Scanning electron micrographs (SEM) of Bihospites bacati n. gen. et sp. A. Ventral view of B. bacati showing a cell covered with rod-shaped and spherical-shaped episymbiotic bacteria (white arrowheads and black arrowheads, respectively), the vestibulum (vt), dorsal flagellum (Df) and ventral flagellum (Vf) (bar = 15 μm). B. High magnification of the vestibular opening (vt), showing the open cytostome (white arrowhead), and the dorsal (Df) and ventral flagella (Vf) without flagellar hairs. C. High magnification SEM showing the posterior end of B. bacati, in ventral view, and the external appearance of the raised articulation zones between S-shaped folds in the host cell surface (black arrowheads). The white arrows show pores on the cell surface. D. High magnification SEM showing the rod-shaped (white arrowheads) and spherical-shaped episymbionts. E. High magnification SEM of the spherical-shaped episymbionts showing discharged threads (black arrows) through an apical pore (bar = 0.5 μm). The white arrow shows the initial stages of the ejection process. (B-D bar = 1 μm).