PREFACE. 



M, 



any years ago I undertook a study of the Danish cretaceous Bryozoa the 

 results of which have not yet been pubhshed, and among the species studied by me 

 were also a small number belonging to the family Melicerititidae (Eleidae d'Orb.) 

 to the members of which d'Orbigny ascribes a calcareous operculum the presence 

 of which, however, has been denied by all the later authors who interprète the 

 supposed operculum as a closure-plate of the same nature as that which has 

 been found both in the Cyclostomata and the Cheilostomata. I came however to the 

 result that d'Orbigny was right in his interpretation of the named structure, and I 

 have published some remarks on this subject in my preliminary communication 

 »Studies on Bryozoa« '). As later I wished to make a more comprehensive study 

 of this interesting group I extended my investigations over a number of foreign 

 species, and in this effort I have been supported by several colleagues abroad. In 

 the first instance I owe a debt of gratitude to Dr. F. Canu the author of so many 

 valuable works on fossil Bryozoa, who has not only sent to me a large number of 

 French species defined by him, but also helped me to acquire materials containing 

 cretaceous bryozoa from a number of French localities. A similar material from a 

 few other French localities has been sent me by Mr. G. Dollfus, and to Mr. M. 

 FiLiozAT who has made a special study of the cretaceous Bryozoa from Vendôme 

 I owe the possession of a number of species from that locality. For the gift or 

 loan of specimens I am also indebted to Mr. A. W. Waters, Dr. E. Pergkns, Prof. Dr. 

 G. Steinmann, Bonn and Prof. Dr. H. Wegner, Münster, and lastly I have been able 

 to acquire a collection of cretaceous Bryozoa from the Chatham chalk, by the aid 

 of Mr. W. Gamble. To all these gentlemen I offer my sincere thanks. 



Zoological Museum of Copenhagen. /^ a/t n r 



August 16. 1912. G. M. R. Levinsen. 



•j 16, 



