yolk cell
71Segmentation of the ovum — Segmentation Seg men*ta tion, n. The act or process of dividing into segments; specifically (Biol.), a self division into segments as a result of growth; cell cleavage; cell multiplication; endogenous cell formation. [1913 Webster] {Segmentation… …
72Segmentation sphere — Segmentation Seg men*ta tion, n. The act or process of dividing into segments; specifically (Biol.), a self division into segments as a result of growth; cell cleavage; cell multiplication; endogenous cell formation. [1913 Webster] {Segmentation… …
73Velvet worm — Taxobox name = Onychophora fossil range = Cambrian – Recent image width = 250px image caption = Velvet worm regnum = Animalia phylum = Onychophora phylum authority = Grube, 1853 subdivision ranks = Extant families subdivision = Peripatidae… …
74Placenta — For the ancient Roman bread, see placenta (food). For the placenta of fruit, see placentation. Placenta Placenta Precursor …
75Chorion — For the chorion in invertebrate eggs, see Chorion (egg). Chorion Diagram showing earliest observed stage of human embryo …
76Annelid — Temporal range: Early Ordovician–Recent[1] …
77lecithin — /les euh thin/, n. 1. Biochem. any of a group of phospholipids, occurring in animal and plant tissues and egg yolk, composed of units of choline, phosphoric acid, fatty acids, and glycerol. 2. a commercial form of this substance, obtained chiefly …
78Caudata — ▪ amphibian order Introduction also called Urodela, one of the major extant orders of the class Amphibia. It includes salamanders (salamander) and newts (newt). The relatively small and inconspicuous salamanders are important members of… …
79egg — The female sexual cell, or gamete; after fertilization and fusion of the pronuclei it is a zygote and no longer an e.. In reptiles and birds, the e. is provided with a protective shell, membranes, albumin, and yolk for the nourishment of the …
80cleavage — /klee vij/, n. 1. the act of cleaving or splitting. 2. the state of being cleft. 3. the area between a woman s breasts, esp. when revealed by a low cut neckline. 4. a critical division in opinion, beliefs, interests, etc., as leading to… …
