Cryptobia are monogenetic (single host) bodonid flagellates with an anteriorly directed flagellum and a recurrent flagellum attached along the entire length of the body, but does not form a prominent undulated membrane. The cytostome is situated far from the flagellar pocket but is linked to it by a prominent preoral ridge. The cell bears a kinetoplast at the base of the flagella. All are parasitic or endo-commensals in host cavities such as reproductive system of gastropods, the gut of fishes. This species, Cryptobia intestinalis from the gut of the fish Box boops (Giemsa).