Abstract
The morphology and infraciliature of the rare heterotrichid ciliate Copemetopus subsalsus Villeneuve-Brachon, 1940 were studied in live and protargol-impregnated specimens and also by scanning electron microscopy. It is characterized by a dumbbell- shaped macronucleus, a specific dorsal brush cilia, an oblique peristome, and a distinct S-shaped adoral zone of membranelles equipped with whip-shaped anterior adoral membranelles.