168 



SPOKOZOA. 



98. Isospora felis Wenyon. (Figs. 75 & 76.) 



Isospora felis, Wenyon, 1923 a, p. 248, pis. ix-xii ; 1926, pp. 808, 



814, figs. 342, 344-8 ; 1926 a, pp. 253-66. 

 ■\Isospora sp., Knowles, 1928, p. 354. 

 Isospora felis, Reichenow, 1929, p. 956, figs. 921 A, 922 ; Kudo, 



1931, pp. 274, fig. 114/. 

 ■fisospora sp. (" type B "), Knowles & Das-Gupta, 1934, pp. 387-90, 

 pi. vii, figs. 1-4, 6. 



Development takes place in the epithelial cells only of the 

 small intestine and not in the deeper layers of the villi. Oocysts 

 egg-shaped, with one pole somewhat narrowed. The oocysts 



Fig. 76. — Mature oocyst oi Isospora felis Wenyon. 

 (From Reichenow, after Dobell.) 



drop out of the epitheHal cells into the lumen of the gut 

 and pass out with the faeces, the formation of sporocysts and 

 sporozoites taking place in the oocysts while outside the body 

 of the host. The macrogametocyte is easily distinguished 

 in shghtly advanced stages, as it has a single nucleus with 

 a characteristic appearance. In the microgametocyte the 

 nucleus divides repeatedly and hundreds of microgametes 

 develop in each. Each microgamete is a flexible rod-like 

 body with two flagella. FertiHzation takes place while the 

 macrogamete is within an epithelial cell. The oocyst develops 



