Family: Mature trophont free-swimming; with ciliated telotrochal band; with or withut oral bristles; swim with aboral pole forward (Illustrated Guide, 1985).
Genus: With conspicuous oral bristle; oral diameter distinctly less than aboral diameter (Illustrated Guide, 1985).
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O. henneguyi
cell 76 x 55 μm
Nagano, 2001
O. henneguyi
cyst formation
Nagano, 2001