Fig. 6. Thin section transmission electron microscopy (TEM) analysis of cellularization. The boxed areas are presented at higher magnification in the panels on the right. (A-C) Wild-type embryo, fast phase. Note the almost triangular furrow canals (arrow in B) and the almost straight, closely apposed plasma membranes that connect the top of the furrow canal to the embryo surface (double arrow in C). (D-F) anillin^HP/RS-derived embryo, slow phase. Furrow canals are lacking (D) or malformed (arrow in E). There are no paired plasma membranes at the top of the furrow canal in F. A line of vesicles is present in its place (double arrows). ER in F indicates an ER lamella. (G-I) anillin^HP/RS-derived embryo in fast phase. The nucleus is mis-positioned (arrow in G). All plasma membranes between nuclei are vesiculated at this stage. Scale bar: 10 µm in A,D,G; 4 µm in B,E,H; 0.8 µm in C,F,I.