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BIOLOGY: GENERAL AND MEDICAL 



body, a vermicular zygote results, which penetrates the 

 intestinal wall and remains attached to its outer surface, 

 projecting into the abdominal cavity. The zygote 

 enlarges, breaks up into numerous zygomeres, each 



FIG. 128. Developmental cycle of the malarial parasite in the mosquito, 

 a, b, c, Zygocytes; d, e, blastomeres with contained sporozoits; /, sporozoits mi- 

 grating into the salivary gland-cells. (From Manson.) 



of which eventually divides into a large number of 

 sporozoits of falciform shape which migrate to the 

 cells of the salivary glands, from which they enter the 

 insect's saliva. This transformation requires from ten 



FIG. 129. Stomach of mosquito with zygocytes on the outer surface. 



to fourteen days, according to the temperature. When 

 the mosquito subsequently bites, the sporozoits entering 

 the blood of the new individual attach themselves to 

 the red corpuscles, and again begin the human cycle. 



