Annual change of the gonadal development of the amphioxus in Xiamen

The study was made by observing the annual change of the gonadal development of amphioxus in Xiamen cohtinuously for two years from November, 1986 to November, 1988. We determined the gonadal diameter, gonadosomatic index of each amphioxus, and observed the histological characteristic of the gonadal development of the female and male by cut section, which provided the basis for dividing the stages gonads and the determining level of the gonadal development of amphioxus in each month.