immediately_preceded_by developmental stage Medaka stage 25 Medaka stage 26 22 somite stage Development of guanophores and vacuolization of the notochord OlatDv:0000290 Zoological Science 11: 825-839 (1994) - 2 days 6 hrs Stage 26 (2 days 6 hrs) 22 somite stage (Development of guanophores and vacuolization of the notochord): Blood containing globular blood cells is pumped out beyond the anterior region of the hind-brain. The caudal vein is observed in the region from the 1st to the 14th somites. The tip of the tail is completely free of the yolk sphere. The anlage of the liver, which first appeared at the 19 somite stage, is not yet well- developed. Red-brown colored guanophores, which first appeared at the ventral side of the mid-brain in the 20 somite embryo, are more clearly seen. Vacuolization of the notochord starts at its anterior region. Differentiating choroidea of the eyes begin to darken due to melanization. - 2 days 6 hrs medaka_ontology