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nts as a result of growth; cell cleavage; cell multiplication; endogenous cell formation. Segmentation cavity (Biol.), the cavity formed by the arrangement of the cells in segmentation or cleavage of the ovum; the cavity of the blastosphere. In the gastrula stage, the segmentation cavity in which the mesoblast is forme…

The loss or obliteration of division into segments; as, a desegmentation of the body.

Segmenting unequally; -- said of telolecithal ova with complete segmentation.

The cavity of the blastosphere, or segmentation cavity.

Having the food yolk placed at the center of the ovum, segmentation being either regular or unequal. Balfour.

e of the lateral axes. -- Cell cleavage (Biol.), multiplication of cells by fission. See Segmentation. -- Cubuc cleavage, cleavage parallel to the faces of a cube. -- Diagonal cleavage, cleavage parallel to ta diagonal plane. -- Egg clavage. (Biol.) See Segmentation. -- Lateral cleavage, cleavage parallel to the l…

toderm and ectoderm; as, the "ectental line" or line of juncture of the two layers in the segmentation of the ovum. C. S. Minot.

Having the food yolk, at the commencement of segmentation, in a peripheral position, and the cleavage process confined to the center of the egg; as, ectolecithal ova.

ll, until finally the original cell wall is ruptured and the new cells are liberated (see Segmentation, and Illust. of Cell Division, under Division). This mode of growth is characteristic of many forms of cells, both animal and vegetable.

plant, or its germ, undergoes a spontaneous division, and the parts again subdivide. See Segmentation, and Cell division, under Division.

Undergoing complete segmentation; composed entirely of germinal matter, the whole of the yolk undergoing fission; -- opposed to meroblastic.

Consisting only in part of germinal matter; characterized by partial segmentation only; as, meroblastic ova, in which a portion of the yolk only undergoes fission; meroblastic segmentation; -- opposed to holoblastic.

A form of spore, usually elongate or falciform, and somewhat amoboid, produced by segmentation of the schizonts of certain Sporozoa, as the malaria parasite.

Of or pertaining to a metamere or its formation; as, metameric segmentation.

One of the smaller cells, or blastomeres, resulting from the complete segmentation of a telolecithal ovum.

of the ovum or egg in the first stages of its development; -- called also mulberry mass, segmentation sphere, and blastosphere. See Segmentation.

The process of cleavage, or segmentation, of the ovum, by which a morula is formed.

(corresponding to the antennules, antennæ, and mandibles), a median eye, and little or no segmentation of the body.

The protoplasmic matter which surrounds the entoblast, or cell nucleus, and undergoes segmentation. -- Per`i*blas"tic, a.

the two bodies or nuclei (called male and female pronuclei) which unite to form the first segmentation nucleus of an impregnated ovum.