Figure 2

Snake DiI injection. Snake embryos (1,2,4 and 5) were removed from the egg and the neural tube injected with DiI. After 12 hrs (A-F) or 24 hrs (G-L) of incubation embryos were fixed and photographed for migrating DiI-positive neural crest cells. Each embryo is shown in sequential higher magnifications. Embryo 1 show delaminated neural crest cells (arrowheads A-C), although it did not have substantial number of crest cells migrating in streams (higher magnification in panels B, C). Embryo 2 had clear robust migrating neural crest cells in streams (arrowhead in D for first coil). At the tail level the cells migrated on the rostral portion of the somites, further magnified in panel F. Embryos 4 and 5 showed a wider range of DiI labeling since it was incubated for 24 hrs and DiI labeling reached the tail end (G-L). Embryo 4 neural crest cells migrated as well as streams on the rostral side of somites (arrowheads in H and I) both in 2^nd and 3^rd coils as well as into the mesonephroi (arrows in H). Embryo 5 showed the rostrally migrating cells, in the 2^nd coil we observe that cells were migrating between the somites (arrowhead in K) as well as cells along what is the presumptive aorta (arrow in K), also as for Embryo 4, DiI cells reached the mesonephroi (yellow arrows in J, K). L showed higher magnification of 3^rd more caudal coil with individual cells migrating on the rostral portion of the somites (arrowheads in L). R is for rostral; C is for caudal orientation in the embryo coils.