GREGARINIDEA 



95 



to form within the enveloping cells a parcel of eight sporozoites in a 

 case. Thus each syzygy produces only one pair of gametes and results 

 in only a single spore. 



Suborder EUGREGARINARIA 



Gregarinidea which have no schizogony. 



The adult trophozoite has a stout cuticle and the ectoplasm con- 

 tains myonemes, longitudinal or transverse, or both. Partitions of the 

 ectoplasm without myonemes may (Fig. 80 F) divide the body into 



«?* >*«%'"«'*; 'r.Va •. fr V, -V >* i'l*.' •-"»\' *' % 



str. 



B 



-gam. 



n^-^yg- 



spz.-j 



Fig. 77. Stages in the life history of Ophryocystis mesnili. A, Agamont, on 

 the epithelium of a Malpighian tubule of the host. B, Syzygy. C, Formation 

 of a cyst (gamocyst) and multiplication of nuclei. D, Formation of gametes. 

 E, Zygote. F, Spore case with sporozoites, still enclosed in residual proto- 

 plasm of gamonts. gam. gamete; nu. nuclei of agamont; nu.' gamete nucleus; 

 nu." nuclei of enveloping (residual) protoplasm; spz. sporozoites; str. striated 

 border of epithelium of Malpighian tubule; zyg. zygote. 



three segments — the epimerite or fixing organ, protomerite^ and deuto- 

 merite, which latter contains the nucleus. When ripe the trophozoites 

 become gamonts, joining in syzygies of two which together form a 

 gamocyst and give rise to gametes (iso- or anisogametes according to 

 species) by multiple fission in which residual protoplasm remains. 

 Syngamy takes place within the cyst between the gametes of one 

 parent and those of the other. The zygotes secrete small oocysts 

 {pseudonavicellae) of their own, and within these divide into several 

 sporozoites ("falciform young"). Passing out of the host these are 



