floor of the tunnel and Carnes fancied that he could see another diving helmet among the litter. Dr. Bird pointed toward the side of the cavern.
"See those floodlights fastened to the cliff so that their beams will sweep across the mouth of the tunnel when they are lighted?" he said. "Apparently the cave is used as a prison and the light beams are the bars. The creature is not at home just now or the bars would be up. My God! Look at that, Carnes!"
Carnes stared and echoed the Doctor's cry of surprise. Clinging to a shelf of rock which extended out from the wall of the cavern and half hidden among the seaweed was a huge marine creature. It looked like a huge black slug with rudimentary eyes and mouth. The thing was fifty feet in length and fully fifteen feet in diameter. It hung there, moving sluggishly as though breathing, and rudimentary tentacles projecting from one end moved in the water.
"What is it, Doctor?" asked Carnes in a voice of awe.
"It is a typical trochosphere of the giant octopus, the devil fish of Indian Ocean legend, multiplied a thousand times," he replied. "When the octopus lays its eggs, they hatch out into the larval form. The free swimming larva is known as a trochosphere, and I am positive that that is what we see; but look at the size of the thing! Man alive, if that ever developed, I can't conceive of its dimensions!"
"I HAVE seen pictures of a huge octopus pulling down a ship," said Carnes, "but I always fancied they were imaginary."
"They are. This monstrosity before us is no product of nature. A dozen of them would depopulate the seas in a year. It is a hideous parody of nature conceived in the brain of a madman and produced by some glandular disturbance. Saranoff spent years in glandular experimentation, and no doubt he has managed to stimulate the thyroid of a normal octopus and produce a giant. I fancy that the immediate parent of the thing before us was of normal size, and so, probably, are its brothers and sisters. The phenomenon of giantism of this nature occurs in alternate generations and then only in rare instances. Its grandparent may not be far away, however. I wish it was safe to use a submarine to explore that cavern."
"Why isn't it?"
"Any creature powerful enough to pull the Arethusa under water would crush a frail submarine without effort. Anyway, a Navy sub isn't built for under-water exploration like this ball is. The window space is quite limited and they aren't equipped with powerful floodlights. I would like to be able to reach that thing and destroy it, but it can wait until later. The best thing we can do is to put out our lights and wait."
His hand sought the light switch, and the globe became dark. Only a tiny glimmer of light came down to them from the surface, a hundred fathoms above. In the darkness they stared into the depths of the sea.
FOR an hour they waited and then Dr. Bird grasped Carnes by the shoulder and pointed. Far in the distance could be seen a tiny point of light. It wavered and winked and at times disappeared, but it was gradually approaching them. Dr. Bird stepped to the telephone and the Minneconsin moved a hundred yards further from the shore. The light disappeared again as though hidden by some opaque body. Their eyes had become accustomed to the dim light and they could dimly see a long snake-like body approach the globe and then suddenly withdraw.
The light appeared again only a few hundred yards away. The water swirled and the sphere swayed drunkenly as some gigantic body moved past it with express train speed and entered the mouth of the cavern. The light turned toward them and they could see
