Figure 3

Regression of the cleavage furrow (marked with arrows) after cytochalasin B treatment. Cytochalasin was added during the first cleavage of a Mnemiopsis zygote. DIC images showing the ingressing cleavage furrow (arrow) (A, B). Once cytochalasin B has been added, cleavage stops (C) and finally the cleavage furrow regresses (D). Additional file2 shows the regression of the cleavage furrow in a time-lapse movie in the same specimen.