PREFACE 



This volume contains the abstracts of contributed papers, demonstrations and films 

 presented at the Xlth International Congress of Genetics. The editorial policy has 

 been to assemble the abstracts into sections not corresponding completely with the 

 titles of the symposia (see vol. II and III). Within each section we have endeavoured to 

 arrange the abstracts in a practical manner which may, however, vary from section 

 to section. Those abstracts delayed in some way are printed at the end of their respective 

 sections. The abstracts are numbered within each section; D refers to demonstrations 

 and F to films. In the alphabetical index of authors at the end of this volume references 

 are given to these numbers. Full addresses of the authors may be found by consulting 

 the membership list supplied at the Congress and printed at the back of volume III. 



S. J. Geerts 



