30 



MARINE AND FISHERIES 



5 GEORGE v., A. 1915 



dantly, spores only rarely. Twenty-five flounders examined all contained the 

 parasite. In Hemitripterus americanus myxosporidia resembling closely the 

 myxosporidia of Ceratomyxa acadiensis were found. As no spores were found it 

 was not possible to make a complete identification of this parasite. 



Fig. 2. Myxidium bergense Auerbach. a, myxosporidium containing eleven 

 nuclei in the endoplasm and sho-Rang the intermediate zone and the ectoplasm; from 

 a preparation stained with Delafield's haematoxylin. b, a similar myxosporidium con- 

 taining a sporoblast with six nuclei and ten other nuclei in the endoplasm; from a pre- 

 paration stained with Grenacher's borax carmine, c, myxosporidium shomng outer 

 resistant membrane (indicated by the clear area between the two contour lines) and 

 numerous green granules ; from a fresh preparation, d, spore showing the two polar cap- 

 sules and the six nuclei ; the two germ-nuclei lie one over the other near the centre, the 

 two polar nuclei lie against the polar capsules and the valve-nuclei are more faintly 

 stained and lie against the valves of the spore; from a preparation stained with Dela- 

 field's haematoxylin. e, f, g, optical cross sections of a spore; e and g, at either end and 

 / at about the middle, h, spore showing shell and polar capsules and placed so as to 

 correspond in position to the sections e,/, g. Figures e-h from fresh preparations. X 1900. 



The spores of Ceratomyxa acadiensis resemble in size most closely those of 

 C. appendiculata Thel. (Th^lohan '95). As Thelohan does not give a figure of 

 the spore and the only measurements given are those of the length and width it 

 is impossible to carry the comparison further. The myxosporidium differs from 

 that of C. appendiculata in being found attached. The spore resembles in form 

 that of C. drepanopsettae Awer. (Awerinzew, '09) but differs from it in size. 



Some interesting stages in the life history of this parasite have been worked 

 out and will form the subject of a separate paper. 



2. Myxidium bergense Auerbach. 



The Myxosporidium is spheroidal, 25-35 n in diameter or elongated up to 

 50 IX in length. There is a clear differentiation into ectoplasm, an intermediate 

 zone resembling that described in M. lieberkulmi, Butschli, by Cohn ('96) and 



