(written from a Production point of view)
Barbara Baldavin (born 18 October 1938; age 78) is an actress who appeared in a handful of smaller roles on TV and feature films between 1966 and 1993. Best known for her role as Nurse Holmby on the TV show Medical Center, Baldavin is the wife of casting director Joseph D'Agosta and later became a casting director herself. She appeared in four episodes of Star Trek: The Original Series.
When Baldavin was called back for a subsequent appearance in "Shore Leave", her character in the script was called "Mary Teller," but crew on the set realized she had played a major character named Angela, so she was called that in dialogue. However, Shatner still calls her "Teller" at one point. Later, she played the character of Lieutenant Lisa in "Turnabout Intruder".
Baldavin filmed her scenes for "Balance of Terror" on Monday 25 July 1966 at Desilu Stage 9. She filmed her scenes for "Shore Leave" on Wednesday 19 October 1966 and Friday 21 October 1966 at Africa, USA. She filmed her deleted scene for "Space Seed" on Wednesday 21 December 1966 at Stage 9.