Fig. 3. The adenohypophyseal anlage is faced by fgf3-expressing telencephalic cells early, and ventral diencephalic cells later. Probes used for in-situ hybridizations are indicated in the corresponding colors in the lower right corners, ages of embryos in the upper right corners. (A-C,F-K,N) Lateral views on head region. (D,E,L,O) Transverse optical sections. (N) Sagittal section. White arrows in B indicate levels of optical cross sections shown in (D,E). Numbers in G mark pharyngeal arches (see Fig. 2). Arrow in H indicates fgf8-positive cells in posteriormost regions of the posterior-ventral hypothalamus. Arrow in I indicates level of optical cross section shown in L, arrow in J indicates sagittal section shown in M, arrow in N cross section shown in O. ad, adenohypophysis; ep, epiphysis; fe, facial ectoderm; h, hypothalamus; i, isthmus; os, optic stalk; pe, placodal ectoderm; po, polster; pvh, posterior-ventral hypothalamus; ppe, pharyngeal pouch endoderm.