Fig. 7
Summary diagram showing behavior of the 1q2 micromeres and 1q1 progeny at later stages of development. Individual cells and their clones are colored, as shown in (a). Orientations or views are indicated under each diagram. Embryos (b-h) are oriented with the future posterior pole directed toward the bottom of the figure. The animal pole is marked with a pink dot in each embryo. a Animal pole view of 25-cell stage and color key. b-e Four different views of an early organogenesis stage embryo showing contributions of the 1q progeny to the developing head. Note that the 1q2 cells now occupy a much smaller area on the dorsal surface of the head. f-h Three views of an advanced veliger larva showing contributions of the formation of the head, anterior surface of the velum and the prototroch by progeny of the 1q1 cells. By this stage the 1q2 cells have been lost from the embryo. ft., foot; lvl, left velar lobe; rvl, right velar lobe; sh, shell; st, stomodeum. Based on the result of this study, as well as those of Hejnol et al. [37]