Prompted by the enthusiastic critical response--and the demand for tickets which that set off, Manhattan Theatre Club has decided to extend its engagement of Leslie Ayvazian's "Nine Armenians" from Dec. 29 to Jan. 12.

Among its distinguished cast (Kathleen Chalfant, Michael Countryman, Sophie Hayden and half a dozen others) is an authentic half an Armenian: Sevanne Martin. In fact, an allusion is made in the play to Martin's real father, son-in-law of the late Margaret Mead. She won the role without tipping that fact.

"I played the Armenian card, but I didn't play the Mead card," admits Martin. Director Lynne Meadow did not realize until rehearsal began that she had cast the granddaughter of the anthropologist as the play's facsimile of Ayvazian.

"When my mother married my father, my grandmother found out about Armenians in a way most people don't. Because she was such a prominent figure, she did a lot of public speaking--using the Armenians and the Turks as an example of how there was a misunderstanding between countries that led to years of conflict--and so a lot of the Armenian community heard about this and started to grow incredibly proud that Margaret Mead talked about them. The idea that Margaret Mead had an Armenian son-in-law became a point of real pride for them."

It still is, she says. "Armenians are coming to see the show again and again." -- By Harry Haun