Stage 18(1 day 2 hrs)
Late neurula stage (Optic bud formation)
Drown by T. Iwamatsu
(Abbr. bl: beak-like mass of cells, ey: optic (eye) vesicle, kv: Kupffer's vesicle, pb: protobrain)
Stage 18 (1 day 2 hrs) Late neurula stage (Optic bud formation):
The brain and nerve cord in the arrow-shaped embryonic body ccdevelop as a solid rod of cells. A solid optic bud (rudimentary eye vesicle) appears on each side of the cephalic end. The beak- like cell mass is still visible. The Kufpper's vesicles enlarge somewhat. A small part of the yolk sphere still forms a blasto- pore at the vegetal pole.