Fig. 7. Scanning electron microscopy of embryos of Hemigrapsus sexdentatus and H. crenulatus fixed after AgNO₃ treatment. AgCl deposits are indicated by arrows. (A) H. sexdentatus stage 4 with outer membrane intact. No silver deposit is visible. (B) H. sexdentatus stage 4 after partial removal of outer membrane. A thick amorphous deposit of AgCl adheres to the surface of the inner membrane. In C–F the outer membrane has been removed. (C) H. sexdentatus at stage 1, blastula. Spots of AgCl are distributed over the whole embryo, typically encircling small holes or craters. (D) H. crenulatus at stage 2, (E) H. sexdentatus at stage 3, and (F) H. crenulatus at stage 4. Scale bar, 25 µm (note that some shrinkage has occurred during processing).