from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The fertilized egg cell or parent cell, whose development produces the child or other organism.
from the GNU version of the Collaborative International Dictionary of English
- n. The fertilized egg cell or parent cell, from the development of which the child or other organism is formed.
from The Century Dictionary and Cyclopedia
- n. In biology, a fertilized egg-cell; an impregnated ovum; the parent cell of any organism.
We have now secured a number of firm standing-places in the labyrinthian course of our individual development by our study of the important embryonic forms which we have called the cytula, morula, blastula, gastrula, coelomula, and chordula.
The ovum after the nucleus had been re-formed became the cytula, which was the ontogenetic counterpart of the amoeba.
ARCHI -: (in compounds) the first or typical -- as, archi-cytula, archi-gastrula, etc. BIOGENY: the science of the genesis of life (bios).
The stem-cell or cytula, formed by fecundation of the ovum, divides by repeated regular cleavage first into two (A), then four (B), then eight (C), and finally a large number of segmentation-cells (D).
The amoeboid nature of the young ovum and the unicellular condition in which (as stem-cell or cytula) every human being begins its existence justify us in affirming that the earliest ancestors of the human race were simple amoeboid coils.
* (* The plasson of the stem-cell or cytula may, from the anatomical point of view, be regarded as homogeneous and structureless, like that of the monera.
Stem-cell of one of the echinoderms (cytula, or "first segmentation-cell" = fertilised ovum), after Hertwig. k is the nucleus or caryon.)
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.)