Bursaria truncatella is one of the largest ciliates that I rarely, but regularly find in some of my sampling sites. In the samples, the specimens usually swim just above the mud layer at the bottom and can be seen with the naked eye.

The oral apparatus of Bursaria truncatella is very complicated designed and difficult to examine in living specimens. Dominant is the adoral zone of membranelles, which begins on the left side of the ventral incision and takes a U-shaped course (s. fig. 2 and 5). Shortly before the posterior end it bends back and ends in the anterior third (s. fig. 2). Bursaria truncatella is omnivorous and can also devour very large prey. Numerous eaten ciliates and colonies of algae are often found. But rotifers are also among the prey organisms.

The macronucleus is vermiform and, according to my observations, lies parallel to the adoral zone of membranelles in unsquashed specimens. In squashed specimens it detaches from the oral tube and becomes entangled (s. fig. 6).

Numerous micronuclei are scattered in the cytoplasm (s. fig. 7), but they are difficult to detect in the highly vacuolated cytoplasm and between the food vacuoles. In addition to these micronuclei scattered in the cytoplasm, I was also able to find micronuclei attached to the macronucleus (s. fig. 8). These micronuclei adjacent to the macronucleus are not mentioned in the literature.