The rearrangement of cells to form a hollow, fluid-filled sphere known as the blastula.

Another excellent, highly detailed Indian subcontinent text focused on comparative embryology.

One of the strengths of this text is its comparative approach. It does not limit itself to a single model organism. Instead, it compares the developmental biology of the frog (amphibian), chick (avian), and mammal. This comparative method helps students understand evolutionary relationships and adaptations.

Digital copies allow users to use the Ctrl + F function to instantly find specific terms like "primitive streak," "delamination," or "microlecithal eggs," saving hours of manual skimming.