Rhynchopus (rink-opus) is one of a small number of genera that make up the diplonemids, a subset of euglenozoa. Although not widely reported, they are often encountered in especially marine habitats where they consume detritus, algae, and other moderately sized particles. They have two flagella which insert into a shallow subapical pocket. There are three genera which look similar: Rhynchopus with a papillum and relatively deep flagellar pocket, Diplonema with two short flagella, and Hemistasia with long flagella. The species are polymorphic, making species and generic boundaries very hard to establish. We assign this organism to Rhynchopus because of the papillum. Phase contrast.