Egg Germination

“Further development of hen’s egg; after Haeckel: A, the mulberry mass of cleavage cells, b, same as seen on top in fig 111, F, here viewed in profile in section, resting upon n, the simply-shaded part of the figure, to represent conventionally the mass of food-yelk. A, morula stage (as before); B, blastula stage, the mass of cells, b, forming the blastoderm, uplifted from the food-yelk, leaving the cleavage-cavity, s; w, the thickened rim of the germ-disc; C, the blastula in process of inversion, by which a layer of entoderm-cells, i, growing from periphery to centre, will apply itself to the layer of exoderm-cells, e, obliterating the cleavage-cavity, s; D, the disc-gastrula completed, by union of entoderm, i, with exoderm, e, leaving the primitive intestinal cavity, d, which is quite similar in appearance to the cleavage cavity, s, but morphologically quite different.” Elliot Coues, 1884

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