(Gould & Pyle) From the article 'A Unique Monstrosity' from Brooks H. Wells, American Journal of Obstetrics, 1888. This is the only actual photograph of Blanche that I've ever been able to find. As you can see it's very poor quality and I would love to see a better copy.

Blanche Dumas was born on the Caribbean island of Martinique in 1860, to a French father and a biracial mother. She had a third leg attached to her sacrum, and her two primary legs were said to be imperfectly developed. The third leg was without a mobile joint but had a bend in it where the knee would have been. Her pelvis was wider than normal and she had double genitalia as well as a duplicate bowel and bladder. To the right of her middle leg was the stump of another limb; it's unknown at this time whether this stump was naturally occurring or the site of a surgical amputation, but promoters sought to maximize its appeal by adorning it with nipples and advertising it a pair of "well-formed" extra breasts!

Stories of Blanche all mention her pronounced libido. She moved to Paris later in life and became a courtesan, and allegedly, upon hearing about the three-legged man, dos Santos, who was touring at the same time, she expressed a desire to have sex with him. According to Gould and Pyle, "There were two vaginae and two well-developed vulvae, both having equally developed sensations. The sexual appetite was markedly developed, and coitus was practised in both vaginae."

Left: Rare photo of young Blanche Dumas, clearly showing her undeveloped (or amputated) fourth leg. Right: Adult, sexualized Blanche with nipples painted on her leg stump. This is the basis for the woodcut above. Both photos submitted by an anonymous reader.