672 



GABRIEL VÔGELl 



6. Da weder im Entoderm der Wirtspolypen noch in den Gastralhôhlen der Chi- 

 mâren markierte Zellen angetroffen wiirden, muss die individuelle Wanderung 

 von Nicht-EMZ in den interstitiellen Râumen des Rumpfektoderms ablaufen. 



7. Weisen Wirtshâlften und Implantate die gleiche Axialpolaritàt auf, so erfolgt 

 die individuelle Wanderung markierter Nicht-EMZ in proximo-distaler 

 Richtung, d.h. ciie Zellen bewegen sich dem disto-proximalen Gewebefluss 

 (Campbell, \961b) entgegen. 



8. Werden die markierten Zellen eines Implantâtes beziiglich der Axialpolaritàt der 

 Wirtsteile einer Konfliktsituation ausgesetzt, so lâsst sich fiir die Wanderung 

 innerhalb des Implantâtes keine Vorzugsrichtung mehr angegeben. 



9. Es wird diskutiert, ob die Richtung der individuellen Zellwanderung durch die 

 Platzverhâltnisse in den interstitiellen Ràumen des Rumpfektoderms beein- 

 flusst wird. 



SUMMARY 



1. The incorporation of ^H-Thymidin into the cell nucleus of Hydra atteimata 

 (Pall.) was analysed at short time intervais. 



2. After six days of starvation, the polyps were fed. Immediately afterwards 

 ^H-Thymidin was injected into the enteron. After the feeding many cells 

 started at the same moment to replicate their DNA. 



3. The possibility that the axial distribution of the mitosis was altered by the 

 movement of the labelled cells can be excluded because only five minutes 

 after the injection labelled cells were found distributed over the whole length 

 of the body. 



4. Radioactive labelling followed by transplantation was used to follow the time 

 course of the migratory capacity of epithelial cells other than muscle cells 

 (called "Nicht EMZ": nematocyts, interstitial cells ^ 1-cells, possibly also 

 nerve cells). 



5. 4 days after ^H-Thymidin labelling of the donor the difîerentiation of labelled 

 " Nicht EMZ " reached a point where the cells were able to migrate. After 

 5 days 70%-80% of ail labelled "Nicht EMZ have moved from the im- 

 planted area into the différent host régions, particularly into the hypostom 

 and the tentacles. 



6. The fact that labelled cells were found neither in the endoderm of the host 

 nor in the enteron of the graft shows that the individuai movement of the 

 " Nicht EMZ " takes place in the interstitial space of the ectoderm. 



7. If the host and the graft showed an identical axial polarity, then the labelled 

 " Nicht EMZ " move individualy in a proximo-distal direction, i.e. the cells 

 are moving against the disto-proximal flow of tissue (Campbell, 1967/?). 



