564 



PROTOZOOLOGY 



long, producing many spores; spore, spherical with 4 (up to 10) 

 sporozoites; in gut of the polychaete, Potamilla reniformis (Mackin- 

 non and Ray, 1933). 



Genus Meroselenidium Mackinnon and Ray. Schizogony intra- 

 cellular, initiated by formation of small masses which give rise 



Fig. 241. a-c, Selenidium potamillae (a, X420; b, cyst with spores, 

 X330; c, spore) (Mackinnon and Ray); d-f, Meroselenidium keilini 

 (d, sporadin, X670; e, f, different views of spore, X930) (Mackinnon 

 and Ray); g-j, Machadoella triatomae (g, a schizont, X1420; h, i, a single 

 and associated sporadins, X710; j, spore, X1920) (Reichenow); k, 1, 

 Syncystis mirabilis: k, a cyst, X470 (Steopoe); 1, spore (Schneider); 

 m, Mattesia dispora, X1480 (Naville); n, Lipotropha macrospora, X800 

 (Keilin). 



to merozoites; about 20 spores from a pair of gametocytes; spores 

 with numerous sporozoites. One species (Mackinnon and Ray, 1933). 



M. keilini M. and R. (Fig. 241, d-f). Large schizonts about 150/x 

 by 30/x; sporadins free in gut 200-300^ by 40-70^; paired gameto- 

 cytes 85/x by 40jli; spores 26-28m by 14-16/x, bivalve (?), trans- 

 verse ridges, with many sporozoites; in gut of Potomilla reniformis. 



Genus Selenocystis Dibb. Sporadins leaf -like with a median ridge; 

 biassociation with posterior ends, forming an elongated cyst, at- 



