1. This polar lobe forms at the vegetal pole during cleavage, and then gets shunted to the D blastomere. 2. The animal pole consists of small cells that divide rapidly, in contrast with the vegetal pole below it. 3. It is thought that these contacts allow the YSL to " tow " the EVL towards the vegetal pole . 4. The vegetal pole contains large yolky cells that divide very slowly, in contrast with the animal pole above it. 5. The cytoplasm in the vegetal pole specifies this axis and removing this cytoplasm leads to a loss of axis information. 6. This layer forms when the cells at the vegetal pole of the blastoderm combine with the yolk cell underneath it. 7. The axis of symmetry passes through on one side the animal pole, and on the other side the vegetal pole . 8. The blastoderm begins to thin as it spreads toward the vegetal pole of the embryo until it has completely engulfed the yolk cell. 9. The YSL also moves towards the vegetal pole , spreading along the surface of the yolk and migrating slightly ahead of the blastomeres. 10. The anterior / posterior axis lies along the animal / vegetal axis set up during nuclei at the vegetal pole of the blastula.
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