Genus: Test ovate, discoid in cross-section; pseudostome a terminal slit
(Illustrated Guide, 1985).
Species: Test 75 μm long, 60 μm wide (Cash, The British Freshwater Rhizopoda and Heliozoa vol. II, 1909).
H. papilio Leidy, 1879: 100-140 μm long, 60-100 μm wide near base; pseudostome oval, 25-30 x 10-12μm; test flask-shaped, base bulbous, neck straight-sided (Illustrated Guide, 1985). Test clear, yellowish, several minute pores in the base; cross section, pseudostome, both biconvex; ameba dose not fill test; many epipodia (How to know the protozoa, 1979).