From Fensome et al., 2019:
Cribroperidinium apione (Cookson and Eisenack, 1958, p.36, pl.3, fig.7; text-figs.3–4) Morgan, 1980, p.20. Holotype: Cookson and Eisenack, 1958, text-figs.3–4; Jan du Chêne et al., 1986a, pl.33, fig.6. Originally Gonyaulax (Appendix B), subsequently Gonyaulacysta, thirdly Millioudodinium, fourthly (and now) Cribroperidinium. Taxonomic senior
synonym: Gonyaulax (as Cribroperidinium) edwardsii, according to Burger (1980a, p.82) — however, Jan du
Chêne et al. (1986a, p.76) retained Cribroperidinium apione. Helenes (1984, p.118) also proposed this combination. Age: Albian.

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Original description: Cookson and Eisenack, 1958, p. 36: Gonyaulax apionis
Shell smooth nearly twice as long as broad, epitheca long, conical, sumounted by a long, stiff horn which is closed at one end by a "lid" with a short central projection. The girdle is strongly helicoid and bordered by low but rather sharp ledges. The hypotheca is more dome-shaped and the antapical plate is square with four small pointed projections at the corners. The ledges borgering the plate are smooth and low. In the type a long narrow pylome straches from the base of the horn to the girdle (plate 3""). The tabulation, though rather distinct, cannot be given in full detail; it appears to be simple.
Dimensions: Type 105x57 Ám, horn 20 Ám. A paratype 114-71 Ám, horn 24 Ám.

Affinities:
Cookson and Eisenack, 1958, p. 36: Gonyaulax apionis
The long narrow shape, smooth surface and absence of ornamentation distinguish G. apionis from all other known fossil species of Gonyaulax.