THEATER REVIEW : ‘Wrong Turn’ a September Song for Scott : lThe Off Broadway play is star-slumming of the highest lowbrow order.

NEW YORK — What becomes a legend (who can’t land good movie roles anymore because Hollywood doesn’t know what to do with a legend) most? If the legend is named Rex Harrison, Katharine Hepburn or Claudette Colbert, it has often meant taking to the stage in frothy cream-puff comedies that allowed them ample opportunity to be grand, adorable and maybe just a little vulgar.

George C. Scott merely flirted with the legend’s ghetto last season in that twinkly Death chestnut “On Borrowed Time.” His newest September song, “Wrong Turn at Lungfish,” is star-slumming of the highest lowbrow order. Not incidentally, it is also the writing co-effort of film director Garry Marshall and screenwriter Lowell Ganz, who independently of one another have churned out some of the most processed screen comedies of the past 15 years. (The show played last May at the Coronet Theatre in Los Angeles.)

For their collaborative stage debut at the Promenade Theater, Marshall and Ganz have whipped up the definitive handbook of drama-by-numbers guidelines. “Wrong Turn at Lungfish” emphasizes two rules of thumb: (1) People go bananas whenever dumb chippies disarm jaded intellectuals (see chapter headings “Educating Rita Redux” and “Born Yesterday, Borne Again Tomorrow: Bimbo-Dynamics From Judy Holliday to Melanie Griffith”) and (2) Audiences can’t get enough of Italian-American muscleheads who love their mothers. This explains Tony Danza.

In “Lungfish,” Scott plays Peter Ravenswaal, a university dean blinded and dying from a degenerative kidney disease. Sequestered in a private New York City hospital room that is glaringly beyond the means of a retired academic, an embittered Ravenswaal ponders the meaning of life and takes a certain solace in harassing his sourpuss nurse (Kelli Williams).

Enter Anita Merendino (Jami Gertz), a hospital volunteer-reader for Ravenswaal. Anita, who Tawks Loik Dis and resembles the entire “Big Spender” chorus from “Sweet Charity,” is every outerborough madonna/whore to have ever been romanticized by male New York emigres to Beverly Hills. This 27-year-old bottled-water plant worker puts out shamelessly and allows herself to be abused by father, boyfriend and boss alike. Anita is redeemed, however, by an abidingly reverent spirit best exemplified by a tendency to gaze upward to heaven when someone croaks and break into “Ave Maria” on a dime.

Before you can sing “Climb Every Molehill,” Anita’s wide-eyed moxie will knock Ravenswaal out of his torpor. Before you can say “Drop dead, Harry,” Ravenswaal will inspire Anita to dump her battering boyfriend, Dominic, a small-time hood with an ethnocentric taste for Verdi and Puccini. Dominic is played with generic worminess by Danza, whose first entrance prompted affirmative grunts from a gorilla in the fifth row.

Matters sober up in the second half, thereby justifying the subheading, “A new play.” Before then, Marshall and Ganz induce the smelliest kind of levity from condescending humor surrounding Anita’s illiteracy and easy virtue. Scott squeezes the bejesus out of vein-popping, Jackie Gleasonesque explosions over Anita’s rambling idiocies and gets to chuckle with “kids say the darndest things” smugness at her malapropisms (she confuses Stendhal with Casey Stengel). To boot, there are enough fellatio jokes to fuel Tailhook revelries into the new millennium.

But then “Wrong Turn at Lungfish” swaggers with the sort of crotch-driven feminism that Hollywood has been dishing out for the last decade: It accuses women of living their lives in terms of men, then points the way to salvation in a man of better breeding. (“Pretty Woman” is Marshall’s box-office bull’s-eye, followed by “Beaches,” memorable for Bette Midler and Barbara Hershey’s department store catfight over a stolen boyfriend.)

Set designer David Jenkins has taken great pains to reproduce a hospital room, adding Crayola-hued ceiling pipes, which tell us not to take it all too seriously. The realistic ambience is for naught, since the credibility factor of “Lungfish” collapses at every wrong turn. Nurses do not appropriate patient’s radios for office parties, academics do not live under isolation tents of Beethoven and Baudelaire. Most professors I met in college knew more about pop culture than the makers of pop culture.

To her credit, Jami Gertz throws herself body and soul into a comic-strip role that is one part Olive Oyl and two parts Betty Boop. She is thoroughly professional, if lacking in a star-making twist that would indicate that someday she will have to worry about becoming an unemployed legend. George C. Scott, who never goes for long without a job, should worry just a little more about where he finds them.