Mary Frances Theban

Mary Frances Theban, known as Polly, died of complications of pneumonia on Feb. 16 at Peconic Bay Medical Center in Riverhead. She was 78.

Ms. Theban, who grew up in Remsenburg, had an aunt with polio who loved being in the water, so in 1948, when Ms. Theban was 9, her father bought a lot on Three Mile Harbor Drive in East Hampton and built a small, unheated cottage on it. It was there that she and her parents and her aunt spent summers. Her friends called her “a passionate sailor and enthusiast of the SS class” of wooden boats built on the South Shore of Long Island. She owned one that she named Loon and that she sailed in Quantuck Bay, near Quogue, and Moriches Bay throughout her life.

Ms. Theban was possessed of an “extraordinarily generous spirit and belief in the ambitions of others,” her friends wrote, and remained “an unwavering source of support for many people.” And not just people: She was a protector of wildlife and a supporter of many animal rescue efforts over the years, they said.

Mary Frances Theban was born in Ohio on Sept. 17, 1939, the daughter of the former Mary Frances Sanborn, known as Molly, and John Gerard Theban, who was a longtime director of Family and Child Services of Washington, D.C., and who had a deep influence on his daughter.

After attending Smith College and the Columbia University School of Social Work, Ms. Theban went to Turkey to teach. Upon her return she taught in Fairfax County, Va.

“With a keen intellect, open mind, and wonderful wit, Polly charmed all who met her,” her friends wrote. “She will be deeply missed by all those whose lives were blessed by her warmth and devotion.”

Ms. Theban did not marry or have children, but she is survived by “a wide net of dear friends,” as well as her four cats. There will be a private gathering in the near future to celebrate her life. Memorial donations have been suggested to the Southampton Animal Shelter Foundation, P.O. Box 696, Hampton Bays 11946.