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tissues, and so at this stage it is also called the encysted 

 zygote or Oocyst. Growth proceeds, and signs of 

 division into several masses appear in the protoplasm. 

 These masses are termed Sporoblasts. Then we reach 

 the stage of large oocyst (with sporoblasts), and by this 

 time the masses of the sporoblast have undergone 

 division into a number of fine curved thread-like bodies, 

 the Sporozoits^ so that eventually the large cyst is almost 

 entirely filled with sporozoits. The capsule of the 

 cyst eventually ruptures, and the sporozoits pass from 

 the tissues of the stomach to the thorax, being found 

 at first amidst the muscles, but eventually all collected 

 in the salivary glands. From here they are injected 

 into the blood by the mosquito, and they then attach 

 themselves to and penetrate the red. cells (as has been 

 actually observed under the microscope by Schaudinn), 

 producing a new infection. 



We may briefly summarize these various steps : 



1. Microgametocyte, and macrogamete in blood. 



2. Development of microgametes = flagellation, 

 on the slide and in nature in stomach of an Anopheline. 



3. Fertilization of the macrogamete producing 

 a zygote or copula, on the slide and in nature in the 

 mosquito. 



4. Vermiculus or ookinet. Only in mosquito 

 stomach. 



5. Oocyst. In stomach wall. 



6. Medium or large oocyst* with sporoblasts. 



7. Sporozoits. (i) In the large cysts, (2) in 

 salivary glands. 



The sexual cycle is known also as sporogony or 

 amphigony, while the asexual cycle is known as schizo- 

 gony or monogony. These two cycles and their 



* Not uncommonly stages 4-6 are also called zygote. 



