into subjects used here, holds good mainly for Vertebrates. Therefore, the 

 systematic arrangement was directly applied within the general subjects 

 for investigations on Invertebrates. 



The names of cooperating embryologists have been arranged alpha- 

 betically. 



The enormous variety of subjects did not allow any entirely consistent 

 and adequate classification, so that in several cases an investigation could 

 have been classified under more than one heading. In order to avoid 

 an enormous extention of this issue we tried to classify every investigation 

 under one heading only, which, however, often required a Solomon's 

 judgment. We have, therefore, added supplementary indices, placed 

 behind the corresponding line, which refer to other headings under which 

 the investigation in question can also be placed. 

 The indices before the corresponding line refer to the systematic group. 



In the above mentioned chapters b — e we have not translated the text 

 received in order to avoid any change in its character. For the same 

 reason any correction of the text has been restricted as much as possible. 



We hope that chapter f will develop into a section in which every 

 embryologist will record new practical technical methods or his own 

 experiences with new technics; in general, data which would not be 

 published otherwise, or which are in danger of being neglected. These 

 annotations can be inserted in the form of references to little known 

 publications, or in the form of very short notes, in which only the essential 

 data are given. The examples may further demonstrate the intended 

 contents of this section. 



Chapter g will discuss general questions and projects, which are o5 

 importance and interest to every embryologist. (Cf. the project of the 

 Central Embryological Library at the Hubrecht Laboratory, and that 

 of the Normal Table of Xenopus laevis). 



Chapter h will finally be destined for communications from the "Institut 

 International d'Embryologie". 



