ABSTRACT
Undifferentiated germinal epithelium was isolated following trypsinization from embryonic duck gonads of 5 to 7 days of incubation. This epithelium was associated with ovarian and testicular medullae taken from sexually differentiated embryos.
Ovarian cortex differentiates from female germinal epithelium of 5 days, whatever the source of the medullary tissue with which it is associated (Plate 1, fig. 3; Plate 2, figs. 5, 6,a, b, c). In control experiments the female epithelium undergoes similar development in the presence of mesonephros (Plate 2, fig. 5).
Five-to seven-day male germinal epithelium is influenced by tissues with which it is in contact. In the presence of testicular medulla it gives rise to male medullary cords (Plate 1, fig. 4). In the presence of ovarian medulla, ovarian cortex differentiates (Plate 3, figs. 7 a, b, c). When in contact with mesonephros no differentiation of the male epithelium ensues. These results are particularly clear in the case of germinal epithelia explanted between 5 and 6 days of incubation.
