From the movie: MAD YOUTH 1940
A combination of Lindy Hop, Shag and you name it. The lead dancers are Ray Hirsch and Patti Lacey. The other dancers are listed as Eugene & Maxine Taylor, Aileen Morris and Pearl Tolson but that would seem to add up to one guy and three girls. I understand the first girl dancing with a guy in a sport jacket is Pearl Tolson.