Fig. 3. Perpendicular divisions start in the 32-cell embryo and continue up to stage 9. For each stage, a whole-mount embryo (A,D,G,J,M,P), and a top (B,E,H,K,N,Q) and side (C,F,I,L,O,R) view of whole-mount embryos with stained mitotic spindles (red) and DNA (yellow) are shown. Red arrows indicate perpendicular divisions. Preparations in F, O and R still have their vitelline membrane.