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Histiocysta palla
Histiocysta palla Davey, 1969
Holotype: Davey, 1969, pl.1, fig.5, text-figs.14A-B
Paratype: Davey, 1969, pl.1, fig.6
Locus typicus: Fetcham Mill, England
Stratum typicum: Cenomanian
Original diagnosis: Davey, 1969, p.138
Shell spherical to subspherical, thin-walled, periphragm smooth and forming a reticulate network of crests. Network consisting of reflected dinoflagellate tabulation with central region of each plate occupied by coarse but simple reticulation.
Dimensions: Shell diameter 25(31.8)38 µm, height of crests 1-5 µm.
Original description: Davey, 1969, p. 138
The precingular and postcingular plates may be observed on most specimens but the exact tabulation has not, as yet, been elucidated. The central region of each plate is occupied by a coarse, subpolygonal reticulation which occasionally extends to the plate boundaries (Figs. I4A, B). The cingular region is clearly defined by crests and encircles the shell. Cingular plates are not usually discernible, the entire region being occupied by coarse reticulation. An apical archaeopyle with an angular margin is typically present, the six-sided operculum often rmaining attached to the shell.
Holotype: Davey, 1969, pl.1, fig.5, text-figs.14A-B
Paratype: Davey, 1969, pl.1, fig.6
Locus typicus: Fetcham Mill, England
Stratum typicum: Cenomanian
Original diagnosis: Davey, 1969, p.138
Shell spherical to subspherical, thin-walled, periphragm smooth and forming a reticulate network of crests. Network consisting of reflected dinoflagellate tabulation with central region of each plate occupied by coarse but simple reticulation.
Dimensions: Shell diameter 25(31.8)38 µm, height of crests 1-5 µm.
Original description: Davey, 1969, p. 138
The precingular and postcingular plates may be observed on most specimens but the exact tabulation has not, as yet, been elucidated. The central region of each plate is occupied by a coarse, subpolygonal reticulation which occasionally extends to the plate boundaries (Figs. I4A, B). The cingular region is clearly defined by crests and encircles the shell. Cingular plates are not usually discernible, the entire region being occupied by coarse reticulation. An apical archaeopyle with an angular margin is typically present, the six-sided operculum often rmaining attached to the shell.