Fig. 7
From: New insights into mesoderm and endoderm development, and the nature of the onychophoran blastopore
Expression of twi In all panels, anterior is to the left, except panel J (anterior up). Panels A represents a ventral view, all other panels represent lateral views (dorsal up). Section (a) (inlay in A) shows the same embryo as in A with increased contrast to better visualize the weak most anterior expression in the somite corresponding to the head lobes (hl) (arrow). The box in panel C marks the same area as shown in panels G and H (thin sections). Panel H shows a magnification of the boxed area in panel G. Boxes in panel D show same areas as in panels I-K (thin sections). Panels A´–D´ and G´–K represent SYBR Green staining of the embryos shown in corresponding panels. Developmental stages are indicated (staging system after [9], their supplementary data). Abbreviations: ect, ectoderm; fap, frontal appendage; hl, head lobe; j, jaw; L, leg; mes, mesoderm; na, nephridial anlagen; saz, segment addition zone; sp, slime papilla