Hall reports the case of a functionally active supernumerary mamma over the costal cartilage of the 8th rib.
Jussieu speaks of a woman who had three breasts, one of which was situated on the groin and with which she occasionally suckled; her mother had three breasts, but they were all situated on the chest.
Saunois details an account of a female who had two supernumerary breasts on the back.

Bartholinus (quoted by Meckel) and Manget also mention mammae on the back, but Geoffroy-Saint-Hilaire questions their existence.

Martin gives a very clear illustration of a woman with a supernumerary breast below the natural organ.

Sneddon, who has collected quite a number of cases of polymazia, quotes the case of a woman who had two swellings in each axilla in which gland-structure was made out, but with no external openings, and which had no anatomic connection with the mammary glands proper.

Shortly after birth they varied in size and proportion, as the breasts were full or empty, and in five weeks all traces of them were lost.