Histiobalantium is easy to distinguish from the similar genus Pleuronema by the stiff long cilia which intersperse the dense somatic ciliation because Histiobalantium have cilia distributed over the whole cell whereas at Pleuronema this cilia are confined to the posterior region. The body of Histiobalantium natans is elliptical, with the right side slightly concave and anterior end a little narrower than the posterior. The peristome is deep, equipped with a well-developed undulating membrane. Several micronuclei are attached to the two round macronuclei. The contractile vacuole is located in the posterior half of the body. 55 - 105 microns. From fresh water ponds and lakes. This free-swimming specimen of Histiobalantium natans was collected in freshwater ponds near Konstanz, Germany The contractile vacuole is located in the posterior. 95 microns. Differential interference contrast.