Congaroo

Whitey's Lindy Hoppers, aka the Harlem Congaroo Dancers (in order of appearance: William Downes and Micky Jones, Billy Ricker and Norma Miller, Al Minns and Willa Mae Ricker, Frankie Manning and Ann Johnson) in Hellzapoppin' (1941).

Charlie Kane

Charles Bennett with RKO Chorus, Orson Welles & cast in Citizen Kane (1941).

Sorry it's cut off at the end! It's only missing a few seconds.

Pink Elephants on Parade

The Sportsmen in Dumbo (1941).