Sporozoa 289 



6. 1, C) to much elongated types (Fig. 6. 1, B). A sucker-like epimeritic 

 organ or a mucron may or may not be present. Spores are typically 

 spindle-shaped. Various species of Monocystis and Nemotocystis have been 

 described in detail by Berlin (7). Many Monocystidae occur in the seminal 

 vesicles of earthworms. The sporozoites of some species enter germinal 

 cells and grow within the developing sperm-morulae. In other species 

 parasitizing the seminal vesicles, development is extracellular. Species 

 within a single genus, such as Apolocystis (133), may differ with respect 

 to intracellular or extracellular development. 



The following genera have been assigned to the family: Apolocystis Cognetti (106, 

 133; Figs. 6. 1, C; 11, H), Echinocystis Bhatia and Chatterjee (11), Enterocystis Zvvetkow, 



Fig. 6. 12. Acephalina. A, B. Stonmtophora simplex, view of mobile 

 anterior "sucker" with central mucron (A), x8U0; trophozoite, light anterior 

 area representmg region of sucker (B), x960 (after Bhatia). C.-E. Urospora 

 rliyacodrili. young trophozoite in gut wall (C), xl225; older trophozoite in 

 seminal vesicle (D), x216; syzygy (E), x216 (after Gabriel). F. Choatiocys- 

 toides costaricensis, anterior end of trophozoite showing "sucker," schematic, 

 730 approx. (after Cognetti). G, H. Gonospora varia Leger, mature stage 

 and a pair in syzygy; x96 approx. (after Hentschel). I. Heteropolar spore 

 of Lithocystis brachycercus, xl396 (after Goodrich). J. Zygocystis wenrichi, 

 young trophozoite, x700 (after Troisi); compare with Fig. 6. 2, E. 



