Hyalodiscus
Probably not a valid genus, some described species are Vannella. Hyalodiscus simplex (Vannella simplex) has been used as a model for cell locomotion for many years
Hyalodiscus at the Protist Information Server
Page, F.C. (1968). "Genetic criteria for Flabellula, Rugipes and Hyalodiscus, with descriptions of species. J.Protozool. 15(1): 9-26.