Fig. 3. Details of microneme and related apical structures in the developing merozoite apex. (A) A longitudinally sectioned microneme, showing the basal bulb (bu) and narrow neck (white arrows). A transversely sectioned neck is also visible (arrowhead). Scale bar, 100 nm. (B) A group of micronemes clustered close to the surface of a rhoptry (rh). Notice the radiating filaments attached perpendicularly to the microneme surfaces. Scale bar, 100 nm. (C) Another group of micronemes transversely sectioned and image-enhanced to clarify their radial surface filaments. Scale bar, 100 nm. (D) Part of a transversely sectioned merozoite apex, enhanced to show filamentous connections (arrowhead) between two rhoptries (rh) and a polar ring (pr). Scale bar, 200 nm. (E) A freeze-fracture preparation showing two micronemes. Notice their bottle-like appearance and the presence of small numbers of intramembranous particles (e.g. arrow). Scale bar, 50 nm.