The shallow valley that extends along the length of the primitive streak[MP]. [ MP:0009330 ]

This is just here as a test because I lose it

Term information

database cross reference

pheno_slim, early_development

external definition

A shallow groove, the primitive groove, appears on the surface of the primitive streak, and the anterior end of this groove communicates by means of an aperture, the blastophore, with the yolk-sac[Wikipedia:Primitive_groove].