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A MANUAL OF BACTERIOLOGY 



are often attached to the naked parasites, and may repre- 

 sent polar bodies (Fig. 58, c and /). Very soon the male 

 cells flagellate (Fig. 58, c), and before long the flagella 

 or " microgametes " break away from the parent cell, 

 and by their own motility make their way through the 

 liquor sanguinis. Should one come in contact with a 

 female cell or " macrogamete," it enters the latter and 

 fuses with its nucleus (Fig. 58, /), fertilisation is thereby 



FIG. 58. Development of the malaria parasite in the mosquito. 

 a, b, and c, the male gametocyte ; d, e, and /, the female gameto- 

 cyte ; /, fertilisation of the female gametocyte by a microgamete. 

 (After Ross and Fielding- Ould.) 



completed, and a " zygote " is formed. As the zygote 

 at this stage is motile it is known as a " travelling 

 vermicule " or " ookinet "; it passes into the outer wall 

 of the mosquito's stomach, where it becomes encysted 

 (Fig. 59, a, 6). At this period the zygote is about 7-8 p in 

 diameter. If development proceeds, it acquires a distinct 

 capsule and begins to grow rapidly, and when mature at 

 the end of a week or more, according to the temperature, is 

 60 ja in diameter, and projects into the body-cavity of the 

 insect (Fig. 59, 6). Its substance next divides into eight 



