Observations on the histology of the ovary of the Costa Rican green turtle, Chelonia mydas L

A preliminary survey of the ovary of the green turtle, Chelonia mydas L., shows that as in Aves the smaller ovarian follicles have a prominent zona radiata. In this a mucopolysaccharide is deposited eventually forming a thick band located in a position analogous to that of the avian perivitelline membrane but which appears to be impermanent since it is no longer present in the larger follicles (> 10 mm diameter). Its disappearance is accompanied by a marked increase in the height of the granulosa cells which become very tall and accumulate large globules of basic protein and sugar in their apical cytosome while at the same time a similar substance is found in the yolk. The granulosa also seems to disappear later in development leaving the highly developed theca interna in contact with the yolk. The theca is then very vascular and contains large numbers of fat cells. No structure comparable to a corpus luteum has been distinguished but ovarian material obtained within the first few days after ovulation has not been available for study and it is not, therefore, possible to be dogmatic on this question.