MONOCYSTIS. 



99 



becomes free from the cell. In the free stage, two indi- 

 viduals may unite in the curious end -to -end manner 

 observed also in Gregarina. Encystation occurs, involving 

 either a single individual or two together. Within the 

 rounded cyst, orderly nuclear division results in the forma- 

 tion of spore-forming masses. These form elliptical spore- 



con 



a/g 



sp< 



FIG. 43. Life history of Gregarina. hil&c Biitschli. 



a.rt;'. Young forms emerging from intestinal cells. 

 ad. Adult with deciduous head-cap and a cuticular partition divid- 

 ing the cell into two. 



con. Two forms conjugating (G. blattaruin.') 

 sp.f. Spore formation. 



,s-/l. Ripe spore of G. blattarnin. within spore-case. 

 sp'-. Spore of G. gp.ga.ntea., after escaping from the spore-case, show- 

 ing long vibratile part which breaks off and develops into the 

 adult. 



cases, or " pseudonavicellae," enclosed in a firm sheath, and 

 each spore-case seems to contain several, usually eight, 

 spores, lying around a residual core. The spores are con- 

 siderably larger than those of Gregarina. Eventually the 

 cyst bursts, the spore-cases are extruded, the spores emerge 

 from their firm chitinoid cases. The young spore is like a 



