536 



PROTOZOOLOGY 



host (Fig, 256), the polar filaments are extruded and perhaps anchor 

 the spores to the gut-epithelium (a). The sporoplasms emerge 

 through the opening after the filaments become completely de- 

 tached (b). By amoeboid movements they penetrate through the in- 

 testinal epithelium and enter the blood stream or body cavity and 

 reach the specific site of infection (c). They then enter the host cells 

 and undergo multiplication at the expense of the latter (d-n).The 

 trophozoites become sporonts, each of which produces a number of 



Fig. 256. The life-cycle of Stempellia magna, X800 (Kudo), a, b, ger- 

 mination of spore in the mid-gut of culicine larva; c-k, division stages; 

 1-p, sporont formation; q-t, formation of 1, 2, 4, and 8 sporoblasts; 

 u, sporoblast; v-x, development of sporoblast into spore. 



spores (p-x) characteristic of each genus. Some spores seem to be 

 capable of germinating in the same host body, and thus the number 

 of infected cells increases. When heavily infected, the host animal 

 dies as a result of the degeneration of enormous numbers of cells thus 

 attacked. Such fatal infections may occur in an epidemic form, as is 

 well known in the case of the pebrine disease of silkworms, the 

 nosema-disease of honey bees, microsporidiosis of mosquito larvae, 

 etc. 



Spore with a single polar filament Suborder 1 Monocnidea (p. 537) 



Spore with 2 polar filaments Suborder 2 Dicnidea (p. 542) 



