germinal disc वाक्य

During embryonic development, transformation of the flat, two-layer germinal disc into a three-dimensional body depends on transition of some cells from an mesenchymal phenotype.
Polyspermy is apparently allowed; when the yolk passes through the infundibulum of the oviduct and is exposed to sperm storage glands, the sperm preferentially seek out the near center ( but not the exact center ) of the germinal disc region and break through the perivitelline membrane.