Eversible trophi of the forcipate or virgate type, which can be used for nibbling, are common in Ploima, notably Rattulidae, and are used for attachment to the host in the parasitic Seisonaceae, &c. In Asplanchnaceae also, From H.
In Bdelloidaceae and Seisonaceae the whole organ is paired, the germary proximal, the vitellary next the cloaca.
The males are unlike the females in most species; only in Eosphora digitata, Rhinops vitrea, Proales werneckii, and the Seisonaceae a complete digestive system is present.
This statement may seem to need qualification; for the male of no Bdelloid has been seen, and there is but a doubtful record of" winter-eggs in this group. But possibly, as in Seisonaceae, the males resemble the females, and have escaped recognition.
Drilophagus and Albertia are parasitic on the surface or within the gut of Naid Oligochaete worms: Seisonaceae are ectoparasitic on the Crustacean Nebalia, Proales werneckii forms galls within the Conferva Vaucheria, and P. parasita infests the central jelly of the Phytoflagellate Volvox; P. petromyzon is a frequent commensal in the gill cavity of some Cladoceran Crustacean Eurycereus lamellatus.