Women's heads were used on anything from etageres to chandeliers from ca. 1860 to ca 1920. I've never seen any unanimity of opinion on who they're supposed to be; the most common answers are Jenny Lind (the Swedish Nightingale, an opera superstar who toured the U.S. multiple times starting in the first half of the 19th century) and Britannia, the Athena-like symbol of Great Britain.
Both could be right, or neither. Perhaps there is no one answer. However, your heads or masks seem to have a Gibson Girl hairdo, so that would make them current from about 1900-1920, thus my date about halfway between the two.
