A fine cast fashions a revised `Pygmalion'. Peter O'Toole, Amanda Plummer give winning performances in Shaw comedy

Pygmalion Comedy by George Bernard Shaw. Directed by Val May. Starring Peter O'Toole, Amanda Plummer, Dora Bryan, Lionel Jeffries, Joyce Redman, John Mills. A star-topped transatlantic cast is reveling in the comic splendors, recalling the social milieus, and embracing the human cross-section of George Bernard Shaw's ``Pygmalion.'' Laughter prevails at the Plymouth Theatre except when Shaw himself is undercutting it by exposing the ambivalent nature of the relationship between Henry Higgins, the fanatic phonetician, and Eliza Doolittle, the cockney flower girl who becomes his pupil in the art of ``proper'' speech.

Director Val May and Peter O'Toole have devised what may be their own ending to ``Pygmalion.'' (At least, it differs from the ending in the published plays.) Instead of Higgins's complacent assumption that the departing Eliza will perform his latest errand, or the happy ending contrived by Lerner and Loewe for ``My Fair Lady,'' the amended May version leaves Higgins laughing uncontrollably at the thought of Eliza's decision to marry the futile Freddy Eynsford Hill. (The professor might not have laughed quite so hard, had he read Shaw's epilogue, detailing the happy fate of Eliza and Freddy.)

Whatever the cause, Mr. O'Toole crowns a fantastically amusing performance in a wholly suitable manner. The lanky Higgins of this revival is not merely an outrageously self-centered intellectual whose rudeness is a byproduct of his fanatical enthusiasm for his subject. The O'Toole Higgins abounds in the nervous and physical energy with which Shaw endowed him. He is, futhermore, rather a dandy. His impeccable attire is matched by a beauty of speech that no fair-minded phonetician could fault.

Higgins's domineering arrogance sets the tone for the progress of the often stormy encounters with the cockney Galatea who becomes errand girl as well as pupil. In the stage directions for the scene when Eliza, in her brave finery, applies for lessons, Shaw observes ``the pathos of this deplorable figure, with its innocent vanity and consequential air.'' Throughout an extraordinary performance, Amanda Plummer never quite loses touch with Eliza's pathos. The actress can emit yowls and growls of outrage. She can play the tea-party scene with uproarious decorum - a scene which brings out the mischievous farceur in Mr. May. But Eliza's stillness on being totally ignored as her mentors congratulate themselves on the triumph she has achieved for them is deeply touching. Eliza, the Edwardian vision in white, is living her own nightmare.

The playwright sums up the tension between Eliza and Henry by observing: ``Galatea never does quite like Pygmalion: his relation to her is too godlike to be altogether agreeable.'' On the other hand, ``Pygmalion'' at the Plymouth is more than agreeable. It is an enormously enjoyable response to Shaw's extravagant wit and witty extravagance.

The magnetic performances in the two central roles are buoyantly supported by the surrounding principals. Lionel Jeffries's Colonel Pickering is chivalrous and avuncular, a thoroughgoing scholar, officer, and gentleman of the old school. Joyce Redman's Mrs. Higgins possesses more than just matronly charm and good-natured tolerance of her unaccountable offspring; she is a distinguished presence. John Mills delights in both sides of Alfred Doolittle: the self-designated representative of the undeserving poor and the miserable beneficiary of an American millionaire's bounty. Dora Bryan's Mrs. Pearce is the kind of housekeeper with enough patience to put up with her eccentric employer and enough common sense to deliver a needed rebuke. The performance as a whole preserves admirable Shavian consistency.

The settings for the handsome production were designed by Douglas Heap, with lighting by Martin Aronstein and costumes - from rags to richest elegance - by Terence Emery.