(pear-o-knee-ma) is one of the better known gliding heterotrophic euglenids. The body is referred to as sac-shaped but this applies best to P. trichophorum
, the most common species and the one illustrated here. At first glance, it would seem that there is just one flagellum, but careful observations, especially at high magnifications, reveal a second flagellum tightly adpressed to the body or lying in a groove in the body surface. The recurrent structure looks a little wider than the normal ridges of the body. The body is metabolic - meaning it squirms, and members of this genus have an ingestion organelle with which to manipulate food into the body. Differential interference contrast.