A FAMILIAR shadow was cast upon the frosted glass of the door-panel. A sturdy fist hammered' out a well remembered rap-a-taptap.

"Come right in, Doctor," I cried, as I pressed the button which released the electrically controlled door-catch. "This is certainly a surprise."

Doctor Destanne swung the door open and entered. It was good to see the little biologist once more. Sibyl, my fiancée, had been acting as his assistant for several months. During this time they had been cruising in the West Indies hoping to complete their extensive research into certain obscure plant forms of that region. Destanne had now returned, weeks in advance of their schedule; which meant that Sibyl must be in the offing.

But Doctor Destanne was unaccompanied, although he turned and closed the door he-hind him so swiftly that his action suggested pursuit. Yet it was not the manner of his entry that startled me; it was his attire that made me stare.

He was wearing a lightweight grey overcoat buttoned well up around his throat, a tweed cap. and a heavy pair of monstrous goggles that were so large they resembled an owlish mask. A truly amazing outfit for a midsummer day in New York City.

Without a word he hurriedly crossed the room and closed the windows that overlooked a sea of roofs. When he removed his goggles from a lace that was streaming with perspiration and sank with a gasp into the large, leather upholstered office chair I keep in readiness for clients, I saw that he was on the verge of collapsing.

"Whew!" he said at last. And I saw that his face, usually so placid with a professional calm, was haggard from sheer exhaustion. "Thought I'd never make it."

I filled a tumbler with ice-water from the cooler. Doctor Destanne took the brimming glass from my hand and swallowed the contents at a gulp. "Whew!" he said again.

Never in all my long friendship with the staid little man had I seen him anything like this. Usually, he made me think of a prosaic, busy little brown sparrow.

True, there was the time when he returned from crossing and recrossing that deadly Valley of gigantic arum lilies west of Zanzibar. That must have taken nerve. Only after his reports were completed had the public earned that the perfume of those tremendous blossoms—large as elephants' ears—had overpowered the pilot while Doctor Destanne was photographing the valley at two thousand feet. They would have plunged to their deaths, stifled by the lethal fragrance, but for Destanne's hair-trigger nerve.

"It's this accursed thing that's such an abomination," he was saying, when I returned with more ice water.

HE had unbuttoned his overcoat and now I saw what had been concealed beneath it.

Surrounding his throat was a massive metal collar which completely covered his neck. Connected to the lower edge of this strange collar, finely interlocked metal links glittered.

"Chain mesh—iron there on down to my knees," he said. "Steel," he added significantly.

"Yes, but why?" I burst out. "Surely you aren't being hunted by gunmen."

"Worse than that, Roger. Much worse. Have you anything to smoke here?"

I drew an open box of Havanas from the desk and pushed them toward him. He had calmed sufficiently to recover his clipped, precise speech, but I saw that he was still far from his usual meticulous self.

"Worse," he mused as he got the cigar burning evenly. "Worse. It's damnable." He paused, inhaling deeply, as if pondering a diagnosis. Then, tossing precision aside with a gesture, he flung his words to the wind.

"I came to you, Roger, for help, because I knew I'd get it. We haven't time to go in to all the details now. If we hurry we can taxi out in time to catch the 9.30 Seaboard Airliner smith. Talk over the problem on our way. It's devilishly complicated. As terrible a doom as ever threatened an unsuspecting world—the air-plant men. They followed me here. Nothing I can say will stir our slow-moving national defense organization 'into action in time to avert a disaster. Our country—even Sibyl's existence—is hanging by a thread, a tentacle."

He stopped suddenly and I seized him by both shoulders. "Sibyl?" I breathed.

"As if we needed concrete evidence," Destanne said, pointing to the window where evening shadows were fast gathering.

I would have stepped forward, but he intercepted me. "Back," he shouted. "As you value your life, leave that window securely fastened."

Then I saw what appeared to be a length of dangling cable, coarse stuff, that was swinging freely a few feet beyond the parapet. Perhaps as heavy as a man's finger, medium-sized, brown hempen cable, I thought.

"Workmen," I said aloud.

But even as I spoke the cable twisted with an uncanny waving motion. Another length descended and hung a foot or so from the first. Then another, and another, until there were fully a dozen of them dangling and swinging, but ever gliding downward.

Curiosity prompted me to crouch and watch the upper edge of the window. I caught a glimpse of some vague grayish bulk that was hanging there; then the mass sailed swiftly down to stop abruptly, hovering directly outside the window.

Destanne coughed slightly. "One of the scouts," he said, with the manner of a curator explaining an interesting specimen. "He doesn't want to lose track of me. From now on, Roger, I'd advise you to be prepared for anything.

Like one hypnotised, I crouched staring at the creature that faced me beyond that expanse of thin window-glass.

Nine eyes in a horizontal row, black orbed, blinking, strangely human eyes with human intelligence and human curiosity shining in the sparkling depths. The row, so compact was it, did not exceed two feet from end to end.

It was moving. The eye at the left-hand end of the row closed and sank away. The row moved along from right to left, a tenth eye became apparent at its right-hand end. Another eye blinked and drifted away. Again the row moved along, again and again.

I felt I was being inspected by a concentrated nightmarish crowd of people. It was a moment before the shock of the thing wore off. But soon I was able to reason sufficiently to understand that the eyes were placed at regular intervals around what appeared to be the neck of a balloon-shaped affair. And that this balloon-like creature was revolving horizontally, so that each of its many eyes was being presented in slow succession.

For awhile I suffered the inquisition of the baleful creature's penetrating stare. Then, so suddenly that it gave the impression of an optical illusion, the thing was gone and the shadows lay long and soft over the adjacent roofs, and the flickering fireflies that were the traffic glittered in the deeper canyons beneath us.

"That's that," Destanne said with forced flippancy. "Up to the five thousand foot level like a shot and practically out of sight from the ground. Now you will understand why I'm wearing this accursed collar, Roger, They wouldn't dare attack us in a crowd, not at this stage of the game, at least; but when they do get a chance those tentacles of theirs are almost as tough as steel—elastic as rubber bands, sensitive as fingers. Directed by a fiendish intelligence, they choke their victims, gouge out his eyes—"

"And Sibyl—is being held by these—these infernal creatures?" I gasped. My voice sounded hollow and I wondered vaguely if I could be talking in a dream.

"She is," replied Destanne brusquely. "If you'll grab your hat, I think we might make a dash for a taxi right now and, with luck, be in time when we reach the airdrome to catch the 9.30."

CHAPTER II.

The Trail of the Death Lily

TOGETHER we shot down to the ground floor of the Fanton Building in an express elevator and darted across the pavement into a waiting taxicab.

Once inside the cab, Doctor Destanne gave the chauffeur terse instructions to take us to the Seaboard Central. Then he closed the window and removed his goggles.

"Be surprised how quickly those things can get you," he commented, pointing upwards.

"We're going empty handed," I reminded him.

"No. I ordered quite a lot of stuff in Miami on my way north. A radio from the flying field will have it meet us when we pass there. Lot of things, including a collar and chain-mesh for you, and goggles. And one of these—"

From just above his belt he seized the scarcely concealed hilt of a machete; jerked the weapon out and stroked its razor-keen edge as lovingly as a Roman gladiator might have toyed with at short sword. I was glad when he slammed the frightful blade back into its scabbard, for the chauffeur had been watching us suspiciously.

We reached the flying field without interference and more than half an hour before the time set for the great amphibian airliner's departure. Here I found the Doctor's arrival had been expected and arrangements had already been made for our passage. A sheaf of telegrams settled my affairs and I was ready to join Destanne in one corner of the luxurious smoking compartment of the wailing ship.

"Sibyl," he said, apparently reading my thoughts "is in the gravest danger, in deadly peril, in fact; but not in altogether imminent danger. That is, I suspect we shall be in ample time if nothing unforeseen occurs.

"You will appreciate the situation better if I begin somewhere near the beginning and give you an outline of what I know of the air-plant men.

"Brisson, a New Orleans police detective, who is also a brilliant Southern botanist, sent me in a joking way a specimen of a tiny and quite rare plant—er, not unlike a hyacinth. He wrote me that his confréres had given this plant the name of 'Death Lily' for a rather curious reason.

"Brisson, it seems, had been at work assembling the data on all the recent murders in the South, especially Florida and Louisiana. They had a string of eight apparently unreasonable, disconnected, uninteresting homicides—unsolved affairs of violence. They were alike, seemingly, in only one respect. Fiendish brutality. Crushed skulls, broken necks, gouged out eyes. In one case, the victim had been practically torn asunder.

"All of them were country people, obscure tenant-farmers or farm laborers of the very poorest class and utterly without money or enemies. The cases were so far apart, however, and the time interval between so short, that not even a fiend killer seemed to fill the bill.

"Brisson's love of botany often led him far a field. In his investigation he found a bed of the tiny hyacinth, a specimen of which he sent me, growing somewhere in the vicinity of each murder. 'Death Lily' they named it."

DESTANNE paused and gazed thoughtfully at the airdrome beacon, a rest-less finger of light which stroked the night sky that lay beyond the smoking-room': heavy curved-glass windows.

"Death Lily" he said again. "Brisson's associates had named it well. A modest, pale-blue bloom with a peculiarly pleasant, sweetish aroma—harmless, fragile, nonpoisonous, shrinking as a violet yet more deadly in its significance than the vilest leper.

"We traced it, Sibyl and I, to what seemed its source—this 'Death Lily'—for it was a newcomer to the South. The beds Brisson found were undoubtedly far-flung colonies of a plant apparently having its origin On a group of uncultivated, tropical islands lying in the Caribbean southeast of Cuba. 'Shadow Island', the map called the largest one. The lines we plotted on our charts converged at that point.

"At this time we haw no thought but for the fun we were having assembling data on an unknown plant recently finding root in North American soil—a seemingly harmless and rather likeable plant at that.

"To test our figures, we decided on a trip to 'Shadow Island'. That was when we left New York, as you remember."

I nodded. "And at 'Shadow Island' you found what?" I asked, rather tired of the details.

"At 'Shadow Island'," Destanne bit out grimly, "we found Hell."

The great airliner was already shaking with the pulsations of its powerful engines. A last passenger arrived followed by 8 white-coated steward. The roaring of the engines rapidly grew in intensity; soon we would he taking oil and anything resembling conversation would be drowned out by the ear-aching thunder.

"But Sibyl?" I shouted.

Destanne shut me a brow-lifted smile. "Don't worry too much about Sibyl," he said, in a shout that was scarcely audible. "If we use our heads we can beat those devils. Guess I'll go turn in. This roaring doesn't bother you so much after a time—restful."

The smoking-room jolted slightly as if shaken by a mild earthquake. We were under way.

CHAPTER III.

The Menace of the Air-Plant Men

NIGHTMARE hours slid by. I was ill. Sleeping became gasps of dreaming horror. The cachet of tissue-wrapped clove-perfumed gauze which the steward brought me, did little to relieve my illness although it was highly recommended as a preventive of airsickness.

And my mental state was even more unhappy than my physical condition. What, exactly, was the peril which threatened Sibyl? What was the connection between the air-plant men and the 'Death Lily'? How did the air-plant men intend to launch their attack against humanity? Would they begin by wrecking the airliner upon which we were travelling? These, and a thousand other questions went racing through my mind during those semi-delirious hours.

But at last I slept. When I woke, Destanne was bending over me. The motors of the airliner no longer roared. The port-glass of my cabin was a disk of brilliant turquoise. The room flooded with sunlight.

"Come along, Roger. Shake it up," the Doctor was saying. "This is Batamano and the launch is waiting to take us ashore."

Batamano, I learned as I dressed, was a fishing village on the Isla of Batamano. This was the Caribbean, upon its deep blue water the great airliner rested, and the splashes of dazzling whiteness which dotted it were the sails of myriad sponge-fishing craft. We were within fifteen miles of "Shadow Island."

"You slept like the proverbial log," Destanne told me. "Here, climb into this. We're getting pretty close now."

From a chair beside me, he lifted a suit of steel chainmesh to which a massive steel collar, similar to the one he was wearing, was attached. "You missed Miami and all the rest," he said. "Just as well though."

Almost unnoticed by our fellow passengers, we clambered down the swinging gangway to the waiting launch. The body of the amphibian airliner stood tall above us as Destanne introduced me to the three bronzed men who helped us into the wabbling launch.

"Pedro is the mechanic," he explained. "Henrique they call 'El Practico', the pilot, and Francisco—well, he's just excess baggage. He owns the launch."

Sturdy, sun-tanned fishermen, they were fearless enough and square. They knew of the peril which lurked around "Shadow Island" but were indifferent to it. They laughed heartily at the chainmesh, collar and goggles we wore. And as they stowed the heavy trunk Destanne had brought, said they wished for nothing better than their machetes.

"That reminds me," put in the Doctor hurriedly. "Stick one under your own belt, Roger, right now. The moment you find yourself within striking distance of one of the tentacles don't hesitate, just whack."

I took the barbarous weapon reluctantly. Such things, I thought, were good for cutting sugar-cane, but not quite the weapon for a civilized man. I was glad I had slipped a .45 automatic into my shoulder holster when I left New York.

We were by now leaving the indigo bay of the Playa of Batamano and entering the greener waters of the open sea. Eagerly we scanned the blazing sky for a sign of a hovering scout of the air-plant men. There were none.

"You will find the goggles a great help," the Doctor told me. "The lenses are slightly tinted and act as color-screens to a certain extent. I've found the air-plant men are experts at hiding in a clear sky by chameleon-like color changes. The balloon-like part, too, is often quite transparent and scarcely more tenuous than a cloud of smoke."

"WHAT," I asked, "are the air-plant men?"

"Now you've asked me something," answered the Doctor gravely. "My opinions are formed from observations made during a hurried and very harassing encounter—Yes, very. This is what I suspect.

"Their amazing intelligence, their physical and mental make-up, everything about them, suggests that instead of being the devilish octopus-like creature which we an by circumstances forced to think them, they are much more highly developed than we are. Therein lies their deadly menace.

"Going back a little, you will remember that our earth has been ruled from time to time by varying types of creatures. Each of these was replaced by newer, more efficient ones until, climbing the evolutionary scale, we find man dominating the scene.

"Good. Now we know the part evolution played in these changes and the extent they were hurried along by the sudden mutations of radically new types. Also, that each of the creatures to dominate the scene—even man himself—put in a first appearance as an almost defenseless creature.

"For ages man survived as a weak and unimportant inhabitant before he slapped up to anything like a dominant place. So weak was he that, if the creatures then dominating had even guessed that he was to be their successor, they could have wiped him out in a day.

"Judging, then, by what had gone before, the fact is pertinent that the creature which' is to replace man must be already somewhere on this earth of ours. By now, man's successor must be gaining a foothold. By now, some mutation or some amazingly new branch of—of man himself, possibly, must be somewhere hiding and growing, furtive and hunted most likely, but gaining strength for the overthrow of the very parent from which he sprang."

Destanne lapsed into speculative silence.

"And you infer that these air-plant men are our superiors?" I asked, with some heat.

"Possibly, possibly," Destanne murmured, quite unmoved. "Don't rush to conclusions, Roger. I believe I'm correct when I say that their superiority—intellectual superiority—is almost beyond our grasp. Of course, I'm puzzled. But that balloon-shaped body of theirs suggests a head—an awe-inspiring, skull-less brain. Their multiple eye suggests something, too. You've noticed that it isn't a mechanical contrivance like the multiple eye of a fly. Each pair of eyes is an individual, characteristic, independent affair."

THROUGH my goggles, I had been watching the blue. horizon of a placid sea. High above us, a single saber-winged bird soared. From beside me, came the idle slap of wavelets against the bow of the launch and the put-puttering of the asthmatic motor. A blazing tropic sun hung in the western sky, but the heat continued to be intense. Blistering heat. A tranquil sea. And a light breeze at our backs, oven-hot.

"Hot enough to hatch devils," I commented.

"Man," Destanne reminded me, with exasperating calm, "had his origin in warm climates."

"Nonsense," I exclaimed. "You've let this heat and the idea of these things run away with your imagination. They're new. They're unpleasant to deal with, like an octopus or a shark; but they're far from being what you think them to be."

Directly ahead of us, land showed as a short, black line thickening the horizon. A shadowy line that would have been scarcely visible had it not been for a growth of palm trees whiskering one end of it.

"If I'm not mistaken—our destination," I announced.

Destanne nodded agreement. "Shadow Island," he said, a touch of awe in his voice.

"Right," I said, fingering the .45 automatic under my armpit, and cursing the heat and the chainmesh. "It is, eh? Well, if Sibyl's there, held by man or superman, I intend to find her and bring her back—or raise Hell trying."

Destanne shot me a quick glance; smiled slightly at my enthusiasm—a trifle sadly, I thought. His manner galled me unreasonably. I pointed at the wretched little capo we were now rapidly approaching.

"Sibyl's there," I said. "For some reason I don't doubt that. That she's being kept there by force in the manner you suggest, is another thing. You've been precious quiet as to how and why these so-called air-plant men, are doing it."

"I really don't know," Destanne said meekly. "At the time we were seized and I managed to hew my way out with a machete, it seemed to me that the air-plant men handled Sibyl with the greatest care. Carlos, the boatman we had hired to come with us, they smashed to a pulp in something less than ten seconds."

We were close in now and headed for a beach where a sunparched sand bank of dazzling whiteness drifted down almost to the waters' edge. A barren shore, spotty with scraggly bunch-grass. and away to our left a stretch of saltmarsh. mangrove-covered.

"Not a sign of life." I commented, standing up in the bow of the launch and tempted to tear off the metal collar which, under the sun's scorching rays, fairly seared my neck. "I wouldn't be surprised if Sibyl—"

I broke off abruptly.

Above the crest of the hogback of sand directly before us, something rose slowly. Like a semitransparent blue bubble it lifted against the skyline until it was just clear of the sandy range. It was roughly pear shaped, some twenty feet tall by?freen wide. '

For a moment it remained, silent and motionless; then it sank behind the ridge. And I stood gaping and speechless and filled with the suspicion that I had been stared at and inspected by some lethargic giant who had merely lifted his head and peered at me over the ridge.

CHAPTER IV.

A Horrible Plan

"A LOOK-OUT, probably," said Doctor Destanne.

I turned to find Francisco was examining his machete, grim-lipped. Henrique was at the helm, whispering to himself in Spanish but keeping the launch on its course. We were headed straight for the beach which was now less than a hundred yards away.

"Will they attack us when we land, do you think?" I asked, suddenly feeling very weak and helpless.

"That remains to be seen," replied Destanne. "I doubt it, for we are to windward of them. We came up on them from that direction because I've found that their flight isn't well controlled. They seem to rise by inflating themselves with some very light gas, internally produced and probably heated. Their direction appeared to me to be largely a matter of selecting the right air currents—like a balloonist. Although, sometimes I suspect they are able to rocket themselves for short distances by the ejection of air from tiny openings placed on their under surfaces."

Henrique shut off the motor. The launch drifted silently forward, until it nosed softly onto the sand at the water's edge. Only the pouring of the waves and the long-drawn hiss of sand-laden water disturbed the utter silence.

Doctor Destanne was the first to spring ashore. I followed quickly after him, and Francisco and Pedro brought up the rear. I was intent upon watching the place at which the air-plant men had peered at us. For this reason I scarcely noticed that the two fishermen were carrying ashore the trunk Destanne had brought along.

We were climbing the ridge by that time and I was too busy struggling up the steep sandy wall to comment on the matter.

This embankment was less than twenty feet high but steep—unnaturally steep, I thought. Every step of our climb was a sweating agony. Many a time the crumbling and uncertain surface gave way beneath us and we slid to the bottom.

But eventually we gazed over the crest and over the amazing expanse which formed the interior of the island. Roughly circular it was, at least a mile in diameter, and deep, like the crater of an extinct volcano.

The similarity ceased at that though, for as I was quick to realize, the whole structure was artificial. The entire area had been scooped out to a depth of some thirty feet. The ground was approximately fifty feet below us.

And it was cultivated ground, watered seemingly from a meagre stream which emerged by way of the mangrove swamp. Without pathway or trial, a single field close-covered with a pale blue flower, it was one sweep of blue—a pastel, dainty hue.

"The 'Death Lily'," murmured Destanne. "The feeding ground."

I blinked and then saw what before I had thought was simply the result of atmospheric heat waves. The air above the field was shimmering as if heated air were flowing into the cooler space above the moist ground.

I saw now that the shimmering had a definite pattern. It was like a roof over the field; a roof formed by a myriad glass domes built row after row. Domes—glass globes, solidly massed. Huge bubbles—air-plant men. Millions of them—their tentacles spread out upon the ground amongst the flowers.

"Feeding," said Destanne slowly. "I'm not quite sure it's that, either. Notice the absence of perfume? The air should be positively reeking with it. I suppose they absorb that perfume—and maybe some infinitely subtle and essential gases with it."

I was staring, drymouthed, paying little heed as Destanne rambled on: "The necessities of their existence—air and water and the perfume of the 'Death Lily'. The latter they seem to need only occasionally, I suspect they take it in large, periodic doses."

MY glance had been wandering far and near for a sign of Sibyl. I had hoped to find her—if Destanne had told me the facts—wandering along the beach. My plans, scant as they had been, were to circle the island and perhaps find Sibyl waiting for US.

Now it seemed to me Sibyl must indeed be lost. What were we against this multitude of super-powerful, super-intelligent creatures?

Destanne was silent, and I was wrapped in thoughts of the most melancholy nature as we stared out across that vast blue field. Perspiration trickled under our goggles. It streamed beneath our metal collars.

Then, as if my worst fears had suddenly materialized, I saw Sibyl! Clear and plain I saw her. She was some three hundred yards to our left, supine as if resting. With the glasses that Destanne handed me I saw how deathlike was the marble pallor of her cheek.

Stifling a shout, I seized Destanne by the arm. He saw her and his face became tenses with the realization of her danger.

"If we go along this side," he said, pointing at the beach, "we might—"

Without waiting for words, I slid down to the beach. Ran, with the Doctor stumbling after me; ran, until I believed I was opposite the spot where Sibyl lay. Then I climbed like a crazy ant up the embankment until I again reached its crest.

A scrap of white paper like a pale pennant faced me. It had been wedged into the end of a short, split stock which was planted on the embankment. Sibyl's handwriting

"If you come:"—the words spun dizzily before my eyes as I crouched and read on. "At first I was dreadfully frightened. They seemed such unnatural, ghastly creatures, these air-plant men.

"But I learned to understand them. Their multiplex personality puzzled me. The idea of a compound creature using a community brain was appalling. It was hard to understand how a group could live on indefinitely by subjugating the personalities of its members.

"Doctor Destanne called them the 'Air-plant Men'. He was nearly correct—except that each one is a composite of many members. In our struggle to escape, the Doctor shot at the group which attacked us. His shot killed one of its members. The groups immediately sloughed off the dead member and prepared to absorb a younger one as a replacement.

"In some way not clear to me, they have selected me to be the replacement. I am to be absorbed and adopted as a member of the group which attacked Doctor Destanne. I understand my body will be unnecessary.

"My mind, entirely different in its views from the usual run of air-plant folk, is considered a very valuable asset—a stimulant to the group. The absorption of it will take time-possibly—"

As it the paper had suddenly become a venomous reptile, I cast it from me; pounded it into the sand with my clenched list.

The Rescue!

AGAIN I stared at Sibyl, down there among the "Death Lilies". Her lace was pale and upturned, eyes closed as if in sleep. Her khaki shirt was open at the throat; khaki brooches and leggings, sand-dusted. She might have been a corpse—yet I knew life still lingered in that sweet face, that a heart still pulsed in that sand-sprinkled form.

The thought sent me berserk. Heedless of the myriad eyes I knew must be staring at me, I sprang to my feet. Gun tight-clasped in my fist, I rushed down the embankment. Seven leaping strides, and I struck bottom.

Sibyl was at my feet and above me loomed great globular forms. I could see them more clearly now. Like captive balloons tipped by the sunlight they swayed, held down by a forest of taut tentacles. Tentacles that moved and reached out for me. A single, sinuous arm slithered serpent-like across the white throat of Sibyl. Another, like a snake of soft glass, was brushing my face.

In a flash I had the machete out. Hack-hack, the razor-edged blade bit through the yielding stuff. Hack-hack, and with each blow, severed ends twisted and contracted like chopped eels.

A moment of madness, an instant of struggling, and I had Sibyl slung over my shoulder, her ankles crooked under my gun arm. Her head was hanging down across my back. How slight she was! How limp! But alive yet. I knew that by her very limpness—by a magnetic warmth.

An arm, a powerful constricting arm, closed around my throat; began lifting with power tremendous. Thwack, the blade of my machete rang with the very swiftness of the blow. Thwack, the handle tingled in my fingers. Ten feet of severed tentacle writhed about me, then hung still and flaccid.

I faced the steep slope of the fifty-loot embankment. Behind me, the air was thick with a lashing, writhing movement; heavy with a sense of soundless commotion.

Up and up I climbed, the blood mist of desperation thick before my eyes. Up and up.

The inner side of the embankment was smooth, moist and firm, due to some extent, perhaps, to the proximity of the damp, cultivated land. It offered a reasonable foothold. Fighting for breath I reached the crest. Destanne was waiting there, machete in hand.

"Down," he yelled, pointing toward the launch. "I'll cover the rear."

One step I took, then toboganned to the beach in a welter of dry sand; straightened up and began staggering off in the direction of the launch.

I could see Henrique in the launch. He was waving his arms wildly. His suntanned figure was black against the sky. His screamed words came to me in garbled Spanish that was meaningless.

Then a faint shadow, indistinct as the shadow of a passing cloud, swept over me. I could hear Destanne shout. A shot rang out. But I staggered on, heels deep-sunk in the sand.

The shadow passed. It was before me now stretched over the whiteness of the beach. Lashing tentacles, hissing like whiplashes, cut the air over my head. Swiftly the thing bore down on the launch.'

Henrique had ceased waving his arms. He stood now quite still, one foot resting on the boat's gunwale. Chest out. Machete flashing.

But the enraged air-plant man was too quick for him. A flick of a tentacle and a jerk. One moment Henrique hung high in the air, his arms gallows-twitching, legs dancing on air, head twisted, neck broken-; the next, he was falling like a dropped weight, feet-foremost, into the blue water beneath him.

FROM somewhere not far behind me, came shouts of encouragement from Destanne. They seemed to me to be strangely out of place. The creature that had murdered Henrique was still floating high over the launch. Soon a horde of them would spring upon us from behind the embankment. Henrique's fate had been merely a demonstration of what was in store for each U! us.

Nevertheless, I plunged on toward the launch. A man struggling for a hopeless cause, my feet sank deeper with every stride. My strength was lessening with each gasping breath.

A little to my left, I saw Pedro and Francisco were also making for the launch. Until now they had been crouching in a hole they had dug at the base of the embankment. They came running now and pointing upward at the evening sky.

Were the air-plant men even now assembling their hordes above us? I gave one swift, despairing glance upward. Only a sky of cloudless blue was there. For some reason I did not understand, the air-plant man which had attacked Henrique was rapidly swinging o?' inland.

* * * *

In a huddle of striving humanity we met at the launch. "The breeze," Destanne was saying. "Thank Heavens it's holding. Had to go. See?" He pointed at the air-plant man drifting swiftly inland. "Couldn't hold his position with this light breeze blowing."

Francisco got the motor ready as I placed Sibyl tenderly in the vessel's stern and took my place beside her. The girl seemed to be sleeping. Destanne was grasping a slender wire to which what appeared to be a battery box and a switch was attached. The wire stretched from the still motionless craft to a point far up the beach.

Then, like a wall of transparent ice, the air-plant men rose above the embankment. A mint breeze still blew in from the ocean. The air was clear and flooded with long rays of a lowering sun. So clear was it, I thought of it as translucent water and the hordes of air-plant men that were rising beyond the ridge, as gigantic jelly-fish that floated; whilst we, infinitesimal creatures, were doomed to crawl over a strange ocean's floor.

Destanne was squatting on a seat; the switchbox in his lap. One arm he raised in a signal to Francisco who waited, hand on the starter.

With a hissed word of command, the little biologist snapped his arm down; shot the switch over.

The mighty roar which followed shook the launch, rocked the island, and blotted out the sunlight.

"Madre de Dios", I heard Francisco groan, as the chug-a-chug-chug of the launch's motor bit into the ear-throbbing silence that followed that blast. The buried trunk had been dynamite packed, I understood that now.

Sand-clouded darkness was all about us as we left "Shadow Island". The sea around us was pelted for miles with the rain of falling debris.

"The embankment," Destanne said, after awhile, "it's broken." Then, abruptly: "Well, well, if Sibyl isn't wide awake once more. Don't he alarmed Sibyl, I think we've beaten them."

The girl rolled her head from side to side. "A little water, nothing more," said Destanne. "Come along, Roger, snap out of it. There's a canteen beside you."

Clumsily I lifted the canteen to Sibyl's lips and she swallowed a little of the lukewarm?uid; rested her head on my shoulder again and closed her eyes.

Swiftly the launch was nosing into the breeze and we sped away from "Shadow Island". The place we Leif behind us was a smoking wreck. Above it, high above it, rose tier upon tier the floating hordes of the air-plant men. Slowly they were drifting away from us, driven by the westerly breeze, they sped eastward. Tier upon tier they rose, a golden argosy of strange and scintillating beauty which towered far into the cloudless sky. Their uppermost members were caught in the crimson streaks' of sunlight which marked them against the sky as golden bubbles. Where would they go next? I wondered, as I glanced at Destanne.

"Their feeding ground flooded, destroyed," he said, noting my glance. "Mighty good thing for us the direction of the wind makes it impossible for them to overtake us for some time." He paused, then: "My original plan was to dynamite their feeding ground whilst they were heavy under the influence of the perfume which plays such an important part in their lives."

"The stuff must leave them groggy," I commented.

"Precisely. An essential food to them, just the same. Brisson has arranged for the destruction of the smaller beds they were establishing throughout the Southern States."

"Which will leave them quite defeated?" I asked-.

"I hardly think so. They are marvellous balloonists,—tireless, effortless motion. They will establish new grounds. Central America, perhaps, or even Africa. "Whenever the 'Death Lily' will flourish. Defeated now but a menace to posterity."

We lapsed into silence. The last of the air-plant men were vanishing into the shadows far astern. Slap-slap, the waves bounced the bow of the launch, and flew past us in threads of white spume.

Sibyl sighed and stirred restfully. I moved a trifle. Something was tangled around my feet.

Destanne followed my movements; he bent over and picked up one end of a ten-foot length of what looked like cable. Limp and dry, it hung from his hand, slick-sun faced.

"Obviously a vegetable tendril," he chuckled, with a knowing smile, as he twisted the thing into a seaman-like coil. "If you delft mind, I'll keep this—er, piece of liana vine."

THE END.