LOS ANGELES, Dec. 8 – The Sharon Tate murder trial has been postponed until Dec. 16 to allow the “associate counsel” of missing defense lawyer Ronald Hughes to study the massive 18,000-page transcript of more than five months of court proceedings.

Superior Court Judge Charles H. Older granted the continuance Monday after Maxwell Keith told him he needs more time to bone up on the transcript. If Keith is ready by that date, closing arguments will begin.

Older denied a motion by other defense attorneys for Charles Manson and two female codefendants that he declare a mistrial in the case of Leslie Van Houten, who was represented by Hughes, and that she be tried separately from the other three defendants.

Hughes disappeared 12 days ago in the Sespe Hot Springs mountain wilderness area north of Los Angeles during a weekend deluge.

Paul Fitzgerald, head of the defense team, said he visited the area during the weekend and because of the rugged terrain he thought it “probable” Hughes had died in floodwaters.

“He may well be dead —it seems probably at this point,” Fitzgerald said, adding that Hughes’ disappearance was “no ploy to bring about a mistrial.”

The jury of seven men and five women has been locked up in the Ambassador Hotel for two weeks because of Hughes’ disappearance. Prosecutor Vincent Bugliosi said Older may allow the jurors to go home if there is a recess for the Christmas holidays.

In other developments relating to the Manson “family,” cult member Bruce Davis, 27, pleaded innocent Monday to murder charges in fee 1969 death of musician Gary Hinman.

Manson and Tate trial codefendant Susan Atkins also are charged in the slaying. Davis’ trial was set for Feb. 16.

Robert Beausoleil, another member of the cult, was convicted of the Hinman murder in May and it was his testimony that resulted in murder indictments against Davis, Manson and Miss Atkins.

Beausoleil is awaiting execution in San Quentin.