IX] LIFE-CYCLE OF MALARIAL PARASITE I35 



and remain slightly connected together by means of cytoplasmic 

 processes. After the formation of the sporoblasts a certain 

 amount of protoplasm is left over, containing all the waste 

 products and also some of the pigment granules originally 

 present in the macrogamete. 



The nucleus of each sporoblast now divides into a large 

 number of smaller ones which become arranged around the 

 periphery. The surface of the sporoblast then exhibits a number 

 of cytoplasmic projections, each of which increases in length 

 and takes with it a daughter-nucleus. Eventually the spindle- 

 shaped process, with its contained nucleus, becomes free from 



Fig. 41. Photomicrograph of sporozoites of malaria from the salivary glands 

 of Anopheles {Pyretophnrus) costalis. x about 1000. After Hill and 

 Haydon. 



the mother sporoblast, and is then known as the sporozoite. 

 Each sporoblast produces large numbers of these bodies, but 

 a certain amount of protoplasm containing waste products is 

 always left unused in their formation. The oocyst, which con- 

 tains the whole of the sporozoites derived from the many 

 sporoblasts, and by this time has increased enormously in size, 

 eventually bursts, and the sporozoites are set free in the body- 

 cavity of the mosquito. As the coelomic fluid bathes all the 

 organs of the mosquito, the sporozoites are brought in contact 

 with all parts of the body. They appear to have a predilection 

 for the salivary glands and the majority bore their way into 



