Transmission electron micrographs (TEM) of Bihospites bacati n. gen. et sp. showing intracellular bacteria and extrusomes. A. TEM showing a cell containing numerous intracellular bacteria (arrowheads) within vacuoles. B. Transverse TEM showing a battery of extrusomes (arrows) (A, B, bar = 500 nm). C. High magnification TEM of extrusomes showing a dense outer region (arrowhead) and a granular core containing a lighter cruciform structure (white arrow). Black arrow denotes the plasma membrane of the host (bar = 100 nm). D. TEM showing a longitudinal section of an extrusome; the proximal end is indicated with a black arrow. Arrowheads denote rod-shaped bacteria on the cell surface (bar = 500 nm).