From Fensome et al., 2019:
"Balmula", Bint, 1986, p.158.
Taxonomic senior synonum: Nyktericysta, according to Fensome et al. (2009, p.46).
Type: Bint, 1986, pl.6, figs.10,14–16, as Balmula tripenta.

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Original description: [Bint, 1986]:

Description:
Large, dorso-ventrally compressed cysts whose full complement of horns is one apical, two lateral, and two antapical, but the two lateral horns may be absent. All horns are long and of similar length; the two antapicals are subequal in size, and the two laterals, when present, are also about equal in size.
Cysts two-layered, both layers very thin.
Periphragm appressed to endophragm or slightly separated from it over much of the cyst surface.
Endocyst forms rounded horn tips; periphragm is incomplete at the horn tips, having an irregular termination at or before the ends of the horns. Paratabulation are not expressed.
Cingulum may be indicated by transverse lines, sulcus not indicated.
Archeopyle apical, operculum usually in place and probably adnate.