apparently been properly devoured, although he could not be
sure whether it had been done by their own kind or by the little
quadrupeds. Nonetheless, he would not willingly disturb their repose.

He went on into the tunnel that led westward and followed it as it began
to angle down. Finally he came to the water's edge.

To a human being, the cold expanse of water that gleamed like ink in the
light of the Nipe's illuminator would have been a barricade as
impenetrable as steel. But to the Nipe the tidal pool was simply another
of his defenses, for it concealed the only entrance he ever used. He
went in after adjusting his scuba mask and began swimming toward the
opening that led to the estuary of the sea, his eight strong limbs
working in unison in a way that would have been the envy of a rowing
team.

At the jagged hole in the tunnel wall, the gap that led into open water,
he paused to check his instruments. Only after he was certain that there
were no sonar or other detector radiations did he propel himself onward,
out into the estuary itself.

An hour later, he was warily circling the spot where his little
submarine was hidden. He pressed a button on a small device in his hand,
and a signal was sent to the submarine. The various devices within it
all responded properly. Nothing had been disturbed since the Nipe had
set those devices weeks before.

This was the touchiest part of any of his expeditions. There was always
the chance, unlikely as it might be, that some one of the bipedal
natives had found his machine. He dared not use it too close to his base
because of the possibility of its drive vibrations being detected