198 



SPOROZOA. 



irregularly. On entering new epithelial cells the merozoites 

 assume a round form and become gametocytes, which are 

 dififerentiated into microgametocytes and macrogametocytes 

 respectively ; the former give rise to a large number of 

 biflagellate microgametes round a small cytoplasmic residuum ; 

 they then break off from the residuum and swim actively, 

 congregating at one end of the female gamete. The latter 

 increase in size and become macrogametes. 



Oocysts perfectly spherical ; tetrasporocystid. Sporocysts 

 show a characteristic lenticular knob at one pole ; tetrazoic. 

 Sporozoites more or less regularly arranged, with broad ends 

 of two sporozoites at each pole. 



Dimensions. — Merozoites 6/i by 2/x or 8/x by 2[x; young 

 gametocytes 6-8 yu, ; oocyst 14-18-5 ju. in diameter ; sporocysts 

 10/Li by S/i. 



Remarks. — In a fresh preparation merozoites were seen 

 actively swimming about with the pointed end directed 



Fig. 98. — Wenyonella hoarei Ray. A, oocyst with developing sporo- 

 blasts ; B, oocyst with distinct sporoblasts ; C, mature 

 oocyst showing sporocysts each containing foiir sporozoites. 

 (After Ray.) 



forward. Female gametocyte showed a micropyle which 

 did not persist in the oocyst. Development of the male 

 gametes was also observed. Advanced male gametes were 

 seen adhering round a central mass of cytoplasm with their 

 actively moving tail-ends directed away from it. Within 

 an hour and a half these gametes broke off and congregated 

 round the micropylar end of the female gamete. 



On keeping the oocysts in 1 per cent, chromic acid these 

 showed the first sign of development after forty-eight hours, 

 when the sporoblasts were seen to be budding out. They 

 separated from each other on the fourth day, were invested 

 with sporocysts on the fifth day, and the sporozoites were 

 well differentiated on the seventh. 



Habitat. — Gut-contents of a squirrel, Sciurus sp. : Bengal, 

 Calcutta. 



