COPEPODA 



3 



among these 13 were new to science. The Ingolf has only collected 21 species of which 3 were new, 

 the Thor has collected 69 different species (8 however ontside the area explored by the Ingolf), of which 

 n were new, and the Danish East Greenland Expedition 1900 has only taken 13 different species, of 

 which only one has not been recorded previously. Of the Calanidac and related families the Ingolf 

 has taken 7 species, the Thor 9 and the 0. Exp. 1900 5, of the Aetidiidae the three expeditions have 

 taken 6, 29 and 3 species respectively, of the Euchcetidae the Ingolf has taken 4, the Thor 12 and the 

 0. Exp. 3 species and of the Scolecithricidae the three expeditions have taken 4, 19 and 2 species 

 respectively. Of species, which by previous authors were recorded from the examined region, only a 

 single one Udinopsis armata Vanh. was not taken by any of the expeditions. 1 ) 



On the Literature. 



Without underestimating the fine papers by E. Canu and Th. Scott, it must be admitted, 

 that Giesbrecht and G. O. Sars are the two modern zoologists, who have contributed most to the 

 knowledge of the Plancton-Copepods. The work of the former indicates a new epoch in the studies 

 of these animals; unfortunately the arrangement of the topics in his main paper is so unpractical, 

 that it is often very difficult a to derive full advantage from the vast amount of information, which is 

 found in it. Giesbrecht has sometimes been blamed for giving unneccessarily many details for 

 the definition and understanding of the species. I do not share this opinion, as it sometimes occurred 

 to me, that details necessary for the limitation of two nearly related species were wanting in his 

 description. G. O. Sars has in many ways contributed greatly to the study of the Copepods as well 

 as to that of the other Crustacea; his descriptions are lucid and supported by numerous practically 

 arranged figures, but might sometimes be a little more exhaustive. 



In the last ten years numerous Plancton-Copepods have been described from the deeper layers 

 of the North-East Atlantic as well as from other ocean tracts; the three principal authors, who have 

 described these species are Farran, Wolfenden and A. Scott. The papers of the first of these 

 naturalists have a direct bearing upon the Ingolf-Investigations ; he has given good descriptions of 

 numerous new species and most useful information about the Copepod-fauna of the Atlantic Slope 

 of Ireland. Wolf end en's papers often include a number of useful characters and details, supported 

 by beautiful drawings, but he does not always seem to have accepted the classic rules of nomenclature. 

 A. Scott's main-paper on the Copepods of the Siboga Expedition, which only partly falls within 

 my sphere, contains most useful lists of synonymy, descriptions of numerous new species and several 

 new characters; his descriptions are according to my opinion often a little too meagre for the definition 

 of nearly related species. 



When speaking of the studies 011 the Plankton-Copepods of later years, I think a few words 

 may be added about a most useful paper by Koefoed & Dam as on the collections brought home 

 by the due d'Orleans. It may perhaps be allowed to set forth a few words of criticism. It is a 

 pity that the authors have not wished under each species to give a full acount of the biological facts, 



x ) Wolfenden (1904 p. 112) has from the cold area of the Faeroe Channel mentioned four species viz: Bradyidius 

 armatus Gbt., Udinopsis bradyi G. O. Sars, Bryaxis brevicornis Fair., Ctenocalanus vanus Gbt. and Scolecthrix similis Gbt., but as 

 they are all found south of the 6o° L. N. I have not included them in this paper. The same is the case with Oothrix 

 bidentata Farr. which according to the due d'Orleans was secured at 75 L,. N. 14 I,. \V., somewhat north of the area, inclu- 

 ded in this paper. 



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