THE OOGENESIS AND FEMALE GONADAL HISTOLOGY OF CELLANA GRATA(GOULD)

The gonad and gametocyte of Cellana grata (Gould) were observed under microscope by puncture and historical section to study the characteristic of female gonad and the morphology and distribution of oogametes at different developing stages. The results showed that: (1) the female folliculus of C. grata were composed of oogoniums and oocytes at different developing stages, and matured oogametes were located around the central region of follicle; (2) The development of gametocytes was asynchronous and spawning came up on successive type. (3) The gametocytes and its nuclei and nucleolus trended to enlarge during the oogenesis with the maturity of the gonad, and 1-2 nucleolus appeared. (4) Characteristic of acido-and baso-philic of oocytoplasma changed with coming up of oocytoyolk. (5) Matured egg were in range of about (120-140) μm × 150 μm in size, which were rounded by an jelly coat with thickness 5-12 μm. (6) The uniformity and acidity of jelly coat were changeable according to the developing stages of gametocyte. It was the signal of oogoniums becoming mature that gaps appeared between jelly coat and the oocyte membrane; and it was another signal of oogoniums being matured and went to spawn that acidophilic of the oogoniums transformed to basophilic.