Sporozoa 273 



Fig. 6. 2. Epimerites and mucrons. A, B. Lobate epimerite of Aclino- 

 cephalus parvus (after Weschenf elder): longitudinal section (A), x2560; polar 

 view (B), xl600. C. Anterior end of Rhynchocystis pilosa, an acephaline 

 gregarine with an epimerite-like organelle; the large nucleus and a portion 

 of the endoplasm are shown; x2800 (after Troisi). D. Epimerite of Polyrhab- 

 dina spionis, attached to epithelium; longitudinal section; xl750 (after 

 Mackinnon and Ray). E. Anterior end of Zygocystis wenrichi, showing 

 mucron; x331 (after Troisi). F. Attached trophozoite of Nina gracilis, ex- 

 panded protomerite with multiple filamentous epimerites extending into 

 intercellular spaces of an epitheliimi; tissue cells not shown; x600 (after 

 Goodrich). G. Anterior end of 7.ygosoma globosum, globular epimerite at- 

 tached to epithelium; x74 (after Noble). H. Trophozoite of Gregarina rigidn 

 with globular epimerite; xl3I5 (after Allegre). I. Epimerite of Lecytliion 

 thalassemae attached to epithelial cell; xl330 (after Mackinnon and Ray). 



In one group (Cephalina) of the Eugregarinida, the body is differen- 

 tiated into two regions, an anterior protomerite and a posterior deuto- 

 merite. The two regions are separated by an optically distinct transverse 

 septum in most of the cephaline gregarines. The unusual protomerite of 

 Nina gracilis (37) may undergo marked changes in form (Fig. 6. 8, B-D), 

 and can be used as a sucker for attachment. The protomerite of the more 



