Geodia hillii Merrill, 1895, p.17; text-fig.21.

NOW Hystrichosphaeridium?. Originally Geodia?, subsequently Hystrichosphaeridium, thirdly (and now) Hystrichosphaeridium?. Questionable assignment: Merrill (1895, p.17).

Holotype: Merrill, 1895, text-fig.21.
Age: Early Cretaceous.