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homogeneous spherical mass of granular endoplasm surrounded by the 
common ectoplasm. When stained the size of the cyst is reduced to 
about 55 jji and the following nuclear changes can be made out. At 
first, while the two sporonts forming the cyst are still distinct, the 
nucleus of each half can be readily seen, but later, when the partition 
has disappeared, the nucleus cannot be seen under any circumstances 
(cf. Figs. 20, 21). However while it can be made out, it is seen to 
grow enormously in size, and its ultimate disappearance may be due to 
its having become commensurate with the cell. Meanwhile it is 
invested by its very definite nuclear membrane. 
Fig. 17. 
Fig. 16. Preparation of gut showing sporonts and newly formed cysts. 
Fig. 17. Cyst showing indications at its poles of the anterior end of the sporonts which 
formed it. 
Fig. 18. 
Fig. 21. 
Fig. 19. 
Fig. 20. 
Figs. 18, 19. Cyst from the gut of a flea-larva. 
Fig. 20. Nucleus in a cyst stained. 
Fig. 22. 
(1st day) (2nd day) (3rd day) 
Fig. 23. 
Fig. 21. Cyst stained showing fusion of the sporonts. 
Fig. 22. Nucleus in a cyst stained. 
Fig. 23. Cj'st examined in vivo at stated intervals after being excreted from the larva. 
