Figure 4

Sections through DiI labeled snake embryo. Snake embryos (Embryo 3 and 4) were cryo-sectioned. A-E shows sections starting at the most caudal portion and ending at the most rostral portion of st.20 Embryo 3. Neural crest cells showed robust migration in the tail region (arrowheads in A-C) and at more rostral levels the numbers were fewer and cells were found along the inter-somitic space (arrow in E). F-H show a transverse section close to the tail, showing thick streams of neural crest migrating ventromedially (F, G) or distally as if beginning to enter the sub-ectodermal space (arrow in H). I Cartoon depicting the axial location and orientation of these sections. DA: dorsal aorta. MN: mesonephroi. R is for rostral; C is for caudal orientation in the embryo coils.