572 



PROTOZOOLOGY 



Family 1 Selenococcidiidae Poche 



Vermiform body and gametic differentiation place this family 

 on the borderline between Coccidia and Gregarinida. 



Genus Selenococcidium Leger and 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. 244. Selenococcidium intermedium, X550 (Leger and Duboscq). 

 a, schizont in host gut; b, c, schizogony; d, microgametocyte; e, micro- 

 gametes; f, macrogametoc} r te; g, macrogamete; h, zygote (oocyst). 



S. intermedium L. and D. (Fig. 244). Octonucleate vermiform 

 schizont 60-100m long, and divides into vermicular merozoites in 

 gut cells; parasitic in gut lumen of European lobster. 



Genus Ovivora Mackinnon and Ray. Trophozoites large and ver- 

 miform (Fig. 245, a) ; gametocytes spherical (c) ; large macrogameto- 

 cytes; small microgametocytes, giving rise to numerous biflagellate 

 microgametes (d): oocyst membrane delicate or lacking; ovoid 

 spores contain variable (averaging 12?) number of sporozoites; 

 schizogony produces many merozoites; one host. One species (Mac- 

 kinnon and Ray, 1937). 



0. thalassemae (Lankester) (Fig. 245). In the egg of the echiurid 

 worm, Thalassema neptuni; merozoites about 10m long (b) ; macro- 

 gametocytes (c) 40-75^ in diameter; microgametocytes (c) 23-65/x; 

 chromosome reduction, 14 to 7, in the zygote; spores (/) 15.5^ by 

 13.5/x (Mackinnon and Hay, 1937). 



Family 2 Aggregatidae Labbe 



Anisogamy results in production of zygotes which become trans- 

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



