The protoplasmic matter which surrounds the entoblast, or cell nucleus, and undergoes segmentation.(noun)
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Use "periblast" in a sentence
"A first cleavage of the stem-cell (cytula), B division of same into four segmentation-cells (only two visible), C the germinal disk divides into the blastoderm (b) and the periblast (p). d nutritive yelk, f fat-globule, c ovolemma, z space between the ovolemma and the ovum, filled with a clear fluid.)"