And now into the battle came a ponderous engine of vengeance and defense. A gigantic, lumbering, pulsating creature, white and translucent but for the dark, active brain showing through its walls, horrible in the slow, implacable deliberation of its movements, floated down with the current. It was larger than the huge red-and-gray creatures. It was formless, in the full irony of the definition—for it assumed all forms. It was long—barrel-shaped; it shrank to a sphere, then broadened laterally, and again extended above and below. In turn it was a sphere, a disk, a pyramid, a pentahedron, a polyhedron. It possessed neither legs, flippers, nor tentacles; but out from its heaving, shrinking body it would send, now from one spot, now from another, an active arm, or feeler, with which it swam, pulled, or pushed. An unlucky invader which one of them touched made few more voluntary movements; for instantly the whole side of the whitish mass bristled with arms. They seized, crushed, killed it, and then pushed it bodily through the living walls to the animal’s interior to serve for food. And the gaping fissure healed at once, like the wounds of Milton’s warring angels. The first white monster floated down, killing as he went; then came another, pushing eagerly into the fray; then came two, then three, then dozens. It seemed that the word had been passed, and the army of defense was mustering. Sick with horror, he watched the grim spectacle from the shelter of the projection, until roused to an active sense of danger to himself—but not from the fighters. He was anchored by his tail, swinging easily in the eddy, and now felt himself touched from beneath, again from above. A projection down-stream was extending outward and toward him. The cave in which he had taken refuge was closing on him like a great mouth—as though directed by an intelligence behind the wall. With a terrified flirt of his tail he flung himself out, and as he drifted down with the combat the walls of the cave crunched together. It was well for him that he was not there. The current was clogged with fragments of once living creatures, and everywhere, darting, dodging, and biting, were the fierce black invaders. But they paid no present attention to him or to the small tentacled animals. They killed the large, helpless red-and-gray kind, and were killed by the larger white monsters, each moment marking the death and rending to fragments of a victim, and the horrid interment of fully half his slayers. The tunnel grew larger, as mouth after mouth of tributary tunnels was passed; but as each one discharged its quota of swimming and drifting creatures, there was no thinning of the crowd.