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have been dcscril^ed, but also the \onnger stages, as far as they sliowed features of auy interest. The 

 descriptions are as a rule rather long, partly on account of the new characters, which are taken into 

 account, partly because it often struck ine, that existing descriptions were often too wanting in details 

 for a sure definition of nearl\' related species. 



Under each species is found a list of synon\ni\', which 1 ha\e tried to make as complete as 

 possibl\- for the \'ears after the publication of Giesbrecht's classical paper; for each species I ha\'e 

 given the measurements of each examiued stage. 



After the description is added a few words of the variations and parasites, if any have 

 been observed. Under occurrence I have only gi\en my personal ol.)ser\'ations, but under distribution 

 I have dealt with the facts, previonsh- published, relating to the occurrence of each species within 

 as well as outside the explored area. Under remarks the whole systematic ]iosition of the species 

 is discussed. 



On variation and parasites. 



In a good many species viz: Rhiuculnmis i/asuf/is. Kiicalaiius clungatiis^ l\iracalaiiiis parvus, 

 Psci(docalaints iiiiniitits, Cliiridius arinatiis, Gaetaiiiis Kntppi, G. pilraliis and G. latifrous, Eiichirrlla 

 roslrata and ciirticauda, Eiiclurtc toiisa and barhafa and Scaphocalauiis iiiai^mis variations of different 

 kinds were observed; most common is variation iu a rudementary fifth pair of legs and in the struc- 

 ture of the setae of the f ureal branches; several of the variations are probably due to traumata and 

 regeneration, others certainly represent a kind of atavism. To study the whole question of variation 

 within the Copepods or to collect all the published facts (cf. Wolfenden and Steuer) does not lie 

 within the frame of this paper. But as such facts are rather scarce, and as they may be im])orlant 

 for a future student of these topics, it seems to me to be the dut\- of each observer to make his jier- 

 sonal observations known, e\'en if the\' are fragmentary. Negative statements are seldom of much 

 value; but nevertheless I think it rather curious, that abnormal segmentation, which is fairly counnon 

 in the Arachnids, Insects and Annelids, was never met with in any of the examiued, I think several 

 thousand, Copepods; to m\- knowledge no case of abnormal segmentation has been observed in any 

 of the Crustacea. 



In se\eral species parasites of different kinds have been obser\ed ; I refer to the description 

 of J\lniicahiinis i/asuf/is, Cliiridius uriiiiil its, Gaidiiis liiiuispiii its and hm'ispii/iis. Gar fan its Knippi, 

 pilcatits and lali/rois. Uiidntclnrtc sitpcrba and Cliintdina iiolticaiitlid. 



Till; IiigolM-xpcJil 



