SCmZOGREGAKINABIA. 



Ill 



II. Suborder SCHIZOGREGARINARIA 



Leger, 1900. 



(Syn. Amgebosporidia A. Schneider, 1884.) 



The Schizogregarines are parasites of the digestive tract and 

 appended organs (e. g., Malpighian tubules) of Arthropods, 

 AimeUds, and Tunicates. The sporocyst gains entrance into 

 the digestive tract of the specific host and the sporozoites are 

 set free. These develop into trophozoites either in the lumen 

 of the gut or within the cells of the host and undergo schizogony. 



Fig. 43. — Life-cycle of a typical Schizogiegarine, Schizocystis gregari- 

 noides Leger. A, sporozoite escaping from the spore ; B-E, 

 growth of the sporozoite into the multinucleate schizont, of 

 which there are two types, the vermiform schizont (a) which 

 attaches itself to the epithelial cell by its anterior end, and 

 the massive schizont (6) which lies free in the gut of the host ; 

 F, division of the schizont into a munber of merozoites, which 

 may grow into schizonts again (G^, G^), or grow into gamonts 

 ((?*) ; H, yoiuig gamonts ; /, association of two full-grown 

 garaonts ; J, formation of a common cyst round the two ; 

 K, division of nuclei in each gametoeyte ; L, formation of 

 gametes ; M, fusion of gametes in pairs ; N, each zygote 

 becomes an oocyst and develops eight sporozoites in it. 

 (After Leger.) 



