The Ebriida or Ebriidae is a small group of marine predatory biflagellates that inhabit planktonic communities in temperate and tropical zones, especially in coastal areas. The group has a rich fossil record and currently contains only two extant genera, Ebria and Hermesinum (see title illustration), comprising three extant species -- E. tripartita, and H. adriaticum and perhaps H. platense (Hargraves, 2002; Patterson et al., 2002; Tiffany, 2002). However, ebriids are best known for their extensive fossil record that dates back to the Cenozoic Era (Korhola and Grönlund, 1999; Taylor, 1990). The name of this group means “drunken” due to their spiralling swimming behavior (Taylor, 1990). Cell dimensions vary from 25-55 μm (Hoppenrath and Leander, 2006b; Throndsen, 1997; Tiffany, 2002). Ebriids are heterotrophic, mixotrophic, bacterivorous, and algivorous (Hargraves, 2002; Hoppenrath and Leander, 2006b; Patterson et al., 2002); most cells are found feeding on filamentous diatoms (Hargraves and Miller, 1974; Taylor, 1990) and dinoflagellates (Patterson et al., 2002; Taylor, 1990; Tappan, 1980).