I thought I read that it was one of the frequent female co-stars of the series, but I cannot find any mention. It was just a single glamour shot repeated throughout the episode. These days, she would have a gotten a credit, but I cannot find any mention of her in the 1963 episode. It is not Samantha Eggar, an actress misidentified in some bios as playing the title character. She played Claire.
shareIt WAS Eggar. I was wondering the same thing. Took a bit of research. Remember how they kept saying she looked just like her? I'm a former makeup artist. I could make anyone look like someone else. After looking at "Marcia" and Samantha side-by-side, I could see it.
shareIt was NOT Eggar. They have different bone structure: e.g., Eggar has a slightly cleft chin and a more pinched nose. The picture was likely of a contract studio player. This was common practice, and they never get a credit. In one scene Templar says they look a little alike; it's a vague resemblance.
This sentence is false. -- The Zurich Gnome
I'm pretty sure it was the pin up queen/small time actress, Eve Eden aka Rosa Dolmai.
I know she is in the cast because her picture is in Movie|Dude's cast list for the episode but is not credited as her appearance would be fleeting anyway.