Transmission electron micrographs of hemocytes of <i>Crassostrea rhizophorae</i>.

<p>(A) Hemoblast-like cell displaying a very evident nucleolus (Nu) within the euchromatic nucleus (N). The cytoplasm shows homogeneously arranged dots, with a few membranous organelles. (B) A cell with many cisternae (asterisks) bounded by membranes, occupying most of the cytoplasm. Note that some of the cisternae have a core with variable electron densities (arrowhead). (C) Another hemocyte displaying cisternae in the cytoplasm, similar to that seen in (B). (D) Electron micrograph of the cytoplasm of a cell similar to those seen in (B) and (C) at higher magnification. Arrowheads indicate small granules surrounded by membranes continuous with the cisternae. (E) Hemocyte with several electron-dense granules (G). Some of the granules seem to be interconnected (white arrows). Note also electron-lucent granules within the cytoplasm, and cisternae (asterisks). (F) A granular cell with many large electron-lucent granules occupying almost the entire cytoplasm, and a few cisternae. Note that the granules are clearly interconnected to one another (white arrows). In (A–C), (E), (F) black arrows indicate finger-like cytoplasmic protrusions. Bars: 1 µm.