part of start stage end stage hypothalamus zebrafish_anatomy ZFA:0000032 Multi-tissue structure which is the largest portion of diencephalon and is ventrally located. The hypothalamus arises near the end of the segmentation period and the embryonic hypothalamic region gives rise to the neurohypophysis and other diencephalic nuclei. TAO:0000032 diencephalon multi-tissue structure segmentation:26+ somites adult