Mosaic and Regulation Phenomena during the Early Formation of the Chick Blastoderm
Figure 9
(a): Ventral view of living hemisectioned unincubated chicken blastoderm (right side), at the start of the culture period: the median part of the right Rauber’s sickle half has been removed and the deep side of the upper layer is visible (*); graphite particle on the cross sectioned part of Rauber’s sickle (indicated by white arrow). Bar = 2 mm. (b): The same hemi-embryo as in Figure 9(a), after 25 hours of culture: a rectilinear primitive streak, with tissue on both sides, starts from the cross-sectioned part of Rauber’s sickle (graphite particle) in the direction of the nodus (indicated by white arrow) and neural plate (N). Bar = 2 mm.
