rough the air. And the snake-devil, with an incredible twist of its
neck, caught the haft of the weapon between its teeth, crunching the
iron-hard substance into powder. But with that move it exposed its
throat, and the arrow from Dalgard's bow was buried head-deep in the
soft inner flesh.

The snake-devil spat out the spear and tried to raise its head. But
the muscles were already weakening. It fought the poison long enough
to take a single step forward, its small red eyes alight with
brainless hate. Then it crashed and lay twisting. Dalgard lowered his
bow. There was no need for a second shot.

Sssuri regarded the remains of his spear unhappily. Not only was it
the product of long hours of work, but no merman ever felt fully
equipped to face the world without such a weapon to hand. He salvaged
the barbed head and broke it free of the shred of haft the snake-devil
had left. Knotting it at his belt he turned to Dalgard.

"Shall we see what lies beyond?"

Dalgard crossed the hall to test the door. It did not yield to an
inward push, but rolled far enough into the wall to allow them
through.

On the other side was a room which amazed the scout. The colonists had
their laboratory, their workshops, in which they experimented and
tried to preserve the remnants of knowledge their forefathers had
brought across space, as well as to discover new. But the extent of
this storehouse with its bewildering mass of odd machines, tanks,
bales, and stocked shelves and tables, was too much to be taken in
without a careful and minute examination.

"We are not the first to walk here." Sssuri had given little attention
to what was stacked about him. Instead he bent over the disturbed dust
in one aisle. Dalgard noted as he went to join the merman that there
were gaps on those tables which ran the full length of the room, lines
left in the grimy deposit of years which told of things recently
moved. And then he saw what had interested Sssuri: tracks, some
resembling those which his own bare feet might leave, except that
there were only three toes!

"_They._"

Dalgard who had been a hunter and a tracker before he was an explorer
crouched for a clearer view. Yes, they were recent, yet not made today
or even yesterday; there was a thin film of dust resettled in each.

"Some days ago. They are not in the city now," the merman declared
with certainty. "But they will come again."

"How do you know that?"

Sssuri's hand swept about to