Genus Lagenodifflugia Medioli & Scott, 1993
Diagnosis: Shell pyriform, often with a constriction of the neck, frequently circular in cross-section but sometimes slightly compressed, composed mainly of agglutinate mineral particles bound by an organic cement: aperture terminal, circular: internally the shell is partitioned into two regions by a diaphragm constructed as part of the shell wall but having a single central orifice. For the function of this diaphragm, see rotifers.
For more information about the differences between Pontigulasia, Lagenodifflugia and Zivkovicia look here.
For the species described by Penard look here.
Type species Lagenodifflugia vas (Leidy, 1874)
Lagenodifflugia bryophila (Penard, 1902)