Transit of heat from three selected points across the blastoderm has been analysed. 2. The shock at the differentiating centre is more drastic than that at a point away from it. 3. The posterior and the middle portion of the embryo are more susceptible than the anterior portion of the same to the thermal shock. 4. Graded types of ontogenesis have been observed after thermal treatment. 5. The epiblast is the most susceptible layer to heat treatment than the other two. 6. Different aspects of the abnormal morphogenesis have been explained from the point of view of morphogenetic movement of cells.
