The Genus EntosiphonStein 1878

Stein, F. R.: Der Organismus der Infusionstiere. III. Abt. Der Organismus der Flagellaten. - Leipzig 1878.

Lee, John J., Hunter, Seymour H., & Bovee, Eugene C. (eds) An illustrated Guide to the Protozoa The Society of Protozoologists. 1985.

Diagnosis:

Both flagella emerge from canal, unequal in length, shorter directed anteriorly, longer trailing posteriorly, longer than cell; colourless, phagotrophic, ingestion apparatus a tube ("siphon") composed of fused rods; cytostome separate from canal opening but both lie in common groove; siphon protruded from cell for ingestion; no eyespot; rigid, slightly flattened, with helical fluting and ridges; canal opening subapical; several freshwater species. (from Illustrated Guide)