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Pontigulasia rhumbleri, with aperture and internal bridge

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.

Key to some species:

Type species: Pontigulasia rhumbleri
Other species: Pontigulasia elisa

Pontigulasia, rather hyaline shell with bridge clearly visible, shell 126 µm, Naardermeer
Pontigulasia rhumbleri
Pontigulasia elisa
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