While baffled authorities expressed the hope that three missing boys in Harford County are somehow alive and acting out Tom Sayweresque daydreams of adventure, the constantly expanding search continued for the eighth day yesterday.

The search party, which has grown to 200, was scouring the marshes, swamps and woods, but all that has been found of the boys are two bicycles, two fishing rods, one pair of gloves, one Hush Puppy shoe and a canoe.

The three boys, who vanished from their homes in Edgewood, Md., last Friday, all require daily medication, according to the Harford County Sheriff's Department. Stephen Hicks, 13, is an epileptic; Fred Stevens, 11, is hyperactive, and Scott McGlothlin, 12, is depressive. There is no indication that any of the boys took medicine with them.

After the boys' parents had looked themselves all weekend, they notified authorities Monday and the official search began. It started with 20 sheriff's deputies and by yesterday volunteers from area fire departments and the state Civil Air Patrol had joined in.

Jordan Watts, the Harford County sheriff's detective who is acting as official spokesman for the search, said the last time anyone saw the boys was Friday afternoon, when Scott McGlothlin--who "was in the habit of running away," according to his grandmother--told his mother he was going to Stephen Hicks' house and would be back in 15 minutes. He left on his bicycle. He hasn't been seen since.

All three boys live in a housing development along the Bush River. Two of their bicycles were found Saturday along the river's edge. The boys took a canoe from the same area, according to the sheriff's department. The canoe was found two miles downriver, with one of its paddles floating nearby. A pair of the boy's gloves and one shoe also were found.

Watts said that as the result of interviews with classmates and teachers, authorities believe the boys disappeared as part of an adventure, inspired by Mark Twain's resourceful and high-spirited pair, Tom Sawyer and Huck Finn. "One teacher said that one of the boys was extremely intrigued with the idea of Tom Sawyer. They had just studied that book in class.

"We've talked to kids who said they planned this. We think that if they're out there someone must be taking care of them. Or else they planned it real well. The parents are hanging on every news broadcast. You wait and hope and every call you get you're afraid. It's an emotional roller coaster."

"We dragged the Bush River for two days. The state police have had helicopters up every day," said Watts. "We've circulated pictures all over the county and the state. Even more people will be searching tomorrow."

Meanwhile, the telephones at the sheriff's department ring constantly, with reports from people who claim to have seen the boys. "There are people who are certain they've seen these kids--on the road, near the school. We try to run down every sighting. We've had over 200," Watts said.

Watts said one man called from Idaho, claiming he had seen the boys on the campus of the Idaho State University. He had apparently seen their pictures in the Idaho Falls Gazette. "He was as sincere as he could be," Watts said."

He said there is a chance the boys went to Minnesota, where the father of one of them lives. "Anything's possible," Watts said. "The Amtrak train runs through here. They could've jumped on one of those slow moving freight trains."