Occurrence of polyovular follicles and its possible significance in the ovary of the bat, Scotophilus heathi

Seasonal changes in the number of polyovular follicles were estimated in a Vespertilionid bat, Scotophilus heathi. The largest number of polyovular follicles was observed during September, which coincided with the period of maximum development of intra-ovarian rete cells cord. It has been suggested that interaction between rete cells cord and follicle may be responsible for giving rise to a number of polyovular follicles in the medullary region of the ovary. Most of the polyovular follicles observed were biovular and they grow maximum up to the late preantral stage. Polyovular follicles with four or more oocytes were observed during September and they do not grow beyond stage I of the follicular development. The polyovular follicles were generally short lived and may contribute to the extensive development of the interstitial cells in S. heathi.