Fig. 6.

DiI/DiO mapping of HMP versus lateral mesoderm cell movements. Dorsal or lateral views of chicken embryos as in Fig. 5, with somite 3 (s3) labelled with DiI and the lateral mesoderm next to somite 1 (lm1; A–D), next to somite 2 (lm2; E–H) or next to somite 3 (lm3; I–L) labelled with DiO. The lateral mesoderm cell groups begin their morphogenetic movements before the deepithelialisation of TMP, with cells originally situated next to somite 1 (C, D; arrowhead) leading the TMP (C, D; arrow). The lateral mesodermal cell group originally found next to somite 2 split into two streams (G, H; arrowheads); the TMP are embedded in the rostral of these two streams (H, arrow). Lateral mesoderm originating from a position next to somite 3 are already displaced ventrolaterally when the TMP begin to head towards the floor of the pharyngeal arches (K, L). Abbreviations: ma, mandibular arch and ov, otic vesicle.