Fig. 4. The CNH, but not the TBM, generate labelled descendants in axis, CNH and tail bud. (A,B) Cultured embryos that received a graft of 10.5 d.p.c. (A) and 12.5 d.p.c. (B) TBM. Grafts remain as distinct clumps and do not incorporate in the host. (C,D) Whole embryo (C) and dissected paraxial mesoderm from a second embryo (D) that received a graft of DiI-labelled 10.5 d.p.c. CNH. Labelled cells are present in CNH (arrowhead) and paraxial mesoderm. Arrow indicates position of somite 20. Labelled cells are also present along the dorsal neural tube, possibly because of incomplete incorporation of the graft during posterior neuropore closure. (E-G) Embryos receiving a graft of DiI-labelled 12.5 d.p.c. CNH. Tail (E) and transverse section (F) of a second embryo showing incorporation in notochord (arrowhead). (G) Dissected paraxial mesoderm of a third embryo showing label in somites.