Continuation of epiboly and neurulation in Notopterus notopterus. (a) Stage 10: evacuation zone (ez) at animal pole and the deepening of the marginal zone (mz) between the animal pole and the vegetal pole, 19h:11min; (b) Stage 11: 50 % epiboly, germ ring (gr) positioned in between of animal pole and vegetal pole, 25h:15min; (c) Stage 12: embryonic shield (es) on the animal pole, note the micropyle (m) and the translucent evacuation zone (ez), 27h:00min; (d) Stage 13: onset of neurulation with vertical view, neural plate (npl), 29h:15min; (e) Stage 14: 75 % epiboly on vertical view, note the yolk plug is mostly constricted by the flat and short germ ring (gr), 36h:00min; (f) Stage 14: transversal view, note the rostral (r) and caudal (c) part of the embryonic shield can be distinguished; (g) Stage 15: 90 % epiboly; note the reduced yolk plug (yp), 39h:10min; (h) Stage 16: latest epiboly, note the tiny remnant of the yolk plug (yp), vertical view; (i) Stage 16: transversal view showing the wedge-shaped neural plate and the rostral (r) and caudal (c) part of the embryonic shield. Arrowhead points to notochord 41h:35min. Scale bar = 1 mm.