Family NASSULOPSIDAE Deroux, 1979

Body generally large but elongate and radially symmetrical; multiple parts to hypostomial frange, encircling much of anterior fifth of body just below level of the cytostome-cytopharyngeal apparatus and separate from preoral suture line; row of 4-5 medially located contractile vacuole pores down ventral surface; macronucleus elongate; quite widely found in fresh-water, oceasionally edaphic, habitats, with one or two species marine.

[Deroux has for some time been planning to establish this group as a family, so I am crediting him with the name (but as of now); Jankowski (1975), working independently, suggested the same name but with no characterization.]

Nassulopsis Fauré-Fremiet, 1959. Several species.
Phasmatopsis Deroux Single species.