Figure 6.

(A-C): Mitotic pattern in the ventral neuromeres after formation of the secondary invagination sites. Flat preparations of embryos stained with phalloidin-rhodamine (red) and anti-Phospho-Histon 3 (green). (A) Only scattered mitotic cells (arrowhead) are present in the ventral neuromeres after invagination of the secondary neural precursors (arrow). The pattern of cell divisions in the cephalic lobe and the prosomal segments at 310 hours of development is representative for the late embryonic stages. (B) Optical section through apical cell layers of the fourth prosomal hemi-neuromere. Only a few mitotic cells (arrowhead) are associated with epithelial vesicles. (C) A similar pattern is visible in basal cell layers of the same neuromere. The arrowhead points to a dividing cell, the arrow points to a dissociating epithelial vesicle. ch, cheliceral neuromere; cl, cephalic lobe; l1 to l2, prosomal hemi-neuromeres corresponding to walking legs 1 to 2; ped, pedipalpal hemineuromere.