Blastula

[blæstjulә]

解释:

(noun.) early stage of an embryo produced by cleavage of an ovum; a liquid-filled sphere whose wall is composed of a single layer of cells; during this stage (about eight days after fertilization) implantation in the wall of the uterus occurs.

杰拉尔丁校对--From WordNet

解释:

(n.) That stage in the development of the ovum in which the outer cells of the morula become more defined and form the blastoderm.

阿奇校对