more sections. The first-named division, which forms the subject of the present 

 Volume, answers to the sub-order Oymoplea of Dr. Giesbrecht, and comprises the 

 most highly organized Copepoda. 



The free-living marine Copepoda of Norway have been partly studied by 

 the late A. Boeck, who, in the Transactions of the Christiania Scientific Society, 

 has given a preliminary account of the species observed by him. I have myself, 

 during a long series of years, given my attention both to the marine and fresh- 

 water forms of our country, and have long since published a synopsis of the latter. 

 Among foreign naturalists who have made these Crustacea the object of special 

 study, may be named the late Prof. C. Glaus, to whom we are indebted for a rather 

 full account of the internal anatomy and development of Copepoda, and Prof. G. S. 

 Brady, whose monograph of the British free and semiparasitic Copepoda is especi- 

 ally valuable for the knowledge of the northern forms. More recently a standard- 

 work on these Crustacea has been published by Dr. W. Giesbrecht, forming one 

 of the admirable series of treatises edited by the Zoological Station of Naples. 

 This excellent work, which, however, only relates to the strictly pelagic forms, 

 comprises, besides Mediterranean species, also forms from all parts of the Oceans, 

 and thus gives by far the most complete account of the species of this kind. 

 Both the descriptions and figures are far superior to any formerly given, and it 

 is only to be regretted that the arrangement of the figures on the plates is such, 

 that no little trouble is entailed to find at once the details relating to each 

 species. Though I do not venture to think that the modest account here given will 

 in any way compete with Dr. Giesbrecht's splendid work, I hope that its arrange- 

 ment may be found somewhat more convenient by students for an easy deter- 

 mination of the northern species. 



