Classification of the follicle population based on oocyte diameter and number of granulosa cells in the ovary of large-eared hedgehog, Hemiechinus auritus gmelin.

The present study includes the classification of ovarian follicle population in H. auritus on the basis of oocyte diameter and granulosa cell layers. Our observations revealed that there was direct relationship in the oocyte diameter and the follicle size under a certain limit. Diameter of oocytes increased from 10 microns to 84 microns with consequent increase in the follicle size from 20 microns to 320 microns. However, the diameter of oocyte did not show further increase, but the follicle size was enlarged gradually up to 500 microns. Based on the diameter of follicle and the number of granulosa cell layers, the follicle population was divisible into 5 categories: 1. primordial follicle which ranged 20 to 80 microns in diameter with few cells to one complete layer of granulosa cells in the largest cross section; 2. small follicle which was 81 to 200 microns in diameter having 2 to 3 complete layers of granulosa cells; 3. secondary or medium-sized follicle which ranged 201 to 320 microns in diameter and consisted of 4 to 6 complete layers of granulosa cells; 4. transitory follicle having diameter 321 to 360 microns and 7 complete layers of granulosa cells; 5. large-sized follicle which ranged 361 to 500 microns in diameter and had more than 7 layers of granulosa cells.