[Teratoid formation after implanting early embryos].

The ability of embryos of different age to form teratoids upon their transplantation under the renal capsule was studied in the CBA mice. The teratoids were shown to form most actively upon transplantation of 10 days old embryos; 7 days old embryos, besides teratoids, may give origin to rapidly growing teratomas. The number of differentiated tissues in teratoids increases with the age of transplanted embryo.