I find Jenningsa glabra rarely, but regularly in the uppermost mud layer of the Simmelried. I have not yet been able to find the species in my other sampling sites.

The pellicle of Jenningsia glabra is covered with xenosomes, which is a characteristic feature (s. fig. 1 d). In my population, the xenosomes were always very loosely distributed on the pellicle of the individuals. Only in rare cases was the pellicle densely covered with xenosomes (s. fig. 3 a-c).

The apical pharynx is quite large for the size of the cells. Below the pharynx the large reservoir is located in the middle of the body, from which the flagellum originated (s. fig. 1 c). The contractile vacuole is attached to the reservoir (s. fig. 1 b). The nucleus lies in the anterior third.