phacus

Century Dictionary and Cyclopedia

1. n. A notable genus of flagellate infusorians, referred to the Chloropeltidea by Stein, by Kent to the Euglenidæ. The several members were originally described by Ehrenberg as species of Euglena, from which they differ in their more persistent forms, and greater induration of the cuticle, which often remains as an empty test after dissolution of its contents. They are such as P. triqueter, P. pyrum, and P. longicauda, all found in fresh water. See cut under Infusoria.