Family PARAMECIIDAE Dujardin, 1840

With characteristics of suborder s.s, (above). Conspicuous prebuccal caviry (formerly called a "vestibulum") leading to equatorially löcated buccal caviry; oral ciliature comprised of distinctive paroral membrane, two peniculi, and single quadrulus; two contractile vacuoles.

[The "slippershaped animalcules," so long and (relatively) well known: see drawings in Plate p279, especially.]

Paramecium O. F. Müller, 1773 (syns. Cypreostoma, Helianter, Param(a)ecidium, Paramaecium, Paramoecium). Many species, now [see Sonneborn (1975a), Vivier (1974)] .
Incertae sedis:
Physanter Jankowski, 1975 (for Faurella Roque, 1966 [hom.] ). Single species.