Caldwell moved a step closer to inspect more carefully the nine-foot-high plastic model standing in the middle of one of the laboratories of the Westwood Biological Institute. Danchekker gave him plenty of time to take in the details before continuing.
"A full-size replica of a Ganymean skeleton," he said. "Built on the strength of the data beamed back from Jupiter. The first indisputable form of intelligent alien life ever to be studied by man." Caldwell looked up at the towering frame, pursed his lips in a silent whistle, and walked in a slow circle around and back to where the professor was standing. Hunt simply stood and swept his eyes up and down the full length of the model in wordless fascination.
"That structure is in no way related to that of any animal ever studied on Earth, living or extinct," Danchekker informed them. He gestured toward it. "It is based on a bony internal skeleton, walks upright as a biped, and has a head on top—as you can see; but apart from such superficial similarities, it has clearly evolved from completely unfamiliar origins. Take the head as an obvious example. The arrangement of the skull cannot be reconciled in any way with that of known vertebrates. The face has not receded back into the lower skull, but remains a long, down-pointing snout that widens at the top to provide a broad spacing for the eyes and ears. Also, the back of the skull has enlarged to accommodate a developing brain, as in the case of man, but instead of assuming a rounded contour, it bulges back above the neck to counterbalance the protruding face and jaw. And look at the opening through the skull in the center of the forehead; I believe that this could have housed a sense organ that we do not possess—possibly an infrared detector inherited from a nocturnal, carnivorous ancestor."
Hunt moved forward to stand next to Caldwell and peered intently at the shoulders. "These are unlike anything I’ve ever come across, too," he commented. "They’re made up of . . . kind of overlapping plates of bone. Nothing like ours at all."
"Quite," Danchekker confirmed. "Probably adapted from the remains of ancestral armor. And the rest of the trunk is also quite alien. There is a dorsal spine with an arrangement of ribs below the shoulder plates, as you can see, but the lowermost rib—immediately above the body cavity—has developed into a massive hoop of bone with a diametral strut stretching forward from an enlarged spinal vertebra. Now, notice the two systems of smaller linked bones at the sides of the hoop . . ." He pointed them out. "They were probably used to assist with breathing by helping to expand the diaphragm. To me, they look suspiciously like the degenerate remnants of a paired-limb structure. In other words, although this creature, like us, had two arms and walked on two legs, somewhere in his earlier ancestry were animals with three pairs of appendages, not two. That in itself is enough to immediately rule out any kinship with every vertebrate of this planet."
Caldwell stooped to examine the pelvis, which comprised just an arrangement of thick bars and struts to contain the thigh sockets. There was no suggestion of the splayed dish form of the lower human torso.
"Must’ve had peculiar guts, too," he offered.
"It could be that the internal organs were carried more by suspension from the hoop above than by support from underneath," Danchekker suggested. He stepped back and indicated the arms and legs. "And last, observe the limbs. Both lower limbs have two bones as do ours, but the upper arm and thigh are different—they have a double-bone arrangement as well. This would have resulted in vastly improved flexibility and the ability to perform a whole range of movements that could never be duplicated by a human being. And the hand has six digits, two of them opposing; thus its owner effectively enjoyed the advantages of having two thumbs. He would have been able to tie his shoes easily with one hand."
Danchekker waited until Caldwell and Hunt had fully studied every detail of the skeleton to their satisfaction. When they looked toward him again, he resumed: "Ever since the age of the Ganymeans was verified, there has been a tendency for everybody to discount them as merely a coincidental discovery and having no direct bearing on the Lunarian question. I believe, gentlemen, that I am now in a position to demonstrate that they had a very real bearing indeed on the question."
Hunt and Caldwell looked at him expectantly. Danchekker walked over to a display console by the wall of the lab, tapped in a code, and watched as the screen came to life to reveal a picture of the skeleton of a fish. Satisfied, he turned to face them.
"What do you notice about that?" he asked.
Caldwell stared obediently at the screen for a few seconds while Hunt watched in silence.
"It’s a funny fish," Caldwell said at last. "Okay—you tell me."
"It is not obvious at first sight," Danchekker replied, "but by detailed comparison it is possible to relate the structure of that fish, bone for bone, to that of the Ganymean skeleton. They’re both from the same evolutionary line."
"That fish is one of those that were found on the Lunarian base on Farside," Hunt said suddenly.
"Precisely, Dr. Hunt. The fish dates from some fifty thousand years ago, and the Ganymean skeleton from twenty-five million or so. It is evident from anatomical considerations that they are related and come from lines that branched apart from a common ancestral life form somewhere in the very remote past. It follows that they share a place of origin. We already know that the fish evolved in the oceans of Minerva; therefore, the Ganymeans also came from Minerva. We thus have proof of something that has been merely speculation for some time. All that was wrong with the earlier assumption was our failure to appreciate the gap in time between the presence of the Ganymeans on Minerva, and that of the Lunarians."
"Okay," Caldwell accepted. "The Ganymeans came from Minerva, but a lot earlier than we thought. What’s the big message and why did you call us over here?"
"In itself, this conclusion is interesting but no more," Danchekker answered. "But it looks pale by comparison with what comes next. In fact"—he shot a glance at Hunt—"the rest tells us all we need to know to resolve the whole question once and for all."
The two regarded him intently.
The professor moistened his lips, then went on: "The Ganymean ship has been opened up fully, and we now have an extremely comprehensive inventory of practically everything it contained. The ship was constructed for large freight-carrying capacity and was loaded when it met with whatever fate befell it on Ganymede. The cargo that it was carrying, in my opinion, constitutes the most sensational discovery ever to be made in the history of paleontology and biology. You see, that ship was carrying, among other things, a large consignment of botanical and zoological specimens, some alive and in cages, the rest preserved in canisters. Presumably the stock was part of an ambitious scientific expedition or something of that nature, but that really doesn’t matter for now. What does matter is that we now have in our possession a collection of animal and plant trophies the like of which has never before been seen by human eyes: a comprehensive cross section of many forms of life that existed on Earth around the late Oligocene and early Miocene periods, twenty-five million years ago!"
Hunt and Caldwell stared at him incredulously. Danchekker folded his arms and waited.
"Earth!" Caldwell managed, with difficulty, to form the word. "Are you telling me that the ship had been to Earth?"
"I can see no alternative explanation," Danchekker returned. "Without doubt, the ship was carrying a variety of animal forms that have every appearance of being identical to species that have been well-known for centuries as a result of the terrestrial fossil record. The biologists on the Jupiter Four Mission are quite positive of their conclusions, and from the information they have sent back, I see no reason to doubt their opinions." Danchekker moved his hand back to the keyboard. "I will show you some examples of the kind of thing I mean," he said.
The picture of the fish skeleton vanished and was replaced by one of a massive, hornless, rhinoceroslike creature. In the background stood an enormous opened canister from which the animal had presumably been removed. The canister was lying in front of what looked like a wall of ice, surrounded by cables, chains, and parts of a latticework built of metal struts.
"The Baluchitherium, gentlemen," Danchekker informed them, "or something so like it that the difference escapes me. This animal stood eighteen feet high at the shoulder and attained a bulk in excess of that of the elephant. It is a good example of the titanotheres, or titanic beasts, that were abundant in the Americas during the Oligocene but which died out fairly rapidly soon afterward."
"Are you saying that baby was alive when the ship ditched?" Caldwell asked in a tone of disbelief.
Danchekker shook his head. "Not this particular one. As you can see, it has come to us in practically as good a condition as when it was alive. It was taken from that container in the background, in which it had been packed and preserved to keep for a long time. Fortunately, whoever packed it was an expert. However, as I said earlier, there were cages and pens in the ship that originally held live specimens, but by the time they were discovered they had deteriorated to skeletons condition, as had the crew. There were six of this particular species in the pens."
The professor changed the picture to show a small quadruped with spindly legs.
"Mesohippus—ancestor of the modern horse. About the size of a collie dog and walking on a three-toed foot with the center toe highly elongated, clearly foreshadowing the single-toed horse of today. There is a long list of other examples such as these, every one immediately recognizable to any student of early terrestrial life forms."
Speechless, Hunt and Caldwell continued to watch as the view changed once more. This time it showed something that at first sight suggested a medium-sized ape from the gibbon or chimpanzee family. Closer examination, however, revealed differences that set it apart from the general category of ape. The skull construction was lighter, especially in the area of the lower jaw, where the chin had receded back to fall almost below the tip of the nose. The arms were proportionately somewhat on the short side for an ape, the chest broader and flatter, and the legs longer and straighter. Also, the opposability of the big toe had gone.
Dancbekker allowed plenty of time for these points to register before continuing with his commentary.
"Clearly, the creature you now see before you belongs to the general anthropoid line that includes both man and the great apes. Now, remember, this specimen dates from around the early Miocene period. The most advanced anthropoid fossil from around that time so far found on Earth was discovered during the last century in East Africa and is known as Proconsul. Proconsul is generally accepted as representing a step forward from anything that had gone before, but he is definitely an ape. Here, on the other hand, we have a creature from the same period in time, but with distinctly more pronounced humanlike characteristics than Proconsul. In my opinion, this is an example of something that occupies a position corresponding to that of Proconsul, but on the other side of the split that occurred when man and ape went their own separate ways—in other words, a direct ancestor to the human line!" Danchekker concluded with a verbal flourish and gazed at the other two men expectantly. Caldwell stared back with widening eyes, and his jaw dropped as impossible thoughts raced through his mind.
"Are you telling . . . that the Charlie guys could have . . . from that?"
"Yes!" Danchekker snapped off the screen and swung back to face them triumphantly. "Established evolutionary theory is as sound as I’ve insisted all along. The notion that the Lunarians might have been colonists from Earth turns out indeed to be true, but not in the sense that was intended. There are no traces of their civilization to be found on Earth, because it never existed on Earth—but neither was it the product of any parallel process of evolution. The Lunarian civilization developed independently on Minerva from the same ancestral stock as we did and all other terrestrial vertebrates—from ancestors that were transported to Minerva, twenty-five million years ago, by the Ganymeans!" Danchekker thrust out his jaw defiantly and clasped the lapels of his jacket. "And that, Dr. Hunt, would seem to be the solution to your problem!"