The last two of 12 men arrested for sexual activity in the Science Center men's bathroom during January admitted to reduced charges yesterday in Cambridge District Court.

Judge Arthur Sherman '50 ordered that court records indicate that Robert F. Burns of East Boston and Lawrence R. Countryman '83 of Cambridge admitted only to misdemeanor charges of lewd and lascivious behavior.

Burns, who initially faced felony charges of open and gross lewdness as well as indecent assault and battery, was fined $500 in court costs. Countryman, who was only charged with open and gross lewdness charge, was fined $400 in court costs. Neither man had a previous criminal record, court officials said.

Sherman continued the cases against the two men without a finding. Under the arrangement, the men will have no criminal record if they obey the law during the next two years.

During yesterday's hearing, a prosecutor gave details of the of the January 18 arrests that had not been made public previously. Assistant District Attorney Anthony Gemma said the defendants had been "exposing their genitals and masturbating" in the center of the bathroom.

Reading from a police report, Gemma said a Harvard police officer was using a urinal in the bathroom when Burns "grabbed the officer's genitals." The defendants were then placed under arrest, he said.

Both of the defendants in yesterday's cases declined opportunities to challenge Gemma's version of the events.

All 12 men arrested on lewdness charges in the basement bathroom of the Science Center during January have admitted in court to misdemeanor charges of indecent exposure or lewdness. The 12 men, who were arrested in four separate incidents, were initially charged with felonies, but those charges were reduced after complaints from gay and lesbian groups.

As a result of discussions with those groups, Harvard Vice President and General Counsel Daniel Steiner '54 had signs placed in the bathroom warning of police patrols.

Harvard police said yesterday that there have been no further arrests' since January.