Importance of timing in development: Retarded “maturation” of extracellular matrix inhibits pigment cell migration in embryos of the white axolotl mutant: J. Löfberg,R. Perris and H.H. Epperlein1. Dept. of Zoology,Uppsala University,S-751 22 Uppsala,Sweden; 1Dept. of Anatomy,Freiburg University, 7800 Freiburg,FRG |