The onset of differentiation in the epiblast of the chick blastoderm (SEM and TEM).
D000367:Age Factors; D000818:Animals; D001755:Blastocyst / Q000648:ultrastructure*; D001756:Blastoderm / Q000648:ultrastructure*; D002454:Cell Differentiation; D002642:Chick Embryo; D002923:Cilia; D004475:Ectoderm / Q000648:ultrastructure; D002479:Inclusion Bodies; D007365:Intercellular Junctions; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning