COCCIDIA 



417 



zoites. Oocysts in the faecal matter become the sources of infec- 

 tion. 



Body vermiform; schizogony in motile stage 



Family 1 Selenococcidiidae 



Body not vermiform 



Alternation of generations and of hosts Family 2 Aggregatidae 



No alteration of hosts 



Gametocytes associate early; many microgametes 



^ Family 3 Dobelliidae (p. 421) 



Gametocytes independent Family 4 Eimeriidae (p. 421) 



Family 1 Selenococcidiidae Poche 

 Vermiform body and gametic differentiation place this family 

 on the borderline between the Coccidia and Gregarinida. 



Genus Selenococcidium Leger et Duboscq. Nucleus of vermi- 

 form trophozoite divides 3 times, producing 8 nuclei; trophozoite 

 becomes rounded after entering gut-epithelium and divides into 

 8 schizonts; this is apparently repeated; schizonts develop into 

 gametocytes ; microgametocyte produces numerous microgametes ; 

 gametic union and sporogony (?). One species. 



Fig. 189. Selenococcidium intermedium, X550 (L^ger and Duboscq). 

 a, schizont in host gut; b, c, schizogony; d, microgametocj^te; e, micro- 

 gametes; f, macrogametocyte; g, macrogamete; h, zygote (oocyst). 



S. intermedium L. et D. (Fig. 189). Octonucleate vermiform 

 schizont 60-1 00/i long, and divides into vermicular merozoites in 

 gut cells; parasitic in gut lumen of European lobster. 



Family 2 Aggregatidae Labbe 

 Anisogamy results in production of zygotes which become 

 transformed into many spores, each with 2-30 sporozoites; in 



