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

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

 II 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 Aetidiidac. the three expeditions have 

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

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

 re-spectiveh'. Of species, which by previous authors were recorded from the examined region, only a 

 single one Udinopsis aniiafa Vanh. was not taken by any of the expeditions.') 



On the Literature. 



Without underestimating the fine papers by E. Canu and Th. vScott, 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 wa\s 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 tlie Copepod-fauna of the Atlantic Slope 

 of Ireland. Wol fend en's papers often include a number of useful characters and details, sui)ported 

 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 partK' 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 loo meagre for the definition 

 of nearly related species. 



When speaking of the studies on the Plankton-Copepods of later >cars, I think a few words 

 may be added about a most u.seful paper by Koefoed &. Da mas 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, 



M WolfeiuU-ii (rgo.). p. ri2) has from the Lold area of the Fx'rocj Ch.uiiicl lueiitioiiod four specios viz: Brmiruiius 

 armatus Gbt., Uifinopsis bradyi G. O. Sar,s, Hrynxis brevicornis F.arr., Cti-nocalanus vamis Gbt. and ScoUcthrix similis Gbt. but as 

 they are all found .south of the 60° L. N. I have not included them in thi.s paper. The same is the ca.sc with Oothrix 

 bidftttata Farr. which according to the due d'Orlean.s was secured at 75° L, N. 14^ I.. W., somewhat north of the area, inclu- 

 ded in this paper. 



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