Hedriocystis brachypous (De Saedeleer, 1930) Siemensma, 1981
Basionym: Monomastigocystis brachypous De Saedeleer, 1930
Diagnosis: Shell colorless, hyaline, polygonal in circumference; holes on top of conical protuberances; stalk not present or shorter than the shell diameter; stalk connected to a somewhat elongated conical protuberance; axopodia finely granulated; nucleus centrally located, zoospores with one flagellum.
Dimensions: Test 13.0-21.1 µm.
Ecology: on waterplants and in sediments of mesotrophic ponds and ditches. I found this species recently in Groeneveld and along the Oppad, both in the Netherlands. This species is known from Europe and North-America (Charles Krebs)
Remarks: The shell can only be distinguished from Hedriocystis pellucida by its short or absent stalk.
Look here for the feeding process of Hedriocystis.