Fig. 9. Stage 19 in Development and gastrulation in Hyloxalus vertebralis and Dendrobates auratus (Anura: Dendrobatidae)

Fig. 9. Stage 19: Muscular response stage of H. vertebralis and D. auratus embryos. Micrographs of H. vertebralis embryos are shown in A, C, E, and micrographs of D. auratus embryos are shown in B, D, F. (A) Lateral view of an embryo. (B) Dorsal view of an embryo. The developing gills were visible. (C–D) Cross sections through the trunk. The dorsal fin was visible in C, and the pronephros in D. (E) Horizontal section at the level of the gut. (F) Horizontal section at the level of the brain and the gut. bn, brain; df, dorsal fin; fg, first gill pair; g, gut; gb, gill bud; hy, hyoid arch; ma, mandibular arch; n notochord; nt, neural tube; p, pronephros; s, somite.