The John F. Kennedy Memorial Library will lose its monumental 85-foot-high glass pyramid in scaled-down construction plans now being prepared by architect I.M. Pei.

The major revision of the plans also includes the possible elimination of two 350-seat theaters and separation of the crescent-shaped complex into two buildings, Donald C. Moulton, assistant vice president for government and community affairs, said yesterday.

Moulton was one of about ten people who met with Pei in New York on March 28 to discuss changes in the library design.

The new plans, according to Moulton, are designed to soothe community concern about the large size of the library and to ease the Kennedy Corporation's tightened pocketbook in face of ever-rising construction prices.

Moulton said the new design is in the most preliminary stages but said he expected Pei to "do a lot in the next month."

Though revisions of the library have been in the rumor-mill for many weeks, the first official indication that changes would be made came March 13 when George Grant, project director for C.E. Maguire's environmental impact study of the library, told the City Council he was still awaiting construction plans.

Grant said at that time that Maguire needed the plans very soon in order to complete the 120-day study deadline.

He told the Cambridge Chronicle last week, "There's nothing missing that we absolutely have to have now, though it is crowding things. There's a lot we can do now to get underway."

The changes in the library design will have a beneficial aesthetic effect on the complex, Moulton said.

If the two movie theaters are eliminated from the plans, Moulton said, the space would be devoted to displays. But visitors would move through the museum more quickly than if they sat down to watch a 20-minute film.

Others present at the meeting with Pei included Grant, Dan H. Fenn Jr. '44, lecturer on Business Administration and director of the Kennedy Library, and Helen Keyes, administrator of the Kennedy Corporation.