Kerans began: "I'm sorry I let slip that we were leaving in three days' time. I hadn't realised you'd kept that from Hardman."

Bodkin shrugged, dismissing this as of little importance. "It's a complex situation, Robert. Having gone a few steps towards unravelling it I didn't want to introduce another slip knot."

"But why not tell him?" Kerans pressed, hoping obliquely to absolve himself of his slight feeling of guilt. "Surely the prospect of leaving might well jolt him out of his lethargy?"

Bodkin lowered his glasses to the end of his nose and regarded Kerans quizzically. "It doesn't seem to have had that effect on you, Robert. Unless I'm very much mistaken you look rather un-jolted. Why should Hardman's reactions be any different?"

Kerans smiled. "Touché, Alan. I don't want to interfere, having more or less dropped Hardman into your lap, but what exactly are you and he playing about with-the electric heater and alarm clocks?"

Bodkin slid the gramophone record into a rack of miniature discs the shelf behind him. He looked up at Kerans and for a few moments watched him with the mild but penetrating gaze with which he had observed Hardman, and Kerans realised that their relationship, until now that of colleagues confiding completely in each other, had become closer to that of observer and subject. After a pause Bodkin glanced away at the program charts, and Kerans chuckled involuntarily. To himself he said: Damn the old boy, he's got me up there now with the algae and nautiloids, next he'll be playing his records at me.

Bodkin stood up and pointed to the three rows of laboratory benches, crowded with vivaria and specimen jars, pages from notebooks pinned to the fume hoods above them.

"Tell me, Robert, if you had to sum up the last three years' work in a single conclusion, how would you set about it?"

Kerans hesitated, then gestured off-handedly. "It wouldn't be too difficult." He saw that Bodkin expected a serious answer, and composed his thoughts. 'Well, one could simply say that in response to the rises in temperature, humidity and radiation levels the flora and fauna of this planet are beginning to assume once again the forms they displayed the last time such conditions were present-roughly speaking, the Triassic."

"Correct." Bodkin strolled off among the benches. "During the last three years, Robert, you and I have examined something like five thousand species in the animal kingdom, seen literally tens of thousands of new plant varieties. Everywhere the same pattern has unfolded, countless mutations completely transforming the organisms to adapt them for survival in the new environment. Everywhere there's been the same avalanche backwards into the past-so much so that the few complex organisms which have managed to retain a foothold unchanged on the slope look distinctly anomalous-a handful of amphibians, the birds, and _Man_. It's a curious thing that although we've carefully catalogued the backward journeys of so many plants and animals, we've ignored the most important creature on this planet."

Kerans laughed. "I'll willingly take a small bow there, Alan. But what are you suggesting-that _Homo sapiens_ is about to transform himself into Cro-Magnon and Java Man, and ultimately into _Sinanthropus_? Unlikely, surely. Wouldn't that merely be Lamarkism in reverse?"

"Agreed. I'm _not_ suggesting that." Bodkin leaned against one of the benches, feeding a handful of peanuts to a small marmoset caged in a converted fume cupboard. "Though obviously after two or three hundred million years _Homo sapiens_ might well die out and our little cousin here become the highest form of life on the planet. However, a biological process isn't completely reversible." He pulled the silk handkerchief out of his pocket and flicked it at the marmoset, which flinched away tremulously. "If _we_ return to the jungle we'll dress for dinner."

He went over to a window and gazed out through the mesh screen, the overhang of the deck above shutting out all but a narrow band of the intense sunlight. Steeped in the vast heat, the lagoon lay motionlessly, pails of steam humped over the water like elephantine spectres.

"But I'm really thinking of something else. Is it only the external' landscape which is altering? How often recently most of us have had the feeling of deja vu, of having seen all this before, in fact of remembering these swamps and lagoons all too well. However selective the conscious mind may be, most biological memories are unpleasant ones, echoes of danger and terror. Nothing endures for so long as fear. Everywhere in nature one sees evidence of innate releasing mechanisms literally millions of years old, which have lain dormant through thousands of generations but retained their power undiminished. The field-rat's inherited image of the hawk's silhouette is the classic example-even a paper silhouette drawn across a cage sends it rushing frantically for cover. And how else can you explain the universal but completely groundless loathing of the spider, only one species of which has ever been known to sting? Or the equally surprising-in view of their comparative rarity-hatred of snakes and reptiles? Simply because we all carry within us a submerged memory of the time when the giant spiders were lethal, and when the reptiles were the planet's dominant life form."

Feeling the brass compass which weighed down his pocket, Kerans said: "So you're frightened that the increased temperature and radiation are alerting similar IRM's in our own minds?"

"Not in our minds, Robert. These are the oldest memories on Earth, the time-codes carried in every chromosome and gene. Every step we've taken in our evolution is a milestone inscribed with organic memories-from the enzymes controlling the carbon dioxide cycle to the organisation of the brachial plexus and the nerve pathways of the Pyramid cells in the mid-brain, each is a record of a thousand decisions taken in the face of a sudden physico-chemical crisis. Just as psychoanalysis reconstructs the original traumatic situation in order to release the repressed material, so we are now being plunged back into the archaeopsychic past, uncovering the ancient taboos and drives that have been dormant for epochs. The brief span of an individual life is misleading. Each one of us is as old as the entire biological kingdom, and our bloodstreams are tributaries of the great sea of its total memory. The uterine odyssey of the growing foetus recapitulates the entire evolutionary past, and its central nervous system is coded time scale, each nexus of neurones and each spinal level marking a symbolic station, a unit of neuronic time.

"The further down the CNS you move, from the hind-brain through the medulla into the spinal cord, the further you descend back into the neuronic past. For example, the junction between the thoracic and lumbar vertebrae, between T-12 and L-1, is the great zone of transit between the gill-breathing fish and the airbreathing amphibians with their respiratory rib-cages, the very junction where we stand now on the shores of this lagoon, between the Paleozoic and Triassic Eras."

Bodkin moved back to his desk, and ran his hand over the rack of records. Listening distantly to Bodkin's quiet, unhurried voice, Kerans toyed with the notion that the row of parallel black discs was a model of a neurophonic spinal column. He remembered the faint drumming emitted by the record player in Hardman's cabin, and its strange undertones. Perhaps the conceit was closer to the truth than he imagined?

Bodkin went on: "If you like, you could call this the Psychology of Total Equivalents-let's say 'Neuronics' for short-and dismiss it as metabiological fantasy. However, I am convinced that as we move back through geophysical time so we re-enter the amnionic corridor and move back through spinal and archaeopsychic time, recollecting in our unconscious minds the landscapes of each epoch, each with a distinct geological terrain, its own unique flora and fauna, as recognisable to anyone else as they would be to a traveller in a Wellsian time machine. Except that this is no scenic railway, but a total re-orientation of the personality. If we let these buried phantoms master us as they re-appear we'll be swept back helplessly in the flood-tide like pieces of flotsam." He picked one of the records from the rack, then pushed it away with a gesture of uncertainty. 'This afternoon I may have been taking a risk with Hardman, using the heater to simulate the sun and raise the temperature well into the 120's, but it was worth a chance. For the previous three weeks his dreams were almost driving him out of his mind, but during the last few days he's been much less disturbed, almost as if he were accepting the dreams and allowing himself to be carried back without retaining any conscious control. For his own sake I want to keep him awake as long as possible-the alarm clocks may do it."

"If he remembers to keep them set," Kerans commented quietly.

Outside in the lagoon the sounds of Riggs' cutter droned past. Stretching his legs, Kerans walked over to the window, and watched the landing craft swing in a diminishing arc around the base. While it berthed by the jetty Riggs held an informal conference with Macready across the gangway. Several times he pointed to the testing station with his baton, and Kerans assumed that they were preparing to tow the station over to the base. But for some reason the imminent departure left him unmoved. Bodkin's speculations, however nebulous, and his new psychology of Neuronics, offered a more valid explanation for the metamorphosis taking place in his mind than any other. The tacit assumption made by the UN directorate-that within the new perimeters described by the Arctic and Antarctic Circles life would continue much as before, with the same social and domestic relationships, by and large the same ambitions and satisfactions-was obviously fallacious, as the mounting flood-water and temperature would show when they reached the so-called polar redoubts. A more important task than map ping the harbours and lagoons of the external landscape was to chart the ghostly deltas and luminous beaches of the submerged neuronic continents.

"Alan," he asked over his shoulder, still watching Riggs stamping about on the landing jetty, "why don't you draught a report to Byrd, I think you should let them know. There's always a chance of-"

But Bodkin had gone. Kerans listened to his feet dump slowly up the stairway and disappear into his cabin, the fatigued tread of a man too old and too experienced to care whether or not his warnings were heeded.