Early cleavages of C. subdepressus under light microscopy.

A Two nuclei (arrows) during cariocinesis of the first cell division. B Embryo with two cells before the second cleavage; hialine layer is visible between cells (arrow). C Animal pole view of an embryo with 4 cells. D Lateral view of an embryo with 8 cells; blastomeres on the vegetal pole are smaller (bottom). E Micromeres (arrow) on the vegetal pole of an embryo with 16 cells. F Lateral view of an embryo with 16 cells. G Arrangement of micromeres and macromeres on the vegetal pole of a 16 cell embryo. H 16 cell embryo showing the mesomere arrangement on the animal pole. I Fifth division cycle showing child-micromeres (arrow) on the vegetal pole; embryo with 32 cells. J Lateral view of an embryo with 32 cells. K Vegetal pole of an embryo with 56 cells. L Lateral view of an embryo with 108 cells. Scale bars =