"Junior!" bellowed Pater.

" Junior! " squeaked Mater, a quavering echo.

"Strayed off again—the young idiot! If he's playing in the shallows, with this tide going out...." Pater let the sentence hang blackly. He leaned upslope as far as he could stretch, angrily scanning the shoreward reaches where light filtered more brightly down through the murky water, where the sea-surface glinted like bits of broken mirror.

No sign of Junior.

Mater was peering fearfully in the other direction, toward where, as daylight faded, the slope of the coastal shelf was fast losing itself in green profundity. Out there, out of sight at this hour, the reef that loomed sheltering above them fell away in an abrupt cliffhead, and the abyss began.

"Oh, oh," sobbed Mater. "He's lost. He's swum into the abyss and been eaten by a sea monster." Her slender stem rippled and swayed on its base and her delicate crown of pinkish tentacles trailed disheveled in the pull of the ebbtide.

"Pish, my dear!" said Pater. "There are no sea monsters. At worst," he consoled her stoutly, "Junior may have been trapped in a tidepool."

"Oh, oh," gulped Mater. "He'll be eaten by a land monster."

"There ARE no land monsters!" snorted Pater. He straightened his stalk so abruptly that the stone to which he and Mater were conjugally attached creaked under them. "How often must I assure you, my dear, that WE are the highest form of life?" (And, as for his world and geologic epoch, he was quite right.)

"Oh, oh," gasped Mater.

Her spouse gave her up. "JUNIOR!" he roared in a voice that loosened the coral along the reef.

Round about, the couple's bereavement had begun attracting attention. In the thickening dusk, tentacles paused from winnowing the sea for their owners' suppers, stalked heads turned curiously here and there in the colony. Not far away, a threesome of maiden aunts, rooted en brosse to a single substantial boulder, twittered condolences and watched Mater avidly.

"Discipline!" growled Pater. "That's what he needs! Just wait till I—"

"Now, dear—" began Mater shakily.

"Hi, folks!" piped Junior from overhead.

His parents swiveled as if on a single stalk. Their offspring was floating a few fathoms above them, paddling lazily against the ebb; plainly he had just swum from some crevice in the reef nearby. In one pair of dangling tentacles he absently hugged a roundish stone, worn sensuously smooth by pounding surf.

"WHERE HAVE YOU BEEN?"

"Nowhere," said Junior innocently. "Just playing hide-and-go-sink with the squids."

"With the other polyps," Mater corrected him primly. She detested slang.

Pater was eyeing Junior with ominous calm. "And where," he asked, "did you get that stone?"

Junior contracted guiltily. The surfstone slipped from his tentacles and plumped to the sea-floor in a flurry of sand. He edged away, stammering, "Well, I guess maybe ... I might have gone a little ways toward the beach...."

"You guess! When I was a polyp," said Pater, "the small fry obeyed their elders, and no guess about it!"

"Now, dear—" said Mater.

"And no spawn of mine," Pater warmed to his lecture, "is going to flout my words! Junior—COME HERE!"

Junior paddled cautiously around the homesite, just out of tentacle-reach. He said in a small voice, "I won't."

"DID YOU HEAR ME?"

"Yes," admitted Junior.

The neighbors stared. The three maiden aunts clutched one another with muted shrieks, savoring beforehand the language Pater would now use.

But Pater said "Ulp!"—no more.

"Now, dear," put in Mater quickly. "We must be patient. You know all children go through larval stages."

"When I was a polyp ..." Pater began rustily. He coughed out an accidentally inhaled crustacean, and started over: "No spawn of mine...." Trailing off, he only glared, then roared abruptly, "SPRAT!"

"I won't!" said Junior reflexively and backpaddled into the coral shadows of the reef.

"That wallop," seethed Pater, "wants a good polyping. I mean...." He glowered suspiciously at Mater and the neighbors.

"Dear," soothed Mater, "didn't you notice ?"

"Of course, I.... Notice what?"

"What Junior was doing ... carrying a stone. I don't suppose he understands why , just yet, but...."

"A stone? Ah, uh, to be sure, a stone. Why, my dear, do you realize what this means ?"

Pater was once more occupied with improving Mater's mind. It was a long job, without foreseeable end—especially since he and his helpmeet were both firmly rooted for life to the same tastefully decorated homesite (garnished by Pater himself with colored pebbles, shells, urchins and bits of coral in the rather rococo style which had prevailed during Pater's courting days as a free-swimming polyp).

"Intelligence, my dear," pronounced Pater, "is quite incompatible with motility. Just think—how could ideas congeal in a brain shuttled hither and yon, bombarded with ever-changing sense-impressions? Look at the lower species, which swim about all their lives, incapable of taking root or thought! True Intelligence, my dear—as distinguished from Instinct, of course—pre-supposes the fixed viewpoint!" He paused.

Mater murmured, "Yes, dear," as she always did obediently at this point.

Junior undulated past, swimming toward the abyss. He moved a bit heavily now; it was growing hard for him to keep his maturely thickening afterbody in a horizontal posture.

"Just look at the young of our own kind," said Pater. "Scatter-brained larvae, wandering greedily about in search of new stimuli. But, praise be, they mature at last into sensible sessile adults. While yet the unformed intellect rebels against the ending of care-free polyphood, Instinct, the wisdom of Nature, instructs them to prepare for the great change!"

He nodded wisely as Junior came gliding back out of the gloom of deep water. Junior's tentacles clutched an irregular basalt fragment which he must have picked up down the rubble-strewn slope. As he paddled slowly along the rim of the reef, the adult anthozoans located directly below looked up and hissed irritable warnings.

He was swimming a bit more easily now and, if Pater had not been a firm believer in Instinct, he might have been reminded of the grossly materialistic theory, propounded by some iconoclast, according to which a maturing polyp's tendency to grapple objects was merely a matter of taking on ballast.

"See!" declared Pater triumphantly. "I don't suppose he understands why , just yet ... but Instinct urges him infallibly to assemble the materials for his future homesite."

Junior let the rock fragment fall, and began plucking restlessly at a coral outcropping.

"Dear," said Mater, "don't you think you ought to tell him...?"

"Ahem!" said Pater. "The wisdom of Instinct—"

"As you've always said, a polyp needs a parent's guidance," remarked Mater.

" Ahem! " repeated Pater. He straightened his stalk, and bellowed authoritatively, "JUNIOR! Come here!"

The prodigal polyp swam warily close. "Yes, Pater?"

"Junior," said his parent solemnly, "now that you are about to grow down, it behooves you to know certain facts."

Mater blushed a delicate lavender and turned away on her side of the rock.

"Very soon now," said Pater, "you will begin feeling an irresistible urge ... to sink to the bottom, to take root there in some sheltered location which will be your lifetime site. Perhaps you even have an understanding already with some ... ah ... charming young polyp of the opposite gender, whom you would invite to share your homesite. Or, if not, you should take all the more pains to make that site as attractive as possible, in order that such a one may decide to grace it with—"

"Uh-huh," said Junior understandingly. "That's what the fellows mean when they say any of 'em'll fall for a few high-class rocks."

Pater marshaled his thoughts again. "Well, quite apart from such material considerations as selecting the right rocks, there are certain ... ah ... matters we do not ordinarily discuss."

Mater blushed a more pronounced lavender. The three maiden aunts, rooted to their boulder within easy earshot of Pater's carrying voice, put up a respectable pretense of searching one another for nonexistent water-fleas.

"No doubt," said Pater, "in the course of your harum-scarum adventurings as a normal polyp among polyps, you've noticed the ways in which the lower orders reproduce themselves; the activities of the fishes, the crustacea, the marine worms will not have escaped your attention."

"Uh-huh," said Junior, treading water.

"You will have observed that among these there takes place a good deal of ... ah ... maneuvering for position. But among intelligent, firmly rooted beings like ourselves, matters are, of course, on a less crude and direct plane. What among lesser creatures is a question of tactics belongs, for us, to the realm of strategy." Pater's tone grew confiding. "Now, Junior, once you're settled you'll realize the importance of being easy in your mind about your offspring's parentage. Remember, a niche in brine saves trying. Nothing like choosing your location well in the first place. Study the currents around your prospective site—particularly their direction and force at such crucial times as flood-tide. Try to make sure you and your future mate won't be too close down-current from anybody else's site, since in a case like that accidents can happen. You understand, Junior?"

"Uh-huh," acknowledged Junior. "That's what the fellows mean when they say don't let anybody get the drop on you."

"Well!" said Pater in flat disapproval.

"But it all seems sort of silly," said Junior stubbornly. " I'd rather just keep moving around, and not have to do all that figuring. And the ocean's full of things I haven't seen yet. I don't want to grow down!"

Mater paled with shock. Pater gave his spawn a scalding, scandalized look. "You'll learn! You can't beat Biology," he said thickly, creditably keeping his voice down. "Junior, you may go!"

Junior bobbled off, and Pater admonished Mater sternly, "We must have patience, my dear! All children pass through these larval stages...."

"Yes, dear," sighed Mater.

At long last, Junior seemed to have resigned himself to making the best of it.

With considerable exertions, hampered by his increasing bottom-heaviness, he was fetching loads of stones, seaweed and other debris to a spot downslope, and there laboring over what promised to be a fairly ambitious cairn. Judging by what they could see of it, his homesite might even prove a credit to the colony (so went Pater's thoughts) and attract a mate who would be a good catch (thus Mater mused).

Junior was still to be seen at times along the reef in company with his free-swimming friends among the other polyps, at some of whom his parents had always looked askance, fearing they were by no means well-bred. In fact, there was strong suspicion that some of them—waifs from the disreputable Shallows district in the hazardous reaches just below the tide-mark—had never been bred at all, but were products of budding, a practice frowned on in polite society.

However, Junior's appearance and rate of locomotion made it clear he would soon be done with juvenile follies. As Pater repeated with satisfaction—you can't beat Biology; as one becomes more and more bottle-shaped, the romantic illusions of youth must inevitably perish.

"I always knew there was sound stuff in the youngster," declared Pater expansively.

"At least he won't be able to go around with those ragamuffins much longer," breathed Mater thankfully.

"What does the young fool think he's doing, fiddling round with soapstone?" grumbled Pater, peering critically through the green to try to make out the details of Junior's building. "Doesn't he know it's apt to slip its place in a year or two?"

"Look, dear," hissed Mater acidly, "isn't that the little polyp who was so rude once?... I wish she wouldn't keep watching Junior like that. Our northwest neighbor heard positively that she's the child of an only parent!"

"Never mind." Pater turned to reassure her. "Once Junior is properly rooted, his self-respect will cause him to keep riffraff at a distance. It's a matter of Psychology, my dear; the vertical position makes all the difference in one's thinking."

The great day arrived. Laboriously Junior put a few finishing touches to his construction—which, so far as could be seen from a distance, had turned out decent-looking enough, though it was rather questionably original in design: lower and flatter than was customary.

With one more look at his handiwork, Junior turned bottom-end-down and sank wearily onto the finished site. After a minute, he paddled experimentally, but flailing tentacles failed to lift him. He was already rooted, and growing more solidly so by the moment.

"Congratulations!" cried the neighbors. Pater and Mater bowed this way and that in acknowledgment. Mater waved a condescending tentacle to the three maiden aunts.

"I told you so!" said Pater triumphantly.

"Yes, dear...." said Mater meekly.

Suddenly there were outcries of alarm from the dwellers down-reef. A wave of dismay swept audibly through all the nearer part of the colony. Pater and Mater looked around, and froze.

Junior had begun paddling again, but this time in a most peculiar manner—with a rotary twist and sidewise scoop which looked awkward, but which he performed so deftly that he must have practiced it. Fixed upright as he was now on the platform he had built, he looked for all the world as if he were trying to swim sidewise.

"He's gone mad !" squeaked Mater.

"I ..." gulped Pater, "I'm afraid not."

At least, they saw, there was method in Junior's actions. He went on paddling in the same fashion and now he, and his platform with him, were farther away than they had been, and growing more remote as they stared.

Parts of the homesite that was not a homesite revolved in some way incomprehensible to eyes that had never seen the like. And the whole affair trundled along, rocking at bumps in the sandy bottom, and squeaking painfully; nevertheless, it moved.

The polyps watching from the reef swam out and frolicked after Junior, watching his contrivance go and chattering eager questions, while their parents bawled at them to keep away from that.

The three maiden aunts shrieked faintly and swooned in one another's tentacles. The colony was shaken as it had not been since the tidal wave.

"COME BACK!" thundered Pater. "You CAN'T do that!"

" Come back! " shrilled Mater. "You can't do that !"

"Come back!" gabbled the neighbors. "You can't do that!"

But Junior was past listening to reason. Junior was on wheels.