He spurted forward, matching the merman's acceleration of speed. But to Dalgard's horror he saw that his companion now ran with one hand brushing along the wall, as if he needed that support.

"Sssuri!"

His thought met a wall of concentration through which he could not break. In a way he was reassured—for a moment, until another of those stabs from their pursuers struck him. He longed to look back, to see what hunted them. But he dared not break stride to do that.

"Ahhhh!" The welcoming cry from Sssuri brought his attention back to his companion as the merman broke into a wild run.

Dalgard summoned up his last rags of energy and coursed after him. Sssuri had halted before a dark lump which protruded from the side of the corridor.

"A sea lock!" Sssuri's claws were clicking over the surface of the hatch, seeking the secret of its latch.

Panting, Dalgard leaned against the opposite wall. Just as a protest formed in his mind he heard something else, the pad of feet, many feet, echoing down the corridor. And somehow he was able now to look.

Round spots of light, dull, greenish, close to the ground, as if someone had flung a handful of phosphorescence into the dark. But this was no phosphorescence! Eyes! Eyes—he tried to count and knew it was impossible to so reckon the number of the pack that ran mute but ready. Nor could he distinguish more than a very shadowy glimpse of forms which glided close to the ground with an unpleasant sinuosity.

"Ahhhhh!" Again Sssuri's paean of triumph.

There was the grate of unwilling metal forced to move, a puff of air redolent with the sea striking their bodies in chill threat, the brightness of violet light stepped up to a point far beyond the lamps in the corridor.