English: The dinoflagellate labeled above is the microscopic algae Karenia brevis. Karenia brevis is the cause of red tide in the Gulf of Mexico. The algae propels itself by using a longitudinal flagellum (A) and a transverse flagellum (B). The longitudinal flagellum lies in a groove- like structure called the cingulum (F). The dinoflagellate is separated into an upper portion called the epitheca (C) where the apical horn resides (E) and a lower portion called the hypotheca (D). Photo used from https://en.wikipedia.org/wiki/Karenia_brevis#/media/File:Karenia_brevis.jpg