Segmentation of egg: the division of the originally single celled egg into a number of coherent cells or blastomeres; = cleavage.
"Explanation of Terms Used in Entomology" by John. B. Smith
In these cases heteromorphosis begins from the first cleavage of the egg.
"The Biological Problem of To-day" by Oscar Hertwig
In ten eggs (KU 62154 from San Salvador, El Salvador) the average diameter of the embryos in first cleavage is 1.3 mm.
"Neotropical Hylid Frogs, Genus Smilisca" by William E. Duellman
In such eggs the first cleavage spindle is four-poled.
"Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8" by Various
CLEAVAGE, the division of the egg-cell into many cells.
"Being Well-Born" by Michael F. Guyer