Primitive

An Illustrated Dictionary of Medicine, Biology and Allied Sciences · 1907 · p. 38

(prim' dt-iv). First-formed; original. P. Chorion. See Chorion . P. Groove, the enlargement and deepening of the primitive streak. See P. Streak. P. Streak, a streak appearing at the end of the germinal disc, and indicating the first trace of the embryo. It represents, according to many, the concrescence of the lips of the blastopore. P. Trace. See P. Streak.