"Neptunians!" whispered Marlin beside me. "Neptunians, Hunt--those squat, flat disk-bodies--those great eyes----!" Neptunians! Yet I had seen myself that they must be so, that only on a great planet like Neptune, with far greater gravitational power than Earth, could those squat, flat bodies have evolved. For the greater the power of a planet's gravitation, the lower and the more squat will be the forms of life that evolve upon it. And just as these Neptunians had evolved in their strange disk-form here on the great planet, due to its greater gravitational power, so had their great light-gathering eyes been evolved by the dimness that reigned here always. And it was these beings, it was clear, who had built the vast compartment-city that covered all of the great planet's surface about us, since it was only beings like these who would have built such strange, low doors in it for their own flat disk-bodies, only such beings as these who, with their seven great limbs, could manipulate the controls of the mechanisms we had seen! "Neptunians!" I whispered it, myself. "But if it's beings like these who inhabit Neptune, who have sent the great force-ray stabbing toward the sun to divide it, where are they all? Why have they left all this city, all this world, dead and deserted?" Marlin, inside his space-walker, shook his head. "God knows, Hunt! If all these Neptunians have deserted their world, where have they gone? I know no more than you. But it's clear that they've come back for more of those great mechanisms." It was, indeed, evident that that was the object of the Neptunians' visit to the compartment-city, for now the score or more in the adjoining compartment were busily working with their tools upon three or four of the great cogged mechanisms that loomed there. Swiftly they were taking down those mechanisms, were dissembling them into a myriad intricate parts which were stowed away in the four great cylinders. More than once some of them passed close to the low door through which Marlin and I were gazing, but none ventured through it into the compartment in which we hid, seeming all to be intent upon the business at hand. And as they worked on we began to understand some of the features about them that had puzzled us in our first horror-stricken sight of them.