Translocations of the Organizer in the Gastrula of Discoglossus.

Summary. 1. Translocations of different regions of the organizer were carried out in young gastrulae of Diacoglossus pictus. In one series of experiments the presumptive anterior mesoderm was exchanged with presumptive posterior mesoderm; in another set the anterior‐posterior axis of the presumptive axial mesoderm was reversed. 2. The translocated pieces retained their original potentialities for gastrula‐tion movements, both in magnitude and direction. 3. The gastrulation movements of the host and of the graft were such that only very incomplete mingling of anterior and posterior regions was brought about; and, perhaps for this reason, little evidence was seen of any inductive interactions between different regions. 4. There was very complete regulation of the host to form a complete embryo within which the graft lay as a more or less independent mass of tissue.