segmentation (seg-men-ta's hun)

The proce of becoming divided into parts; especially as in germ s. discoidal s. A variety of s. in which the germinal layer alone is involved, duplicative S. A s. of the microorganism of gonorrhea in which there is an interval between the two segments, free s.s. The The s.division' of naked cells, germ of the fecundated ovum. "A proce of division and multiplication" of the blastospheres, ''after the manner of cell cleavage." metameric s. The division of embryo into metameres. partial s. of the vitellus. That sort of s. of a mesoblastic ovum which takes place only in the formative vitellus. primordial s. A supposititious archetypal form of s. pro to vertebral s. A division of the mesoblast on each side of the notochord into the pro to vertebrae. regular s. A form of s. in which the ovum is converted into spheres of equal size and regularly disposed, s. of the ovum, s. of the yolk. See germ s. superficial s., surface s. A variety in which the s. occurs upon the surface of the ovum. total s. of the vitellus. That complete form of germ s. in which the whole yolk divides into two, four, eight, and so succe ively into smaller divisions, each with its nucleus, all destined to take part in the further development of the ovum. unequal s. A form of s. in which, after the ovum is divided into four equal segments, the spheres of one pole are smaller than those of the opposite pole and afterward are much more numerous. [Lat., segmentatio, from secare, to cut.]