anatomical structure development yolk syncytial layer development YSL development hjd The "yolk syncytial layer" structure can be found in Teleostei, Myxini, Chondrichthyes, Lepisosteiformes and Cephalopoda according. The progression of the yolk syncytial layer over time, from its initial formation to the mature structure. The yolk syncytial layer is the peripheral layer of the yolk cell including nuclei and non-yolky cytoplasm. GO:0106336 biological_process 2020-11-05T17:56:43Z