1. K. T. Rajan andA. M. Hopkins, Nature, Lond.227, 621 (1970).
2. M. B. Adelotte andD. Kochhar, Devel. Biol.28, 191 (1972).
3. D. Kochhar, inSymposium of Metabolic Pathways in Mammalian Embryos During Organogenesis and its Modification by Drugs (Eds.R. Bass, F. Beck, H. J. Merker, D. Neubert andB. Randhahn; Free University Berlin Press 1973).
4. D. Kochhar, Devel. Biol., in press.
5. D. Neubert, submitted for publication in Naunyn-Schmiedeberg's Arch. Pharmac. (1974 a and b).