title: Properties of the primary organization field in the embryo of Xenopus laevis. V. Regulation after removal of the head organizer, in normal early gastrulae and in those already possessing a second implanted organizer.
mesh_terms: D001003:Anal Canal / Q000196:embryology; D000818:Animals; D002454:Cell Differentiation; D005314:Embryonic and Fetal Development; D006257:Head / Q000196:embryology; D008962:Models, Theoretical; D013116:Spinal Cord / Q000196:embryology; D013623:Tail / Q000196:embryology; D013997:Time Factors; D014981:Xenopus / Q000196:embryology*