studies on marine Ostracods 263 



to information received by me from the collector, Fil. lie. If.J. OsTERGREN, all the specimens 

 were quite active and emitted an intensely phosphorescent light. This fact, like the circum- 

 stance that a number of specimens were found in the uterus, decidedly indicates that they had 

 not been swallowed by the fish as food, i. e. that they had not passed through the alimentary 

 canal, but it must be assumed that they penetrated actively into the fish, where they lived 

 on waste products and, at least in the uterus, as parasites. 



Curiously enough all the twenty-five specimens were found in a single specimen of the 

 above-mentioned fish, although no less than about a hundred specimens of the latter were in- 

 vestigated (according to information received from Fil. lie. OsTERGREN). As I have carefully 

 investigated myself about sixty specimens of this Etmopterus species caught in Trondhjem 

 Fjord without finding a single specimen of Cijpridina and Fil. lie. 0. Nybelin has investigated 

 about 150 from the same fjord with a similar negative resujt, this habitat must perhaps be 

 regarded as a rare one, in spite of the curiously large number of specimens found in one fish. 

 — It ought perhaps to be pointed out that C (V.) norvegica seems to be very rare in Trondhjem 

 Fjord: ,,Sparsim in siuu Nidarosiensi" (G. 0. Sars, 1865). (Is it possible that all these 

 25 specimens are the offspring of one and the same fertilized female which have left the mother 

 after the latter had penetrated into the fish?) 



I was unable to discover any morphological differences between free-living specimens 

 and the parasitic specimens, although they were subjected to a very minute examination. 



There may be an increased interest attached to this find because this is not the first 

 nor the only time that a Cy p r i d i n i d has been found under conditions that seem to indicate 

 a certain tendency to parasitism. 



The first mention of a case of this sort in the literature is to be found in 0. G. CoSTA's 

 work in 1847, p. 6. Here we find the following statement: ,,Dopo la pubblicazione della Memoria . . 

 dissecando una Scorpaena scrofa, trovammo tutta la cavita addominale, o meglio il peritoneo 

 in ogni punto attaccato da questo ostracode parassito, che a primo sguardo presentavasi 

 come di glandolette bianche di cui pareva disseminato il cavo addominale. Noi potemmo 

 trarve 120 di tutte le grandezze, niimo uguagliando pero i precedenti ospitanti nell' Ofisuro. 

 La qual causa rafferma essere propria una tale specie del Mediterraneo, e vivere abitualmente 

 parassita su i pesci." 



The latter find is mentioned in the same treatise, p. 1. Here we find that a Cypridinid, 

 presumably the same species as in Scorpaena scrofa, i. e. Cypridina mediterranea, was found 

 on the body of a Ophisurus ,,Noi trovammo nel corpo di un Ofisuro". 



The next find is mentioned by A. BRIAN in a short essay on parasitic Crustacea (1909). 

 In this we find that a number of specimens of Cypridina mediterranea (?) were found in ,,seni 

 e canali frontale" of a &sh Cory phaena hippurus. The length of these specimens was only 2,5 mm., 

 which suggests that they were not sexually mature. With regard to this case the author writes 

 as follows: ,,Questa specie d'o s t r a c o d e uon e da ritenersi parassita per quanto trovata 

 su di un pesce. Esse vive liberamente e non si tratta qui che di un semj^licc caso di commen- 

 salismo." In other words this author considers this habitat quite an accidental one, as I 

 did above. 



