Thaumatomastix tripus (Takahashi and Hara, 1984) Beech and Moestrup, 1986. Cells are ovoid (8-15 microns x 12-21 microns) with slight dorso-ventral flattening. A long flagellum, which is slightly longer than the cell, is directed forwards and then curves back towards the posterior end. This flagellum and the shorter one emerge from a latero-anteriorly located "mouth" or flask-shaped invagination, both flagella are anchored at the base of the mouth. The cells have often a creeping motion with the long flagellum trailing and gliding over the coverslip. The cells sometimes move freely with the long flagellum flicking in an arhythmical manner. Rarely a specimen may be attached at its anterior end to pieces of detritus. A furrow can be seen in cells as a slit, bordered by trichocyst-like bodies. It originates at the mouth and continues over the ventral cell surface towards the posterior. Often the furrow appears merely as a pair of parallel lines. A nucleus with sometimes distinct nucleolus is situated just proximal to the mouth and the basal bodies. The bulk of the cytoplasm has a granular appearance and contains numerous refractile bodies (often bright red in colour) and globules of unknown composition. There are no chloroplasts. Cell cleavage is anterior to posterior.
