144 AN INTRODUCTION TO ZOOLOGY 



The remaining protoplasm with the pigment and odd karyosomes 



en. 



G. 



K. 



J. 



H. 



FIG. 46. Figures illustrating the stages of the life cycle of the malarial 

 parasite found in Anopheles. From Bourne. 



/4., crescent-shaped gametocytes of Plasmodium immaculatum of pernicious tropical malaria; 

 cf , the microgametocyte.; 9 , the macrogametocyte. B., further stages in the development of d* the 

 microgametocyte and 9 the macrogametocyte of Plasmodium vivax ; the nucleus of the macro- 

 gametocyte has divided unequally to form a polar body, pb. C., the nucleus of the microgametocyte 

 has broken up into eight karyosomes, ky., each surrounded by a ring of chromatin granules ; the 

 polar body has separated from the macrefgametocyte. D., formation of microgamctes from the 

 microgametocyte- ., a single microgamete ; ky., the central karyosome. F., fertilisation of the 

 macrogamete 'by the microgamete ; n. tf , male pronucleus ; n. ? , female pronucleus. G., the 

 motile zygpte or ookinete ; few., fertilisation nucleus. H., the ookinete (oocyst) surrounded by 

 a very delicate cyst wall, at rest in the tissues of the wall of the stomach of the mosquito ; n., 

 nucleus ; p., pigment. /., multiplication of nuclei in the oocyst. K., the protoplasm of the oocyst 

 has divided into numerous sporoblasts, sp. bl., each containing a nucleus. L., early formation 

 of sporozoites from the sporoblasts. M., a ripe oocyst full of minute sporozoites, spz , which arc 

 escaping by the bursting of the cyst. ; rp., residual protoplasm containing an abortive nucleus 

 (B.-G. after Schaudinn, the remaining figures after Grassi. The figures are not all drawn to the 

 same scale). 



constitutes the residual protoplasm, and plays no further part in 

 the life history. The filiform bodies so formed are the microgametes, 



