VI 



student, instead of labouring through such a complicated table, will in most cases 

 prefer the much more simple and direct method of determination by comparing 

 his specimen with the figures, and, if still in doubt, consulting the short diagnoses 

 given of the respective families, genera and species. 



In the elaboration of this Volume, I have been assisted by several di- 

 stinguished naturalists both in my own country and abroad ; and I desire here to 

 tender them my best thanks. Among foreign naturalists, my thanks are due to 

 Canon A. M. Norman, Mr. Th. Scott, Prof. Brady and Prof. Cleve, for sending me 

 interesting specimens. I am also greatly indebted to the Zoological Station at 

 Naples for a very interesting series of plankton-samples, which have been of great 

 use to me in comparing the Mediterranean species with those of the northern 

 seas. The Norwegian naturalists to whom I wish to offer my hearty thanks are 

 Mr. 0. Nordgaard, director of the Biological Station in Bergen, and Dr. J. Hjort, 

 director of the Norwegian marine fisheries. To the latter gentleman I am especi- 

 ally indebted for the opportunity he gave me of examining the numerous plankton- 

 samples taken during the cruise of the "Michael Sars" in different parts of the 

 Norwegian Sea. A most important addition to the Oalanoid fauna of Norway 

 has thereby been gained, as will be shown in the course of the account here 

 given. Finally, I beg to thank the direction of the Bergen Museum for the read- 

 iness with which it has undertaken the continued publication of the present ex- 

 tensive work. 







G. O. Sars. 



