Rhynchopus
When food is scarce, mobile flagellated cells are produced, suggesting the presence of a fully flagellated and dispersive phase in the life cycle, serving to distinguish Rhynchopus from Diplonema.They have been found feeding on planktonic diatoms cytoplasm and gills of crayfish and crabs.In the trophic stage, the cells are predominantly elliptical and flattened laterally, but often change their shape .The two flagella, which are normally hidden in the sub-apical pocket, are short and of unequal length and have conventional axonemes, but seems to lack the paraxonemales rods.Swimmer cells, which are only occasionally seen, are smaller and have two conspicuous flagella, more than twice the length of the body.