Stage 27(2 days 10 hrs) 24 somite stage
Drown by T. Iwamatsu
(Abbr. cd: Cuvierian duct, ha: atrium of heart, hv: ventricle of heart, ot: otolith)
Stage 27 (2 days 10 hrs) 24 somite stage (Appearance of pectoral fin bud):
The tip of the tail where the notochord attaches is pointed. The embryonic body with the tail free from the yolk sphere encircles 5/8 of the yolk sphere. The rudiments of the pectoral fins protrude from the body trunk behind the base of the Cuvierian ducts. The eminences of liver rudiment are clearly seen on the left side beneath the 1st-3rd somites, and the gut tube can be seen beneath the 1st-13th somites curving to the left-ventral in the region between the 1st and 3rd somites. The arterial end of the heart has shifted to the right. The tail is free of the yolk sphere, and its vein is observed from the 10th to the 16th somites.