126 SOME MINUTE ANIMAL PARASITES 



Some of the growing forms become larger than the 

 schizonts, and store up large quantities of reserve 

 food within their substance. These parasites are 

 destined to become female forms (Fig. 28, /, ? ). On 

 the other hand, some are smaller, and contain no 

 reserve of food. These are the progenitors of the 

 male parasites (Fig. 28, /, (). 



The potential female forms (Fig. 28, /, $ ), which 

 are scientifically termed macrogametocytes, are large. 

 They rapidly accumulate food, which is stored in the 

 form of faintly yellowish granules, and they also 

 secrete substances that are for future use in making 

 a protective coat or sheath (Fig. 28, K, $). The 

 latter have a strong resemblance to nuclear sub- 

 stances, and as they stain intensely, they are known 

 as the chromatoid granules (Figs. 27, ode. ; 28, K, ? ). 

 When the female mother cell is almost mature, it 

 passes its chromatoid granules outwards to its sur- 

 face, where they fuse together, become chemically 

 altered, and form the coat known later as the oocyst 

 (Fig. 28, K, $ ). 



Meanwhile, 'the cells destined to give rise to male 

 organisms have remained finely granular, and instead 

 of expending their energies on food storage and wall 

 construction, have utilized it in nuclear division. 

 The nucleus divides rapidly, and smaller collections 

 of nuclei (Figs. 27, <? ; 28, /, c?) are produced, so 

 that the surface of the microgametocyte (commonly 

 called the male mother cell) becomes covered with 

 a meshwork of nuclear fibrils (Fig. 28, /, c?). Each 

 fibril is made of granules, and at first is looped. 

 The loops concentrate and gradually become slender, 



