Buxtehudea J. I. R. Larsson 1980

Monomorphic, monokaryotic throughout life cycle; merogony presumed absent; sporogonial plasmodia with unpaired nuclei develop within membrane bound vacuoles and give rise to 50100 uninucleate sporoblasts and spores; spores, 2.53.5 µm, are spherical or lenticular with one U-shaped nucleus; endospore is thick and of equal thickness over the whole spore; exospore is a narrow layer; polaroplast in the classical form nonexistent; polar tube is isofilar, with 911 coils arranged in two disorderly rows; outer membrane is raised in spirally wound ridges, giving a stellate appearance to the polar tube in cross section; connection between the polar sac and the polar tube is of a special Chytridiopsis type i.e. the posterior, central area of the polar sac is shaped like a socket to which the anterior, disclike part of the polar tube attaches; type species B. scaniae Larsson, 1980 in midgut epithelium of Petrobius brevistylis (Thysanura, Machilidae).