"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.