Histiona (hist-ee-own-a) is a jakobid flagellate related to Jakoba. As with other excavates, there is a ventral groove and the flagella insert at the head of the groove. There are two flagella, one lying in the groove and one curving outwards from the point of insertion. The margins of the groove can be mistaken for flagella. Unlike most other excavates, Histiona sits in a stalked lorica when feeding. Lorica with a cyst is evident. Phase contrast.