360 



THE PROTOZOA 



Y 



Vllb. 



TO. 





FIG. 156. Life-cycle of a malarial parasite : combined diagram (the figures are 

 not in all cases from the same species, and some of them are schematic). 

 All the figures above the dotted line represent stages passed in human blood ; 

 those below are the stages that are found in the mosquito. 



I- V. and 6 10, Schizogony of the tertian parasite, Plasmodium vivax, after 

 Schaudinn (130), magnified about 1,500 diameters. I., Youngest intracor- 

 puscular stage, which has arisen either from a sporozoite (XIX.) or a merozoite" 

 (10) that has penetrated into, or is attached to, the corpuscle (represented 

 by a circular outline). II. IV., Further stages of the growth of the para- 

 site ; a vacuole is formed in its body which gives it the characteristic " signet- 

 ring " appearance (IV.). V. and 6, Later stages of growth; the vacuole 



[Continued at foot of p. 361. 



