MANCHESTER, N.H.--Three Harvard undergraduates remained in custody in the Manchester, N.H. armory yesterday for their participation in the two-day occupation of the site of the proposed Seabrook, N.H. nuclear power plant during the April 30-May 1 weekend.

Thomas Arnold '80, Jefferey Ferris '77 and Geoffrey Wisner '80 have all declined to post the required 100 bail to obtain release from the armory, pending a ruling on a petition filed yesterday in U.S. District Court in Concord, N.H..

The petition asks for the immediate release of all demonstrators arrested at Seabrook on personal recognizance bail, on the grounds that their constitutional rights have been violated.

Lawyers representing the Clamshell Alliance, an organization opposed to the use of nuclear power that sponsored the occupation, submitted the petition to the federal tribunal yesterday after the New Hampshire Supreme Court denied the petition on Friday.

Violations of the constitutional rights of the prisoners cited in the petition include inadequate medical care, irregularities committed in the arrest process, and insufficient shower and phone facilities.

Six of the arrested demonstrators testified yesterday during the first day of the federal court hearing, discussing overcrowded jail conditions, unsanitary hygiene facilities and a general lack of privacy at the five National Guard armories scattered across New Hampshire where the remaining 756 prisoners are still being detained.

New Hampshire state police arrested 1414 anti-nuclear power demonstrators at Seabrook on May 1, but that number has steadily dwindled to the present figure of 756 prisoners as increasing numbers of prisoners have chosen to post the 100 bail over the past ten days.

Most of the Harvard-affiliated prisoners bailed themselves out of the Manchester armory at various times last week.

"The original commitment was to stay in jail for four days," Richard C. Innes '78 said Friday. Innes decided to post bail on Friday when he learned that his trial date had been set for July 28.

Talli S. Naumann '79, who bailed herself out on Friday night, said yesterday that she caught a cold during her five-day detention in Manchester. "They left all the windows and doors wide open early Wednesday morning and it was really drafty," she said.

She added that doctors did take a strep throat culture on Friday, but she has not yet learned the results of that culture.

Ferris, who is currently on a leave of absence, said Friday that he had no plans as to when he would get out of jail. Wisner said last weekend that he would probably bail himself out in five days, according to John S. Golden '80, roommate of Wisner who spoke with him.

Arnold told Daniel A. Rabuzzi '80 last weekend that "he wasn't going to leave at all," and that "he was beginning to worry about what Harvard is going to do if he has to stay in jail indefinitely." Arnold's trial date is set for sometime in late May, Rabuzzi said.

Turner Graybill, a second-year law student who is Arnold's proctor, said last night that University policy would leave the responsibility up to the individual professor or section leader to decide on an incarcerated student's academic standing in a course.

While most Harvard students complained of poor ventilation and inadequate food supplies in the Manchester armory, Arnold sounded a more positive note about his incarceration on Friday afternoon.

"People are pulling together well and we're building a strong sense of community here," Arnold said, adding "besides, it's not that much worse than the Union.