*tubiferum (Ehrenberg, 1837b, pl.1, fig.16) Deflandre, 1937b, p.68. Emendation: Davey and Williams, 1966b, p.56–58, as Hystrichosphaeridium tubiferum. Holotype: Ehrenberg, 1837b, pl.1, fig.16. Originally Xanthidium tubiferum (Appendix A), subsequently Hystrichosphaera tubifera (combination not validly published), thirdly (and now) Hystrichosphaeridium tubiferum, fourthly Ovum hispidum subsp. tubiferum (combination not validly published; Appendix A). Taxonomic junior synonym: Xanthidium (as Hystrichokolpoma) bulbosum, according to Stover and Evitt (1978, p.55) — however, Lentin and Williams (1989, p.134) retained Xanthidium (as Hystrichokolpoma) bulbosum. The validity/authorship of this name may need to be reconsidered as it appears that Ehrenberg (1837b) did not provide a description. Age: Late Cretaceous?.