Like many ctenophores, Bolinopsis produces glassy-clear though very yolky eggs. The zygote has a thick outer layer of yolk-free cytoplasm surrounding close-packed yolk globules (left-most picture). The embryo undergoes unequal and oriented divisions in which the yolk segregates into large cells that will form the embryonic endoderm, and the clear cytoplasm is mostly apportioned into smaller blastomeres. The second picture below shows the difference between the micro- and macromeres, and the fourth picture shows a macromeres in the process of segregating clear cytoplasm to one end in preparation for division.