62 STRUCTURAL AND SYSTEMATIC ZOOLOGY 



Probably the parasite which causes malaria in man 

 belongs in this group. 



FIG. 7. Sporozoa: a, embedded in the striated muscle fiber of the ox; b, Gregarina 

 in the intestine of the beetle ; c, cyst and young germs of Klossia from the snail. 

 All much magnified. 



Reproduction is by means of spores. The individ- 

 uals become surrounded by a thickened covering or cyst 

 secreted from their bodies. Within this cyst division 

 into numerous smaller masses takes place. Each mass 



FIG. 8. Gregarina gigantea, highly magnified : a, nucleus. 



then secretes a thickened coat and becomes a spore. 

 When mature, the protoplasmic mass within breaks 

 through the wall of the cyst and enters the organ or 

 animal in which the parasite reaches its adult condition 

 (Fig. 7> 



