382 PROTOZOOLOGY 



Family 1 Monocystidae Biitschli 



Trophozoites spheroidal to cylindrical; anterior end not dif- 

 ferentiated; solitary; spores bi conical, without any spines, with 

 8 sporozoites. 



Genus Monocystis Stein. Trophozoites variable in form; motile; 

 incomplete sporulation in cyst; spore biconical, symmetrical; in 

 coelom or seminal vesicles of oligochaetes. Numerous species. 



M. ventrosa Berlin (Fig. 175, a-c). Sporadins 109-183 ju by 

 72-135m; nucleus up to 43)u by 20/x; cysts 185-223^ by 154-182^; 

 spores 17-25m by 8-10/^; in Lumbricus rubellus, L. castaneus and 

 Eisenia foetida. 



M. lumhrici Henle (Fig. 175, d, e). Sporadins about 200/i by 

 60-70ju; cysts about 162ju in diameter; in Lumbricus terrestris, 

 L. rubellus, and L. castaneus. 



Genus Apolocystis Cognetti. Trophozoites spherical; without 

 principal axis marked by presence of any special peripheral 

 organ; solitary; spore biconical; in seminal vesicles or coelom of 

 various oligochaetes. Many species. 



A. gigantea Troisi (Fig. 175, /). In seminal vesicles of Helo- 

 drilus foetidus and Lumbricus rubellus; late October to March 

 only; fully grown trophozoites 250-800/x in diameter; whitish to 

 naked eyes; pellicle thickly covered by 10-15/* long 'hairs'; 

 endoplasm packed with spherical paraglycogen grains (S/j, in 

 diameter); nucleus 35-43/i in diameter; cysts 400-800ai in 

 diameter; spores IQyu by 8.6/x. 



A. minuta Troisi (Fig. 175, g). In seminal vesicles of Lumbricus 

 terrestris, L. castaneus and L. rubellus; mature trophozoites 40- 

 46m in diameter; endoplasm yellowish brown, packed with spheri- 

 cal paraglycogen grains (5.3-7^ in diameter); nucleus lO/z in 

 diameter; cysts 68-74;u by 55-65iu; spores of 3 sizes, 11/i by 5.5/i, 

 18.8m by 7n and 21. 6m by 9.8m. 



Genus Nematocystis Hesse. Trophozoites elongate, cylindrical 

 and shaped like a nematode; solitary. Many species. 



N. vermicularis H. (Fig. 175, h). In seminal vesicles of Lumbri- 

 cus terrestris, L. rubellus, Helodrilus longus, Pheretima barba- 

 densis; trophozoites 1 mm. by 100m; cylindrical, both ends with 

 projections; nucleus oval; endoplasm alveolated, with para- 

 glycogen grains; sporadins become paired lengthwise; cysts and 

 spores unknown. 



Genus Rhabdocystis Boldt. Trophozoites elongate, gently 



