STUDY ON THE OVARIAN DEVELOPMENT IN MONOPTERUS ALBUS

An anatomical observation was made on the morphological characteristics of the ovary of Monopterus albus. Oogenesis, ovarian development and annual cycle of ovary were investigated using paraffin-section method, histochemical method and scanning electron microscopy. Oogenesis in M. albus can be divided into five stages, i.e. the chromation-nucleolus stage, perinucleolns stage (including early and late phases), primary yolk stage (including early and late phases), secondary and tertiary yolk stage (including early, middle and late phases), stage and mature stage. Ovarian development is divided into four stages: previtellogenesis ovary, vitellogenesis ovary (including early, middle and late phases), mature ovary and spent ovary.The ovarian development is partially synchron zed. Fish with this type of development usually spawn once a year. The vitellogenesis, the stages of ovarian development and the spawning type in M. albus are discussed.