88 PROTOZOA THE SIMPLEST ANIMALS. 



Third Type— Monocystis. 



Monocystis, a type of those Sporozoa in which the cell 

 is not divided into two parts by a partition. 



Description.— Two species (M. agilis and M. magna) 

 infest the male reproductive organs of the earthworm almost 



ayg 



ad 



Y\g. 35. — Life history of Gregarina. — After Btitscbli. 



a.yg. 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. blattarum). 

 sp.f. Spore formation. 



spt. Kipe spore of G. blattaruvi, within spore-case. 

 sp-z. Spore of G. gigantea, after escaping from the spore-case, show- 

 ing long vibratile part which breaks of and develops into the 

 adult. 



constantly. The full-grown adults are visible to the naked 

 eye. They are usually flattened worm-like cells, but the 

 shape alters considerably during the sluggish movements. 

 There is a definite contractile rind, which is sometimes 

 nbrillated, and a more fluid medullary substance, in which 

 the large nucleus floats. In one species there is an anterior 



