INTRODUCTION 



In the twelfth issue the organization of the various chapters has undergone 

 no change. In order to reduce the cost of printing as well as the size of the 

 volumes, smaller type has been used for the Directory of Names and Addresses 

 and for the Directory of Institutes. 



India and the U.S.S.R. show a considerable increase in the numbers of 

 institutes listed. Contact was again established with Uruguay. 



Information concerning the Hubrecht Laboratory may be found on page 263. 

 For information regarding the "International Institute of Embryology" (in- 

 cluding the latest membership list), please see page 264. This section also gives 

 details concerning the Vlth International Congress of Embryology (topic: 

 "Nucleocytoplasmic interactions during differentiation") (Paris, 1 — 7 Sept. 

 1968). 



P. D. NIEUWKOOP 

 J. FABER 



