Above him lay the great black steep that rose to the summit of the monster's humped back, a mountain to be climbed.
Near the crest of the monster's back, he stumbled and fell hands and knees on the shagreen-roughness of the skin.
Unmistakably even in the misty dawn-light, the hills and valleys of the rugose back were changing shape, as the vast protoplasmic mass below crawled, flowed beneath its integument.
Fingers shaking, he unhitched the light ax from his belt and began to hack with feverish industry at the monster's crusted hide.
The scaly, weathered epidermis seemed immeasurably thick. But at last he had chopped through it, reached the softer protoplasm beneath.The slabs of flesh he had cut off were gray and unappetizing, but he knew from the studies he had helped Sutton make that the monsters, extraterrestrial though they were, were in the basic chemistry of proteins, fats and carbohydrates one with man or the amoeba, and therefore might be—food.
The scientists had found, in the burst bodies of the Titans that had been killed by atomic bombs, the answer to the riddle of these creatures' crossing of space: great vacuoles, pockets of gas that in the living animal could be under exceedingly high pressures, and that could be expelled to drive the monster in flight like a reaction engine. Rocket propulsion, of course, was nothing new to zoology; it was developed ages before man, by the squids and by those odd degenerate relatives of the vertebrates that are called tunicates because of their gaudy cellulose-plastic armor....
Robert Abernathy, Strange Exodus
Read Scott's essay about Strange Exodus & The Rotifers here.