The first and second cleavages from the single cell zygote of "P. flava" are equal cleavages, are orthogonal to each other and both include the animal and vegetal poembryo has four blastomeres both in the vegetal and the animal pole.
The first and second cleavages from the single cell zygote of "P. flava" are equal cleavages, are orthogonal to each other and both include the animal and vegetal poles of the embryo. The third cleavage is equal and equatorial so that the embryo has four blastomeres both in the vegetal and the animal pole.