McCulloch was beginning to molt. The sensation, inescapable and unarguable, horrified him—it felt exactly as though his body was going to split apart, which it was— and yet it was also completely familiar, expected, welcome. Wave after wave of keen and dizzying pain swept through him. Burrowing down deep in the sandy bed, he waved his great claws about, lashed his flat tail against the pure white sand, scratched frantically with quick worried gestures of his eight walking-legs.

He was frightened. He was calm. He had no idea what was about to happen to him. He had done this a hundred times before.

The molting prodrome had overwhelming power. It blotted from his mind all questions, and, after a moment, all fear. A white line of heat ran down his back—no, down the top of his carapace—from a point just back of his head to the first flaring segments of his tail-fan. He imagined that all the sun’s force, concentrated through some giant glass lens, was being inscribed in a single track along his shell. And his soft inner body was straining, squirming, expanding, filling the carapace to overflowing. But still that rigid shell contained him, refusing to yield to the pressure. To McCulloch it was much like being inside a wet-suit that was suddenly five times too small.

—What is the sun? What is glass? What is a lens? What is a wet-suit?

The questions swarmed suddenly upward in his mind like little busy many-legged creatures springing out of the sand. But he had no time for providing answers. The molting prodrome was developing with astounding swiftness, carrying him along. The strain was becoming intolerable. In another moment he would surely burst. He was writhing in short angular convulsions. Within his claws, his tissues now were shrinking, shriveling, drawing back within the ferocious shell-hulls, but the rest of him was continuing inexorably to grow larger.