■2*i2 



y\r.K SKOOSIlKUr. 



Synonyini/. 



iediiction of the 

 lird ftircal clan: 



me of occurrence. 



Specimens from 

 afferent regions. 



Pnr(i!!ite<! of this 



Phenomena of 

 parasitism. 



Tin- fiirm that is dealt with l)v (I. O. S\liS, IS*!"), p. I(i4, is also lalhcr iiicom- 

 plotoly dfsoribod. As. in addition, the description is not accoiniKiiiied by ilhistrat ions, tiiis 

 form should roally ho denoted as unident iliaiile. Tlie description given by me above is, liowever, 

 from .specimens — found at Ijofoten - that this investigator had determined to be Cifpridina 

 norregica. For this rea.stm I have considered it best to look upon all the int'onnaiion given 

 Ity this writer about ('. notTegica as really referring to the species dealt with here, altlioiigh 

 all the separate statements have not been tested by me. 



Wliether the form described by (J. S. Bhahv and A. M. NORMAN, 189(5, p. 647, imder 

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

 above, is not quite certain, at least if attention is only j)ai(l to the description and figures. 

 Dirt'erences 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 incliKh'd 

 this form as a synonym of the species dealt with above, because G. S. Bl; amy 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. NORMAX, 1868, p. 439, 1869, pp. 2o6, 257, 260, 295, 1891, pp. 119, 121; G. S. BHADY and 

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

 these statements were not accompaiii(>d by any figures or information at all to verify 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. Vanhoffeni (G. ^^^ MCllrr). 



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

 and the 5th of August on the West Coast of Sweden and between the 3rd and 11th 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. O. Sars), 

 concerning which I will only quote G. 0. S-\l^s's statement, 1899, p. 235: ,,1 have not infrequently 

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



norvegica Baird The parasite, when full}' 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 Cypridinae; 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 specimens 

 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 the cloaca and uterus oiEtmoptents spinax (LiNNE). According 



