Miss Thomas, who was born in Newport, R.I., began acting at 4 years old, in a Metropolitan Opera production of ''The Merchant of Venice.'' By the 1930's, she was appearing regularly on Broadway and on the radio and became known for her gravelly voice, studied Brooklyn accent and her comical portrayals of secretaries and switchboard operators.

She performed in more than 4,000 radio dramas, including such long-running shows as ''Easy Aces'' and ''We Love and Learn.'' On Broadway, she appeared in more than 40 productions from the 1920's to the 1970's, including ''Having Wonderful Time,'' ''Two on an Island,'' ''A New Life,'' ''Sailor, Beware,'' ''Counselor at Law,'' ''Burlesque'' and ''Dance me a Song.'' She also acted in about 10 films, including ''Duffy's Tavern'' (1945), and made frequent appearances on television variety shows in the 1950's and 1960's.

Miss Thomas served on the Council of Actors Equity, and was a member of the national board of the American Federation of Television and Radio Artists. She also was known for her collection of more than 2,000 antique dolls.

She is survived by her husband, Chet Gierlach, of Pelham, N.Y.