(brack-on-ella), a heterotrich ciliate, with an adoral zone of membranelles (not well imaged here) and normal cilia on the body. The anterior end of cell is twisted. Distinguished from Metopus
by its spiralling adoral zone of membranelles as opposed to the obliquely oriented but not spiralling AZM of Metopus
.These cells mostly found in anoxic sites. Phase contrast.