to determine whether or not any pancreatic islet cell type arises from rhombencephalic levels of neurectoderm , lengths of presumptive rhombencephalon ( containing potential neural crest ) of black australorp chick embryos at 6- to 9-somite stages were replaced isotopically and isochronically by neural tube of japanese quail embryos .
C1518271
neurectoderm
C0231024
neural tube