Genus Pontigulasia Rhumbler, 1896
Diagnosis: shell pyriform, in transverse-section round or compressed; aperture round or elliptical. Shell commonly with a constriction between the neck and the main body. The test is divided internally into two parts by a small bridge, thus creating two openings. Shell composed of mineral particles, more or les mixed with diatoms, and cemented together with organic material. Because of this structure, the internal bridge is hard to detect. It is sometimes visible as a dark band at about one third of the shell length from the aperture. For the function of this bridge, see rotifers.
For more information of the differences between Pontigulasia, Lagenodifflugia and Zivkovicia look here.
See for the species described by Penard here.
Key to some species: