Genus Multicilia (Cienkowki, 1881) Lauterborn, 1895
Diagnosis: Cells small, 20-40 µm, spherical or slightly ovoid, with amoeboid locomotion. Surface covered with numerous long cilia, 1.5-3 times the cell diameter. Between the cilia one can often observe short blunt bulges. No difference between endo- and ectoplasm. One or more vesicular nuclei. Contractile vacuoles only observed in freshwater species. Feeding by means of blunt pseudopodia.
Remarks: Lauterborn describes the cilia as true cilia (flagella), which never change, not disappear or appear, but are always present.
Multicilia lacustris Lauterborn, 1895
Diagnosis: Cell body spherical or slightly ovoid, usually with slight amoeboid locomotion. Outer layer of cytoplasm with numerous embedded granules. Cilia 1.5-2 X the cell diameter, usually of different length. Several nuclei present; contractile vacuoles small, very numerous, close to the cell membrane. Cell body always filled with preyed flagellates (Chlamydomonas sp.)
Dimensions: body 30-40 µm
Ecology: Freshwater, River Rine, Germany (Lauterborn)
Multicilia marina Cienkowski, 1881
Diagnosis: Cell body spherical, colorless, rather vivid amoeboid locomotion. Cilia up to three times the cell diameter, slowly moving. One nucleus; no contractile vacuoles observed.
Dimensions: Cell diameter 20-30 µm
Ecology: Marine; White Sea, Black Sea, Mediterranean
Remarks: Multicilia marina is a multiciliated amoeboid protist that was first isolated in 1880 by L. Cienkowski (Cienkowski,1881) at the Solovetskaya station (Onega Bay, White Sea). Its cells are usually spherical, about 30–40 µm in diameter, although some of them can have an oblong or irregular form. Typically, each cell has approximately 20–30 cilia.
Multicilia marina normally feeds by phagocytosis, using lobopodia for the capture of large prey (gymnamoebae). Cells in culture roll over the substratum without any polarity, and have normally 20–30 long cilia beating more irregularly and without visible coordination; a peculiar formation of small cells with 2–4 cilia and giant, branching and budding ones with 100–200 cilia is described.
Ultrastructural study (Mikrjukov et al, 1998) shows the cells to be covered with a free glycocalyx, to have a single central nucleus, mitochondria with tubular cristae, and to have no modifications in the cortical cytoplasm. The basal apparatus of each cilium is represented by a single kinetosome, an open conical microtubular sheath surrounding it, and a microtubular fiber connecting each kinetosome with the sheath of a neighboring one. No structural connection between the basal apparatus and the centrally located nucleus has been observed. The irregular movement of Multicilia seems to result from its adaption to capturing its main food: naked amoebae.
Mikrjukov (1998) proposed a new phylum Multiflagellata to include the genus Multicilia, and amended the diagnosis of M. marina.
Lauterborn, R (1895) Protozoenstudien. III. Über eine Süßwasserart der Gattung Multicilia Cienkowsky (M. lacustris nov. spec.) und deren systematische Stellung. Zeitschrift für wissenschaftliche Zoologie Bd.60: 236-248