Name: late blastula stage
ECAO ID: 0000280
Definition: "The embryo is composed of about 400 cells and is surrounded by a fertilization envelope. The embryo is still spherical but the wall is thinner and smoother than at previous stages. The vegetal plate has not formed. Many cells are ciliated, and in some species (e.g. P. lividus) the embryo has begun to rotate within the fertilization envelope, while in others (e.g. S. purpuratus) it is still non-motile. Note for euechinoid indirect developers: molecular labeling typically indicates the presence of 32 large micromere descendants and 4 to 8 small micromere descendants at this stage ."
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