150 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



agreement is Lymphosporidium truttce, the cause of a 

 brook-trout epidemic in America. In most respects this 

 parasite, described by Calkins (1), is very different from 

 Lymphocystis, the adults being amoeboid, relatively 

 minute, and with no well-defined nucleus — the chromatin 

 being in the " distributed " form. The two parasites are, 

 however, not without certain points of resemblance. 

 Lymphosporidium is, especially in the adult sporulating 

 stage, chiefly met with in the lymph-spaces surrounding 

 the various organs and of the dermis. Moreover, its 

 manner of reproduction rather recalls that of Lympho- 

 cystis. According to Calkins, deeply-staining granules 

 collect in masses to form many spores. The chro- 

 matin next forms a layer around the periphery of each 

 such centre, and breaks up into rounded granules, eight 

 in number, which separate ( ?) to form the sporozoites. 

 From Calkin's figures, it does not seem to me unlikely 

 that the complicated reticular areas in Lymphocystis (i.e. 

 the threads of rodlets or granules above described) may 

 represent a modification of this process, although at 

 present one cannot say so with certainty- In that case 

 the ultimate germs must be extremely minute (only 

 about 1 or lj /j) and numerous. Whether the little 

 spherules at the margin of the endoplasm have any con- 

 nection with spore-formation and are in any way com- 

 parable to the reproductive organella or " pansporo- 

 blasts " of Myxosporidia has also yet to be ascertained. 



In conclusion, Lymphocystis would appear to com- 

 bine, to a certain extent, Grregarine and Microsporidian 

 characters — with remarkable results. I do not feel 

 inclined to place it in the Serosporidia (the order to which 

 Lymphosporidium belongs),^ as these forms, though of 

 similar habitat, are all very small. I have, unfortu- 

 nately no alternative but to leave it for the present, to 

 swell the ranks of the " unattached " Sporozoa. 



