Abstract

The developmental stage of germ cells during oogenesis in the giant abalone Haliotis gigantea can be categorized into six stages with histological features: (1) oogonium, (2) previtellogenic oocyte, (3) initial vitellogenic oocyte, (4) early active vitellogenic oocyte, (5) late active vitellogenic oocyte and (6) ripe oocyte. The size of oocyte, nucleus and nucleolus illustrated the increase tendency but size ratio of nucleolus to nucleus was decreased during oogenesis. During oogenesis the stainability in the cytoplasm of oocyte changes from basophilic to eosinophilic in H-E stain. And egg stalk and outer jelly membrane was developed in the oocyte. These histological changes are seemed to be preparation process for the yolk accumulation in the oocyte and the spawning.