Fig. 12
From: Cleavage modification did not alter blastomere fates during bryozoan evolution
Bryozoan development in comparison to spiral cleavage. Line drawings represent cleavage, blastula, and larval stages of a generalized spiral-cleaving embryo (based on [19]) and the biradial-cleaving embryo of the bryozoan M. membranacea. Shades of grey indicate the first, second, and third quartets and their respective fates in the blastula and larval tissues. The fourth quartet, macromeres, and descendants are depicted in white. A simplified summary of the gene expression domains is mapped to the blastula stage