Fig. 4

A Germinal bands and germinal plate formation of A. lata embryo. (a) Early stage 7 (b) late stage 7. (c) Lateral view. (d) Early stage 8. (e) Middle stage 8 dorsal view. (f) Middle stage 8 ventral view. (g) Late stage 8 dorsal view. (h) Late stage 8 ventral view. (i) Late stage 8 lateral view. Scale bar in all images 100 μm. B Organogenesis and hatching of A. lata embryo. (a) Lateral view of early stage 9 embryo, indicating the coelomic cavities (cc) arising within the mesoderm in anterior to posterior progression after the completion of germinal plate (gp) formation. (b) Lateral view of middle stage 9 embryo, showing the formation of the ventral nerve cord (vnc) and dorsal ganglion (dg). (c) Lateral view of early stage 10 embryo, showing the everted proboscis (pb). (d) Lateral view of late stage 10 embryo in which the everted proboscis is more notorious and the provisional epithelium is being displaced towards the dorsal midline. (e) Lateral view of early stage 11 embryo showing proboscis retraction and gut formation. (f) Dorsal view of middle stage 11 embryo showing the crop ceca (cpc), intestine (in) and posterior sucker (ps) formed, also showing detachment of the vitelline membrane (vm). Anterior is up in all views unless indicated otherwise. Scale bar in all images 100 μm