Gummo was not in any of the movies; Zeppo appeared in the first five films in relatively straight (non-comedic) roles. Source: Internet
Groucho was unavailable to film the scene in which the Beaugard painting is stolen, so the script was contrived to include a power failure, which allowed Zeppo to play the Spaulding part in near-darkness.) Kanfer, pp. 139–140. Source: Internet
'Monkey business: The lives and legends of the Marx Brothers: Groucho, Chico, Harpo, Zeppo with added Gummo.' Source: Internet
Most of the comedians provided their own voices for their animated counterparts, except for Fields and Chico Marx (both had died), and Zeppo Marx (who had left show business in 1933). Source: Internet
Origin of the stage names The stage names of the brothers (except Zeppo) were coined by monologist Art Fisher Joe Adamson, Groucho, Harpo, Chico and Sometimes Zeppo: A Celebration of the Marx Brothers New York: Simon and Schuster, 1973. Source: Internet
The Home Again tour reached Flint, Michigan in 1915, where 14-year-old Zeppo joined his four brothers for what is believed to be the only time that all five Marx Brothers appeared together on stage. Source: Internet