Family SPIROSTOMIDAE Stein, 1867

Syns.

Blepharismidae, Spirostomatidae

Large, often elongate, cylindrical forms, some highly contractile, some pigmented; long, narrow peristomial field, sometimes with buccal ciliature relatively inconspicuous; somatic ciliation uniform, often dense, and typically complete; contractile vacuole posterior, frequently large, and may have lengthy collecting canal; macronucleus compact, ovoid to elongate-moniliform; free-living in fresh-water (predominantly), marine, or edaphic habitats.

[I am removing the controversial genus Protocruzia from this family, where it is customarily placed, provisionally considering it (sensu stricto) to be a philasterine scuticociliate (class Oligohymenophora). But quite possibly two or three totally different organisms have been included over the years under the same name! Thus, I am here resurrecting (with a large degree of uncertainty) Mansfeld's genera Diplogmus and Propygocirrus, suggesting that they may represent the "heterotrichine" moiety of the Protocruzia (sensu lato) of the literature.]

Anigsteinia Isquith, 1968. Several species.
Blepharisma Perty, 1849. Many species (all valid?).
Gruberia Kahl, 1932. Few species.
Parablepharisma Kahl, 1932. Few species.
Pseudoblepharisma Kahl, 1926. Few species.
Spirostomum Ehrenberg, 1833. Several to many species.
Incertae sedis:
Diplogmus Mansfeld, 1923, resurrected genus, with single (or more?) species.
Propygocirrus Mansfeld, 1923, resurrected genus, with single (or more?) species.