Marvin Barnes, the Detroit Pistol - er, Piston - brought a new lawyer with him to Province Superior Court but lost a last-ditch appeal for a continuation and was carted off to prison yesterday to begin a one-year sentence. He could be parole in four months, in time for next pro basketball season.

Judge Anthony A. Glannini assigned the 6-foot-9 athlete, who violated probation on his 1974 conviction of assaulting Providence College teammate Larry Ketvirtis by carrying a gun at a Michigan airport in 1976, to the Adult Correctional Institution in Cranston, R.I.

Corrections department spokesman Barry Levia said Barnes would be housed in the maximum security unit probably for the duration - "He'll be treated just like anyone else except he's taller" . . .

The Cincy Reds' shot at catching the Dodgers in the NL West grow a bit longer with grim word from catcher Johny Bench. He missed the three-game weekend series with the Giants because of a troublesome knee and says, "Surgery is a real possibility." The World Series MVP suspects cartliage damage because there is a "click" in the knee when he moves it - "I could play now, but I don't know what damage I would do or wouldn't do to the knee."

Remember, hockey fans, the to-do last year when Montreal players Don Awrey and John Van Boxmeer didn't have their names engraved on the Stanley Cup because they never saw playoff action? Fear not for Canadien captain Yvan Cournoyer, who missed the 1977 playoffs with a back injury. Cournoyer will get a mention on the silverware, coach Scotty Bowman assured everyone at a City Hall reception after a victory parade through Montreal's streets yesterday with Cournoyer aboard the lead float, along with acting captain Serge Savard and the Cup. "The rules have been changed now," Bowman related.

While Montreal was rejoicing, in Weston, Ontario, and Philadelphia, fans and friends of Barry Ashbee were paying last respects to the Flyer defenseman and coach who died of leukemia Thursday at 37. A thousand gathered at Philly's Spectrum for a memorial service while the funeral was being conducted in Huber Heights, Ontario, and burial in Weston, Ashbee's hometown. Capital defenseman Bryan Watson was among the Spectrum group and said, "I didn't know Barry that well, [but] I think the reason I'm here is out of respect for his ability as a defenseman, for the way he played the game. I always had tremendous respect for an individual who played so long in the minors. He really stuck with it."

The family requests that donations be made to the cancer institute at Hahnemann Hospital in Philadelphia, where Ashbee fought his last fight. Was Ashbee as great a guy as teammates maintained? A local lady called FanFare after last week's obituary to relate how the ailing Ashbee had cheered up a fellow patient her 15-year-old nephew in for bone marrow tests, giving him a hockey stick that hadbelonged to Bobby Clarke, the Flyer captain . . .