Studies on the acephaline gregarine of some oligochaete annelids
Transactions American Microsc Society 52(4): 326-352
The morph. and life-hist. of 5 spp. of acephaline gregarines are given: Rhynchocystis pilosa, R. porrecta, Zygocystis wenrichi* (p.334) and Apolocystis gigantea* (p.337), in Lumbricus rubellus and Helodrilus foetidus, and A. minuta* (p.339) in L. terrestris, L. castaneus, and L. rubellus. These organisms were obtained as a result of the examination of over 1000 earthworms from the region of Philadelphia and southern New Jersey. The average length of R. pilosa in this country is 217.3[mu] as compared with 500[mu] in Europe. The hitherto unrecognized process of plasmotomy before encystment in R. pilosa and R. porrecta is descr. Three out of 6 L. terrestris were successfully infected by feeding them spores of A. minuta. Attempts to infect H. foetidus with this organism were unsuccessful. It is suggested that infection takes place by ingestion of spores rather than by copulation since stages of the parasite are rarely found in the seminal vesicles.