68 AGRICULTURAL EXPERIMENT STATION. 



an infested mosquito (fig. i6, four and one-half days after infec- 

 tion), with a low power of the microscope. Still, the growth 

 continues (fig. 15, 9-15). Jmd now^ we find that there has been 

 a division of the nucleus and the more the amphiont (as it is 

 called) increases in size, the more numerous become the nuclei. 

 Each nucleus gathers to^ itself a stellate mass of protoplasm. 



"Then within this mass still further divisions of the nucleus 

 take place, the now minute daughter nuclei crowding to the sur- 

 face of the irregular mass of protoplasm (fig. 15, 15). Each tinv 



N 





\\ 



'^>^ 



Al\ \ ir ^" 



\ 



V 





/v 



Figure 16. 



Stomach of Anopheles maculipennis, siiowing the malarial zygotes 4^-2 days old in the 

 meshes of the muscular fibres. N, neck of stomach; M, malpighian tubules; I, ileum. 

 (From Berkeley's Lab. Work with Mosquitoes.) 



nucleus is soon the center of a rod-shaped body, and there are 

 several thousands of these rod-like bodies (the sporozoits) in the 

 enormously enlarged amphiont. Large groups of them lie paral- 

 lel to each other, producing the characteristic striated appearance 

 (fig. 15, 17). The capsule bursts and the 10,000 or more sporo- 

 zoits are set free in the mosquito body cavity. Owing tO' some 

 attraction of unknown nature, but presumably chemotaxis, they 

 gather in the large vacuolated cells of the salivarv glands. Thence 



