Photographs taken above a light box of 25 μm thick sections of fetal elephant ovaries recovered between 15 and 21 months of gestation (Scale bar = 10 mm). a) 15.2 months; the cortical region surrounds a central medulla filled with small growing and antral follicles and dark staining interstitial tissue. b) 16.7 months; showing maximum recorded antral follicle development. c) 17.1 months; the number of antral follicles is less than in (b) and more interstitial tissue is apparent. d) 17.5 months; increasing vascularisation of the ovary is apparent. e) 19.3 months; ovarian size has increased significantly from (d) due to hypertrophy and hyperplasia of interstitial cells. f) 20.2 months; the fetal ovary is approaching maximum size. Few antral follicles remain and, as in e), the interstitial tissue is partially obscured by extravasated red blood cells.