II 



add that the reason why there is only a small number of descriptions of species 

 in the latter part of the work is, that I desired to come to an end with a work, 

 which has already laid a heavy toll on too many years of my life. 



As will be seen, I have been obliged to make great changes with regard to 

 the delimitation of most families and genera, and if I have not been able to refer 

 a larger number of the earlier described species to my genera, the reason is that 

 I have only had opportunity to examine a small number of these species and 

 the descriptions and figures published in many cases do not give sufficient infor- 

 mation regarding their structure. I hope, therefore, that this work will lead to 

 renewed investigation of the numerous species, which are preserved in museums 

 and private collections, and which have not been examined since they were 

 described. 



The first Plates to this work were prepared in the year 1901, which will ex- 

 plain why a number of the generic names used on the Plates have later been 

 replaced by others on the accompanying explanations. In some cases, namely, 

 I have often been obliged to name the figures given on a Plate at a period when 

 I was not yet certain to what genus a given species should be referred, and I have 

 therefore been obliged provisionally to use the earlier given generic name; in 

 other cases I have later been obliged to use another generic name, because it had 

 been shown in the interval that an older had the priority. In many cases I have 

 followed the view of the priority question expressed by the Rev. A. M. Norman 

 in his »Notes on the Natural History of East Finmark Polyzoa«. In some few 

 cases it has also been necessary to alter the specific name. 



As the Danish coasts are extremely poor in Bryozoa, I have made several 

 endeavours to obtain material from foreign countries which had been preserved 

 in such a manner, that it was suited to the investigation of the nature of the 

 calcification process and of the structftre of the ocecia; but as these endeavours 

 have led to no result I have been obliged to give up my attempt at solving the 

 first question, and with regard to the structure of the ooecia I have been unable 

 as a rule to give information on the internal membranous parts. I have used 

 the microtome for these investigations in a number of cases; but the spirit ma- 

 terial employed was too old to show what I wished to see. 



That I have been able to include so many forms within the scope of my in- 

 vestigations is due for a great part to the help a number of colleagues in foreign 

 countries have given me, and first and foremost my work will bear witness of 

 my great indebtedness to Miss G. Jelly, the author of »A synonymic Catalogue of 

 the Recent Marine Bryozoa «, to whom the Zoological Museum of Copenhagen owes 

 the possession of so many interesting Australian and South African species. Mr. 



