A melusine is a female being with the upper body a woman and the lower body of a fish or serpent, sometimes she has wings. The lower body or "tail" can be doubled with fins or single with no fin.
She is a freshwater mermaid found in springs and streams, and has traits in common with the undine and the banshee.
In folklore, Melusine was the name of a water-fairy who was cursed to become a serpent from the waist down every Saturday.
According to the legend, Raymond, the son of Count Poitou, found Melusine in the forest, they fell in love that day and he asked her to marry him. She said yes on the condition that he would never enter her room on Saturday. Raymond agreed.
They lived together in a great palace and she bore him several children each one with a peculiar deformity including pendulous ears, fur, claws, red eyes, and other disfigurements, but each child grew up to be a great hero or warrior.
After many years, gossip began to spread about Melusine's weekly seclusion, and Raymond was prodded into taking a peek into her private room, where he saw her in the bath with the tail of a serpent. As soon as she became aware of what he had done she flew out the window and was gone.
She is said to appear hovering over the castle as a an omen of death for one of her descendants or for a king of France. Her wail is also an omen of death or great destruction.
In heraldry the double tailed melusine is often depicted with one tail held up in each arm.
Also known as Melusina.
See Also: Creatures by Type » Mermaids, Serpents
Baring-Gould, Sabine. Curious Myths of the Middle Ages. London: Rivingtons, 1873.