262 



TAGB SKOGSBERG 



Synonymi/. 



Bfdiirliiin (if the 

 third jiircnl clcuv. 



Time of neeurrenre 



Specimens from 

 different regions. 



Parasites of this 

 species. 



Phenomena of 

 parasitism. 



The form that is dealt with by G. O. Sars, 1865, p. 104, is also rather incom- 

 pletely described. As, in addition, the description is not accompanied by illustrations, this 

 form should really be denoted as unidentifiable. The description given by me above is, however, 

 from specimens — found at Lofoten — that this investigator had determined to be Cypridina 

 norvegica. For this reason I have considered it best to look upon all the information given 

 by this writer about C. norvegica as really referring to the species dealt with here, although 

 all the separate statements have not been tested by me. 



Whether the form described by G. S. Brady and A. ^M. NORMAN, 1896, p. 647, under 

 the name of Cypridina norvegica is to be considered as identical with the species dealt with 

 above, is not quite certain, at least if attention is only paid to the descrijjtion and figures. 

 Differences are found both in regard to the shell and the furca and limbs, as is soon shown by 

 even a superficial comparison between the two descriptions. In spite of this I have included 

 this form as a synonym of the species dealt with above, because G. S. BRADY and A. M. NORMAN 

 have, if we judge from the text, based their description on specimens from the coast of Norway 

 and because I knew that these writers often take very little care about the correctness of their details. 

 On the other hand it did not seem proper to me to include as synonyms Cypridina norvegica 

 A. M. NORMAN, 1868, p. 439, 1869. pp. 256, 257, 260, 295, 1891, pp. 119, 121; G. S. BRADY and 

 D. ROBERTSON, 1872, p. 70 and C.H. Ostenfeld and 0. Wesenberg-Lund, 1909, p. 113, because 

 these statements were not accompanied by any figures or information at all to verif\^ them. 

 The reduction of the third furcal claw, though only slight, ought perhaps to be specially 

 mentioned; it has a certain interest because it is just this claw that is exceedingly reduced 

 in another species of this sub-genus, V. Vanhdfleni (G. W. MULLliR). 



Sexually mature males and females with embryos were found both on the 18th of May 

 and the 5th of August on the West Coast of Sweden and between the 3rd and llth of September 

 in Trondhjem Fjord. 



There was no difference in size between the specimens from northern regions, the Lofoten 

 Islands, and those from more southern places, Koster Fjord. From both localities comparatively 

 large as well as comparatively small specimens were recorded. 



Especially conspicuous was a parasitic I s o p o d, Cyproniscus cypridinae (G. 0. Sars), 

 concerning which I will only cpiote G. 0. Sars's statement, 1899, p. 235: ,,I have not infrequently 

 found this interesting form off the Lofoten Islands and at Bodo and Selsovig, infesting Cypridina 



norvegica Bauu) The parasite, when fully developed, is easily observable through the 



semipellucid valves of the Cypridina, always occupying the place where otherwise the ova and 

 embryos of the latter are carried during their development. Occasionally the parasite also 

 occurs on male (Jypridinae; but in no instance have I found it in this case fully developed, and 

 it is very probable that under such circumstances it does not ever reach maturity." This parasite 

 occurred on about 30 per cent, of the specimens of the above species recorded from the Trondhjem 

 Fjord and the Koster Fjord, but curiously enough no specimen of it was found on the s})ecimens 

 of Cypridina from the Lofoten Islands that I have examined. 



The specimens of this species that are mentioned below as having been caught in Trond- 

 hjem Fjord were all found in tlie cloaca and uterus oiEtmopterus spinax (LiNNE). According 



