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HH14 | (50-53 hours). 22 somites. Forebrain and hindbrain fonn about a right angle. Visceral (branchial) arches 1 and 2, and clefts 1 and 2 distinct. Primary optic vesicle invaginating; lens placode formed. Opening of auditory pit constricted. Rathke's pouch can be recognized. Ventricular loop of heart now ventral to atrio-ventricular canal. Amnion extends to somites 7-10. |