Studies on spermiogensis of the pacific oyster, Crassostrea gigas Thunberg

The spermiogensis of pacific oyster, Grassostrea gigas was studied with electron microscope. Spermatid consisted of proacrosomal granules, mitochondria, golgi body, centriole and many other organelles. There are plenty of proacrosomal granules and mitochondriaes is spermatid. At the stage of metamorphosis, proacrosomal granules gathered and cicatrized gradually and formed a bigger acrosomal vesicle, which covered at the anterior part of nucleus and formed cap-shaped acrosome. Mitochondria gathered reverse with proacrosomal granules and fused with 4 bigger globe-shaped mitochondria. Centriole moved to post end of nucleus and formed exoneme by the distal centriloe. The nucleus condensed. Its size reduced gradually and changed into a cup shape in the end. Golgi body and redundant cytoplasm went down the drain at last.