Family ANCISTRIDAE Issel, 1903

Syns.

Ancistrumidae, Boveriidae, Dragescoidae, Protophryidae

Body of small to medium size, occasionally elongate, with anterior thigmotactic ciliature not set apart from other somatic kineties; ventral oral area courses nearly length of body, with cytostome moving progressively posterior-poleward; buccal ciliature conspicuous, winding in arc of >360° around antapical pole in some species; widely found in mantle cavity and, less often intestine of marine and fresh-water molluscs (prosobranch limpets, pulmonates, lamellibranchs) and respiratory organ of holothurian echinoderms.

Ancistrella Cheissin, 1930. Single species.
Ancistrum Maupas, 1883 (syns. Ancistruma, Ancystrum). Probably only a few bonafide species, though many described.
Ancistrumina Raabe, 1959 (for Ancistrina). Many species [Raabe] .
Boveria Stevens, 1901. Few species [well known in shipworms] .
Dragescoa Jankowski, 1974. Few species [deserve family of their own?] .
Eupoterion MacLennan & Connell, 1931 (syn. of Ancistrum?). Single species.
Penchelia Raabe, 1970. Single species.
Proboveria Chatton & Lwoff, 1936. Few species.
Protophrya Kofoid, 1903. Single species.
Protophryopsis Raabe, 1959. Single species.
Semiboveria Raabe, 1970. Single species.
Nomen inquirendum:
Isselina Cépède, 1910. Single species. [If this questionable name is judged valid, the now well-established Ancistrumina (above) might be obliged to fall as a junior synonym of Isselina, an unfortunate event which Raabe (1970a) apparently did not foresee in his consideration of the genera involved.]