Fig. 1. HNK-1 immunohistochemistry (red) and DAPI staining (blue) of 11-34ss chick embryos. (A,A') NCC located on the dorsal aspect of the embryo, adjacent to somites 1-2 (bracketed). (B,B') NCC grouped at the base of somites 1-3, adjacent to an accumulation of cells arising from the post-otic region (dashed line). (C,C') NCC concentrated at the base of somites 3-5 (bracketed). (D,D') NCC ventral to somites 1-5. Arrow indicates cells advancing towards the foregut from the base of somite 3. (E,E') NCC are absent from somites 3-6, and reduced in numbers in somites 1, 2 and 7. (F,F') A small stream of NCC progressing towards the foregut (arrow). OV, otic vesicle. Scale bars: 100 µm in A, 50 µm in D and F.