Cycle of the Seminiferous Epithelium in the Grey-headed Fruit Bat, Pteropus poliocephalus

The seminiferous epithelial cycle of wild P. poliocephalus could be divided into eight stages on the basis of cellular associations and nuclear morphology. The relative frequencies of the stages (1-8) were, respectively: 15'8,20'5,9'4,8'9,11'1,7'7,9'8, and 16·8%. The duration of the cycle was determined by intratesticular injection of [3Hlthymidine followed by autoradiography and estimated to be 16·0 days. The duration of meiotic prophase and spermiogenesis were both 23· 3 days. Spermatocyte DNA synthesis appeared to occur in leptotene primary spermatocytes in stage 2. The duration of spermatogenesis is similar to that in man although the organization of the cycle resembles that of rodents.