122 R. KUDO. 



Quite frequently the sporont when discharged into the body 

 cavity of the host transforms into a sporoblast and later into a 

 spore without any nuclear division stated above. This process 

 probably is responsible for the production of abnormally large 

 spores (Fig. 3, e). 



The cytoplasm of the sporont is more vacuolated and less 

 deeply stained than that of the schizont, of which I remarked 

 before ('21). Schroder ('09) and Schuberg and Rodriguez ('15) 

 mentioned a similar difference in the cytoplasm between the 

 schizonts and sporonts of the Microsporidia they studied. 



The sporoblast which varies greatly in size as the natural 

 sequence of the difference in its production, is rounded or oval in 

 form. It has a nucleus composed of peripheral chrornatin 

 grains and a karyosome. There is to be seen one or more 

 chromatin grains near one end. The nucleus moves toward the 

 other end of the sporoblast, while deeply staining granules appear 

 in the clear space at the other extremity. These granules become 

 smaller in size and larger in number as the filament is formed, 

 which probably indicates that they are used for the formation of 

 the polar filament. When nearly formed, the spores present the 

 appearance shown in figure 3, /;; the sporoplasm with one 

 nucleus is near the round end and the coiled filament is present 

 near the other extremity of the spore. 



From the sporogony described above, it becomes obvious that 

 the microsporidian cannot be placed in the genus Thelohania 

 which is characterized by an octosporous sporont, as I held at 

 first ('20, '21, '22), but should be placed in the genus Stempellia 

 which Leger and Hesse ('10) established for Stempellia mutabilh. 



THE SPORE 



In fresh state, the fully formed spore is elongated pyriform, 

 often bent slightly toward one side. In cross-section it is 

 circular. One end which is ordinarily called as the posterior end, 

 is rounded, while the other, the anterior end, is less rounded, 

 though not attenuated. The spore is moderately refractive and 

 presents somewhat varied aspects. In a large number of spores, 

 there is to be seen an oval, cap-shaped or round area, through 

 which a fine protoplasmic strand sometimes runs tnm^vrrsely 

 (Fig. 4, c], while the other part is finely granulated and >li<>\\> line 



