166 R- KUDO 



two parts. No polar capsule is mentioned, the filament being 

 coiled directly inside of the shell. The binucleate sporoplasm, 

 instead of being girdle-shaped is a roimded and more or less well- 

 defined body imbedded in a clear space at the posterior part of 

 the spore. 



The same authors ('16 a) later reported a similar observation 

 on the structure of the spore of Plistophora macrospora. They 

 stated that the polar capsule hes close to the shell, occupying the 

 greater part of the intrasporal space; that the filament is coiled 

 in the capsule without a central axis; that the sporoplasm is a 

 rounded binucleate body imbedded in the posterior vacuole of 

 the spore; that the girdle-shaped structure, thought by numerous 

 authors to be the sporoplasm, is none other than the retracted 

 substance composing the polar capsule, so that one or two turns 

 of the filament were mistaken in optical sections as a variable 

 number of nuclei, and that the granule in the posterior vacuole, 

 which was regarded as a metachromatic granule by some authors, 

 is really the nucleus of the true sporoplasm. George vitch ('17) 

 agreed with this view in his study on Nosema (Glugea) marionis, 

 although he noticed that some spores did not contain any polar 

 capsule. 



The writer ('20) remarked that the microsporidian spores do 

 not seem to be unique in structure, and that they may be classi- 

 fied into at least two types: one, represented by Thelohania 

 magna, the other, by Nosema bombycis. Studjdng carefully the 

 forms which are described in the paper, he strongly maintains 

 this view. To this first type may belong Thelohania varians 

 (Debaisieux, '13), Phstophora elegans (Auerbach, '10 a), Plisto- 

 phora macrospora (Leger and Hesse, '16 a), Thelohania illinoisen- 

 sis (see below), and T. acuta (Schroder, '14). The spore of this 

 last form, according to Schroder, has a structure similar to that 

 in Thelohania magna, although Schroder could not make the 

 filament visible or extruded. 



