We entered the opening, swimming in a group with Atar leading. It was already new territory for us. Our hunting expeditions had never taken us even as far as this; we were always content to remain in Marinoid waters. As we advanced, the rocky ceiling overhead was closing down on us, until soon there was no more than twice the length of our bodies between it and the floor.
On both sides the dark water stretched out as far as we could see into blackness also. We were descending now at an angle of perhaps forty-five degrees.
We had gone what you would call a mile possibly, when we came suddenly to a tangle of coral—a barrier that reached from floor to ceiling. I call it coral. It might have been a petrified vegetation. An all but impenetrable thicket—white like the frosted underbrush of you
