“You think I’m mad. Perhaps I am. But listen, Henry Frankenstein. While you were digging in your graves, piecing together dead tissues, I, my dear pupil, went for my materials to the source of life. I grew my creatures like cultures, grew them as nature does, from seed.” – Dr. Septimus Pretorius, Bride of Frankenstein
The Homunculi are miniature humanoids artificially created by Dr. Septimus Pretorius. Unlike Frankenstein’s Monster, the Homunculi are grown from organic seeds and kept in jars to prevent them from escaping.
The six known Homunculi created by Pretorius are a Queen, an Archbishop, a Priest, a Devil, a Ballerina (who won’t dance to anything but Mendelssohn’s “Spring Song”) and a Mermaid (described as the result of an experiment with seaweed).
The tiny mermaid in Dr. Pretorius’ bottle was Josephine McKim, a member of the 1924 and 1928 U.S. Women’s Olympic Swim Teams and one of the four members of that team to win the 1928 gold medal in the 400-Meter Freestyle Relay.
Information from Fandom: Homunculi (Bride of Frankenstein) and IMDb Trivia: Bride of Frankenstein (1935).