BEIJING -- Everywhere Jia Lanpo turns in his dark, cozy apartment are reminders of his old age. Above the armchair where the paleontologist reads with a magnifying glass is a scroll with the character for long life -- "shou" -- stamped in red ink 100 times.

On the other wall hangs a watercolor of a white crane; on the windowsill sits a glass bowl with a tiny, live, green turtle, symbols of longevity and gifts on his 90th birthday last Nov. 25.

"No one in my family lives beyond 90," Jia smiles, his thin voice warbling.

Jia accepts his mortality with the resignation of someone who has lived a full life. Even so, he can't help making one last request: He wants his skulls back.

For more than a half-century, Jia has been tormented by the disappearance of the greatest discovery of his life. When he was 28 and part of an international team digging for fossils in the hills southwest of Beijing, he unearthed a trove of ancient skulls and bones whose clear clues to the origin of man thrilled the scientific world.

The skulls of the apelike, shaggy, short, stooped men and women who lived 650,000 years ago came to be known singularly as Peking Man. Jia wasn't the first to discover a skull of Peking Man, but his specimens were better preserved than any previous finds.

The world did not have many years to savor Jia's fossils. The relics were lost during a failed attempt to sneak them out of the country during World War II in two wooden crates escorted by evacuating U.S. Marines.

The boxes never made it to the American Museum of Natural History.

Were the wooden cases marked "A" and "B" seized by Japanese soldiers when they took the Americans as prisoners of war?

Or were they stashed in a secret place, undisturbed to this day?

Scientists tracked leads from Tianjin to Tokyo and Taipei. A Chicago millionaire once offered $100,000 for clues. Japanese spies tried to find the skulls during the war years.

But nothing.

Jia used to scoff at suggestions that the skulls could be found, snapping that it was a waste of time. But his views have changed. Jia wants to make one last stab at locating his skulls. He doesn't have a plan. He doesn't have financial backers. All he has is the final wish of an old man.

"I realize that there isn't a lot of hope in finding the skulls. They've been lost for so long," he concedes. "But shouldn't we try? Just in case. If we don't find them now, it will be really hard in the future."

But the truth of what happened may be as secret as the fossils themselves once were.

Through the ages, the fragments of bones, teeth, skullcaps, jaws and tools from the Peking Man clan were entombed in limestone and granite at Dragon Bone Hill, about 30 miles from downtown Beijing.

From his big armchair, eyes puffy from recent cataract surgery, the white-haired Jia recounts the snowy November morning in 1936 that he discovered the skulls. He cups his ear to hear questions, but has no trouble describing that Sunday.

The bespectacled self-taught paleontologist loomed over the dozens of workers like a hawk, always fearful something might escape his eye. He inspected every basket of rubble before workers hauled it away.

A technician retrieved from the sandy soil a piece of bone about the size of a silver dollar.

"What's that," Jia asked excitedly.

"It's just a rotten bone," the worker replied.

"Give it to me. I want to have a look," he demanded.

"I ran over immediately," Jia recalled. "I checked it and I knew: This was a human skullcap."

They found more fragments. Four men worked through the night to dry and glue the bones together. More pieces were unearthed. In the end, Jia had three almost complete Peking Man skullcaps.

"I thought, 'Oh, this is really wonderful,' " Jia remembers.

Soon after, Japanese troops attacked Beijing. Chinese scientists locked the relics in a safe at Peking Union Medical College.

In November 1941, the Chinese scientists decided to get the fossils to safety in the United States. Paleontologist Hu Chengzhi wrapped the skulls in layers of lens paper, thick cotton, gauze and cardboard. Each was placed in a box and packed in one of two unmarked wooden crates.

There have been many theories on what happened next. Scholars and FBI agents, philanthropists and publicity hounds, veterans of the war and Japanese agents -- all sniffed out leads that led to dead ends.

At this point, the best hope for Jia is the most obvious possibility -- that the crates with the skulls were stashed somewhere in China and are still hidden. But to believe that theory, Jia has to believe the tale of William T. Foley, a U.S. Navy lieutenant in the Chinese port of Tianjin in 1941.

Foley surfaced in the 1970s with the claim that he was the last known person in possession of the cases.

In Foley's version, widely reported at the time, he was to escort the boxes out as part of a secret plan.

But Foley never got farther than the docks of Qinhuangdao, east of Beijing. Japan bombed Pearl Harbor, and all U.S. troops in China were prisoners of war.

Foley maintained that as an officer, he was given a couple of days to put things in order before prison camp. Foley said he left the trunks with the fossils with two Chinese friends in Tianjin. But he refused to name them.

"He was always very mysterious about it," says his daughter, Lucy L. Foley of Washington. "He always wanted to go back to see if he could find the people he left the trunks with, but he felt that those people would get in trouble with the current Chinese government."

In 1980, after China renewed relations with the United States, Jia was able to write to Foley.

"I asked him, 'Can you come to China? I'm young. I can take you around to look for the boxes,' " Jia recalls.

Foley replied: "Finally, after all these years, the scientist who last dealt with the specimens is introduced to an officer who was entrusted with their transportation to safety."

But Foley laid down a condition: He would travel to China only if he could meet China's most senior leaders.

The Manhattan cardiologist's request struck Jia as arrogant. "His letter made me feel really angry," he says. "I had no connections with top officials. I'm a scientist."

Foley never came to China, and Jia lost contact. The American died in 1992, never revealing the identity of his Chinese friends in Tianjin.

As the days pass, Jia is haunted by the thought that perhaps Japanese soldiers took the cases from Foley, opened them, saw skulls and tossed them out back with the garbage.

"If it was wine, the Japanese soldiers could drink it. If it was food, they could eat it," Jia said. "But these were just skulls. Maybe they just threw them away."

And maybe Jia will never know.