Fig. 4. TEM of E. hepatopenaei sporoblasts in hepatopancreatic tubule epithelial
cells of P. monodon. (A) Sporoblast at the periphery of a sporogonal plasmodium
showing the nucleus, early posterior vacuole (asterisks), immature polar filaments
with five cross sections (arrowhead) and a dense cap or anchoring disk (arrow). (B)
Late stage sporoblast showing mature polar filaments (arrowhead). N, nucleus; PV,
posterior vacuole.