Portrait

Description :

Ventral view of the large metopid ciliate, Brachonella caduca (Kahl 1927, Jankowski, 1964). Synonym of Metopus caduca (Kahl, 1927). The cell is pyriform with a broadly domed anterior and tapered truncate posterior end. The long peristome spirals from the dorsum anteriorly around the circumference of the cell to terminating posteriorly at the cytostome on the same longitudinal line as the peristome origin. 2 to 3 kinities lie anterior and parallel to the peristome. Approximately 9 longitudinal somatic kineties occur posterior to the peristome. The anterior margin of the peristome is paralleled by a peristomal stripe of kineties, the posterior margin by an adoral zone of membranelles. The somatic kineties of the right and left side terminate anteriorly at a bare suture. There is a long tuft of caudal cilia. A single contractile vacuole is located at the posterior end. There is a single large eccentric spherical macronucleus and adjacent micronucleus. B. caduca is an obligate anaerobe. From stagnant freshwater sapropelic sediment rich in hydrogen sulfide near Boise, Idaho. DIC optics.