STUDIES ON THE ANNUAL REPRODUCTIVE CYCLE OF THE SEA URCHIN AND THE ACID PHOSPHATASE ACTIVITY OF RELICT OVA

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Abstract
Specimens of the sea urchins Anthocidaris crassipina and Hemicentrotus pulcherrimus were collected each month, their ovaries were fixed and embedded in Epon 812, and thick sections were observed with the light microscope. The sea urchin ovary has a clearly defined state in which nutrient globules are produced and stored in accessory cells. In H. pulcherrimus, this state continued from May-Nov. The number of globules in the accessory cells fluctuated with the course of the reproductive cycle. Toward the end of the breeding season, strong acid phosphatase activity was detected in the unshed (relict) ova as they degenerated and numerous large mosaic globules containing cortical granules appeared in the accessory cells. The cytoplasm of relict ova is probably disrupted by the activity of their lysosomes.