When the Rev. Jim Jones learned Saturday that Rep. Leo J. Ryan had been killed but that some members of the congressman's party had survived, Jones called his followers together and told them that the time had come to commit the mass suicide they had rehearsed several times before.

"They started with the babies," administering a potion of Kool-aid mixed with cyanide, Odell Rhodes recalled yesterday when I revisited Jonestown to view the horrifying sight of 405 bodies - men, women and children, most of them grouped around the altar where Jones himself lay dead.

Rhodes is the only known survivor of Jonestown who witnessed a part of the suicide rite before managing to escape. He was helping Guyanese authorities identify the dead yesterday.

Most of those who drank the deadly potion served to them by a Jonestown doctor, Lawrence Schact, and by nurses, did so willingly, Rhodes said. Mothers would often give the cyanide to their own children before taking it themselves, he said.

But others who tried to escape were turned back by armed guards who ringed the central pavilion where the rite was carried out, Rhodes said. They were then forced to drink the poisoned Kool-aid and shortly after the mass killing began, Rhodes said, "it just got all out of order. Babies were screaming, children were screaming and there was mass confusion."

It took about five minutes for the liquid to take its final effect. Young and old, black and white, grouped themselves, usually near other family members, often with their arms around each other, waiting for the cyanide to kill them.

They would go into convulsions, their eyes would roll upward, they would gasp for breath and then fall dead, Rhodes said.

All the while, Jones was talking to them, urging them on, explaining that they would "meet in another place." Near the end, Rhodes said, Jones began chanting, "mother, mother, mother" - an apparent reference to his wife who lay dead not far from the altar.

Of the 405 members of the community who died, Jones and two others were shot rather than poisoned, according to C.A. Robert, the chief Guyanese police official at Jonestown yesterday.

Another who was shot was Maria Katsaris, whose brother, Anthony, had come with Ryan Friday to try to persuade their sister to leave Jonestown. Anthony Katsaris was one of those badly wounded during the Saturday massacre that left five dead and approximately 12 wounded.

Rhodes said he managed to escape when the doctor said he needed a stethoscope. Rhodes volunteered to go with a nurse to the infirmary, about 300 feet from the open-air pavillion where the suicides were being carried out.

Rhodes said the armed guards let him through with the nurse and he hid under a building when she went into the doctor's office for the stethoscope. At 7:30 p.m., when it seemed that the mass suicide had ended, he left his hiding place and walked through the jungle to Port Kaituma, five miles away.

It was Rhodes, according to Robert's, who gave the first hint to Guyanese authorities that hundreds had died in a mass suicide. Rhodes said he had hoped to reach Guyanese officials in time to stop more people from being killed.

Rhodes also recalled yesterday that shortly after Ryan and his party left Jonestown, Jones told his followers that Ryan's plane was going to "fall out of the sky."

The plan, according to Rhodes and other information made available late yesterday, was that one of the defectors, who really was a plant acting on Jones' orders, would shoot the pilot of Ryan's plane after it left the Port Kaituma airstrip.

The person apparently chosen for the task, however, boarded the wrong plane and started shooting before it was off the ground. Two passengers in that plane were badly wounded. According to Dale Parks, a bona fide detector from Jonestown who was aboard that plane, the man who did the shooting was Larry Layton, a U.S. citizen who is so far the only person under arrest here in connection with any of the violence.

In addition to the man sent to infiltrate the defectors and shoot the pilot, Jones took the extra precaution of ordering a group of his followers to go to the airstrip in a tractor and trailer loaded with guns, apparently to shoot whoever was not aboard the congressman's plane. The clear intent was that everyone who had gone to Jonestown with Ryan was to be killed.

The assailants returned to Jonestown and reported, out of the hearing of lawyers Mark Lane and Charles Garry, who had stayed behind, that the congressman was dead but others had lived. It was then that Jones announced that all of his followers must come immediately to Jonestown's open-air pavilion.There he told them Ryan had been killed and that there would be "trouble."

"We've all got to kill ourselves," Jones told everyone, according to Rhodes. One woman, Christine Miller, protested Rhodes said, "but the crowd shouted her down."

Yesterday, a stilled Jonestown looked much as it must have moments after the mass suicide ended two days earlier. The bodies were where they had fallen, the half-empty vat of cyanidelaced Kool-aid was still on a table near the altar in the open air pavilion. The faces of the dead bore the anguished expressions of their terrible deaths.

More than 390 of the bodies were grouped around the altar, many of them are-in-arm. They were so thickly bunched together beneath them.

Even the dogs that lived in Jonestown had been poisoned and now lay dead on sidewalks near the pavilion. The Peoples Temple's pet around the altar, many of them arm-in-arm.

In Jones' house, approximately 10 others lay dead. C.A. Roberts, the Guyanese police commissioner in charge of investigating th killings, said his men were "finding new bodies in isolated places" throughout the Jonestown property.

It was a gruesome scene.

The bodies, which had been on the ground for almost three days in the muggy climate here, were beginning to bloat. A Guyanese doctor was sent in yesterday to puncture them because it was feared many would burst open before today, when U.S. Army medical teams are scheduled to arrive at Jonestown to begin identifying and shipping the back to the United States.

Roberts said that so far the only non-Americans found among the more than 400 known dead were seven Guyanese children apopted by the Jonestown community.

As Guyanese police officials continued their search Jonestown yesterday they discovered more than 800 American passports loaded in a trunk. They found cash, checks and valuable jewelry and metals, including gold.

he most perplexing question left to be answered was the whereabouts of the approximately 400 Jonestown residents whose bodies have not been found.

There was speculation that hundreds of people fled to the jungle and simply have not yet found their way out. But there was also another theory: that some of the Jonestown security men took hundreds of the Commune's residents to a remote area possibly to be shot.

Lending some support to that theory was the fact that the body of Tom Kice, one of those believed to have been among the gunmen who attacked Ryan's party, has not been found.

Also, lawyers Lane and Garry, who escaped into the forest when the killing began, reported yesterday that they heard scattered screaming and shooting in the forest while they were in hiding.

According to several of the Jonestown residents who left with Ryan on Saturday and survived the attack at the airstrip, residents of Jonestown had gone through several rehearsale for a mass suicide.

The procedure even had a name. When Jones decided that his church was finished, he had told followers here he would send a coded message to his church's other headquarters in Georgetown, Guyana, and San Francisco that they should join the Jonestown faithful in taking their lives.

They were to wait for these words "white knight." CAPTION: Picture 1, Rev. Jimmy Jones: He died with his followers, Copyright (c) 1978, The San Francisco Examiner; Picture 2, San Francisco Examiner photographer Greg Robinson, later killed by followers of Jones, took this picture of the Jonestown compound while covering the visit of Rep. Ryan's fact finding group, Copyright (c) 1978, The San Francisco Examiner