166 



SPOEOZOA. 



Remarks. — This parasite is usually found in the subepithelial 

 tissue of the vilh, where it completes its sporogony, so that 

 immature oocysts are not passed out in the fseces. Wenyon 

 and Sheather (1925) had an opportunity of studying the 

 intestine of a dog which had been killed durmg an acute phase 



Fig. 75. — Section of villus of cat, showing Isospora bigemina in the 

 subepithelial tissues and Isospora felis in the epithelium 

 ( X 1000). Six mature oocysts of I. bigemina are seen in the 

 subepithelial tissues. In the epithelium are seen a micro- 

 gametocyte with microgametes, and one partially grown 

 and two mature macrogametocytes. (After Wenyon.) 



of infection. The whole of the epithelium of the small intestine 

 was found to be crowded with reproducing parasites ; but 

 the subepithelial tissue was not invaded. The schizonts 

 were small, measuring up to 5/x, and giving rise to eight minute 



