the eggs of mollusks, roundworms, insects, ascidians, and other organisms. They are distinguished for early and uneven differentiation of various regions of the cytoplasm. When there is artificial division of the blastomeres (which are formed during cleavage of the mosaic egg), usually only parts of the embryo are formed from them; however, under certain experimental conditions, entire embryos may develop from the blastomeres in the same fashion as regulation eggs. The differentiation of eggs into mosaic eggs and regulation eggs is artificial, since the differences between them are temporal and quantitative in character rather than qualitative.
