In one scene, someone is shown marking off days on a calendar dated May, 1872.
The show now uses a 'cold open', airing a part of the episode before the opening credits.
A decade later, James Gregory and David Watson would be co-stars in Beneath the Planet of the Apes (1970), respectively as the gorilla General Ursus and the chimpanzee Cornelius, taking over that role for one movie from Roddy McDowall.