Fig. 6
From: Formation of the germ-disc in spider embryos by a condensation-like mechanism
Germ-disc formation in Parasteatoda tepidariorum. A contiguous blastoderm is present at stage 2 of embryonic development. The mid-blastula transition (MBT) is at the end of stage 2 and germ-disc formation needs the onset of zygotic gene expression. The germ-disc is formed by a condensation like mechanism. Cell membranes (red); nuclei (grey circles); perinuclear cytoplasm (black); yolk (yellow). Upper left corner: schematic representation of the cross-section of blastodermal cells (st. 2). Upper right corner: schematic representation of the cross-section of germ-disc cells (st. 4). Lower right corner: schematic representation of the cross-section of an extra-embryonic cell (st. 4). Not to scale