(Downloading may take up to 30 seconds.
If the slide opens in your browser, select File -> Save As to save it.)
Click on image to view larger version.

Fig. 11. Hh signaling specifies the ability of the stomodeum to condense neural
crest cells on its roof. (A) Schematic of a 10 hpf embryo. Shh
(yellow) secreted from the ventral presumptive brain signals to stomodeum
precursors (red) in the anterior ectoderm. Premigratory neural crest cells
(green) are distant from the Hh source. (B) Later in development,
starting at 21 hpf, the stomodeum signals to neural crest cells through an
unknown mechanism, causing anterior craniofacial neural crest cells to
condense.