Lethal LessonStarting tonight the Hallmark Channel is presenting a week of Perry Mason movies, each weeknight at 9 p.m., to kick off the station’s August "Month of Mystery." Between 1985 and 1993, Raymond Burr and Barbara Hale, who played Perry Mason and Della Street, respectively, in the long-running TV series, reprised their roles in a series of more than two-dozen TV movies. The films are entertaining and diverting, though not nearly as interesting as the original TV series, with its interesting, often noirish atmosphere and sharply drawn characters. The Mason movies are rather reminiscent of Matlock, which is not a surprise given the involvement of Matlock creator and longtime TV mystery writer-producer Dean Hargrove. They’re worth watching and are enjoyable if you can accept that they don’t greatly resemble the TV series.