AbstractThe oogenesis of the common prawnP. serratusis described. The reproductive cycle is annual and there is little evidence for a second spawning period. Oogenesis under the electron microscope follows a typical crustacean pattern and has been divided into seven stages according to the structure of the oocytes. The production of yolk is mainly intra‐oocytic, with a small extra‐oocytic contribution. Yolk, in the form of small granules, arises within the lamellar elements of the rough endoplasmic reticulum. These were then transformed into finely granular yolk bodies. Lipid droplets, as in other crustacean species, arisede novoin the cytoplasm and there is no association between lipids and cell organel