138 



AN INTRODUCTION TO ZOOLOGY 



sporocyst. Curved pieces of protoplasm are separated off and 

 enclose each nucleus, leaving a small mass of residual protoplasm. 

 The eight minute bodies so formed are termed the sporozoites or 

 falciform young, the last name being bestowed on them from their 



FIG. 44.' Diagram of life history of Monocystis, adapted from 

 various authors. 



A., trophozoite ; B., two individuals, conjugants or gametocytes, encysted ; 



C., formation of gametes ; D., union of gametes to form zygotes or sporoblasts ; 



E., mother cyst with sporocysts ; F., one sporocyst under higher magnification to 

 show sporozoites. 



somewhat fanciful resemblance to a sickle blade. Thus we have 

 inside the original mother cyst a large number, at least fifty, and 

 probably many more, of sporocysts, each containing eight sporo- 

 zoites, and this is the stage most commonly found. No further 



