Although there is a "Morgana" who appears in the magic-themed "Diana's Disappearing Act" episode from Season 2, this is not Morgana (AKA Morgan Le Fay) from Wonder Woman Comics' Rogue Gallery. This is just Morgana, a random woman with no magical powers who is an assistant to the main magician in the episode, Count Cagliostro.
This is the first appearance of Ed Begley, Jr. as Harold Farnum, he would later appear as this character in Season 3 "The Fine Art of Crime" (1978).