We swam hurriedly forward, but my arm was still around my Nona. Soon we were in the coral barrier. Behind us, down the passageway, we could hear Og and the others shouting as they followed us. We threaded our way through the coral, slowly, laboriously, as one would force a way through the thick frozen underbrush of your winter forests on Earth. But it was a shallow barrier—two hundred feet through, no more. Again we were in the open passageway; and Og and his party were approaching the barrier from the other side. We hastened onward and upward. It was a short distance only, and we were at the mouth of the tunnel. The open Water of Wild Things loomed before us. Somewhere up there through that inky void was the entrance which would lead us into Marinoid waters. * * * * * Atar gripped me, as with Nona beside me I would have launched myself out of the tunnel-mouth. And I heard Caan’s low exclamation of dismay. A light had leaped out of the blackness—a single huge light of green; and then, behind it, a myriad others. Like tiny green stars they dotted the void. We had no time for conjecture. The darkness out there took shape—a sinuous, serpentine shape. The thing was coming toward us. Its huge head seemed to radiate green fire; the body and tail behind the head were black, but like barnacles, a thousand luminous parasites clung to it, and glowed. We drew back, but not before the serpent had become aware of us. It turned over with a long, gliding undulation and came at the mouth of the passageway. But it came hastelessly, lazily, as though in its own good time to pick up this food that was offered. I caught a glimpse of opened jaws—fangs half the length of my body. And its breath, a fetid stench, seemed to precede it. Trembling, we flung ourselves back down the dim tunnel. Ahead through the coral, the vague reflected radiance from the cave was visible. In the coral we could hear Og and his followers, calling to one another as they threaded their way through. There was no choice. The narrow walls of the passageway hemmed us in; behind us, the serpent was gliding quietly forward. We swam back to the coral. A Maagog forced his way out, and instantly I drove my spear into him. He crumpled with a gasp, and sank in a heap with the spear impaling him from back to chest. “Nemo!” I turned, and Nona pushed me to one side. A small black opening was there—an opening at right angles to the main tunnel. It was barely three feet wide and twice as high. Caan and Atar were already in it. Nona glided in, pulling me after her. We swam back a dozen feet and paused. The green head of the serpent was out there in the tunnel we had left; it loomed there a vivid spot of light, at the entrance to this narrow slit which sheltered us—a head too large to enter. It stayed there a moment, and then, as though yielding to the inevitable, it quietly withdrew.